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  • 1985-1989  (1,699)
  • 1965-1969  (4,020)
  • 1985  (1,699)
  • 1969  (1,926)
  • 1968  (2,094)
  • General Chemistry  (3,165)
  • Inorganic Chemistry  (2,476)
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  • 1985-1989  (1,699)
  • 1965-1969  (4,020)
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  • 1
    Electronic Resource
    Electronic Resource
    Response covariance in cat visual cortex (1985)
    Springer
    Experimental brain research 60 (1985), S. 559-563 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Visual cortex ; Multiunit recordings ; Response variance ; Response covariance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The activity of pairs of neurons in the visual cortex (area 17) of anaesthetized, paralysed cats was recorded using two independently manipulated micropipettes. The number of spikes in the evoked responses of pairs of single neurons were analyzed for response covariance. Responses of the majority of cell pairs (83%) did not covary. Covariance was restricted to closeby neurons with distances of less than 150 μm and with identical orientation and ocular dominance preference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236942
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  • 2
    Electronic Resource
    Electronic Resource
    Differences in synaptic size in the superficial and deep layers of the molecular layer of the cerebellar cortex of the cat (1985)
    Springer
    Anatomy and embryology 172 (1985), S. 303-309 
    Details
    ISSN: 1432-0568
    Keywords: Synaptology ; Cerebellum ; Quantitative analysis ; Autoradiography ; Electron microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a previous study observations in semithin sections of E-PTA-stained cerebellar cortex of the cat revealed differences in size of synaptic grids between the molecular and granular layer (Van der Want et al. 1984). In addition, synaptic size differences were observed between superficial and deep levels in the molecular layer. The present study was an attempt to analyze synapses in ultrathin sections of the cerebellar cortex with special emphasis on size differences of distinct types of synapses at different levels in the molecular layer. Climbing fibers were identified by means of anterograde transport of 3H-leucine injected in the inferior olive and parallel fibers were identified on account of fine structural criteria. Synaptic profiles were measured semi-automatically in the neuropil of the cerebellar cortex at the supra-Purkinje level and the subpial level. Measurements of the trace- and chordlength were obtained from random sections. The frequency distribution of the true diameters of the synapses was reconstructed with a discrete “unfolding”-procedure. The overall diameter at the superficial level was 390.2±1.5 nm, at the deep level 406.6±1.5 nin. Climbing fibers exhibited mean values of 431.9±4.7 and 461.3±4.1 nm at these levels and parallel fiber terminals mean values of 370.7±2.9 and 395.8±3.0 nm. The frequency distributions showed remarkable and statistically significant differences compared with the overall distributions observed at the superficial and the deep levels respectively. The frequency distributions of synaptic diameters at the superficial and deep levels also differ significantly. The results suggest that synapses are characterized by a specific size which might be related to the region of termination or might be determined by the afferent neuron. This is in agreement with earlier observations in E-PTA treated material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318978
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  • 3
    Electronic Resource
    Electronic Resource
    The projection from the superior colliculus to the lateral reticular nucleus in the cat as studied with retrograde transport of WGA-HRP (1985)
    Springer
    Anatomy and embryology 173 (1985), S. 269-274 
    Details
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Superior colliculus ; Retrograde transport of WGA-HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Medium-sized and large superior collicular neurons were retrogradely labelled after small ejections of the wheat germ agglutinin-horseradish peroxidase complex in the lateral reticular nucleus of the feline medulla. The projection from the superior colliculus to the lateral reticular nucleus is bilateral with a contralateral predominance. It originates mainly from the intermediate, but also from the deep gray layer of the superior colliculus. Our observations provide evidence that the lateral reticular nucleus is an important target of tectal efferents. The findings are discussed in relation to the organization of other fiber connections of the superior colliculus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316308
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  • 4
    Electronic Resource
    Electronic Resource
    The size and curvature of synapses in the cerebellar cortex of the cat (1985)
    Springer
    Anatomy and embryology 171 (1985), S. 83-89 
    Details
    ISSN: 1432-0568
    Keywords: Quantitative anatomy ; Synaptic length ; Synaptic curvature ; Cerebeller cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary At the supra Purkinje layer and the subpial level in the molecular layer of lobules V and VI of the cerebellar cortex of the cat, synaptic profiles were measured in ultrathin serial sections treated with either osmium tetroxide (OsO4) or ethanolic phosphotungstic acid (E-PTA). From trace and chord lengths of the intercepts of synaptic profiles the curvature and the mean caliper diameter of the synapse was calculated. In OsO4-material the curvature of synapses yielded an average angle of about 47 degrees and about 36 degrees in E-PTA material. Although these values are contrary to the assumption of a flat disc, which is commonly required in stereological procedures to estimate caliper diameter, the effect of the curvature on the estimation of the mean caliper diameter is limited. This is shown by serial reconstruction analysis of the largest diameter of synapses from maximal arc and chord length measurements at the subpial and supra Purkinje level. The results provide quantitative data concerning synaptic size, curvature and the frequency of intercepts per synapse at the subpial and supra Purkinje level in the cerebellar cortex in OsO4 and E-PTA material. In addition the advantages and disadvantages of E-PTA and osmiumtetroxide staining in quantitative analysis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319057
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  • 5
    Electronic Resource
    Electronic Resource
    Distribution of the neurons of origin of the great cerebral commissures in the cat (1985)
    Springer
    Anatomy and embryology 171 (1985), S. 105-120 
    Details
    ISSN: 1432-0568
    Keywords: Cerebral cortex ; Corpus callosum ; Anterior commissure ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Large injections of horseradish peroxidase throughout major portions of the right cerebral hemispheres of four cats revealed extensive distributions of the neurons of origin of the corpus callosum, the anterior commissure and the hippocampal commissures in the uninjected left hemispheres. The distributions of labelled neurons were mapped by semiautomatic computer microscope. The radial and tangential neuron distributions presented here are of a higher density and greater extent than those in previously published studies based on injections of transportable label to more circumcribed areas of the cerebral cortex of the cat. Generally, commissural neurons in the cat were distributed in a bilaminar fashion with supragranular cells more numerous than infragranular cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319060
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  • 6
    Electronic Resource
    Electronic Resource
    Retinal input to the nucleus of the optic tract of the cat assessed by antidromic activation of ganglion cells (1985)
    Springer
    Experimental brain research 59 (1985), S. 395-403 
    Details
    ISSN: 1432-1106
    Keywords: Nucleus of the optic tract ; Direction-selective retinal ganglion cells ; Optokinetic reflex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied the physiological properties of ganglion cells in the retina of the cat. The experiments were designed to identify those ganglion cells which project to direction-selective cells in the nucleus of the optic tract (NOT), by demonstrating their antidromic activation at low threshold from an electrode in the NOT. These ganglion cells presumably provide the retinal drive to the optokinetic reflex. Altogether, 11 such ganglion cells were identified in a population of 578 cells studied. All 11 were W-cells, with slow-conducting axons. Five of the 11 had on-centre direction-selective receptive fields; the other 6 had a variety of receptive field patterns. Thus, on centre-selective cells form a much higher proportion of the retinal input to direction-selective cells in the NOT than of the overall ganglion cell population. However, their receptive field properties were too varied fully to account for the selectivity of NOT cells for horizontal stimulus movement. In summary the retinal input to the NOT appears to be formed principally or entirely by W-class ganglion cells, including many which are direction selective. It still seems necessary, however, to postulate, some non-retinal mechanism to account for all the receptive field properties of direction-selective NOT cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230920
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of nitrous oxide on the functional characteristics of cells in the extrastriate cortex of the cat (1985)
    Springer
    Experimental brain research 59 (1985), S. 463-469 
    Details
    ISSN: 1432-1106
    Keywords: Nitrous oxide ; Visual cortical cells ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The directional preferences, receptive field areas, peristimulus-time (PST) histograms and spontaneous activities of 112 feline visual cortical (area 18) cells were studied before, during, and after the administration of nitrous oxide. These cellular characteristics were altered by nitrous oxide inhalation; some quite substantially. The data indicate that the functional characteristics of cortical visual cells, such as the receptive field and the directional preference, are variable; and, among other factors, depend also on the anaesthetic administered to the animal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261335
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  • 8
    Electronic Resource
    Electronic Resource
    The relationship between feline pupil size and luminance (1985)
    Springer
    Experimental brain research 59 (1985), S. 485-490 
    Details
    ISSN: 1432-1106
    Keywords: Vision ; Cat ; Pupil dimensions ; Luminance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relationships between luminance and height, width or area of the feline pupil were investigated in awake, normal adult cats whose pupils were photographed over a range of light levels with the aid of electronic flash. The results are compared with previous measurements of pupil width and height in awake animals (Kappauf 1943); and with estimates of pupil width, height and area in lightly-anaesthetised cats (Wilcox and Barlow 1975). The implications of these results for retinal illumination and colour discrimination are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261338
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  • 9
    Electronic Resource
    Electronic Resource
    Long term survival of cat retinal ganglion cells after intracranial optic nerve transection (1985)
    Springer
    Experimental brain research 59 (1985), S. 633-635 
    Details
    ISSN: 1432-1106
    Keywords: Retinal ganglion cells ; Cat ; Optic nerve cut ; Retrograde labeling ; HRP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After intracranial transection of the optic nerve in cats the retinal stump of the nerve was injected with HRP. Surviving retinal ganglion cells can be retrogradely labeled at least up to 15.5 months of postoperative survival.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261356
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  • 10
    Electronic Resource
    Electronic Resource
    Somatotopic termination of spinal afferents to the feline lateral cervical nucleus (1985)
    Springer
    Experimental brain research 57 (1985), S. 576-584 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Lectin-conjugated horseradish peroxidase ; Lateral cervical nucleus ; Spinocervical tract ; Somatotopic termination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The labelling pattern of the feline lateral cervical nucleus (LCN) was investigated after pressure injections of lectin-conjugated horseradish peroxidase into cervical, thoracic or lumbar segments of the spinal cord. Sixteen cats received a 5–8 nl injection staining large parts of mainly the ipsilateral grey matter of a single segment. Light microscopic examination of frozen sections reacted with tetramethylbenzidine showed a somatotopic organization in the LCN. Rostral segments of the spinal cord projected mainly to rostroventral and medial parts of the ipsilateral LCN, while more caudally located segments projected to more dorsocaudal and lateral parts of the nucleus. Minor contralateral labelling with a similar somatotopic arrangement was seen in animals given cervical and lumbar injections. No significant labelling was found in the LCN of three control animals, the segmental injections of which were engaged mainly into the ipsilateral dorsal columns and the dorsolateral funiculus. Ultrastructural analysis in two animals which received multiple cervical or lumbar injections showed that about 70% of the peroxidase-positive structures in the LCN were boutons and the rest small myelinated axons. The precise termination pattern of ascending afferents to the LCN is compatible with the somatotopic organization of the other relay centres in the spino-cervicothalamic pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237844
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  • 11
    Electronic Resource
    Electronic Resource
    Combined lesions of septum, amygdala, hippocampus, anterior thalamus, mamillary bodies and cingulate and subicular cortex fail to impair the acquisition of complex learning tasks (1985)
    Springer
    Experimental brain research 58 (1985), S. 346-361 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Learning ; Limbic system ; Memory ; Multiple lesions ; Plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous investigations (Irle and Markowitsch 1982a, 1983, 1984) demonstrated that triple or fourfold lesions within the cat's limbic system fail to produce learning impairments, as opposed to lesions of single or double loci, when tasks of visual reversal, delayed alternation, and active two-way avoidance were used. On the basis of these results, limbic regions of the cat's brain might be considered unessential for intact learning and mnemonic functions. Therefore, in order to obtain indisputable information on the importance of the limbic system for learning and memory, lesions of nearly all limbic core regions of the cat were performed. Ten cats received lesions of seven limbic core regions: the septum, amygdala, anterior thalamus, mamillary bodies, cingulate cortex, subicular cortex, and the hippocampus proper. Nine of these animals were tested postoperatively in the acquisition of a visual reversal task, a spatial alternation and delayed alternation task, and an active two-way avoidance task, and were then compared to the performance levels of ten control animals. The experimental animals turned out to be unimpaired in all tasks tested; the performance scores in the visual reversal and delayed alternation task and — for some experimental animals in the active two-way avoidance task even indicate a slight, though statistically insignificant, facilitation in the learning behavior of these animals. It is assumed that the learning functions underlying the tasks used were taken over by other brain regions, which, prior to massive limbic lesions, may be suppressed or otherwise inhibited. Alternatively, utilization of spared tissue in the damaged limbic regions must be considered as the possible explanation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235316
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  • 12
    Electronic Resource
    Electronic Resource
    Is the retina sensitive to the effects of prolonged blur? (1985)
    Springer
    Experimental brain research 58 (1985), S. 427-434 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Retinal ganglion cells ; Atropine ; Optical blur ; Acuity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two preparations were used to study the developmental effects of prolonged blurring of retinal images on the acuities of retinal ganglion cells. Five kittens were raised from three weeks to six months of age with daily administration of atropine to one eye. Another two kittens were raised from three weeks to 16 weeks with a contact lens of high refractive power fitted to one eye. Behavioural estimates of the visual acuity were made for two animals from each group. Animals of both groups demonstrated an amblyopia in the experimental eye: visual acuity varied from 1.8 to 2.5 cycles per degree compared with 6.0 to 7.5 cycles per degree when using the normal eye. The spatial resolving properties were measured for retinal ganglion cells within the amblyopic eyes of two lens-reared cats and three atropinized cats. Brisk-sustained (X) cells were recorded from along the naso-temporal division. The acuities of ganglion cells from the lens-reared cats were indistinguishable from those from normal cats at comparable eccentricities. However, for the cats raised with atropine administration, sub-normal acuities were determined for retinal ganglion cells from all regions that were studied in the experimental eye. We conclude that blur of retinal images produced by external means has no effect on the resolving power of retinal ganglion cells. The lowered ganglion cell acuities encountered with the atropinised cats must be attributable to a secondary effect of the atropine administration. Organic changes in the retinal blood vessel pattern support this contention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235859
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  • 13
    Electronic Resource
    Electronic Resource
    Connections between pericruciate cortex and the medullary reticulospinal neurons in cat: an electrophysiological study (1985)
    Springer
    Experimental brain research 61 (1985), S. 109-116 
    Details
    ISSN: 1432-1106
    Keywords: Motor cortex ; Reticulospinal neuron ; Corticobulbar pathways ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The connections between the pericruciate cortex and the medullary reticulospinal (RS) neurons were studied in anesthetized cat. Intracellular recordings were made from reticulospinal neurons and the effects of stimulating different areas of the pericruciate cortex were compared. (1) EPSPs were elicited in all the 93 neurons studied which were antidromically activated by spinal stimulation and had an IS-SD notch on the ascending limb of their antidromic spikes. According to the conduction velocity (c.v.) of the axon and the minimal EPSP latency to cortical stimulation, the neurons could be divided into two groups, i.e. fast-conducting RS neurons (FRS neurons, c.v. 〉 45 m/s) and slow-conducting RS neurons (SRS neurons, c.v. 〈 45 m/s). The minimal latencies of FRS neurons were equal to or shorter than 2 ms whereas those of SRS neurons were longer than 2 ms. (2) EPSPs with short latency (〈 2 ms) could be evoked in FRS neurons by stimulating a relatively wide cortical area including the major part of precruciate area 4 and area 6, with a central area of strongest excitatory effect located in area 4 slighthly medial to the tip of the cruciate sulcus. Stimulation of the postcruciate area 4 only produced long latency EPSPs. (3) By extrapolation from the cortical and peduncular latencies and the conducting distances it was revealed that the earliest part of the minimal latency EPSPs were monosynaptically evoked in FRS neurons and were mediated by fastconducting corticobulbar fibers. (4) FRS neurons could be excited by stimuli applied to both ipsilateral and contralateral pericruciate cortex. The influence from the contralateral cortex was slightly stronger.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235626
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  • 14
    Electronic Resource
    Electronic Resource
    An intracellular HRP-study of cat tensor tympani motoneurons (1985)
    Springer
    Experimental brain research 57 (1985), S. 499-511 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Tensor tympani motoneurons ; Somadendritic morphology ; Intracellular HRP ; Auditory nuclei ; Tensor tympani motor nucleus of V ; Trigeminal motor nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphology of single tensor tympani motoneurons was investigated following antidromic identification and intracellular injection of horseradish peroxidase. Eight motoneurons were selected for complete reconstruction and quantitative analysis. The mean size of tensor tympani somata (26.3±1.8 μm) make this parvocellular cluster of motoneurons below the trigeminal motor nucleus a population of the smallest cranial motoneurons yet described. Axons emerged from either the soma or a primary dendrite. They coursed dorsolaterally frequently through the trigeminal motor nucleus before looping ventrolaterally into the Vth nerve. No collaterals were observed within the brainstem. The 5 primary dendrites of each cell branched heavily and, on average, exhibited 40 terminal branches with an average tree expansion of 1262.5 μm. The dendritic arborization extended far beyond the nuclear boundaries described by the distribution of cell bodies. These data suggest that the overall membrane area for synaptic innervation is large and thus it provides morphological evidence for the hypothesis that tensor tympani motoneurons receive divergent multisensory synaptic input. The latter assumption was supported by morphological and electrophysiological evidence including close the proximity of motoneuronal dendrites to auditory (superior olivary complex) and somatosensory (trigeminal) relay centers. Since no dendrite ever entered the trigeminal motor nucleus proper the tensor motoneuron pool is distinct from the trigeminal not only in terms of soma size, location and function, but also the disposition and expansion of the postsynaptic receptive field. Based on these criteria the tensor tympani motoneuron pool should no longer be regarded as an accessory trigeminal nucleus but be recognized in its own right as the tensor tympani motor nucleus of V.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237837
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  • 15
    Electronic Resource
    Electronic Resource
    Substantial reduction of noradrenaline in kitten visual cortex by intraventricular injections of 6-hydroxydopamine does not always prevent ocular dominance shifts after monocular deprivation (1985)
    Springer
    Experimental brain research 59 (1985), S. 30-35 
    Details
    ISSN: 1432-1106
    Keywords: Developmental plasticity ; Visual cortex ; Noradrenaline ; Cat ; 6-hydroxydopamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ten kittens had cannulas inserted into their lateral ventricles for daily injections of 6-hydroxydopamine (6-OHDA). At 5–6 weeks of age one eye was sutured shut, and one week later recordings were made from the visual cortex to assay the ocular dominance of a sample of cells. In six kittens the injections of 6-OHDA were continued until the day before recording, while in four kittens the injections were stopped around the time of eye suture, on the assumption that continued injections of 6-OHDA over several days has effects that are not specific to the noradrenaline (NA) system and that the two procedures might show different results. In all animals the concentration of NA in the visual cortex near the site of recording was reduced by approximately 90%. In all animals the ocular dominance histograms recorded from the visual cortex were shifted so that the majority of cells (83 ± 13%) were dominated by the open eye. There were no substantial differences between the two groups of experimental animals or between the experimental animals and two control animals that had cannulas implanted and ascorbate alone injected without 6-OHDA. We conclude that the concentration of NA in the visual cortex can be reduced substantially by injections of 6-OHDA into the lateral ventricle without preventing the shift in ocular dominance that usually occurs after suturing shut the eyelids of one eye.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237662
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  • 16
    Electronic Resource
    Electronic Resource
    Task-related coding of stimulus and response in cat motor cortex (1985)
    Springer
    Experimental brain research 57 (1985), S. 427-442 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Motor cortex ; Single unit activity ; Tracking ; Input switching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a previous study in the cat, we have reported that motor cortex neurons discharging before the initiation of an aimed forearm response (lead cells) are better timed to movement of a display (stimulus) than to the response. The present study was done to distinguish the coding of stimulus and response features in the discharge patterns of such early activity in motor cortex. Single neurons were recorded in the arm area of motor cortex in three cats performing the same pair of responses (forearm flexion and extension) but to display movements in either of the two directions by changing display polarity. The modulation of lead cell activity was contingent on the occurrence of the learned motor response and timed to the stimulus in all conditions. The majority of lead cells (88%, n = 50) fell into one of two distinct classes. In one class of neurons, force-direction (56%, n = 32), activity was contingent on a single direction of forelimb response (flexion or extension) and was thus independent of the direction of the display stimulus. The only muscles whose patterns matched the activity of this class of response-related neurons were forelimb flexors and extensors. In these neurons, the onset of modulation was timed to one or the other of the two stimuli according to the stimulus direction which elicited the appropriate response. Thus, the display-related input to these neurons varied according to the response required. In the second class of neurons, stimulus-direction (32%, n = 18), modulation was associated with a specific stimulus direction rather than the response direction. The pattern of activity of these neurons was similar to the pattern of EMG signals of shoulder and neck muscles during the different task conditions. The contraction of proximal and axial muscles corresponded to a second response elicited by the stimulus, namely attempts at head rotation towards the moving display and was independent of the conditioned forelimb response in both time of onset and direction. To test the possibility that stimulus-direction neurons participated in the control of head rotation we trained two of the animals to also produce isometric changes in neck torque in the direction of the moving display without making the forelimb response. The activity of stimulus-direction neurons was similarly modulated during performance of the neck task. By contrast, force-direction neurons examined during the neck task were either unmodulated or discharged after the neck response. These data suggest that force-direction neurons participate in response initiation and that their activity is triggered by stimuli specific for the task. The reorganization of the inputs to motor cortex is likely to result from gating mechanisms associated with behavioral set. Such neural gates could provide for the efficient transfer of any member of an array of behaviorally relevant stimuli to restricted sectors of the somatotopically organized motor areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237829
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  • 17
    Electronic Resource
    Electronic Resource
    The cholinergic innervation of the visual thalamus: an EM immunocytochemical study (1985)
    Springer
    Experimental brain research 59 (1985), S. 206-212 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; ChAT-immunocyto-chemistry ; Cholinergic pathways ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study we demonstrate at the ultrastructural level that both the dorsal lateral geniculate nucleus (dLGN), the visual relay of the thalamus, and the perigeniculate nucleus (PGN), the visual segment of the thalamic reticular nucleus (TRN), are densely innervated by fibres with Choline-Acetyl-Transferase (ChAT) like immuno-reactivity. These axons make synaptic contacts with interneurones considered to be inhibitory, both in the PGN and within the synaptic glomeruli of the dLGN. In addition, Chat positive terminals form intra- and extraglomerular synapses with dendrites thought to arise from relay cells. We interpret these results as evidence for direct cholinergic modulation of both relay cells and inhibitory interneurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237681
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  • 18
    Electronic Resource
    Electronic Resource
    Canal-neck interaction in vestibular neurons of the cat's cerebral cortex (1985)
    Springer
    Experimental brain research 61 (1985), S. 94-108 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Canal-neck interaction ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Interaction of semicircular canal and neck proprioceptive inputs was studied in the cerebral cortex of awake, intact cats. Neuronal responses were recorded extracellularly in the anterior suprasylvian gyrus of the left hemisphere. Stimulations consisted of horizontal rotations in the dark applied as sinusoids or position ramps. There were three stimulus conditions: (1) Pure canal stimulation; rotation of whole body. (2) Pure neck stimulation; rotation of trunk about stationary head. (3) Canalneck interaction; rotation of head about stationary trunk. (1) We recorded 105 neurons with either Type I or Type II canal response. These showed often pronounced non-linearities such as a clear firing increase upon rotation in the “on-direction” and hardly any decrease in the opposite direction. The responses reflected mostly angular velocity, but angular position signals were also obtained. (2) In 79 neurons, either Type I or Type II neck responses were obtained. They coded either angular velocity, velocity plus position, or position. (3) Canal-neck convergence was found in 67 of 88 neurons tested. In the majority of neurons, interaction was “dantagonistic” in the sense that the canal and neck responses tended to cancel each other during rotation of the head about the stationary trunk. These neurons could signal trunk rotation in space rather than head in space or head relative to trunk. Most of the remaining neurons showed a “synergistic” interaction such that the response upon head rotation was enhanced as compared to whole body or trunk rotation. These neurons might be involved in the dual task of monitoring head rotation in space and relative to trunk. Interaction was compatible with linear summation of canal and neck inputs in 70% of the neurons. In part of these, however, the assumption had to be made that the interaction had taken place already at some stage prior to the cortical neurons investigated. The response characteristics of cortical canal neurons are discussed in comparison to vestibular nuclear neurons. Furthermore, parallels are drawn between the observed canal-neck interactions in the cortical neurons and (i) interactions of canal and neck dependent postural reflexes in the decerebrate cat, and (ii) interactions of canal and neck induced turning sensations in man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235625
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  • 19
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    Electronic Resource
    Variability in the effects of monocular deprivation on the optokinetic reflex of the non-deprived eye in the cat (1985)
    Springer
    Experimental brain research 61 (1985), S. 117-127 
    Details
    ISSN: 1432-1106
    Keywords: Horizontal optokinetic nystagmus ; Nucleus of the optic tract ; Monocular deprivation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Six cats monocularly deprived by eye lid closure within the first week after birth showed the same deficits in the optokinetic reflex (OKR) when tested through the deprived eye as adults irrespective of whether the deprivation period was 6, 24 or 36 months. Closed loop gain (eye velocity/ stimulus velocity) during temporo-nasal stimulus movement was below 0.8 and approached zero at stimulus velocities above 20°/s. Naso-temporal stimulus movement was ineffective in eliciting OKR gain higher than 0.1 at velocities above 10°/s. 2. Different optokinetic deficits were found when the non-deprived eye was tested. In 3 cats OKR gain of the non-deprived eye was reduced with temporally directed stimulus movement when compared to normal whereas the gain of nasal OKR was uneffected. In these cats only monocular cells could be found in the nucleus of the optic tract (NOT), a pretectal cell aggregation involved in the optokinetic reflex pathway. In the other 3 cats the OKR of the non-deprived eye was not different from normal and could be elicited almost equally well in both directions. In these cats binocular cells were found in the NOT ipsilateral to the non-deprived eye. Again duration (6, 24 or 36 months) of monocular deprivation had no influence on this dichotomy. 3. In a cat with asymmetric OKR of the non-deprived eye, the removal of the visual cortex ipsilateral to the non-deprived eye produced a small but significant gain decrease for temporal OKR of the non-deprived eye but no change when the deprived eye was tested. Visual cortex lesion ipsilateral to the deprived eye in the same cat had also no effect on the deprived eye's performance but reduced nasal OKR gain for the non-deprived eye at high velocities. 4. The effects induced by long term monocular deprivation were not reversed after intensively forcing the use of the deprived eye by closing the non-deprived eye. Also enucleation of the deprived eye had no effect on the gain of the non-deprived eye. 5. These optokinetic deficits are discussed in relation to functional changes in the NOT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235627
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  • 20
    Electronic Resource
    Electronic Resource
    Patterns of cytochrome oxidase activity in areas 17, 18 and 19 of the visual cortex of cats and kittens (1985)
    Springer
    Experimental brain research 58 (1985), S. 125-133 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Kitten ; Cytochrome oxidase ; Visual cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The laminar pattern of cytochrome oxidase activity was studied in visual cortical areas 17,18 and 19 in adult cats and kittens, following electrophysiological determination of the boundaries of these areas in all but the youngest animals. The patterns of cytochrome oxidase staining and the cytoarchitectonic appearances of areas 17, 18 and 19 were compared. At all ages activity was especially high in the region of layers IV and VI in areas 17 and 18, and was low in all laminae in area 19. The results suggest that the degree of cytochrome oxidase activity in these regions of the visual cortex may be related to the strength and type of projection that they receive from the lateral geniculate nucleus. The cytochrome oxidase technique is a useful means of defining the 18/19 border, and may help locate the boundary between areas 17 and 18, in both adult cats and kittens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238960
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  • 21
    Electronic Resource
    Electronic Resource
    Interaction between inhibitory pathways to principal cells in the lateral geniculate nucleus of the cat (1985)
    Springer
    Experimental brain research 58 (1985), S. 134-143 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Lateral geniculate nucleus ; Recurrent inhibitory system ; Variable gain regulator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Inhibitory interactions between interneurones of the lateral geniculate nucleus (LGN) of the cat were studied with an indirect method based on intracellular recordings of synaptic responses in principal cells. Recurrent inhibitory postsynaptic potentials (IPSPs), evoked by antidromic activation of principal cell axons in the visual cortex, were depresse by a preceding stimulation of the optic tract or the visual cortex. Disynaptic feed-forward IPSPs, evoked by optic tract stimulation, were likewise depressed after cortex stimulation. The duration of the depression was in both cases about 100 ms. The effect was not due to conductance changes in the recorded principal cells or to activation of corticogeniculate fibres. The observations indicate that perigeniculate neurones, the recurrent inhibitory interneurones of the LGN, have mutual inhibitory connexions and that they also project to intrageniculate interneurones, the inhibitory cells in the feed-forward pathway to principal cells. These conclusions were supported by intracellular recordings from a few interneurones. No evidence was found for interaction between feed-forward interneurones activated from separate eyes or for a projection from intrageniculate interneurones to perigeniculate cells. The results point to an unexpected similarity in the organization of the recurrent inhibitory system of principal cells in the LGN and of spinal motoneurones. It is suggested that the recurrent system of the LGN serves as a variable gain regulator in analogy with a recently proposed model for the spinal system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238961
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  • 22
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    Electronic Resource
    The effect of stimulation of the reticulo-hypothalamic-hippocampal systems on the cerebral blood flow and neocortical and hippocampal electrical activity in cats (1985)
    Springer
    Experimental brain research 60 (1985), S. 551-558 
    Details
    ISSN: 1432-1106
    Keywords: Reticulo-hypothalamic-hippocampal system ; Cerebral blood flow ; ECoG ; Hippocampal electrical activity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of stimulation of the medial and lateral reticulo-hypothalamic-hippocampal (RHH) systems on cerebral blood flow (CBF) and electrical activity of the hippocampus and neocortex was examined in 19 encéphale isolé cats. ECoG was recorded from posterior sigmoid gyri and marginal gyri and hippocampal activity from dorsal hippocampus. Changes in hippocampal activity were evoked by electrical stimulation of RHH systems. CBF was measured by external monitoring of the clearance of 133Xe given as a single bolus in the carotid artery. Stimulation of the lateral system resulted in desynchronisation of ECoG and hippocampal activity without changes in CBF. Stimulation of the medial system elicited desynchronisation in ECoG modulated by theta-like synchrony, theta activity in the hippocampus and a 45% CBF increase. After atropine administration, low frequency, high voltage waves appeared in both ECoG and hippocampal activity, but no change in CBF was observed. During stimulation of the medial system there were no changes in the type of electrical activity but the CBF response was still preserved (increase by 50%). Stimulation of the lateral system did not change either the type of electrical activity or the CBF. The results indicate that the two systems of neuronal pathways, which mediate two different patterns of electrical response in the dorsal hippocampus but similar ECoG activity in the neocortex, elicit different CBF responses. It is argued that the alterations of electrical activity of the neocortex and hippocampus mediated by these two pathways depend on the cholinergic system, whereas the CBF changes depend on a different mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236941
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  • 23
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    Electronic Resource
    A developmental study of retinal afferents and visual responses in the cat pretectum (1985)
    Springer
    Experimental brain research 60 (1985), S. 350-362 
    Details
    ISSN: 1432-1106
    Keywords: Pretectum ; Development ; Retinal afferents ; Visual responses ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal responses in the pretectum (PT) were analyzed in 4–16 week old kittens after visual and electrical stimulation and compared with adult responses from a previous study. All three retinal fiber types projecting to the adult PT could be electrically activated in kittens from 4 weeks on. There was a dramatic reduction of response latencies to electric shocks to retinal afferents applied at the optic chiasm (OX) and optic tract (OT) in postsynaptic cells as a function of age, involving X-, Y-, and Wfibers. At four through six weeks postnatally the reduction in latency was found to be due to enhanced signal transmission at the axonal terminal region. Latency reduction continued after six weeks of life due to sharp increases in conduction velocity of the afferent fibers. Different steps in the maturation of visual response specifity were found for neurons of different functional types. Possible relationships are discussed between the development of neuronal responses of pretectal cells and the maturation of oculomotor behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235930
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  • 24
    Electronic Resource
    Electronic Resource
    Functional and developmental analysis of a visual corticopretectal pathway in the cat: a neuroanatomical and electrophysiological study (1985)
    Springer
    Experimental brain research 60 (1985), S. 363-374 
    Details
    ISSN: 1432-1106
    Keywords: Pretectum ; Development ; Cortical influence ; Receptive field properties ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The sensory corticopretectal projection in the cat and in its postnatal development were investigated combining neuroanatomical and electrophysiological techniques. The anatomical pattern of fiber termination was studied in relation to age using the anterograde HRP tracing method. Large injections were made in areas 17 and 18 of one or both hemispheres in 1–13 week old kittens and cats. Terminal label in the ipsilateral pretectum was seen only after the fourth week of life. Electrical stimulation in the same cortical areas evoked postsynaptic orthodromic excitation in 9–18% of cells at 4 weeks increasing to about 60% in the adult. In cats, but not in kittens, successful stimulation depended on the retinotopic matching of stimulation and recording sites. In adult cats a high incidence of direction and velocity tuning and a high degree of binocularity were seen in cells driven by the cortex as opposed to cells not so driven. Cortex driven cells in cats and kittens received convergent retinal input mainly via direct W-fibers, whereas cells not driven from cortex shock mainly received delayed W-fiber input. In kittens visual responses lacked sensitivity for direction and high movement velocity of patterns until 6 weeks postnatally, whereas ocular dominance distribution was not age-dependent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235931
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  • 25
    Electronic Resource
    Electronic Resource
    Motion after-effects in cat striate cortex elicited by moving gratings (1985)
    Springer
    Experimental brain research 60 (1985), S. 411-416 
    Details
    ISSN: 1432-1106
    Keywords: Vision ; Motion after-effects ; Cat ; Visual cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of striate cortical neurones to bars of optimal orientation and width, moving with fixed velocity, were recorded in the lightly anaesthetized cat. Effects of periods of pre-adaptation with square-wave gratings of variable spatial frequency and velocity, drifting continuously in each cell's preferred or null directions, were investigated. Variations of cells' directional bias and responsiveness to oriented bars were assessed in relation to the degree and time-course of pre-adaptation to drifting gratings, compared with the preceding level of firing when exposed to uniform backgrounds of the same average luminance. All cells showed some susceptibility to pre-adapting moving gratings: subsequent responses to a bar were initially depressed in the direction of pre-adaptation and, in direction-biased or bidirectional cells, were enhanced in the opposite direction, compared with bar responses following exposure merely to a uniform background. These effects were strongest and most consistent amongst standard complex cells and weakest amongst special complex cells: maximal effects were obtained with adapting gratings of optimal velocity and spatial frequency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235938
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  • 26
    Electronic Resource
    Electronic Resource
    Convergent strabismic amblyopia in cats (1985)
    Springer
    Experimental brain research 60 (1985), S. 1-9 
    Details
    ISSN: 1432-1106
    Keywords: Strabismic amblyopia ; Cat ; Retina ; Acuity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experiments were carried out to determine the effects of different types of experimental strabismus on the acuities of retinal ganglion cells. Six kittens were raised from twenty-one days of age with an esotropia surgically induced by myectomy of the lateral rectus muscle and a large portion of the superior oblique muscle. The results are compared with those, previously reported, from five other cats also made esotropic, but by tenotomy of the lateral rectus. All animals tested behaviourally were amblyopic in the strabismic eye. For square wave gratings, the visual acuities were 1.0 to 2.5 cyc/deg through the strabismic eye compared with 6.0 to 7.5 cyc/deg through the non-deviating eye. The cut-off spatial frequencies were determined for 132 brisk sustained cells from five of the myectomized strabismic cats. There was a loss of approximately 20% in cut-off spatial frequency when compared with both normal and tenotomized cats. A correlate of the physiologically observed difference between the tenotomized cats and the myectomized cats was also found in the morphology of cells in the lateral geniculate nucleus. The tenotomized cats showed no evidence of cell shrinkage in laminae receiving a projection from the amblyopic eye whereas in the myectomized cats large differences were observed in cell cross-sectional areas between laminae receiving input from the amblyopic eye and those receiving input from the non-deviating eye. Together, these findings indicate that the presence of a neural deficit in the retina of strabismic cats is associated with the actual removal of extra-ocular muscle and probably has little to do with the optical quality of images arriving at the retina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237012
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  • 27
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    Electronic Resource
    Binocular depth perception in the cat following early corpus callosum section (1985)
    Springer
    Experimental brain research 60 (1985), S. 19-26 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Binocular depth perception ; Stereoacuity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of the corpus callosum in the mediation of binocular depth perception was examined by measuring monocular and binocular depth discrimination thresholds in cats which had undergone section of the corpus callosum shortly after birth. Three kittens had the posterior callosum sectioned at the age of eleven days. A fourth kitten underwent a sham operation and one additional animal served intitially as an unoperated control. Monocular and binocular depth thresholds were measured for all kittens when they were between three and five months old. Although there was some individual variability, none of the callosum-sectioned kittens showed any deficits of binocular depth perception relative to normal animals. The initially unoperated kitten had its callosum sectioned at five months and was retested following surgery. Its performance did not change from preoperated levels. Finally, the three neonatal callosum-sectioned kittens underwent section of the optic chiasm when they were six months old, causing a complete breakdown in binocular depth discrimination. The results are interpreted to indicate that although the corpus callosum may be a sufficient pathway for the maintenance of stereopsis in cat, it is not necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237014
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  • 28
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    Electronic Resource
    Efferent connections of area 20 in the cat: HRP-WGA and autoradiographic studies (1985)
    Springer
    Experimental brain research 60 (1985), S. 179-183 
    Details
    ISSN: 1432-1106
    Keywords: Area 20 ; Corticofugal connections ; Pupilloconstrictor area ; Near reflex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following injections of horseradish peroxidase-wheat germ agglutinin conjugate (HRP-WGA) and tritiated leucine into area 20 of the cat, terminal labeling was observed in visual areas 19, 21, the splenial visual area, the lateral suprasylvian area as well as in premotor, association and limbic related cerebral cortical regions. Labeled terminals in the subcortex were distributed in the caudate nucleus, the claustrum, the putamen, the anterior ventral nucleus, the intralaminar nuclei, the caudal division of the intermediate lateral nucleus, the lateralis posterior-pulvinar complex, the parvocellular C laminae of the dorsal lateral geniculate nucleus and the ventral lateral geniculate nucleus. In HRP-WGA preparations, retrogradely labeled somata were observed in these regions with the exception of certain subcortical structures. The projections are discussed with respect to the possible role area 20 plays in the cortical control of pupillary constriction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237029
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  • 29
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    Electronic Resource
    A β-carboline antagonizes benzodiazepine actions but does not precipitate the abstinence syndrome in cats (1985)
    Springer
    Psychopharmacology 86 (1985), S. 132-136 
    Details
    ISSN: 1432-2072
    Keywords: β-Carbolines ; FG 7142 ; Benzodiazepines ; Diazepam ; Ro 15-1788 ; Drug dependence ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The β-carbolines, which are potent ligands for benzodiazepine receptors, antagonize the pharmacological actions of benzodiazepines. In the cat, the stable β-carboline derivative methylamide-β-carboline-3-carboxylate, FG 7142, and the specific benzodiazepine antagonist Ro 15-1788 reversed behavioral and electroencephalographic (EEG) changes produced by a single dose of diazepam. Surprisingly, the β-carboline did not elicit signs of withdrawal when given after 22 days of a daily dose regimen of diazepam, while Ro 15-1788 precipitated an acute abstinence syndrome largely characterized by tremors, increased muscle tone, back arching, myoclonic jerks and pupil dilatation. Unlike Ro 15-1788, the β-carboline produced effects of its own such as behavioral states of arousal and fearfulness. These findings indicate that the β-carboline functionally interacts with benzodiazepine receptors in a manner unlike that seen with typical agonists and antagonists.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00431697
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  • 30
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    Electronic Resource
    Electrical stimulation of arterial and central chemosensory afferents at different times in the respiratory cycle of the cat: I. Ventilatory responses (1985)
    Springer
    Pflügers Archiv 403 (1985), S. 415-421 
    Details
    ISSN: 1432-2013
    Keywords: Arterial chemoreceptors ; Cat ; Control of breathing ; Electrical stimulation ; Intracranial chemosensitivity ; Oesophageal pressure ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ventilatory responses to stimulation of chemoreceptor afferents were studied in the anesthetized, spontaneously breathing cat. Short bursts of electrical stimuli were applied, at various times in the inspiratory or expiratory phase of consecutive breaths, to the carotid sinus (CSN) and aortic nerves (AN) and to the ventral medulla (VM), and effects on tidal volume (V T), inspiratory, expiratory and cycle durationst I,t E,t tot) and in ventilation (E) were measured. The responses evoked by stimulating CSN, AN and VM were qualitatively the same, although there were quantitative differences. It was found that effects of stimulation in expiration were restricted to the expiratory phase, and vice versa for inspiration. Stimulation during both inspiration and expiration resulted in increasedV T, by increasing end-inspiratory or decreasing end-expiratory lung volume, respectively, and also increased ventilation, E. These effects were most marked in response to stimulation in inspiration. During both phases there was an increasing effect with increasing delay of the stimulus,t St, from onset of inspiration or expiration, respectively. There was a continuous increase int I, from below control to above control values, with increasingt St during inspiration and similarly fort E during expiration. Hence, the total respiratory cycle duration was shortened when a stimulus was applied early in either phase, and was prolonged, when it was applied late. The results show that stimulation of peripheral and of central chemoafferents exerts qualitatively similar effects on respiration. The central neuronal mechanisms generating both inspiration and expiration show the same changes in reactivity in the respiratory cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00589255
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  • 31
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    Electronic Resource
    Characteristics of the receptors in the isolated capsule of the hip in the cat (1985)
    Springer
    International orthopaedics 9 (1985), S. 123-127 
    Details
    ISSN: 1432-5195
    Keywords: Hip Capsule ; Cat ; Afferent receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les auteurs ont étudié les propriétés des nerfs afférents à la capsule de la hanche, chez le chat en imprimant à l'articulation des mouvements de rotation et sur des préparations de capsule isolée et ouverte en l'étirant directement grâce à un dispositif mécanique. In situ, on a trouvé deux types de nerfs afférents, les uns ayant en réponse à la rotation articulaire une étendue complète de sensibilité et les autres seulement une sensibilité limitée. Sur la capsule isolée les nerfs afférents sont indentiques en ce qui concerne le seuil et la sensibilité et on ne trouve aucun récepteur complet. On en conclut que les récepteurs de toute l'étendue de la sensibilité qui pénètrent les nerfs articulaires de la hanche sont des fibres en fuseau d'origine musculaire et non des récepteurs capsulaires. Sur ces bases et sur les résultats précédemment obtenus chez l'animal et chez l'homme, les auteurs discutent le rôle des récepteurs articulaires dans la cénesthésie et le sens des positions.
    Notes: Summary The properties of the afferent fibres from the capsule of the hip joint have been studied in the cat in situ, in relation to joint rotation, and in an isolated capsule preparation which was opened and stretched directly with an actuator. In situ two types of afferent fibres were found, those having a full range of sensitivity and others having only a limited range in response to the joint rotation. When studied in isolated tissue the afferent fibres of the capsule were uniform in threshold and sensitivities, and no full range receptors were found. We conclude that the full range receptors which enter the articular nerve of the hip are spindle afferents and not capsule receptors. On the basis of these and previous results in animals and man the role of joint receptors in kinaesthesia and position sense is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266954
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  • 32
    Electronic Resource
    Electronic Resource
    Immuno-electron-microscopic localization of a centriole-related antigen in ciliated cells (1985)
    Springer
    Cell & tissue research 239 (1985), S. 43-50 
    Details
    ISSN: 1432-0878
    Keywords: Centriolar antigen ; Basal body ; Immunoelectron microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antigen common to purported centriolar and basal body regions of a variety of cell types was previously visualized by immuno-fluorescence microscopy. The present study demonstrates the localization of the antigen relative to the defined basal body structures of ciliated tracheal cells at the electron-microscopic level. After ethyldimethylaminopropyl carbodiimide-glutaraldehyde-saponin (EGS) fixation and permeabilization, immunoferritin labeling is consistently found associated with amorphous electron-opaque material in proximity to basal bodies and their ciliary rootlets, but not with basal body microtubules themselves. This distribution pattern is distinct from that of other proteins found in the apical region of ciliated cells, such as calmodulin. It is proposed that the dense material may be analogous to pericentriolar material of centrosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214901
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  • 33
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    Electronic Resource
    Oligodendrocytes in the pons and middle cerebellar peduncle of the cat (1985)
    Springer
    Cell & tissue research 240 (1985), S. 541-552 
    Details
    ISSN: 1432-0878
    Keywords: Oligodendroglia ; Neuroglia ; Perineuronal satellites ; Interfascicular glia ; Pons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphology, microtopography and numerical density of oligodendrocytes were analyzed by light microscopy in the pontine gray and middle cerebellar peduncle of adult cats. The cells were selectively stained by use of the dicyanoargentate technique (Ogawa et al. 1975) that visualizes the entire cell population including perikarya and characteristic features of processes. On the basis of different microtopographical relations to neuronal perikarya and/or transversely oriented axon bundles, six groups of oligodendrocytes were separately analyzed: interfascicular, intrafascicular, perifascicular, perineuronal satellite, perifascicular-perineuronal, and “neuropil” cells. The cell morphology did not co-vary with any of these groups, but the shape of oligodendrocytes was on an average more elongated in the peduncle than in the pontine gray. The average cell density was similar in the gray and white matter (55000–56000 cells/mm3). However, 76% of the cells were concentrated near neuronal perikarya and axon bundles in a volume fraction of only 34%. Between adjacent neurons and axon bundles the cell density was even higher suggesting an additive behavior of these two topographical groups of oligodendrocytes. Axon bundles within the pontine gray contained only very few oligodendrocytes (density 6% that of the peduncle). These observations and quantitative data suggest that the perifascicular cells belong to the group of oligodendrocytes that are topographically related to axons (similar to interfascicular glia of the white matter) rather than to neuronal perikarya or neuropil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216343
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  • 34
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    Electronic Resource
    Extravasation of polymorphonuclear leukocytes from the cerebral microvasculature (1985)
    Springer
    Cell & tissue research 242 (1985), S. 399-407 
    Details
    ISSN: 1432-0878
    Keywords: Cerebral microvasculature ; Inflammatory reaction ; Polymorphonuclear leukocytes ; α-Bungarotoxin ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Postcapillary venules represent the segment of the microvasculature most vulnerable to inflammatory processes. While there is a considerable body of data on the peripheral vasculature, little is known about the primary events occurring during inflammatory reactions in cererbral blood vessels. We introduce here a model by which the migration of polymorphonuclear leukocytes through the CNS endothelial barrier can be studied. Alpha-bungarotoxin is used as a chemotactic agent and is shown, for the first time, to act by activating the complement cascade. Leukocytes migrate through the endothelium transcellularly. Two modes of migration are described: (i) a direct mode whereby the cells use temporary pores in the vessel wall as portals, and (ii) an indirect mode whereby the leukocytes leave the vascular compartment after being enveloped by and incorporated into endothelial cells. The functional implications of these findings lead us to conclude that the direct mode of migration is a causal agent in the massive breakdown of the blood-brain barrier under acute inflammatory conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214554
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  • 35
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    Electronic Resource
    Substance P-immunoreactive neurons in the brainstem of the cat related to cardiovascular centers (1985)
    Springer
    Cell & tissue research 241 (1985), S. 31-41 
    Details
    ISSN: 1432-0878
    Keywords: Substance P ; Cardiovascular system ; Central nervous system ; Immunohistochemistry ; Mapping ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of substance P-immunoreactivity (SP-IR) in the brainstem and spinal cord of normal and colchicine-pretreated cats was analysed using the peroxidase-antiperoxidase (PAP) technique. Numerous SP-IR fibers are present in the nucleus solitarius, nucleus dorsalis nervi vagi and nucleus spinalis nervi trigemini, various parts of the formatio reticularis, substantia grisea centralis mesencephali, locus coeruleus and nucleus parabrachialis. SP-IR perikarya occur in the substantiae gelatinosa and intermedia of the spinal cord, the nucleus spinalis nervi trigemini-pars caudalis, the nucleus dorsalis nervi vagi, and the nucleus solitarius, as well as in the adjacent formatio reticularis and the medullary nuclei of the raphe. In addition, SP-IR cell bodies are located in the nuclei raphe magnus and incertus, ventral and dorsal to the nucleus tegmentalis dorsalis (Gudden), nucleus raphe dorsalis, substantia grisea centralis mensencephali, locus coeruleus, nucleus parabrachialis and colliculus superior. The results indicate that SP-IR neurons may be involved in the regulation of cardiovascular functions both at the central and peripheral level. A peripheral afferent portion seems to terminate in the nucleus solitarius and an efferent part is postulated to originate from the nucleus dorsalis nervi vagi and from the area of the nuclei retroambiguus, ambiguus and retrofacialis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214623
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    Einfluß der Substituenten auf Aktivierungsenthalpie-,-entropie und -volumen beim Zerfall organischer Perester (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 240-245 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Substituents on the Enthalpy, Entropy and Volume of Activation in the Decomposition of Organic PerestersThe influence of the ester group on the decomposition of organic peroxides was studied on peresters of the pivalic and neodecanoic acid with tert-butyl, tert-amyl, 1-methyl-1-propylpentyl and 1,1,4-trimethylpentyl groups at temperatures of 393 to 473 K and pressures up to 3000 bar using a flow method. As expected the half-live times decrease with increasing temperature and increase with rising pressure. With increasing bulkiness of the substituents the rates of decomposition as well as the enthalpies of activation increase. This surprising fact can be explained by the simultaneous increase of the entropies and the volumes of activation.
    Notes: Der Einfluß der Estergruppe auf den Zerfall organischer Peroxide wurde an Perestern der Pivalin- und der Neodecansäure mit tert-Butyl-, tert-Amyl-, 1-Methyl-propylpentyl- sowie 1,1,4-Trimethylpentylresten bei Temperaturen von 393 bis 473 K und Drücken bis 3000 bar in einer Strömungsapparatur untersucht. Die Zerfallshalbwertszeiten nehmen erwartungsgemäß mit steigender Temperatur stark ab und mit steigendem Druck zu. Mit zunehmender Größe der Substituenten steigen sowohl die Zerfallsgeschwindigkeiten als auch die Aktivierungsenthalpien. Dieser überraschende Effekt kann durch die Vergrößerung der Aktivierungsentropie und des Aktivierungsvolumens erklärt werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180123
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    Zur Lewis-Acidität von Nickel(0), III. Alkalimetall-hydridotrialkylaluminat-Komplexe von Ni(CDT) (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 313-322 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Lewis Acidity of Nickel(0), III. Alkali Metal Hydridotrialkylaluminate Complexes of Ni(CDT)Ni(CDT) reacts with hydridotrialkylaluminates of the alkali metals in ether/THF or ether/amine mixtures at temperatures below -50°C to form the temperature-sensitive compounds [MA(n-Donor)n]+[R3Al—H—Ni(CDT)]- (1-7) (MA = Li, Na; R = Me, Et, iBu). An Al—H—Ni three-centre bond is present in these complexes. On the basis of NMR data, the strength of the hydridoaluminate-nickel bond and the charge on nickel, caused by the hydridoaluminate residue, are compared with the corresponding characteristics of other ligand-Ni(CDT) complexes in which donor-acceptor σ-bonds are present.
    Notes: Ni(CDT)Abkürzungen: CDT = trans, trans, trans-1,5,9-Cyclododecatrien, COD = 1,5-Cyclooctadien, MA+ (solvatisiertes) Alkalimetall-Ion, PMDTA = N,N,N′,N″N″-Pentamethyldiethylentriamin, TMEDA = N,N,N′,N′-Tetramethylethylendiamin. reagiert mit Alkalimetall-hydridotrialkylaluminaten in Ether/THF-oder Ether/Amin-Mischungen als Lösungsmittel unterhalb von -50°C zu den thermisch labilen Verbindungen [MA(n-Donor)n]+[R3Al—H—Ni(CDT)]- (1-7) (MA = Li, Na; R = Me, Et, iBu). In diesen Komplexen liegt eine Al—H—Ni-Mehrzentrenbindung vor. Anhand NMR-spektroskopischer Daten lassen sich die Stärke der Hydridoaluminat-Nickel-Bindung und die Beladung des Nickels durch den Hydridoaluminat-Rest mit den Bindungsverhältnissen in anderen Ligand-Ni(CDT)-Komplexen mit Donor-Akzeptor-σ-Bindungen vergleichen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180128
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  • 38
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    Zur Lewis-Acidität von Nickel(0), I. Methyllithium-Komplexe von Nickel(0) (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 275-297 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Lewis Acidity of Nickel(0), I. Methyllithium Complexes of Nickel(0)The synthesis and properties of the methyllithium complexes of nickel(0) of the type (n-Donor)m-(LiCH3)Ni0(π-Ligand)n (1a-c, 16a-c, 20a-c) [n-Donor = chelating amine or THF; π-Ligand = CDT, ethene, or CO] are described. The structure of (PMDTA)(LiCH3)Ni(C2H4)2 (1b) has been determined by X-ray crystallography.  -  In these ate complexes, a carbanionic methyl group is σ-bonded to a nickel atom, the acceptor strength of which depend on the π-ligands. The chemical and spectroscopic properties indicate that the Ni—CH3 bond in the carbonyl complex is largely covalent whereas in the CDT and ethene compounds it is more polar. The CDT complex is thermolabile in solution. The findings are in agreement with the following series of increasing acceptor strength: Ni(CDT) 〈 Ni(C2H4)2 〈 Ni(CO)3.
    Notes: Es wird über die Synthese und Eigenschaften der Methyllithium-Komplexe von Nickel(0) (n-Donor)m(LiCH3)Ni0(π-Ligand)n Wir bezeichnen mitπ-Liganden solche Liganden, die als π-Akzeptoren mit einem Übergangsmetallatom dπ—pπ—oder dπ—dπ-Rückbindungen auszubilden vermögen (Alkene, CO, auch Phosphane);n-Donoren solche Liganden, die als „harte Basen“ (Ether, Amine) über ihre freien Elektronenpaare vornehmlich Hauptgruppenmetall-Ionen, d.h. „harte Säuren“ komplexieren;σ-Donoren solche Liganden, die  -  ohne über Akzeptororbitale zu verfügen  -  entweder polare Bindungen enthalten und Mehrzentrenbindungen eingehen können (Metallalkyle und -hydride) oder ein freies Elektronenpaar bereitstellen (Carbanionen, Phosphorane, Hydrid-Ion), wobei σ-Bindungen zu einem niederwertigen Übergangsmetallatom ausgebildet werden. (1a-c, 16a-c, 20a-c) mit Chelataminen oder THF als n-Donoren und CDTAbkürzungen: CDT = trans,trans,trans-l,5,9-Cyclooctadien; COT = Cyclooctatetraen; PMDTA = Pentamethyldiethylentriamin; TMEDA = Tetramethylethylendiamin; MA+A = Alkalimetall- bzw. quartäres Ammonium-Kation., Ethen oder CO als π-Liganden berichtet. Die Struktur von (PMDTA)(LiCH3)Ni(C2H4)2 (1b) wurde röntgenographisch bestimmt.  -  In diesen at-Komplexen ist eine carbanionische Methylgruppe über eine σ-Bindung an ein Nickelatom gebunden, dessen Akzeptorstärke von den π-Liganden abhängt. Chemische und spektroskopische Eigenschaften der Komplexe lassen für CDT oder Ethen als π-Liganden auf vergleichsweise polare, für den CDT-Komplex in Lösung dazu thermolabile Ni—CH3-Bindungen schließen, während für den Carbonyl-Komplex aufgrund von 13C-NMR-Daten eine überwiegend kovalente Ni—CH3-Bindung anzunehmen ist. Die Befunde stehen mit folgender Reihe zunehmender Akzeptorstärke im Einklang: Ni(CDT) 〈 Ni(C2H4)2 〈 Ni(CO)3.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180126
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  • 39
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    Über das korrespondierende Verhalten von heteroatom-stabilisierten Carbokationen und dem Cycloheptatrien-Norcaradien-Gleichgewicht (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 620-633 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Correspondence of Heteroatom-stabilized Carbocations and the Cycloheptatriene-Norcaradiene EquilibriumThe effects of alkoxyiminium substituents on the cycloheptatriene-norcaradiene equilibria 1 ⇄ 2 have been investigated. Due to the energetics two classes of compounds were found (ΔH° 〈 0, and ΔH° 〉 0). The transfer of the substituent effect from carbocation to carbocyclus is inhibited by a p-phenylene group. From 1H and 13C NMR spectra at variable temperatures thermodynamic parameters are deduced and correlated with σR-constants obtained from 19F NMR spectroscopy. By extrapolation, the enthalpy difference for the unsubstituted cycloheptatriene and norcaradiene is calculated as 9.3 kcal/mol.
    Notes: Der Einfluß von Alkoxyiminium-Substituenten an C-7 auf die Lage des Cycloheptatrien-Norcaradien-Gleichgewichts 1 ⇄ 2 wird untersucht. Auf Grund der Energetik gibt es Verbindungen, bei denen Temperaturabsenkung eine Verschiebung des Gleichgewichts zum Norcaradien (ΔH° 〈 0) ergibt, bei anderen Beispielen ist ΔH° 〈 0. Eine p-Phenylenbrücke zwischen Kation und Carbocyclus blockiert den Substituenteneffekt. Aus den 1H- und 13C-NMR-Spektren bei verschiedenen Temperaturen wurden thermodynamische Daten ermittelt und mit den durch 19F-NMR bestimmten σR-Konstanten korreliert. Durch Extrapolation konnte die Enthalpiedifferenz des unsubstituierten Cycloheptatriens und Norcaradiens zu 9.3 kcal/mol abgeschätzt werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180221
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    Hydrated oxocarbons, IV. Silylation of 1,1-dihydroxy compounds (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 661-669 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydratisierte Oxokohlenwasserstoffe, IV. Silylierung von 1,1-Dihydroxy-VerbindungenDie Anwendung von verschiedenen Silylierungsreagenzien auf mono- und polyvicinale 1,1-Di-hydroxy-Verbindungen wurde untersucht. Mit einigen dieser Reagenzien konnten aus Ninhydrin (2) und Rhodizonsäure (17) die entsprechenden geminalen Bis(trimethylsilyloxy)-Derivate 1 und 20 gewonnen werden. Während 1 leicht zu Hexamethyldisiloxan und Indantrion (4) fragmentiert, ist 20 thermisch relativ stabil, es gibt pyrolytisch bei 500°C nur Spuren des Tetraketons 21 ab. Andere Silylierungsreagenzien bewirken unerwartete C-Alkylierung oder C-Amidierung am Dihydroxykohlenstoff. Silylierungen von Perhydroxycyclobutan und -cyclohexan führen zu Ringaufspaltungs- bzw. Verengungsprodukten.
    Notes: The action of various silylating agents on mono- and polyvicinal 1,1-dihydroxy compounds has been investigated. Some of these reagents converted ninhydrin (2) and rhodizonic acid (17) into the corresponding geminal bis(trimethylsilyloxy) derivatives 1 and 20, respectively. Compound 1 readily fragments to form hexamethyldisiloxane and indantrione (4). The rhodizonic acid derivative 20 is, however, rather stable and even on pyrolysis at 500°C gives only traces of the tetraketone 21. With other silylating agents unexpected C-alkylation or C-amidation at the dihydroxy carbon is observed. Silylation of perhydroxycyclobutane and -cyclohexane leads to ring opened and contracted products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180225
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    Cycloadditionen des Triphenylallenyl-Kations mit Cyclopentadien  -  Studium des Reaktionsmechanismus unter stabilen Ionen-Bedingungen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 694-703 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions of the Triphenylallenyl Cation with Cyclopentadiene  -  Investigation of the Reaction Mechanism under Stable Ion ConditionsThe triphenylallenyl cation (5) reacts with cyclopentadiene in a concerted [4 + 2] and a stepwise [2 + 2] cycloaddition. The reaction mechanisms are elucidated by NMR spectroscopic observation of the intermediate carbenium ions.
    Notes: Das Triphenylallenyl-Kation (5) geht mit Cyclopentadien eine konzertierte [4 + 2]- sowie eine stufenweise [2 + 2]-Cycloaddition ein. Die Reaktionsmechanismen werden durch NMR-spektro-skopische Beobachtung der intermediären Carbenium-Ionen aufgeklärt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180229
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  • 42
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    Synthese und Struktur Platin-haltiger Tripeldecker- und Tetradecker-Komplexe (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 729-740 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Platinum-Containing Triple-Decker and Tetra-Decker ComplexesStacking of the acceptor sandwich bis(η5-2,3-dihydro-1H-1,3-diborolyl)platinum 1 (≙ (C2B2C)2Pt) with (C5H5)M fragments leads to the unsymmetrical triple-decker complexes (η5-C5H5)M-μ-(η5-C2B2C)Pt(η5-C2B2C) 2 (M = Co) and 3 (M = Ni) as well as to the symmetrical tetra-decker complexes [(η5-C5H5)M-μ-(η5-C2B2C)]2Pt 4 (M = Fe) and 5 (M = Ni). In these reactions 1 and (C5H5)Fe(C8H12) yield the tetra-decker 4, whereas with (C5H5)Co(C2H4)2 only the triple-decker 2 is formed. With [(C5H5)Ni(CO)]2 both the triple-decker 3 and the tetra-decker 5 are obtained. NMR studies on the diamagnetic complexes 2 (30 valence electrons), 4 (42 VE), and 5 (46 VE) indicate high-symmetrical conformations, or free rotation of the ligands. 2 and 3 crystallize isotypic; the X-ray structure analyses exhibit the triple-decker arrangement with antiperiplanar conformation of the heterocycles. 3 in comparison with 2 is elongated along the molecular axis. The tetra-deckers 4 and 5 also crystallize isotypic; for the first time a synclinale conformation of the bridging ligands is found.
    Notes: Aufstockung des Akzeptor-Sandwichs Bis(η5-2,3-dihydro-1H-1,3-diborolyl)platin 1 (≙ (C2B2C)2Pt) mit (C5H5)M-Fragmenten führt zu den unsymmetrischen Tripeldecker-Komplexen (η5-C5H5)M-μ(η5-C2B2C)Pt(η5-C2B2C) 2 (M = Co) und 3 (M = Ni) sowie zu den symmetrischen Tetradecker-Komplexen [(η5-C5H5)M-μ-(η5-C2B2C)]2Pt 4 (M = Fe) und 5 (M = Ni). Dabei ergibt die Reaktion von 1 mit (C5H5Fe(C8H12) den Tetradecker 4, während mit (C5H5)Co(C2H4)2 nur der Tripeldecker 2 entsteht. Mit [(C5H5)Ni(CO)]2 werden der Tripeldecker 3 und der Tetradecker 5 gebildet. NMR-Untersuchungen an den diamagnetischen Komplexen 2 (30 Valenzelektronen), 4 (42 VE) und 5 (46 VE) sprechen für hochsymmetrische Konformationen oder freie Rotation der Liganden. 2 und 3 kristallisieren isotyp; die Röntgenstrukturanalysen zeigen die Tripeldeckeranordnung mit antiperiplanarer Konformation der Heterocyclen. 3 ist im Vergleich zu 2 entlang der Molekülachse aufgeweitet. Die Tetradecker 4 und 5 kristallisieren ebenfalls isotyp, es wird erstmals eine synclinale Konformation der Brückenliganden gefunden.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180232
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    Ein neuer Zugang zu Alkylthio(trifluoracetyl)furanen durch thermische [3 + 2]-Cycloadditionen neuer mesoionischer 1,3-Oxathiol-4-one an Alkine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 785-795 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Entry to Alkylthio(trifluoroacetyl)furans by Way of Thermal [3 + 2]Cycloaddition Reactions of New Mesoionic 1,3-Oxathiol-4-ones to AlkynesAs cyclic carbonyl ylides, the novel 2-alkylthio-5-trifluoroacetyl-1,3-oxathiolylium-4-olates of type 1a-d combine with dimethyl acetylenedicarboxylate across the 2,5-position with formation of non-isolable primary adducts, which release COS to give the furandicarboxylic diesters 3a-d. Methyl propiolate reacts with 1a-c to produce mixtures of the regioisomeric furancarboxylic esters 4a-c and 5a-c, whose main components 4a-c are isolable. On the other hand, the reactions of phenylacetylene, 1-diethylaminopropyne, or (Z)-1-methoxy-1-buten-3-yne with 1a proceed with regiospecific formation of the furan derivatives 6, 7, or 8, respectively. The observed regioselectivities are qualitatively discussed on the basis of MO-perturbation theory.
    Notes: Als cyclische Carbonyl-ylide nehmen die neuen 2-Alkylthio-5-trifluoracetyl-1,3-oxathiolylium-4-olate vom Typ 1a-d in 2,5-Stellung Acetylendicarbonsäure-dimethylester unter Bildung nicht-isolierbarer Primäraddukte auf, die unter COS-Abspaltung Furandicarbonester 3a-d liefern. Mit Propiolsäure-methylester reagiert 1a-c zu Gemischen aus den regioisomeren Furancarbonestern 4a-c und 5a-c, deren Hauptkomponenten 4a-c isolierbar sind. Dagegen vereinigen sich Phenylacetylen, 1-Diethylaminopropin bzw. (Z)-1-Methoxy-1-buten-3-in mit 1a regiospezifisch zu den Furan-Derivaten 6, 7 bzw. 8. Die beobachteten Regioselektivitäten werden qualitativ auf der Basis der MO-Störungstheorie diskutiert.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180237
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    Notizen. Thermolysis and photolysis of hexachloro-tris-σ-homotropone and related compounds (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 840-844 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolyse und Photolyse von Hexachlor-tris-σ-homotropon und verwandten VerbindungenTroponethylenacetal (2) reagiert mit überschüssigem CCl2 zu den Mono-, Bis- und Tris-Addukten 3, 4a, b und 5. Thermolyse von 5 führt nicht zum Hexachlor-tris-σ-homobenzol (1), ebensowenig wie die Photolyse des Ketons 6a, bei der unter Öffnung einer Cyclopropan-Brückenbindung das sterisch mehr gehinderte Isomere 6b erhalten wird. Die Photolyse von 8 verläuft ebenfalls nicht unter Decarbonylierung (→ 7) sondern unter Cyclopropanring-Öffnung zu 9 bzw. 10, wobei hier die von der Carbonylgruppe am weitesten entfernten Bindungen geöffnet werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180241
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  • 45
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    Schwefelextrusion aus 5(2H)-Isothiazolonen und 5(2H)-Isothiazolthionen zu intermediären Imidoylketenen und -thioketenen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 851-862 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur Extrusion from 5(2H)-Isothiazolones and 5(2H)-Isothiazolethiones to give Intermediate Imidoyl Ketenes and Imidoyl ThioketenesFrom 5(2H-isothiazolethiones (2) and propylene oxide a series of new 5(2H-isothiazolones (7) was prepared. With tributylphosphane (or cyanide ions) 2 and 7 eliminated one sulfur atom. The resulting assumed imidoyl ketenes (8) and imidoyl thioketenes (3) could not be detected spectro-scopically. But by isolation of dimeric imidoyl thioketenes (1,3-dithietanes, 1) and trapping with alcohols, amines, or benzylideneisopropylamine to give derivatives of acrylic acid (4-6) or dihydropyrimidones (9) it is shown that 3 and 8 are probably intermediates.
    Notes: Aus 5(2H)-Isothiazolthionen (2) wurde mittels Propylenoxid eine Reihe neuer 5(2H)-Isothiazolone (7) hergestellt. Beide Substanzklassen reagieren mit Tributylphosphan (oder Cyanid-Ionen) unter Abspaltung eines Schwefelatoms zu vermuteten, spektroskopisch aber nicht nachgewiesenen Imidoyl-thioketenen (3) bzw. Imidoylketenen (8). Ihr intermediäres Auftreten wurde durch die Isolierung von dimeren Imidoyl-thioketenen (1,3-Dithietanen, 1) und durch Abfangreaktionen mit Alkoholen, Aminen oder Benzylidenisopropylamin zu den Derivaten der Acrylsäure 4-6 bzw. den Dihydropyrimidonen 9 wahrscheinlich gemacht.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180302
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    Heterocyclische β-Enaminoester, 36. Das Cycloadditions-Ringerweiterungsprinzip beim 4,5-Dihydropyrrol: 6,7-Dihydro-1H-azepine, Pyrimido[4,5-b]azepine und 1,2,4-Triazolo[5′,1′: 2,3]pyrimido[4,5-b]azepin (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 863-872 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic β-Enamino Esters, 36. The Cycloaddition-Ring Enlargement Principle on 4,5-Dihydropyrroles: 6,7-Dihydro-1H-azepines, Pyrimido[4,5-b]azepines, and 1,2,4-Triazolo[5′,1′: 2,3]pyrimido[4,5-b]azepineThe 2-amino-1-tosyl-Δ2-pyrroline enamino esters 2a, b react with dichlorotriphenylphosphorane to give the iminophosphoranes 3a, b. With acetylenic esters (4a-c) the 6,7-dihydro-1H-azepines 6a-d are formed according to the cycloaddition-ring enlargement principle. Acids hydrolyze to afford the free azepine enamino esters 7a, c, d. With phenyl isocyanate 6a gives the carbodiimide 9, which upon treatment with 5% aq. NaOH cyclizes to give the pyrimido[4,5-b]azepine 10. Analogously, isopropylamine and hydrazine lead to the 2-N-substituted bicycles 11a, b; with triethyl orthoformiate 11a yields the novel 5:6:7-tricycle 13.
    Notes: Die 2-Amino-1-tosyl-Δ2-pyrrolin-enaminoester 2a, b reagieren mit Dichlortriphenylphosphoran zu den Iminophosphoranen 3a, b. Mit Acetylenestern (4a-c) entstehen nach dem Prinzip Cycloaddition-Ringerweiterung die 6,7-Dihydro-1H-azepine 6a-d. Säuren hydrolysieren zu den freien Azepin-enaminoestern 7a, c, d. Mit Phenylisocyanat ergibt 6a das Carbodiimid 9, das sich mit 5proz. Natronlauge zum Pyrimido[4,5-b]azepin 10 ringschließen läßt; Isopropylamin und Hydrazin führt analog zu den 2-N-substituierten Bicyclen 11a, b, 11a ergibt mit Orthoameisensäure-triethylester den neuen 5:6:7-Tricyclus 13.
    Additional Material: 5 Tab.
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    Carbonylvanadate(-I) mit ungesättigten Liganden: 51V-NMR-und IR-spektroskopische Charakterisierung der Tieftemperaturspezies [V(CO)5L]-; L = N2, Alkin, Alken, CS2 und SO2 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 895-904 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylvanadates(-I) Containing Unsaturated Ligands:51V NMR and IR Characterization of Low-temperature [V(CO)5L]- Complexes; L = N2, Alkyne, Alkene, CS2, and SO2UV irradiation of [Et4N]V(CO)6 + L in THF (L = alkyne, alkene) or 2-Me-THF (L = N2) at 200 K yields the pentacarbonylvanadates [V(CO)5L]- with end-on (N2) and side-on (alkynes, alkenes) coordinated ligands, respectively. [V(CO)5SO2]- (η1S) and [V(CO)5CS2]- (η2-C,S) were obtained from the reaction between [V(CO)5THF]- and L at 200 K. The N2 complex is also formed from [V(CO)5OCMe2]- and N2. The complexes are characterized by their IR and 51V NMR spectra. Shielding of the 51V nucleus decreases in the order alkene 〉 alkyne ≍ N2 〉 SO2 〉 CS2 〉 {O}. Compared to η1-coordination, η2-coordination gives rise to a deshielding contribution of 110 to 280 ppm. The compounds decompose at temperatures above 225 K (L = N2, 2-pentyne, 3-hexyne, cyclopentene, cyclohexene), 240 - 250 K (SO2, CS2, 1-pentene), or 285 K (1-hexyne); with PPh3, [V(CO)5PPh3]- is formed.
    Notes: Die UV-Bestrahlung von [Et4N][V(CO)6] + L in THF (L = Alkin, Alken) oder 2-Me THF (L = N2) bei 200 K führt zu Pentacarbonylvanadaten [V(CO)5L]- mit end-on (N2) bzw. side-on (Alkine, Alkene) gebundenen Liganden. [V(CO)5SO2]- (η1-S und [V(CO)5CS2]- (η2C,S) wurden durch Umsetzung von [V(CO)5THF]- mit L bei 200 K erhalten. Der N2-Komplex entsteht auch aus [V(CO)5OCMe2]- und N2. Die Komplexe werden durch ihre IR- und 51V-NMR-Spektren charakterisiert. Die Abschirmung am Kern 51V nimmt in der Reihe Alken 〉 Alkin ≍ N2 〉 SO2 〉 CS2 〉 {O} ab. Die η2-Koordination liefert gegenüber der η1-Koordination einen Entschirmugsbeitrag von 110 - 280 ppm. Die Verbindungen zersetzen sich bei Temperaturen oberhalb 225 K (L = N2, 2-Pentin, 3-Hexin, Cyclopenten, Cyclohexen), 240 - 250 K (SO2, CS2, 1-Penten) bzw. 285 K (1-Hexin); mit PPh3 erfolgt Umsetzung zu [V(CO)5PPh3]-.
    Additional Material: 2 Ill.
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    (Trifluormethyl)selen(VI)-Verbindungen, Synthese und Eigenschaften von Tetrafluor(trifluormethyl)selen-halogeniden sowie Trifluormethanselenonaten (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 943-951 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Trifluoromethyl)selenium(VI) Compounds, Synthesis and Properties of Tetrafluoro(trifluoromethyl)selenium Halides and TrifluoromethaneselenonatesFluorination of CF3SeF3 with liquid F2 or AgF2 leads to CF3SeF5, which decomposes to CF4 and SeF4. With water CF4 and SeOF2 are formed. Addition of ClF to CF3SeF3 gives CF3SeF4Cl, which splits mainly into CF3Cl and SeF4. Hydrolysis provides analogously CF3Cl and SeOF2. A neutral concentrated solution of KMnO4 oxydizes CF3SeO2H in water in good yields to CF3SeO3K, the free acid of which is obtained with 74% HClO4. The aqueous solution can be concentrated up to 90%, but above this concentration spontaneous decomposition to CF4, COF2, and SeO2 occurs. Trifluoromethaneselenonates are stable at room temperature but decompose when heated.
    Notes: Die Fluorierung von CF3SeF3 mit flüssigem Fluor bzw. AgF2 führt zu CF3SeF5 das thermisch in CF4 sowie SeF4 zerfällt und mit H2O zu CF4 und SeOF2 hydrolysiert. Durch Addition von ClF an CF3SeF3 entsteht CF3SeF4Cl, das sich hauptsächlich zu CF3Cl und SeF4 zersetzt. Die Hydrolyse liefert analog CF3Cl und SeOF2. Mit wäßr., gesättigter KMnO4 liefert CF3SeO2H in guter Ausbeute CF3SeO3K, aus dem die freie Säure mit 74proz. HClO4 erhalten wird. Sie läßt sich in wäßriger Lösung bis zu 90% anreichern und zerfällt bei weiterem Konzentrieren spontan zu CF4, COF2 und SeO2. Ihre Salze sind bei Raumtemperatur stabil und explodieren beim Erhitzen.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180312
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    Metallkomplexe mit biologisch wichtigen Liganden, XXXIV. Allyl-Palladium(II)- und Triphenylphosphan-Gold(I)-Komplexe mit Nucleobasen und Nucleosiden (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 931-942 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes with Biologically Important Ligands, XXXIV. Allyl-Palladium(II) and Triphenylphosphane Gold(I) Complexes with Nucleobases and NucleosidesThe reactions of (η3-allyl)Pd(μ-Cl)2Pd(η3-allyl) (A) and (COD)Rh(μ-Cl)2Rh(COD) with nucleobases and nucleosides give the complexes (η3-C3H5)Pd(L)Cl (1) (L = inosine, adenosine, guanosine, cytosine, cytidine, 2-thiouracil, 2-thiocytosine) and (COD)Rh(cytosine)Cl (2), respectively. With adenosine and purine also ligand bridged complexes (η3-C3H5)(Cl)Pd—L—Pd(Cl)(η3-C3H5) (3) have been obtained. Ph3PAuCl reacts with the anions L′ of purine, adenine, uridine, and inosine to give the complexes Ph3PAuL′ (5). Ph3PAu+ is added to both N atoms of the dianion of uracil with formation of 6. The coordination of the nucleobases is discussed on the basis of the 1H and 13C NMR spectra. The X-ray structure of Ph3PAu(adeninate) (5b) has been determined.
    Notes: Die Umsetzung von (η3-Allyl)Pd(μ-Cl)2Pd(η3-Allyl) (A) sowie von (COD)Rh(μ-Cl)2Rh(COD) mit Nucleobasen und Nucleosiden liefert unter Spaltung der Chlorobrücken die Komplexe (η3C3H5)-Pd(L)Cl (1) (L = Inosin, Adenosin, Guanosin, Cytosin, Cytidin, 2-Thiouracil, 2-Thiocytosin) bzw. (COD)Rh(Cytosin)Cl (2). Mit Adenosin und Purin wurden auch Ligand-verbrückte Komplexe (η3-C3H5)(Cl)Pd—L—Pd(Cl)(η3-C3H5) (3) erhalten. Ph3PAuCl setzt sich mit den Anionen L′ von Purin, Adenin, Uridin und Inosin zu Ph3PAuL′ (5) um; Ph3PAu+ addiert sich an die beiden N-Atome des Dianions von Uracil unter Bildung von 6. Die Koordination der Nucleobasen wird anhand der 1H- und 13C-NMR-Spektren diskutiert. Die Struktur von Ph3PAu (Adeninat) (5b) wurde röntgenographisch bestimmt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180311
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    Bicyclofulvene, XI. Zur Frage der Spirokonjugation bei Spiro[cycloheptatrien-7,7′-norbornadien] (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1000-1007 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bicyclofulvenes, XI. On the Question of Spiroconjugation in Spiro[cycloheptatriene-7,7′-norbornadiene]The title compound 4 as well as the derivatives 5 und 6 have been prepared. The first band in the UV spectrum of 4 in n-heptane is blue-shifted by ca. 20 nm with respect to those of 5 and 6. Model calculations with the CNDO/S-CI method indicate that this hypsochromic shift as well as the bathochromic shift of the corresponding band of 2 relative to that of 3, cannot be explained by spiroconjugation. The thermolysis of 4 yields benzene, heptafulvalene (15), and fulveneallene (16). The latter products are probably derived from cycloheptatrienylidene (14) as an intermediate.
    Notes: Die Titelverbindung 4 sowie die Derivate 5 und 6 wurden dargestellt. Die erste Bande im UV-Spektrum von 4 in n-Heptan zeigt eine hypsochrome Verschiebung um ca. 20 nm verglichen mit den Banden in 5 und 6. Modellrechungen mit der CNDO/S-CI-Methode zeigen, daß, sowohl diese hypsochrome Verschiebung als auch die bathochrome Verschiebung der entsprechenden Bande von 2 im Vergleich zu 3 nicht auf Spirokonjugation beruht. Die Thermolyse von 4 ergibt neben Benzol Heptafulvalen (15) und Fulvenallen (16). Diese Produkte machen eine Spaltung von 4 in Benzol und Cycloheptatrienyliden (14) wahrscheinlich.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180316
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    Neue Reagenzien, XXXII. Alkyldiphenylbismutane: Synthese, Eigenschaften und Halogenolyse (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1031-1038 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Reagents, XXXII. Alkyldiphenylbismutanes: Synthesis, Properties, and HalogenolysisAlkyldiphenylbismutanes 1 have been synthesized for the first time (61-92%). These compounds are air sensitive, not spontaneously inflammable liquids which decompose not below ≍ 170°C. The diphenylbismutino group is a very good equivalent for Cl- or Br-substituents at aliphatic residues since halogenolysis of the Bi-Alk bond with SO2Cl2 or Br2 already occurs at -40 to 0°C (corresponding fissions of As-Alk and Sb-Alk bonds afford heating to ≍ 130 or ≍ 220°C).
    Notes: Erstmals konnten Alkyldiphenylbismutane 1 synthetisiert werden (61-92%). Es sind luftempfindliche, nicht selbstentzündliche Flüssigkeiten, die sich erst bei ≍ 170°C zersetzen. Die Diphenylbismutino-Gruppe ist ein sehr gutes Äquivalent für aliphatisch gebundenes Chlor oder Brom, da die Halogenolyse der Bi-Alk-Bindung mit SO2Cl2 oder Br2 bereits bei - 40 bis 0°C abläuft (entsprechende Spaltungen von As-Alk- und Sb-Alk-Bindungen erfolgen bei ≍ 130 bzw. ≍ 220°C).
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180319
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    Dimere Phospha- und Thiastannylene: Ylidartige Diphospha- und Dithiadistannetane (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1045-1049 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimeric Phospha- and Thiastannylenes: Ylide-type Diphospha- and DithiadistannetanesBis(di-tert-butylphosphino)tin(II) (1) is obtained from the reaction of potassium di-tert-butyl-phosphide with stannous chloride or with the stannous chloride-triethylphosphane complex. Bis(tert-butylthio)tin(II) (2) is prepared by reaction of (η5-C5H5)2Sn with 2-methyl-2-propanethiol or from stannous chloride and (tert-butylthio)trimethylsilane. In solution, 1 and 2 are PR2-and SR-bridged dimers, respectively. NMR spectra indicate that rapid scrambling of terminal and bridging substituents occurs in 2 but not in the cyclic \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm P}\limits^ + - \mathop {\rm S}\limits^{\rm - } {\rm n} $\end{document} ylide 1.
    Notes: Bis(di-tert-butylphosphino)zinn(II) (1) entsteht durch Reaktion von Kalium-di-tert-butylphos-phid mit Zinndichlorid oder dem Zinndichlorid-Triethylphosphan-Komplex. Bis(tert-butylthio)-zinn(II) (2) wird hergestellt durch Umsetzung von (η5-C5H5)2Sn mit 2-Methyl-2-propanthiol und entsteht auch bei der Reaktion von Zinndichlorid mit (tert-Butylthio)trimethylsilan. 1 und 2 liegen in Lösung als PR2- bzw. SR-verbrückte Dimere vor. Kernresonanzspektren zeigen, daß bei dem cyclischen \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm P}\limits^ + - \mathop {\rm S}\limits^{\rm - } {\rm n} $\end{document}-Ylid 1 im Gegensatz zu 2 auch in Ethern keine raschen Platzwechselvorgänge (Brücke/terminal) ablaufen.
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    URL: http://dx.doi.org/10.1002/cber.19851180321
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    Regioselektive Addition von Grignard-Reagenzien an 3-Methoxy- und 3-Nitrophthalsäureanhydrid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1058-1070 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselective Addition of Grignard Reagents to 3-Methoxy- and 3-Nitrophthalic AnhydrideThe regioselectivity in the addition of the grignard reagents 5a and 6a to the anhydrides 1 and 2 is determined by the solvent system: in a highly selective manner (3: 97), the meta carbonyl group is attacked in tetrahydrofuran/tetramethylethylenediamine, while predominant, but relatively unselective (maximum 78:22) addition to the ortho carbonyl group is observed in diethyl ether. The influence of the solvent system on the regioselectivity is discussed. The LUMO-coefficients of the carbonyl carbon atoms in 1 and 2 were calculated.
    Notes: Die Addition der Grignard-Reagenzien 5a und 6a an die Anhydride 1 und 2 wird entscheidend vom Reaktionsmedium beeinflußt: in Tetrathydrofuran/Tetramethylethylendiamin wird hochselektiv (3: 97) die meta-ständige, in Diethylether dagegen überwiegend, aber mit nur geringer Selektivität (maximal 78: 22), die ortho-Carbonylgruppe angegriffen. Die Strukturen der dabei erhaltenen Addukte werden durch Umwandlung in die Ester 7-10, in die Lactone 11 sowie in die Ketone 12 und 13 bewiesen. Im Zusammenhang mit dem Versuch, die lösungsmittelabhängige Regioselektivität zu interpretieren, wurden die LUMO-Koeffizienten der Carbonylkohlenstoff-atome in 1 und 2 berechnet.
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    Cyanphosphorverbindungen, 8. Das ungewöhnliche Anion P2C10N102- (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1078-1085 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyanophosphorus Compounds, 8. The Unusual Anion P2C10N102-The reaction P(CN)3 + CN- (as [18]crown-6-sodium salt) leads via the spectroscopically identified P(CN)4 - to a disproportionation PIII → PI + PV. P(CN)2 - and P2C10N102- (1) have been isolated as products (with Ph3PCHPPh3 + as counter ion). In the latter an anionic aminomalononitrile bridge connects a dicyanophosphino and a pentacyanophosphate group, -P(CN)2 and - P(CN)5-, respectively.
    Notes: Die Reaktion P(CN)3 + CN- (als [18]Krone-6-Natriumsalz) führt über das nur spektroskopisch erkennbare P(CN)4- zur Disproportionierung PIII → PI + PV. Als Produkte können (mit Ph3PCHPPh3 + als Kation) P(CN)2- und P2C10N102- (1) gefaßt werden. In letzterem sind ein Dicyanphosphino-und ein Pentacyanophosphatrest, -P(CN)2 bzw. - P(CN)5-, über eine anionische Aminomalononitrilbrücke miteinander verbunden.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180325
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    Addition von Aldehyden an aktivierte Doppelbindungen, XXXV. α-Ketosäuren als Äquivalent für Aldehyde in der Thiazoliumsalz-katalysierten Addition (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1115-1125 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XXXV. α-Keto Acids as an Equivalent for Aldehydes in the Thiazolium Salt-Catalyzed Additionα-Keto acids can be used instead of aldehydes in the thiazolium salt-catalyzed addition to vinyl ketones. The yields of γ-diketones 1-7 resulting from the aliphatic α-keto acids are equivalent with those obtained from the aldehydes. The diketo acids 9-19 are prepared from the easily accessible 2-oxodiacids. Phenylpyruvic acids are easier to prepare than the phenylacetalehydes and give better yields compared with the corresponding aldehydes in the addition to vinyl ketones leading to the γ-diketones 20-29. These diketones are converted to cyclopentenones. The dihydrofurylglyoxylic ester 40 leads to the diketone 43, which is converted to the diketone 44. There is no aldehyde known equivalent to that keto acid.
    Notes: α-Ketosäuren können anstelle von Aldehyden in die Thiazoliumsalz-katalysierte Addition an Vinylketone eingesetzt werden. So entstehen die γ-Diketone 1-7 aus den α-Ketosäuren der aliphatischen Reihe in Ausbeuten, die der Aldehydaddition entsprechen. Aus den gut zugänglichen 2-Oxodisäuren werden die Diketosäuren 9-19 erhalten. Phenylbrenztraubensäuren sind besser als Phenylacetaldehyde zu synthetisieren und liefern in der Addition an Vinylketone zu den γ-Diketonen 20-29 bessere Ausbeuten. Diese Diketone wurden in Cyclopentenone übergeführt. Aus dem Dihydrofurylglyoxylsäure-ethylester 40 kann das Diketon 43 und daraus das Diketon 44, erhalten werden, ein entsprechender Aldehyd ist nicht bekannt.
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    URL: http://dx.doi.org/10.1002/cber.19851180328
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    Masthead (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180501
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    Heterocyclische 8π-Systeme, 16. Eliminierung an 2-Alkoxy-3-hydroxyindolinen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1726-1731 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterocyclic 8π-Systems, 16. Elimination Reactions of 2-Alkoxy-3-hydroxyindolinesThermolysis of 2-ethoxy-3-hydroxyindolines 1a-f affords oxindoles 3a-f as main products and the corresponding 3-indolinones 2a-f as by-products. The reaction course via indole 2,3-oxide intermediates is discussed. For this reason rearrangement reactions of 3-hydroxyindoleninium salts 4a, f are investigated.
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    Chirale Lactole, IV. Selektivitäten bei Acetalisierungsreaktionen enantiomerenreiner Lactole am Beispiel von Octahydro-8,9,9-trimethyl-5,8-methano-2H-1-benzopyran-2-ol (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1733-1745 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chiral Lactols, IV. Selectivities in Acetal Formation Reactions of Enantiomerically Pure Lactols using Octahydro-8,9,9-trimethyl-5,8-methano-2H-1-benzopyran-2-ol as a ModelA synthesis of the lactol 1 is described and its application as a reagent for the resolution of racemates is demonstrated in several examples. By means of X-ray and conformation analysis a general rule is given, which allows to predict the absolute configuration of acyclic alkyl-aryl-carbinols from the course of acetal formation between an enantiomerically pure lactol and the racemic alcohol.
    Notes: Eine Synthese für das Lactol 1 wird beschrieben und seine Eignung als Reagens zur Racemattrennung an einigen Beispielen gezeigt. Aufgrund einer Röntgenstruktur und konformationsanalytischer Überlegungen wird eine allgemeine Regel erarbeitet, nach welcher die Absolutkonfiguration acyclischer Alkyl-aryl-carbinole aus dem Verlauf der Acetalisierungsreaktion eines enantiomerenreinen Lactols mit dem racemischen Alkohol vorhergesagt werden kann.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180502
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    Aufbau Germylidin-verbrückter Drei- und Vierkerncluster (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1746-1757 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Buildup of Germylidyne-bridged Tri- and Tetranuclear ClustersReaction of organogermanium trihalides with KCo(CO)4 yields the trinuclear clusters RGeCo3(CO)9 (1, R = Me, Ph, tBu) as well as the new tetranuclear clusters (RGe)2Co4(CO)11 (3, R = Ph, tBu). The dinuclear complexes LnM — GeI2 — MLn (4-6, = FeCp(CO)2, Co(CO)4, NiCpCO) resulting from insertion of GeI2 into metal-metal bonds react with KCo(CO)4 to form the clusters LnM — GeCO3(CO)9 (7-9). Metal exchange reactions produce the hetero tetranuclear clusters (tBuGe)2Co3(CO)8M′Ln = MoCp(CO)2, NiCp). Crystal structure analyses were performed for Cp(CO)2Fe — GeCo3(CO)9 (7) and (tBuGe)2Co3(CO)8NiCp (11).
    Notes: Die Umsetzung von Organogermaniumtrihalogeniden mit KCo(CO)4 liefert sowohl die Dreikerncluster RGeCo3(CO)9 (1, R = Me, Ph, tBu) als auch die neuen Vierkerncluster (RGe)2Co4(CO)11 (3, R = Ph, tBu). Die durch Insertion von Gel2 in Metall-Metall-Bindungen entstehenden Zweikernkomplexe LnM — GeI2 — MLn (4-6, MLn = FeCp(CO)2, Co(CO)4, NiCpCO) setzen sich mit KCo(CO)4 zu den Clustern LnM — GeCO3(CO)9 (7-9) um. Metallaustauschreaktionen liefern die Heterovierkerncluster (tBuGe)2Co3(CO)8M′Ln (10, 11, M′Ln = MoCp(CO)2, NiCp). Von Cp(CO)2Fe — GeCo3(CO)9 (7) und (tBuGe)2Co3(CO)8NiCp (11) wurden Kristallstrukturanalysen durchgeführt.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180503
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    1,3-Dithienium- und 1,3-Dithioleniumsalze, II. Synthese monocyclothioacetalisierter 1,3-Diketone aus Silylenolethern (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1798-1808 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dithienium- and 1,3-Dithiolenium Salts, II. Synthesis of Monocyclothioacetalized 1,3-Diketones from Silyl Enol EthersThe 1,3-dithienium and 1,3-dithiolenium salts 3, available from the dithiols 1 or the cyclic thioacetals 4 (n = 2, 3) by reaction with the acyl chlorides 2, trityl tetrafluoroborate (5), and sulfuryl chloride (7), react in good yields with the silyl enol ethers 10 to give the new monocyclothioacetalized 1,3-Diketones 11. The synthetic of 11 as partially protected 1,3-Diketones is demonstrated exemplarily by dethioacetalization to the 1,3-dicarbonyl compounds 13.
    Notes: Die aus den Dithiolen 1 oder den cyclischen Thioacetalen 4 (n = 2, 3) durch Umsetzung mit den Acylchloriden 2, Trityl-tetrafluoroborat (5) und Sulfurylchlorid (7) erhältlichen 1,3-Dithienium-bzw. 1,3-Dithioleniumsalze 3 reagieren in guten Ausbeuten mit den Silylenolethern 10 zu den neuen monocyclothioacetalisierten 1,3-Diketonen 11. Das synthetische Potential von 11 als partiell geschützten 1,3-Diketonen wird exemplarisch durch Dethioacetalisierung zu den 1,3-Dicarbonylverbindungen 13 demonstriert.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180507
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    Syntheses and ENDOR studies of selectively deuterated galvinoxyl radicals. Complete Determination of the 13C hyperfine coupling constants of Coppinger's radical (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1782-1797 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesen und ENDOR-Untersuchungen selektiv deuterierter Galvinoxyl-Radikale. Vollständige Bestimmung der 13C-Hyperfeinkopplungskonstanten von Coppingers RadikalDie Synthese einiger selektiv deuterierter Galvinole und deren Oxidation zu den korrespondierenden Galvinoxyl-Radikalen, z.B. Coppingers Radikal und Yangs Biradikal, wird beschrieben. Am Beispiel der Dublettradikale wird gezeigt, daß 13C-ENDOR-Spektroskopie auch ohne 13C-Isotopenanreicherung möglich ist. Im Falle von Coppingers Radikal gelang die vollständige Ermittlung der 13C-Hyperfeinkopplungskonstanten. Die ENDOR-Untersuchung von selektiv deuteriertem Yangs Biradikal in glasartiger Matrix erlaubte eine eindeutige Zuordnung der Singale zu Molekülpositionen, und es ließen sich Rückschlüsse auf die Radikalsymmetrie und die behinderte Rotation der tert-Butylgruppen ziehen. In den ENDOR-Spektren regellos orientierter Bisgalvinoxyl-Biradikale im Triplettzustand findet man scharfe Signale bei den freien Kern-Zeeman-Frequenzen, die von NMR-Übergängen im Ms = 0-Spinzustand herrühren. Es wird gezeigt, daß die betreffenden Deuterium-Signale infolge der Quadrupolwechselwirkung der Deuteriumkerne aufgespalten sind.
    Notes: The synthesis of selectively deuterated galvinols is described. Oxidation results in the formation of the respective galvinoxyl free radicals, e.g., Coppinger's radical and Yang's biradical. It is shown that 13C ENDOR signals can be detected for the doublet radicals without 13C labelling, i.e., in natural abundance. The complete set of 13C hyperfine coupling constants of Coppinger's radical could be determined. The ENDOR study of selectively deuterated Yang's biradical in a glassy matrix allowed an unambiguous assignment of the signals to molecular positions, and conclusions with respect to the symmetry of the radical and the hindered rotation of the tert-butyl groups could be drawn. Randomly oriented bisgalvinoxyl biradicals in the triplet spin state give rise to sharp ENDOR lines at the free nuclear Zeeman frequencies due to NMR transitions in the Ms = 0 electron spin manifold, and it is demonstrated that the respective 2H ENDOR lines show quadrupole splittings.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180506
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    Darstellung von (η6-Aren)2Cr2(CO)3-Komplexen mit einer formalen Cr ≡ Cr-Dreifachbindung aus η6-ArenCr(CO)2NCCH3 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1825-1835 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (η6-arene)2Cr2(CO)3 Complexes Containing a Formal Cr ≡ Cr Triple Bond Starting from η6-areneCr(CO)2NCCH3The photochemical reaction of η6-ArCr(CO)3 (Ar = benzene, toluene, m-xylene, mesitylene, methyl benzoate, and fluorobenzene) with acetonitrile in hexane or p-tolunitrile in THF, resp., yields complexes η6-ArCr(CO)2NCR (1 - 10). Solutions of the red acetonitrile complexes yield on warming or UV photolysis by dissoziation of the nitrile and one CO ligand in the presence of benzene the new black coordination compounds (η6-Ar)2Cr2(CO)3 (11 - 16). The spectra and an X-ray structure determination of the benzene derivative 11 verify a Cr2-unit with a formal triple bond bridged by three CO ligands. The asymmetric unit of 11 contains two halves of molecules with Cr — Cr distances of 222.6 and 221.6 pm.
    Notes: Bei der photochemischen Umsetzung von η6-ArCr(CO)3 (Ar = Benzol, Toluol, m-Xylol, Mesitylen, Benzoesäure-methylester und Fluorbenzol) mit Acetonitril in Hexan bzw. p-Tolunitril in THF entstehen Komplexe η6-ArCr(CO)2NCR (1-10). Lösungen der roten Acetonitrilkomplexe bilden in der Wärme oder bei UV-Bestrahlung unter Abspaltung des Nitril- und eines CO-Liganden in Gegenwart von Benzol die neuen schwarzen Komplexe (η6-Ar)2Cr2(CO)3 (11-16). Die Spektren und die Röntgenstrukturanalyse des Benzolderivats 11 belegen eine von drei CO-Liganden verbrückte, formal eine Dreifachbindung aufweisende Cr2-Einheit. Die asymmetrische Enheit von 11 enthält zwei Molekülhälften mit Cr — Cr-Abständen von 222.6 bzw. 221.6 pm.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180509
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    Reaction of 1-oxa-3-azabutatrienium salts with tertiary carboxamides (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1876-1886 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktion von 1-Oxa-3-azabutatrienium-Salzen mit tertiären CarbonsäureamidenDie α-Chlorisocyanate 1 reagieren mit tertiären Carbonsäureamiden oder Acyliminen 3 in Gegenwart von Lewis-Säuren (SbCl5, FeCl3) unter milden Bedingungen zu den aminosubstituierten 2-Azaallenium-Salzen 5a - t. Die nur mäßig starken Elektrophile 5 setzen sich mit Methanol zu den Acetalen 8 und 10 um. Eine Röntgenstrukturanlyse von 5a zeigt, daß die -Einheit dieses Moleküls gewinkelt ist (128°). Es besteht eine Proportionalität zwischen der Wellenzahl der antisymmetrischen Valenzschwingung von 2-Azaallenium-Salzen und dem -Bindungswinkel. Die durch die sp2-Kohlenstoffe der -Einheit von 5a definierten Ebenen stehen nahezu senkrecht (84°) aufeinander.
    Notes: α-Chloro isocyanates 1 react with tertiary carboxamides or acylimines 3 in the presence of Lewis acids (SbCl5, FeCl3) to give the amino-substituted 2-azaallenium salts 5a - t under mild conditions. With methanol the moderately strong electrophiles 5 afford the acetals 8 and 10. According to an X-ray structural analysis, the C = N = C unit of 5a is bent by 128°. There exists a linear relationship between the wave number of the antisymmetric stretching vibration of 2-azaallenium salts and the bond angle. The planes defined by the sp2 carbons of the moiety of 5a are almost perpendicular (84°) with respect to each other.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180513
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    Bildung von Oxetanen bei der photosensibilisierten Oxidation von Enaminen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1927-1935 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation of Oxetanes via Photo-sensitized Oxidation of EnaminesPhotooxidations of the enamines 1 and 5 in toluene give rise to the formation of the usual reaction products. In methanol, however, the oxetanes 8 and 13, respectively, are isolated as the main photooxidation products. Both the mechanism of their formation as well as some reactions of 8 and 13 are discussed. Oxidation of 13 with m-chloroperbenzoic acid produces the aldehyde 15 via a multi-step reaction.
    Notes: Die Photooxidation der Enamine 1 bzw. 5 in Toluol liefert die erwarteten Reaktionsprodukte. In Methanol entstehen dagegen die Oxetane 8 bzw. 13 als Hauptprodukt der Photooxidation. Die Reaktionen dieser Verbindungen werden beschrieben. Die Oxidation von 13 mit m-Chlorperbenzoesäure führt über einen mehrstufigen einheitlichen Reaktionsablauf zum Aldehyd 15. Der Bildungsmechanismus der Oxetane 8 und 13 wird diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180517
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    Die Elektronenstruktur von 1,4-disubstituierten Butantetronen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1917-1926 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Electronic Structure of 1,4-Disubstituted ButanetetronesThe He(I) photoelectron (PE) spectra of the disubstituted butanetetrones 1 a - e have been recorded. The assignment of the first PE bands is based on semiempirical calculations. For 1 a - e the first bands could be assigned to ionization events from lone pair combinations on the oxygen atoms and in the case of 1 b - e additionally to ionizations from π-orbitals localized on the aromatic rings. The comparison between the PE bands of 1 d, 1,3-diphenyl-1,2,3-propanetrione, benzil, and benzophenone yields the result that the energy split between the n-orbital energies con-verges towards a value of about 3 eV. The interactions among the lone pairs and between lone pairs and the σ frame in 2 b - d are discussed, based on INDO calculations using localized orbitals.
    Notes: Die He(I)-Photoelektronen(PE)-Spektren der 1,4-disubstituierten Butantetrone 1 a - e wurden gemessen und anhand semiempirischer Rechnungen zugeordnet. Bei 1 a - e wurden die ersten Banden Ionisationen aus Linearkombinationen der einsamen Elektronenpaare an den Sauerstoffen und im Fall von 1 b - e noch zusätzlich Ionisationen aus den aromatischen π-Orbitalen zugeordnet. Der Vergleich zwischen den PE-Banden von 1 d, 1,3-Diphenyl-1,2,3-propantrion, Benzil und Benzophenon zeigt, daß die Aufspaltung zwischen den n-Orbitalenergien einem Grenzwert von etwa 3 eV zustrebt. Die Wechselwirkung zwischen den n-Orbitalen, den n-Orbitalen und dem σ-Gerüst (Through-Space- und Through-Bond-Wechselwirkung) in den vic. Di-, Tri- und Tetra-ketonen 2 b - d wird anhand von lokalisierten Orbitalen, die nach der INDO-Methode erhalten werden, diskutiert.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180516
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    Azaborolinyl-Komplexe, XVI. Synthese und Untersuchung von (1,2-Azaborolinyl)tricarbonyl-Komplexen des Chroms, Molybdäns und Wolframs (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1949-1958 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azaborolinyl Complexes, XVI. Synthesis and Investigation of (1,2-Azaborolinyl)tricarbonyl Complexes of Chromium, Molybdenum, and Tungsten1-tert-Butyl-2-methyl-1,2-azaborolinyllithium reacts with the hexacarbonyls of chromium, molybdenum, and tungsten to give the complex salts Li[(Ab)M(CO)3] (Ab = azaborolinyl ligand, M = Cr (2), Mo (3), and W (4)). With Me3ECl (E = Ge, Sn, Pb) they form the corresponding germyl, stannyl, and plumbyl derivatives. The molecular and crystal structures of (Ab)(CO)3Cr—SnMe3 (2b) and (Ab)(CO)3Mo—SnMe3 (3b) show the azaborolinyl rings to be pentahapto-bonded, inspite of a small folding of the rings, leading to a longer distance of the boron atoms to the metal atoms. The IR, 1H, 11B, and 13C NMR data prove equivalent structures for the other complexes. The existence of enantiomers in the cell results from the crystal structure investigations of 2b and 3b and is caused by the prochiral character of the azaborolinyl rings.
    Notes: 1-tert-Butyl-2-methyl-1,2-azaborolinyllithium reagiert mit den Hexacarbonylen von Chrom, Molybdän und Wolfram zu den komplexen Salzen Li[(Ab)M(CO)3] (Ab = Azaborolinyl-Ligand, M = Cr (2), Mo (3) und W (4)). Diese bilden mit Me3ECl (E = Ge, Sn, Pb) die entsprechenden Germyl-, Stannyl- und Plumbylderivate. Die Molekül- und Kristallstrukturen von (Ab)(CO)3Cr—SnMe3 und (2b) und (Ab)(CO)3Mo—SnMe3 (3b) weisen die Azaborolinylringe als pentahapto-gebunden aus, trotz einer leichten Faltung der Ringe, durch die die Boratome einen größeren Abstand zu den Metallatomen erreichen. Die IR-, 1H-, 11B- und 13C-NMR-Daten beweisen äquivalente Strukturen für die übrigen Komplexe. Aus den Kristallstrukturuntersuchungen von 2b und 3b geht die Anwesenheit von Enantiomeren in der Zelle hervor, verursacht durch den prochiralen Charakter der Azaborolinylringe.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180519
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    2,4-Diazabicyclo[3.3.1]nonan-Gerüste aus cis-Benzoltrioxid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2044-2078 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2,4-Diazabicyclo[3.3.1]nonane Skeletons from cis-Benzene TrioxideBy treating cis-benzene trioxide (1) with guanidine in buffered tert-butyl alcohol solution the 1:1-adducts DL-(1α,2β,4β,5α,6α,10α)- 8-imino-3-oxa-7,9-diazatricyclo[4.3.1.02,4]decane-5,10-diol (13a) and DL-(1α,2α,3β,5β,6α,7α)- 9-imino-4-oxa-8,10-diazatricyclo[5.3.0.03,5]decane-2,6-diol (12a) resulting from 1,3(1,2)-bridging in 1 are obtained in 88 - 91% (9 - 12%) yields. Trifluoroacetamidine (acetamidine) is also selectively 1,3-added to 1. From 13a via generally regiospecific hydrolysis (26a), thiolysis (30a, d) ammonolysis (34a), hydrazinolysis (34d), and HCl-/HBr- addition (39a, c) access to highly functionalised 2,4-diazabicyclo[3.3.1]nonane derivatives is opened. During the “ring-chain tautomerism” observed for 26a and 34d (28a, 36d) the adamantoid orthocarbonic acid intermediates (27a, 35d) cannot be identified directly. The spectroscopic structure elucidations (not always unequivocal because i.a. of conformational flexibility of the skeletons) are confirmed by X-ray structural analysis for 29f, 36e, 38, und 43.
    Notes: Bei der Umsetzung von cis-Benzoltrioxid (1) mit Guanidin in gepufferter tert-Butylalkohol-Lösung werden mit 88 - 91% (9 - 12%) Ausbeute die aus der 1,3(1,2)-Überbrückung in 1 hervorgehenden 1:1-Addukte DL-(1α,2β,4β,5α,6α,10α)- 8-Imino-3-oxa-7,9-diazatricyclo[4.3.1.02,4]decan5,10-diol (13a) und DL-(1α,2α,3β,5β,6α,7α)- 9-Imino-4-oxa-8,10-diazatricyclo[5.3.0.03,5]decan-2,6-diol (12a) gewonnen. Auch Trifluoracetamidin (Acetamidin) wird an 1 bevorzugt 1,3-addiert. Aus 13a gewinnt man durch jeweils regiospezifische Hydrolyse (26a), Thiolyse (30a, d), Ammonolyse (34a), Hydrazinolyse (34d) und HCl/HBr-Addition (39a, c) Zugang zu hochfunktionalisierten 2,4-Diazabicyclo[3.3.1]nonan-Derivaten. Bei der für 26a und 34d beobachteten „Ring-Ketten-Tautomerie“ (28a, 36d) sind die adamantoiden Orthokohlensäure-Intermediate (27a, 35d) nicht nachweisbar. Die u. a. wegen der konformativen Flexibilität der Gerüste nicht immer eindeutigen spektroskopischen Strukturzuordnungen werden durch Röntgenstrukturanalysen für 29f, 36e, 38 und 43 gesichert.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180527
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    Untersuchungen an Diazoverbindungen und Aziden, 58. Dikation-ether, 5. Formamidinium-substituierte Diazophosphoryl-Verbindungen: Synthese, Eigenschaften und Reaktionen zu Tetrazolen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2105-2117 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Diazo Compounds and Azides, 58. Dication Ethers, 5. Formamidinium-substituted Diazophosphoryl Compounds: Synthesis, Properties, and Reactions Leading to TetrazolesElectrophilic diazoalkane substitution of diazophosphoryl compounds 4a - c by bis(formamidinium) ethers 3a, b leads to formamidinium-substituted (diazomethyl)phosphoryl compounds 5. These can also be considered as alkenediazonium salts, but the contribution from this resonance structure is low according to 1H NMR and IR data. Reaction of 5a - c with another equivalent of 4a - c under slightly modified conditions yields 2-vinyl-2H-tetrazoles 6 and 7. The identity of the tetrazoles has been confirmed by X-ray structure analysis of 6c as well as by thermolysis of 6c leading to pyrazole 12 which then was hydrolyzed to give the NH-pyrazole 13.
    Notes: Die Diazophosphoryl-Verbindungen 4a - c reagieren mit den Bis(formamidinium)ethern 3a, b im Sinne einer elektrophilen Diazoalkan-Substitution zu Formamidinium-substituierten (Diazomethyl)phosphoryl-Verbindungen 5. Diese lassen sich auch als Olefindiazoniumsalze auffassen, jedoch deuten 1H-NMR- und IR-Daten nur auf einen geringen Anteil dieses Bindungszustandes hin. Unter leicht modifzierten Reaktionsbedingungen reagieren 5a - c mit einem weiteren Äquivalent von 4a - c zu den 2-Vinyl-2H-tetrazolen 6 und 7. Die Identität der Tetrazole wird durch eine Röntgenstrukturanalyse von 6c sowie die Thermolyse von 6c zum Pyrazol 12 und dessen Hydrolyse zum NH-Pyrazol 13 belegt.
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    URL: http://dx.doi.org/10.1002/cber.19851180530
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    The molecular and electronic structure of dipiperidinosquaraine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2118-2126 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molekulare und elektronische Struktur von DipiperidinoquadratainDipiperidinoquadratain (9) kristallisiert im orthorhombischen Gitter, Raumgruppe Pnab, mit 4 Molekülen in einer Elementarzelle mit den Abmessungen a = 7.1798(9), b = 9.5362(8) und c = 18.788(2) Å. Das Molekül liegt auf einem Symmetriezentrum, d.h. der Vierring (C — C = 1.456(1) Å) ist genau planar; die Stickstoff- und Sauerstoffatome sind fast mit dem Ring coplanar, mit C — O = 1.2396(7) und C — N = 1.3112(7) Å. Sowohl die experimentellen als auch die theoretischen Daten zeigen beachtliche C — N- und C — O-π-Bindungen, aber nur eine geringfügige C — C-π-Bindung im Quadratainsystem. Die Berechnungen ergeben starke 1,3-abstoßende Wechselwirkungen im Vierring. Ringfaltung, ein sonst üblicher Mechanismus bei der Vermeidung solcher Abstoßungen, wird hier durch die starke C — N-π-Bindung verhindert.
    Notes: Dipiperidinosquaraine (9) crystallizes in the orthorhombic system, space group Pnab, with four molecules in a cell of dimensions a = 7.1798(9), b = 9.5362(8), and c = 18.788(2) Å. The molecule is located over a center of symmetry, so the four-membered ring (C - C = 1.456(1) Å av) is exactly planar; the nitrogen and oxygen atoms are nearly coplanar with the ring, with C — O = 1.2396(7) and C — N = 1.3112(7) Å. Both experimental and theoretical evidence indicates the presence of considerable C — N and C — O π-bonding, but only a small amount of C — C π-bonding in the squaraine system. The calculations indicate the presence of strong 1,3-repulsive interactions within the four-membered ring. Ring puckering, which is a common mechanism to alleviate these repulsions, is prevented here by the extensive C — N π-bonding.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180531
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    The He(Iα) PE spectra and electronic absorption spectra of hexafluorocyclobutanone and of tetrafluoro-1,2-cyclobutane-dione (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2127-2133 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die He(Iα)-PE-Spektren und Elektronenabsorptionsspektren von Hexafluorcyclobutanon und Tetrafluor-1,2-cyclobutandionDie He(Iα)-PE-Spektren und die Elektronenabsorptionsspektren von Hexafluorcyclobutanon (3) und Tetrafluor-1,2-cyclobutandion (4) wurden gemessen. Die Zuordnung der ersten Banden beider Spektrentypen basiert hauptsächlich auf der Korrelation mit den entsprechenden Spektren der unsubstituierten Verbindungen Cyclobutanon (1) und 1,2-Cyclobutandion (2) sowie auf den Resultaten semiempirischer Rechnungen. Die Banden in den PE-Spektren von 3 und 4 werden im Vergleich zu den PE-Banden von 1 und 2 durch den Perfluor-Effekt um 1.6 bzw. 1.5 eV zu höheren Energien verschoben. Vergleicht man die Energie der ersten Bande in den Elektronenspektren von 1 und 3 bzw. 2 und 4, so findet man, daß diese Bande bathochrom um etwa 5000 cm-1 durch die Perfluor-Substitution verschoben wird. Dies wird dadurch erklärt, daß beim Ersatz der H-Atome durch F-Atome die Energie des LUMOs (π*) stärker abgesenkt wird als die des HOMOs (n).
    Notes: The He(Iα) PE and the electronic absorption spectra of hexafluorocyclobutanone (3) and tetrafluoro-1,2-cyclobutanedione (4) have been recorded. The assignment of the observed bands in both types of spectra is mainly based on the correlation with the corresponding spectra of the parent compounds cyclobutanone (1) and 1,2-cyclobutanedione (2), and in addition on the results of semiempirical calculations. As a result of the perfluoro effect, the bands in the PE spectra of 3 and 4 are shifted towards higher ionization energies by 1.6 eV and 1.5 eV relative to the corresponding bands in the PE spectra of 1 and 2. A comparison of the positions of the first band in the electronic spectra of 1 and 3, as well as of 2 and 4, shows that this band is shifted bathochromically by about 5000 cm-1 as a consequence of the perfluoro substitution. This is explained as being due to a stronger lowering of the LUMO (π*) energy than that of the HOMO (n) energy, induced by the replacement of the H-by F-atoms.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180532
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    Cycloadditionen des 1-(4-Methoxyphenyl)-2,2-dimethylvinyl-Kations an Olefine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2974-2992 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions of 1-(4-Methoxyphenyl)-2,2-dimethylvinyl Cation to Olefins1-Bromo-1-(4-methoxyphenyl)-2-methyl-1-propene (1) reacts with cyclohexene, cycloheptene, (Z)-cyclooctene and the silver salts AgBF4, via the vinyl cation 2 by cycloaddition to form the cyclobutenes 7b-d. Cyclobutene 8 is obtained from (Z)- and (E)- and (E)-2-butene. Besides the cyclobutene derivatives, the isomeric cyclopropane compound 10d is also formed in the reaction of 1 with (Z)-cyclooctene under the same conditions, with cyclopentene only the cyclopropane derivative is formed. Copper (I) triflate-olefin complexes can be used in place of silver slats to generate the vinyl cation 2, whereby cyclobutenes 7 are formed preferably. - In contrast to vinyl bromide 1, 1-(4-methoxyphenyl)-2-methyl-1-propenyl triflate (5) reacts with cyclopentene, cyclohexene, cyloheptene, (Z)- and (E)-cyclooctene to give mostly the corresponding cyclopropane derivatives 10. The stereoisomeric cyclopropyl compounds 19 are obtained from (Z)- and (E)-2-butene. - The mechanisms of silver-catalysed and silver-free cycloaddition reactions are discussed.
    Notes: 1-Brom-1-(4-methoxyphenyl)-2-methyl-1-propen (1) reagiert mit Cyclohexen, Cyclohepten, (Z)-Cycloocten und den Silbersalzen AgBF4 bzw. AgSbF6 über das Vinylkation 2 unter Cycloaddition überwiegend zu den Cyclobutenen 7b-d. Mit (Z)- und (E)-2- Buten wird das Cyclobuten 8 erhalten. Bei der Umsetzung von 1 unter den gleichen Bedingungen entsteht mit Cyclopenten das Cyclopropanderivat 10a, mit (Z)-Cycloocten entsteht neben dem Cyclobutenderivat 7d die isomere Cyclopropanverbindung 10d. An Stelle der Silbersalze können auch Kupfer(I)-triflat-Olefin-Komplexe zur Erzeugung des Vinylkations 2 verwendet werden, wobei ebenfalls bevorzugt die Cyclobutene 7 erhalten werden. - Im Gegensatz zum Vinylbromid 1 reagiert das 1-(4-Methoxyphenyl)-2-methyl-1-propenyl-triflat (5) mit Cyclopenten, Cyclohexen, Cyclohepten und (Z)- bzw. (E)-Cycloocten überwiegend zu den entsprechenden Cyclopropanderivaten 10. Mit (Z)- und (E)-2-Buten werden die stereoisomeren Cyclopropylverbindungen 19 erhalten. - Die Mechanismen der silbersalzkatalysierten und silberfreien Cycloadditionsreaktionen werden diskutiert.
    Additional Material: 3 Tab.
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    Basische Metalle, LVI Reaktionen von (Pentamethylcyclopentadienyl)rhodium(I)-Komplexen mit Dihalogen- und Trihalogenmethanen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3032-3040 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Basic Metals, LVI. Reactions of (Pentamethylcyclopentadienyl)rhodium(I) Complexes with Dihalo- and TrihalomethanesC5Me5Rh(CO)2 and C5Me5Rh(CO)L (L=PMe3, PMe2Ph, P(OMe)3) react with dihalo- and trihalomethanes to give (pentamethylcyclopentadienyl)rhodium complexes containing CH2X and CHX2 (X=Cl, Br, I, CN) as ligands. The reactions of [C5Me5RhCH2I(L)I] (L=CO, PMe3) with NaOCH3, PMe3, and PPh3 lead in some cases to substitution (e.g., formation of [C5Me5RhCH2OMe(PMe3)I] and [C5Me5Rh(CH2PPh3)(PMe3)I]X), in some cases to cleavage of the Rh - C bond. [C5Me5RhCH2I(CO)I] reacts with CH2(PPh2)2 to form the cyclic ylide complex [Ph2(I)]I.
    Notes: Durch Reaktion von C5Me5Rh(CO)2 und C5Me5Rh(CO)L (L=PMe3, PMe2Ph, P(OMe)3) mit Dihalogen- und Trihalogenmethanen werden (Pentamethylcyclopentadienyl)rhodium-Komplexe mit CH2X und CHX2 (X=Cl, Br, I, CN) als Liganden synthetisiert. Die Umsetzungen von [C5Me5RhCH2I(L)I] (L=CO, PMe3) mit NaOCH3, PMe3 und PPh3 verlaufen teilweise unter Substitution (Bildung z.B. von [C5Me5RhCH2OMe(PMe3)I] und [C5Me5Rh(CH2PPh3)(PMe3)I]X), teilweise aber auch unter Spaltung der Rh - C-Bindung. [C5Me5RhCH2I(CO)I] reagiert mit CH2(PPh2)2 zu dem cyclischen Yild-Komplex [Ph2(I)]I.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180804
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    Monoozonolysen von acyclischen konjugierten Dienen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3041-3057 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monoozonolyses of Acyclic Conjugated DienesMonoozonolyses of isoprene (1a), 2-methyl-3-phenyl-1,3-butadiene (1b), 2,3-diphenyl-1,3-butadiene (25), and 2,3,4,5-tetramethyl-2,4-hexadiene (34) have been examined in pentane and in methanol. The dienes 1a, b and 25 afforded all possible α,β-unsaturated monoozonides and α,β-unsaturated methoxy hydroperoxides, respectively, whereas diene 34 gave no ozonide and no α,β-unsaturated methoxy hydroperoxide. From the dienes 25 and 34, the corresponding monoepoxides have been formed additionally. The results allow some conclusions concerning the regioselectivity of ozone attack at the unsymmetrically substituted dienes 1a, b as well as concerning the cleavage directions of primary ozonides.
    Notes: Monoozonolysen von Isopren (1a), 2-Methyl-3-phenyl-1,3-butadien (1b), 2,3-Diphenyl-1,3-butadien (25) und 2,3,4,5-Tetramethyl-2,4-hexadien (34) in Pentan und in Methanol wurden untersucht. Die Diene 1a, b und 25 lieferten alle möglichen α,β-ungesättigten Monoozonide bzw. α,β-ungesättigten Methoxyhydroperoxide; das Dien 34 ergab kein Ozonid und kein α,β-ungesättigtes Methoxyhydroperoxid. Aus den Dienen 25 und 34 wurden zusätzlich auch die entsprechenden Monoepoxide erhalten. Die Ergebnisse erlauben Rückschlüsse auf die Regioselektivität des Ozonangriffes an den unsymmetrisch substituierten Dienen 1a, b sowie über die Spaltungsrichtungen von Primärozoniden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180805
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    Photolyse des 9-Azidotriptycens. - Struktur des Dimeren eines extrem gespannten Brückenkopfimins (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3058-3069 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photolysis of 9-Azidotriptycene. - Structure of the Dimer of a Severely Strained Bridgehead IminePhotolysis of 9-azidotriptycene (4) in cyclohexane affords molecular nitrogen and a dimer of the intermediate bridgehead imine 5 in 69% yield. The dimer is very sensitive towards traces of acid and irradiation in the presence of oxygen. The structure of the dimer is elucidated by spectroscopic methods as well as by an X-ray diffraction analysis. In solution approximately equal amounts of the (racemic) diastereomers 10 A and B are present which interconvert via an energy barrier of ΔG413≠ = ca. 90 kJ · mol-1. In contrast, in the crystalline state only diastereomer 10 A exists. The distereomer 10 A crystallizes as a racemate in the monoclinic space group P21/n (No. 14) with four molecules per cell. As the first step in the formation of 10 A, B we assume a dimerization of the bridgehead imine 5 producing 12 which rearranges to 10 A, B via a proton shift (→13) and subsequent opening of one of the 4H-azepine rings. The results are indicative of some diradical character of the bridgehead imine 5.
    Notes: Die Photolyse des 9-Azidotriptycens (4) in Cyclohexan ergibt neben Stickstoff mit 69% Ausbeute ein Dimeres des intermediären Brückenkopfimins 5. Das Dimere ist sehr empfindlich gegen Säurespuren und Belichten in Gegenwart von Luftsauerstoff. Die Struktur des Dimeren wird spektroskopisch und durch Röntgenbeugungsanalyse aufgeklärt. In Lösung liegen etwa gleiche Mengen der Diastereomeren 10 A und B vor, die sich mit ΔG413≠ =ca. 90 kJ · mol-1 ineinander umwandeln. Im Kristall existiert dagegen nur das Diastereomere 10 A, das als Racemat monoklin in der Raumgruppe P21/n (Nr. 14) mit vier Molekülen in der Elementarzelle kristallisiert. Als ersten Schritt der Bildung von 10 A, B nehmen wir eine Dimerisierung des Brückenkopfimins 5 zu 12 an, das sich durch Protonenwanderung (→13) und Öffnung eines 4H-Azepinrings in 10A, B umlagert. Die Ergebnisse sprechen für einen gewissen Diradikalcharakter des Brückenkopfimins 5.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180806
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    Über sterisch gehinderte freie Radikale, XII. Das Radikal tert-Butyldiphenylmethyl, sein Dimeres sowie deren Autoxidation. Eine Neuuntersuchung (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 450-456 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sterically Hindered Free Radicals, XII. The Radical tert-Butyldiphenylmethyl, Its Dimer, and Their Autoxidation. A ReinvestigationThe radical Ph2C.  -  tBu (1) dimerizes giving reversibly the quinonoid derivative 3, and not the ethane-like 2 as reported in the literature. In equilibrium there are less radicals 1 than in the case of triphenylmethyl, ΔHdiss = 18.5 ± 2 kcal/mol for 3. Both the radical 1 and its dimer 3 are rapidly oxidized by oxygen. 1 gives the dialkyl peroxide 6 which fragmentates already at 20°C mainly to benzophenone and tBu., 3 leads to the ketone 7, probably via the hydroperoxide 10. 3 rearranges catalysed by acid and by base as well via a 1,5-hydrogen migration forming the benzenoid derivative 4. Preparative and ESR details are given.
    Notes: Das Radikal Ph2C.  -  tBu (1) dimerisiert reversibel zum chinoiden Derivat 3 und nicht zum ethan-artigen 2, wie in der Literature berichtet. Im Gleichgewicht liegt weniger Radikal 1 vor als im Fall von Triphenylmethyl, ΔHDiss = 18.5 ± 2 kcal/mol für 3. Sowohl das Radikal 1 wie sein Dimeres 3 werden durch Sauerstoff rasch oxidiert. 1 gibt das Dialkylperoxid 6, das schon bei 20°C fragmentiert, hauptsächlich zu Benzophenon und tBu., 3 führt zum Keton 7, wahrscheinlich über das Hydroperoxid 10. 3 lagert sich, sowohl säure- wie basenkatalysiert, unter 1,5-H-Verschiebung um in das benzoide Derivat 4. Einzelheiten zu den Darstellungen sowie zur ESR-Spektroskopie werden angegeben.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180206
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    Beiträge zur Chemie des Bors, 146. Über die Reaktion von Tetrazadiborinanen mit Heterokumulenen: Pseudodipolare [2 + 3]-Cycloadditionen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 483-494 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 146 Reactions of Tetrazadiborinanes with Heterocumulenes: Pseudodipolar [2 + 3]-CycloadditionsCO2, COS, and CS2 scavenge the 1,3-dipolar unit \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R'}\mathop {{\rm B - }}\limits^ \oplus {\rm NR - }\mathop {\rm N}\limits^{\rm \Theta } {\rm R} $\end{document} from the tetrazadiborinanes 3. [2 + 3]-Cycloadducts are formed in a pseudodipolar reaction, namely oxadiaza- and thiadiazaborolidines of type 7, 8 and 4. A reaction mechanism is suggested.  -  The thiadiazaborolidine 4b contains a planar five-membered ring according to an X-ray structure determination. Short BN, NN, and CN bond distances suggest a heteroaromatic ring system. High polarity is associated with the thioxo group. In contrast, the oxadiazaborolidinones 8a, b are in an equilibrium with their dimers in solution.
    Notes: CO2, COS und CS2 fangen aus den Tetrazadiborinanen 3e) den 1,3-Dipol \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R'}\mathop {{\rm B - }}\limits^ \oplus {\rm NR - }\mathop {\rm N}\limits^{\rm \Theta } {\rm R} $\end{document} ab. In einer pseudodipolaren Reaktion bilden sich als [2 + 3]-Cycloaddukte die Oxadiaza- und Thiadiazaborolidine 7, 8 und 4. Ein Reaktionsmechanismus wird diskutiert.  -  Nach Röntgenstrukturanalyse enthält 4b einen planaren Fünfring. Kurze BN-, NN- und CN-Abstände legen ein heteroaromatisches System nahe, wobei der Thioxo-Gruppe eine erhebliche Polarität zuzuweisen ist. Die Oxadiazaborolidinone 8a, b stehen in Lösung im Gleichgewicht mit ihrem Dimeren.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180210
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    The colour of chelates of boron. An X-ray structural investigation of bis(4-methylphenyl)boryl and 9-borabicyclo-[3.3.1]nonyl acetylacetonates (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 670-675 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Farbe von Bor-Chelaten. Röntgenstruktur-Untersuchung von Bis(4-methylphenyl)boryl- und 9-Borabicyclo[3.3.1]nonyl-acetylacetonatenDie Molekülstrukturen des farblosen Bis(4-methylphenyl)boryl- und des orangefarbenen 9-Borabicyclo[3.3.1]non-9-yl-acetylacetonats (4 und 5) wurden durch Röntgenstrukturanalyse ermittelt. Die C—O-Abstände in 4 sind merklich (ca. 0.029 Å) länger als die in 5. Es wird vermutet, daß der unterschiedliche π-Charakter in den C—O-Bindungen die Verschiebungen im Elektronenspektrum der verschiedenen Chelate von 1,3-Diketonen und verwandten Verbindungen verursacht.
    Notes: The molecular structures of the colourless bis(4-methylphenyl)boryl and the orange coloured 9-borabicyclo[3.3.1]non-9-yl acetylacetonates (4 and 5, respectively) have been determined by X-ray analysis. The C—O bond lengths in 4 are significantly (about 0.029 Å) longer than in 5. It is suggested that variation of the π bond order in the C—O bonds is responsible for the shifts in the electronic spectra observed for the various chelates of 1,3-diketones and related compounds.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180226
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    2-Azaallenium salts from the reaction of 1-oxa-3-azabutatrienium salts with cyanamides and carbodiimides (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1887-1902 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung von 2-Azaallenium-Salzen durch Reaktionen von 1-Oxa-3-azabutatrienium-Salzen mit Cyanamiden und CarbodiimidenDie 1-Oxa-3-azabutatrienium-Salze 2 reagieren mit disubstituierten Cyanamiden unter [2 + 2 + 2]-Cycloaddition zu den 2-(Alkylidenamino)-4,6-diamino-1,3,5-oxadiazinium-Salzen 7a - o, die man als oxysubstituierte 2-Azaallenium-Salze betrachten kann. Durch Anlagerung von Methanol entstehen die Oxadiazinium-Salze 8a, d, p. Aus 2n und Dimethylcyanamid erhält man das 2-Azaallenium-Salze 11, dessen Bildung eine [1,5]-isocyanatotrope Umlagerung einschließt. Die Butatrienium-Salze 2 reagieren meist mit zwei Äquivalenten Carbodiimid vom Typ R1 — N = C = N — CHR22 zu den 2-Azaallenium-Salzen 17a - k, die durch eine [1,5]-Hydridverschiebung entstehen. Sterisch anspruchsvoll substituierte Butatrienium-Salze 2 lagern drei Moleküle Diisopropylcarbodiimid and und ergeben die 1,3,5-Triazinium-Salze 20n, o. Es werden Röntgenstruktur-analysen der Verbindungen 7a und 17a angegeben.
    Notes: 1-Oxa-3-azabutatrienium salts 2 react with disubstituted cyanamides under [2 + 2 + 2] cycloaddition affording the 2-(alkylideneamino)-4,6-diamino-1,3,5-oxadiazinium salts 7a - o, which can be regarded as oxy-substituted 2-azaallenium salts. Addition of methanol leads to the oxadiazinium salts 8a, d, p. From 2n and dimethylcyanamide the 2-azaallenium salt 11 was obtained, which must be formed by an [1,5] isocyanatotropic rearrangement. Most butatrienium salts 2 react with two equivalents of carbodiimides R1 — N = C = N — CHR22 to form the 2-azaallenium salts 17a - k. The reaction mechanism includes an [1,5] hydride shift. Bulky substituted butatrienium salts 2 add three molecules of diisopropylcarbodiimide to give the 1,3,5-triazinium salts 20n, o. X-Ray structural analyses for 7a and 17a are reported.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180514
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    Iminokohlenstoff-Dianionen der C4-Reihe mit Cyaniminofunktionen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1903-1916 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iminocarbon Dianions of the C4-Series with Cyanoimino GroupsSuitable activated squaric acid derivatives react with the anion of cyanamide to yield novel iminocarbon dianions of the C4-series 8 - 11, in which the oxygens of the squarate dianion are successively replaced by one, two, three, or four cyanoimino groups. Besides the synthesis of mixed substituted iminocaron monoanions such as 12, 13, 25, and 26 is described. Spectroscopic data are discussed, 13C NMR data are compared with those of other pseudooxocarbons of the C3- and C4-series. The structure of the first isolable C4-iminocarbon 11′ is proved by X-ray diffraction, which confirmed 11′ to be a delocalized bond system just like the squarate dianion or the other pseudooxocarbons of the C4-series.
    Notes: Geeignet aktivierte Quadratsäurederivate lassen sich mit dem Anion des Cyanamids zu neuen Iminokohlenstoff-Dianionen der C4-Reihe 8 - 11 umsetzen, in denen die Sauerstoffunktionen des Quadratats sukzessive durch ein, zwei, drei oder vier Cyaniminogruppen ersetzt sind. Daneben wird die Darstellung gemischt substituierter Iminokohlenstoff-Monoanionen wie 12, 13, 25 und 26 beschrieben. Spektroskopische Daten werden diskutiert, 13C-NMR-Daten mit denen anderer Pseudooxokohlenstoffe der C3- und C4-Serie verglichen. Die Konstitution des ersten isolierbaren C4-Iminokohlenstoffs 11′ wird durch eine Röntgenstrukturanalyse belegt, die bestätigt, daß 11′ analog dem Quadratat und den anderen Pseudooxokohlenstoffen der C4-Reihe ein delokalisiertes Bindungssystem besitzt.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180515
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  • 80
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    Anisotropieeffekte konjugierter cyclischer Systeme, VI. Struktur und magnetische Anisotropie mesitylsubstituierter Ferrocene (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1968-1982 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anisotropy Effects of Conjugated Cyclic Systems, VI. Structure and Magnetic Anisotropy of Mesityl-substituted FerrocenesTwo isomeric ferrocene derivatives have been obtained from 2-(2-ethyl-4,6-dimethylphenyl)-1,3-dimethylcyclopentadiene (22a). The exo,exo- (9) as well as the endo,endo-configuration (10) of these were determined by X-ray structure analysis. The assignment of the 1H NMR signals of the methyl groups in the spectrum of 1,1′,3,3′-tetramethyl-2,2′-dimesitylferrocene (7) is derived from the spectra of 9 and 10. Signals of methyl groups in exo-position of the mesitylferrocene are shifted by -0.74 ppm to higher magnetic field. Signals of methyl groups in endo-position directed towards the iron atom are shifted downfield by +0.71 ppm. Therefore, ferrocene develops a diamagnetic anisotropy which is similar to that of benzene.
    Notes: Aus 2-(2-Ethyl-4,6-dimethylphenyl)-1,3-dimethylcyclopentadien (22a) werden zwei isomere Ferrocenderivate erhalten. Durch Röntgenstrukturanalysen wird deren exo,exo-(9) bzw. endo,endo-Konfiguration (10) bestimmt. Anhand der 1H-NMR-Spektren dieser Ferrocene ist die Zuordnung der Methylgruppensignale im 1H-NMR-Spektrum des 1,1′,3,3′-Tetramethyl-2,2′-dimesitylferrocens (7) bewiesen. Signale von Methylgruppen in exo-Stellung des Mesitylferrocens werden um -0.74 ppm nach hohem Magnetfeld und solche von zum Eisenatom gerichteten in endo-Stellung um +0.71 ppm nach tiefem Feld verschoben. Daraus leitet sich für Ferrocen eine dem Benzol ähnliche diamagnetische Anisotropieverteilung ab.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180521
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  • 81
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    Synthese und Struktur von Lithiumkomplexen mit pentahapto-gebundenen Tris(trimethylsilyl)cyclopentadienyl-Liganden (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1959-1967 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Lithium Complexes with pentahapto-Bonded Tris(trimethylsilyl)cyclo-pentadienyl LigandsReaction of tris(trimethylsilyl)cyclopentadienyllithium (2) with the nitrogen bases quinuclidine, tetramethylethylenediamine, and pentamethyldiethylenetriamine leads to the isolation of the crystalline, air-sensitive 1:1-adducts 3, 4, and 5, resp., which are monomeric in the gas phase, in solution, and in the solid state. X-Ray structure determinations show that in 3-5 the cyclopentadienyl ring is pentahapto-bonded to the lithium atom. The bonding in these π-complexes is discussed; the complex 3 fulfills the criteria for a nido-cluster.
    Notes: Umsetzung von Tris(trimethylsilyl)cyclopentadienyllithium (2) mit den Stickstoffbasen Chinuclidin, Tetramethylethylendiamin und Pentamethyldiethylentriamin führt zur Isolierung der kristallinen, luftempfindlichen 1:1-Addukte 3, 4 und 5, die in der Gasphase, in Lösung und im festen Zustand monomer vorliegen. Kristallstrukturuntersuchungen zeigen, daß in 3-5 der Cyclopentadienylring pentahapto an das Lithiumatom gebunden ist. Die Bindungsverhältnisse in diesen π-Komplexen werden diskutiert; der Komplex 3 erfüllt die Kriterien für einen nido-Cluster.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180520
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  • 82
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    Selektive Reduktion von Cyclohexadienonen mit Fe2(CO)9 und Wasser (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1983-1995 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Selective Reduction of Cyclohexadienones with Fe2(CO)9 and waterSelective monohydrogenation of cross conjugated 2,5-cyclohexadien-1-ones 1 with Fe2(CO)9 and water forming under unusually mild conditions the cyclohexadienol complexes 2 is applied to various related compounds. The regioselectivity of this reaction is tested with differently substituted derivatives. A mechanism explaining the observed regioselectivities and the pH dependence of the stereochemistry is discussed.
    Notes: Die unter ungewöhnlich milden Bedingungen verlaufende selektive Monohydrierung gekreuzt konjugierter 2,5-Cyclohexadien-1-one 1 mit Fe2(CO)9 und Wasser zu den Cyclohexadienol-Komplexen 2 wird auf verschiedene verwandte Verbindungen übertragen. Die Regioselektivität der Reaktion wird an unterschiedlich substituierten Derivaten geprüft. Es wird ein Mechanismus diskutiert, der die beobachteten Regioselektivitäten und die pH-Abhängigkeit der Stereochemie erklärt.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180522
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  • 83
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    Synthese mittlerer und großer Ringe, X. (+)- und (-)-[6]Paracyclophan-8-carbonsäure aus (+)- und (-)-3,6-Hexanooxepin-4-carbonsäure (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1996-2010 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Medium and Large Rings, X. (+)- and (-)-[6]Paracyclophane-8-carboxylic Acid from (+)- and (-)-3,6-Hexanooxepin-4-carboxylic AcidThe racemic 3,6-hexanooxepin-4-carboxylic acid ((±)-2d), available in five steps from cyclooctyne and 3-(acetoxymethyl)furan, can be resolved into the enantiomers (+)- and (-)-2d using (+)(R)-1-(1-naphthyl)ethylamine. A stereospecific synthesis of (+)- and (-)-[6]paracyclophane-8-carboxylic acid ((+)- and (-)-4b) is possible from (+)- and (-)-2d as starting materials. Key steps of this synthesis are the transannular addition of bromine to give (-)- and (+)-3a and a subsequent McMurry reaction. The problems involved in the interpretation of the CD-spectra of the oxepin ester (+)-2e and of (+)-4b are discussed in detail.
    Notes: Die aus Cyclooctin und 3-(Acetoxymethyl)furan in fünf Stufen erhältliche racemische 3,6-Hexanooxepin-4-carbonsäure ((±)-2d) kann mit (+)(R)-1-(1-Naphthyl)ethylamin in die Enantiomeren (+)- und (-)-2d gespalten werden. Ausgehend von (+)- und (-)-2d ist eine stereospezifische Synthese von (+)- und (-)-[6]Paracyclophan-8-carbonsäure ((+)- und (-)-4b) möglich. Schlüsselschritte sind dabei die transannulare Bromaddition zu (-)- und (+)-3a und eine anschließende McMurry-Reaktion. Die Probleme der Interpretation der CD-Spektren des Oxepinesters (+)-2e und der Phancarbonsäure (+)-4b werden eingehend diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180523
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  • 84
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    Beiträge zur Chemie des Bors, 152. 1,3,2,4-Diazaphosphaboretidine und 1,3,2,4-Diazasilaboretidine durch intra- und intermolekulare Cyclokondensation (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2030-2043 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 152. 1,3,2,4-Diazaphosphaboretidines and 1,3,2,4-Diazasilaboretidines Prepared via Intra- and Intermolecular Cyclocondensation1,3,2,4-Diazaphospha(sila)boretidines 5 and 9 are accessible via thermal decomposition of compounds of type E(NR′—BR2)2 (8) or from organoboron dihalides or boron trihalides and E(NR′Li)2 [E = Si(CH3)2, CH3(O)P, R(S)P, CH3P]. The formation of 1,3-di-tert-butyl-4-methyl-(or ethyl)-1,3,2,4-diazaphospha(sila)boretidines from the precursor E(NR′—BR2)2 proceeds by an intramolecular cyclocondensation. NMR data reveal less shielded B and P atoms in the new heterocycles as compared with noncyclic compounds; this is attributed to a strained ring system. A tetracoordinated as well as a tricoordinated boron atom is observed in CH3(O)P(NR′BR2)2 compounds resulting from intramolecular BO coordination.
    Notes: 1,3,2,4-Diazaphospha(sila)boretidine 5 und 9 sind über die thermische Zersetzung von Verbindungen des Typs E(NR′-BR2)2 (8) oder durch Umsetzung von Organylbordihalogeniden bzw. Bortrihalogeniden mit N-Lithio-Verbindungen E(NR′Li)2 [E = Si(CH3)2, CH3(O)P, R(S)P, CH3P] zugänglich. Es wird gezeigt, daß die 1,3-Di-tert-butyl-4-methyl-bzw. -4-ethyl-1,3,2,4-diazaphospha(sila)boretidine aus der Vorstufe E(NR′-BR2)2 durch eine intramolekulare Cyclokondensation entstehen. Nach NMR-Daten sind die Bor- und Phosphor-Kerne in den Vierring-Heterocyclen als Folge der Ringspannung schlechter abgeschirmt als in nichtcyclischen Derivaten. Vierfach koordiniertes Bor liegt neben dreifach koordiniertem in den Verbindungen CH3(O)P-(NR′BR2)2 vor. Dies geht auf intramolekulare BO-Koordination zurück.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180526
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  • 85
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    Synthese von 4-Oxo-4H-benzothiazolo[3,2-a]pyrimidin-1-ium-2-olaten und ihre Cycloadditionen an elektronenarme und elektronenreiche Alkine sowie an o-Chloranil (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2079-2094 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 4-Oxo-4H-benzothiazolo[3,2-a]pyrimidin-1-ium-2-olates and their Cycloaddition Reactions to Electron-poor and Electron-rich Alkynes as well as to o-ChloranilThe synthesis and physical properties of the title compounds 3a - d, prepared from 1 and bis(2,4,6-trichlorophenyl) malonates 2a - d, are described. As cyclic 1,4-dipoles, the betaines 3 combine with dimethyl acetylenedicarboxylate, dibenzoylethyne or bis(diethylamino)ethyne with formation of primary adducts of type 4, which release methyl isocyanate to give pyrido[2,1-b]-benzothiazole derivatives 5a - g, whereas the reaction of 3a with bis(diethylamino)ethyne yields the betaine 7. With unsymmetrically substituted alkynes like methyl propiolate or 1-(diethyl-amino)propyne, 3 reacts with regiospecific formation of 8a - f. On the other hand, the reaction of 3a with o-chloranil proceeds with regiospecific formation of the 1,4-benzodioxin derivative 11. In the case of 8, the observed regiospecificities are in agreement with the results of MNDO calculations and MO-perturbation theory.
    Notes: Die Synthese und physikalischen Eigenschaften der Titelverbindungen 3a - d aus 1 und Malonsäure-bis(2,4,6-trichlorphenylestern) 2a - d werden beschrieben. Als cyclische 1,4-Dipole vereinigen sich die Betaine 3 mit Acetylendicarbonsäure-dimethylester, Dibenzoylethin oder Bis(diethyl-amino)ethin zu Primäraddukten vom Typ 4, die unter Methylisocyanat-Abspaltung Pyrido-[2,1-b]benzothiazol-Derivate 5a - g liefern, während 3a mit Bis(diethylamino)ethin das Betain 7 ergibt. Mit unsymmetrisch substituierten Alkinen, wie Propiolsäure-methylester oder 1-(Diethyl-amino)propin, reagiert 3 regiospezifisch zu 8a - f. Andererseits führt die Umsetzung von 3a mit o-Chloranil regiospezifisch zu dem 1,4-Benzodioxin-Derivat 11. Die bei 8 beobachteten Regiospezifitäten sind mit den Ergebnissen aus MNDO-Rechnungen und der MO-Störungstheorie in Einklang.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180528
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  • 86
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    Thermolabile Hydrocarbons, XXVII. 2,3-Di-1-adamantyl-2,3-dimethylbutane; Long Bonds and Low Thermal Stability (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 4665-4673 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermolabile Kohlenwasserstoffe, XXVII. 2,3-Di-1-adamantyl-2,3-dimethylbutan; lange Bindungen und geringe thermische StabilitätDie Titelverbindung 2 wurde durch Wurtz-Synthese dargestellt und eine Kristallstrukturanalyse durchgeführt. Die Strukturdaten des sehr stark deformierten Molekülgerüstes - drei benachbarte CqCq-Bindungen sind länger als 164 pm, CqCqCq-Bindungswinkel sind bis 118° aufgeweitet - werden durch Rechnungen mit dem MM 2-Kraftfeld sehr gut wiedergegeben. Nach den Kraftfeldrechnungen ist 2 der am stärksten gespannte, nach kinetischen Messungen der thermisch labilste Vertreter der bereits früher bearbeiteten CqCq-Alkane.
    Notes: The title compound 2 was prepared by a Wurtz procedure. Its highly deformed structure was determined by X-ray analysis and matched with high precision by MM 2 force field calculations. The three neighbouring CqCq bonds are longer than 164 pm and the CqCqCq bond angles are 118°. According to MM 2 calculations and a kinetic investigation 2 is the most strained and least stable member of the CqCq alkane series investigated previously2).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851181203
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  • 87
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    Vitamin-Synthese mit Carben-Komplexen, VI. Stereospezifische Darstellung von Pentacarbonyl[(Z)-dimethoxy-vinyl]carben-Komplexen des Chroms und Wolframs (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1126-1132 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vitamin Syntheses via Carbene Complexes, VI. Stereospecific Synthesis of Pentacarbonyl[(Z)-dimethoxyvinyl]carbene Complexes of Chromium and TungstenThe addition of (E,Z)-1-lithio-1,2-dimethoxyethene (1) to hexacarbonylchromium and -tungsten followed by protonation or alkylation, respectively, provides a stereospecific route to pentacabonyl[(Z)-1,2-dimethoxyvinyl]carbene complexes 2-5. Established by X-ray analysis, the carbene ligand of the methoxycarbene chromium complex 3 is nearly coplanar.
    Notes: Die Addition von (E,Z)-1-Lithio-1,2-dimethoxyethen (1) an Hexacarbonylchrom und -wolfram liefert nach Protonierung bzw. Alkylierung stereospezifisch die Pentacarbonyl[(Z)-1,2-dimeth-oxyvinyl]carben-Komplexe 2-5. Nach der Röntgenstrukturanalyse des (Methoxycarben)chrom-Komplexes 3 ist der gesamte Carbenligand annähernd koplanar.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180329
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    Zwei neue Metallcarbonyle: Darstellung und Struktur von RuCo2(CO)11 und Ru2Co2(CO)13 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1133-1142 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Two New Metal Carbonyls: Preparation and Structure of RuCo2(CO)11 and Ru2Co2(CO)13RuCo2(CO)11 (1) results from the stoichiometric and heterogeneous reaction between KCo(CO)4 and [Ru(CO)3Cl2]2 in water. Its decomposition in hexane at 65°C yields Ru2Co2(CO)13 (2). The crystallographically determined molecular structures of both compounds show that their metal atom cores are located inside approximately regular ligand polyhedra.
    Notes: RuCo2(CO)11 (1) entsteht durch stöchiometrische heterogene Umsetzung von KCo(CO)4 und [Ru(CO)3Cl2]2 in Wasser. Seine Zersetzung bei 65°C in Hexan liefert Ru2Co2(CO)13 (2). Die kristallographisch bestimmten Molekülstrukturen beider Verbindungen lassen erkennen, daß ihre Metallatom-Kerne sich in annähernd regelmäßigen Ligandenpolyedern befinden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180330
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  • 89
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    Synthese und Struktur eines hochsubstituierten Tetracyclo[3.3.0.02,8.04,6]octans (Nortriasteran) (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1176-1182 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of a Highly Substituted Tetracyclo[3.3.0.02,8.04,6]octane (Nortriasterane)The 4,8-dibromobicyclo[3.3.0]octa-2,6-diene-2,6-dicarbonitrile 2 reacts with sodium methoxide in methanol quantitatively and with complete stereoselectivity to afford the nortriasteranedicarbonitrile 5. This dinitrile crystallizes triclinically in the space group P1 with two enantiomorphous molecules per cell. Some geometric parameters involving the cyclopropane rings and the mechanism of formation of 5 are discussed.
    Notes: Das 4,8-Dibrombicyclo[3.3.0]octa-2,6-dien-2,6-dicarbonitril 2 reagiert mit Natriummethanolat in Methanol quantitativ und vollständig stereoselektiv zum Nortriasterandicarbonitril 5. Dieses kristallisiert triklin in der Raumgruppe P1 mit zwei enantiomorphen Molekülen in der Elementarzelle. Einige geometrische Parameter der Cyclopropanringe und der Bildungsmechanismus von 5 werden diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180333
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  • 90
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    Umsetzung organischer Thiocyanate, Selenocyanate und Cyanate mit Malonylchlorid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1371-1382 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Organic Thiocyanates, Selenocyanates, and Cyanates with Malonyl ChlorideOrganic thiocyanates and selenocyanates react with malonyl chloride to form the pyrano-oxazinediones 1a, b and 2 a, b. Compound 4 is obtained in the case of phenacyl thiocyanate. With the exception of compound 6, nucleophilic substitution of the bromine atom in compound 1 a is not possible. Excess n-propylamine leads to 7, while reaction in acidic medium gives 5. The reaction product of malonyl chloride and aromatic cyanates is strongly dependent on the reaction conditions. At temperatures up to + 20°C, β-lactams 8a - g and hydrolysis products 9 a - e, respectively, are formed. At 30 - 70°C substances 11a, d - f, at 60 - 90°C cyclization products 10a, d - g, and at temperatures of approx. 120°C decarboxylation products 12a, b, d are formed. An X-ray structural analysis is made of 9b.
    Notes: Organische Thio- und Selenocyanate reagieren mit Malonylchlorid zu den Pyrano-oxazindionen 1a, b und 2a, b; im Falle von Phenacylthiocyanat entsteht 4. Nucleophile Substitution des Bromatoms in 1a ist außer zu Verbindung 6 nicht möglich, ein Überschuß an n-Propylamin führt zu 7, während Umsetzung in saurem Medium 5 ergibt. Das Reaktionsprodukt von Malonylchlorid und aromatischen Cyanaten ist stark abhängig von den Reaktionsbedingungen - bei Temperaturen bis + 20°C entstehen die β-Lactame 8a-g bzw. die Hydrolyseprodukte 9a-e, bei 30 - 70°C die Substanzen 11a,d - f, bei 60 - 90°C die Cyclisierungsprodukte 10a, d - g und bei Temperaturen von ca. 120°C die Decarboxylierungsprodukte 12a, b, d. Von 9b wird eine Röntgenstruktur-analyse durchgeführt.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180408
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    Darstellung und Eigenschaften neuer perhalogenierter 1,3-Dithietan-S-oxide, Thiirane und Sulfine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1415-1420 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of New Perhalogenated 1,3-Dithietane S-Oxides, Thiiranes, and SulfinesThe series of new tetrabromo-1,3-dithietane S-oxides 2, 3, 6, and 7 were synthesized, and the dibromosulfine 4 could be obtained from the 1,3-dioxide 3. The oxidation of 1,3-dithietane-2-one 12 yields dichlorosulfine 8, whereas 14, gives no difluorosulfine. From the hitherto unknown 2,2,4-trichloro-4-fluoro-1,3-dithietane (21) the 4-chloro-4-fluoro-1,3-dithietane-2-one (22) was prepared as a potential sulfine precursor. A convenient synthesis of tetrachlorothiirane (16) from tetrachloro-1,3-dithietane 1,1-dioxide (13) by thermolysis is reported.
    Notes: Die Reihe neuer Tetrabrom-1,3-dithietan-S-oxide 2, 3, 6 und 7 wurden synthetisiert, und, ausgehend vom 1,3-Dioxid 3, konnte das Dibromsulfin 4 erhalten werden. Die Oxidation des 1,3-Dithietan-2-ons 12 ergab Dichlorsulfin 8, die von 14 jedoch nicht das Difluorsulfin. Ausgehend vom bisher unbekannten 2,2,4-Trichlor-4-fluor-1,3-dithietan (21) wurde das 4-Chlor-4-flour-1,3-dithietan-2-on (22) als potentielles Sulfin-Vorprodukt dargestellt. Eine günstige Synthesemethode für Tetrachlorthiiran (16) aus Tetrachlor-1,3-dithietan-1,1-dioxid (13) durch Thermolyse wird beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180411
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    Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, XLII. Die P = S-Gruppe als Baustein in der heteroanalogen Alkin-Cyclocotrimerisierung (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1398-1414 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of, and Reactions with, Metal-Containing Heterocycles, XLII The P = S Group as a Building Block in the Heteroanalogous Alkyne CyclocotrimerizationThe S isomeric complexes LnFe(CO)(I) - SPHR½ (3 a - e) [R1 = CH3 (a), C2H5 (b), n-C3H7, (c) t-C4H9 (d), c-C6H11 (e)] are obtained by substitution of CO in LnFe(CO)2I (1) [LnFe = (n-C3F7)-Fe(CO)2] by the phosphane sulfides SPHR1/2 (2a - e). Base supported HI elimination from 3a, b results in the formation of the η2-thiophosphinito complexes (4a, b) which can be regarded as starting points of the P = S heteroanalogues alkyne trimerization. 4b reacts with the electrophilic alkynes 5x - z to give the ferracyclopentadienes (6 bx - z) [R2 = CO2C2H5 (x), CO2CH(CH3)2 (y, CO2C6H11 (z)]. Towards alkynes 6 bx - z behave kinetically labile and are transformed with 5x - z to the bicyclic compounds 7 bx - z under CO separation. According to X-ray structural determinations, 3a, 4 b, und 6 bz crystallize in the monoclinic and triclinic space groups P21/n (3a), C2/c (4b), and P1 (6 bz) with Z = 4, 8, and 2, respectively.
    Notes: Bei der Substitution von CO in LnFe(CO)2I (1) [LnFe = (n-C3F7Fe(CO)2] durch die Phosphansulfide SPHR1/2 (2a - e) [R1 = CH3 (a), C2H5 (b), n-C3H7 (c), t-C4H9 (d), c-C6H11 (e)] erhält man die S-isomeren Komplexe LnFe(CO)(I) - SPHR1/2 (3a - e). Basenunterstützte HI-Eliminierung liefert aus 3a, b die η2-Thiophosphinito-Komplexe (4a, b), welche als Ausgangspunkte der P = S-heteroanalogen Alkintrimerisierung anzusehen sind. Mit den elektrophilen Alkinen 5x - z reagiert 4b zu den Ferracyclopentadienen (6bx - z) [R2 = CO2C2H5 (x), CO2CH(CH3)2 (y), CO2C6H11 (z)]. Diese verhalten sich gegenüber Alkinen kinetisch labil und gehen mit 5x - z unter CO-Abspaltung in die bicyclischen Verbindungen 7 bx - z über. Aufgrund von Röntgenstrukturanalysen kristallisieren 3a, 4 b und 6 bz in den monoklinen bzw. triklinen Raumgruppen P21/n (3 a), C2/c (4b) bzw. P1 (6 bz) mit Z = 4, 8 bzw. 2.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180410
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    Chemoselective addition of organotitanium reagents to carbonyl compounds (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1421-1440 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemoselektive Addition von Organotitan-Agenzien an Carbonyl-VerbindungenDie Überführung von klassischen Carbanionen wie RMgX, RLi oder deprotonierten Nitrilen, Sulfonen oder Carbonsäureestern in Titan-Analoga ergibt Agenzien, die in Gegenwart von anderen funktionellen Gruppen chemoselektiv an Carbonylverbindungen addieren. Das Standard-Titanierungsagens ist Chlortriisopropoxytitan (1). Grignard-artige Reaktionen sowie Aldoladditionen sind aldehyd-selektiv in Gegenwart von Ketonen. Andere funktionelle Gruppen wie Alkyl- und Arylhalogenide, Ester, Amide sowie Nitro- und Cyanreste werden toleriert. Die Unterscheidung zwischen zwei Aldehyden oder zwei Ketonen ist ebenfalls möglich. Der Ersatz von Alkoxyliganden durch Methylgruppen hat eine drastische Erhöhung der Reaktivität zur Folge, d.h. die relativen Geschwindigkeiten nehmen in folgender Serie zu: CH3Ti(OCHMe2)3 〈 (CH3)2Ti-(OCHMe2)2 〈 (CH3)4Ti. Das letztere Agens sowie das Zirkon-Analogon methylieren sterisch gehinderte und/oder enolisierbare Ketone, die normalerweise keine Grignard-Reaktionen eingehen. Der At-Komplex H2C = CHCH2Ti(OCHMe2)4 MgCl (63) ist aldehyd-selektiv, während die entsprechende Aminoverbindung H2C =CHCH2Ti(NMe2)4MgCl (64) selektiv mit Ketonen in Gegenwart von Aldehyden reagiert.
    Notes: The conversion of classical carbanions such as RMgX, RLi, or deprotonated nitriles, sulfones, and carboxylic esters into titanium analogs results which add chemoselectively to carbonyl compounds in the presence of other functional groups. The standard titanating agent is chlorotrisopropoxytitanium (1). Grignard-type reactions and aldol additions are aldehyde-selective in the presence of ketones. Other functional groups such as alkyl and aryl halides, esters, amides as well as nitro and cyano moieties are tolerated. Discrimination between two aldehydes or two ketones is also possible. Replacing alkoxy ligands by methyl groups at titanium increases reactivity dramatically, relatives rates increasing in the series CH3Ti(OCHMe2)3 〈 (CH3)2Ti-(OCHMe2)2 〈 (CH3)4Ti. The latter reagent and its zirconium analog methylate sterically hindered and/or enolizable ketones which normally fail to undergo Grignard reactions. The ate complex H2C = CHCH2Ti(OCHMe2)4MgCl (63) is aldehyde-selective, while the amino analog H2C = CHCH2Ti(NMe2)4MgCl (64) adds selectively to ketones in the presence of aldehydes.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180412
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    (Trifluormethylthioamino)borane, IV. Darstellung und Eigenschaften von [(CF3S)2N]nBX3-n mit n = 3; n = 2, X = Cl, Br, N3 und n = 1, X = N3 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1463-1475 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Trifluoromethylthioamino)boranes, IV. Preparation and Properties of [(CF3S)2N]nBX3-n with n = 3; n = 2, X = Cl, Br, N3, and n = 1, X = N3Hg[N(SCF3)2]2 (4a) reacts with BBr3, B(SCF3)3, and BCl3 to give B[N(SCF3)2]3 (1) in decreasing yields. The thermal stable 1 is a very weak Lewis acid and sensitive to hydrolysis. 4a or (CH3)3-SiN3 react with (CF3S)2NBX2 to form [(CF3S)2N]2BX (X = Cl, Br, 2a, b) and (CF3S)2NB(N3)2 (3c), respectively, in good yields. Similarly 2a, b and (CH3)3SiN3 give [(CF3S)2N]2BN3 (2c). Reactions of [(CF3S)2N]nEn [E = Hg, n = 2; (CH3)3Sn, (CH3)3Si, CF3S, n = 1, 4a-d] with BX3′ (X′ = F, Cl, Br, SCF3) were investigated with regard to multiple substitution at the boron atom. Empirical evaluated relative reactivities of element-nitrogen bonds and substitution series for reactions of boron compounds with HgII compounds are presented. Spectroscopical data of the newly prepared substances are discussed.
    Notes: Umsetzungen von Hg[N(SCF3)2]2 (4a) mit BBr3, B(SCF3)3 und BCl3 führen in abnehmenden Ausbeuten zu B[N(SCF3)2]3 (1). Das thermisch stabile 1 ist eine sehr schwache Lewis-Säure und hydrolyseempfindlich. Setzt man 4a bzw. (CH3)3SiN3 mit (CF3S)2NBX2 um, so erhält man [(CF3S)2N]2BX (X = Cl, Br, 2a, b) bzw. (CF3S)2NB(N3)2 (3c). Aus 2a, b und (CH3)3SiN3 erhält man [(CF3S)2N]2BN3 (2c). Reaktionen von [(CF3S)2N]nEn [E = Hg, n = 2; (CH3)3Sn, (CH3)3Si und CF3S, n = 1, 4a-d] mit BX3′ (X′ = F, Cl, Br, SCF3) werden im Hinblick auf eine Mehrfach-Substitution am Bor untersucht. Empirisch ermittelte relative Reaktivitäten der Element-Stickstoffbindung und Substitutionsreihen von Borverbindungen bezüglich HgII-Verbindungen werden angegeben. Spektroskopische Daten der neu hergestellten Verbindungen werden diskutiert.
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    URL: http://dx.doi.org/10.1002/cber.19851180415
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    Stereoselective Addition of Organotitanium Reagents to Carbonyl Compounds (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1441-1454 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselektive Addition von Organotitan-Agenzien an Carbonyl-VerbindungenTitanierung von Alkyllithium- oder -magnesium-Verbindungen mittels ClTi(OR)3 ergibt Reagenzien, die eine deutlich erhöhte Diastereoselektivität (80-90%) bei Reaktionen mit α-chiralen Aldehyden oder Ketonen zeigen. Titanierung ist auch die Methode der Wahl im Falle von Grignardartigen Additionen an substituierte Cyclohexanone; CH3Ti(OCHMe2)3 (6a) greift bevorzugt von der äquatorialen Seite an, während die Allyltitan-Reagenzien 11b und 12 hauptsächlich axialen Angriff eingehen. Crotyltitan-Agenzien reagieren mit Carbonyl-Verbindungen unter bevorzugter Bildung von Addukten mit der anti-Konfiguration, eine besonders wertvolle Reaktion im Falle von Ketonen (anti/syn-Verhältnisse bis zu 99:1). Titanierung von (Trimethylsilyl)allyllithium (48) mit Ti(OCHMe2)4 kehrt die Regioselektivität bei Additionen an Aldehyde und Ketone um, denn die einzigen Produkte sind β-Hydroxysilane 50. Sie haben die anti-Konfiguration und können mit Hilfe der Peterson-Eliminierung unter basischen bzw. sauren Bedingungen in Z- oder E-Diene übergeführt werden.
    Notes: Titanation of alkyllithium or -magnesium compounds using ClTi(OR)3 results in reagents which show markedly increased diastereofacial selectivity (80-90%) in reactions with α-chiral aldehydes or ketones. Titanation is also the method of choice in Grignard-type additions to substituted cyclohexanones; CH3Ti(OCHMe2)3 (6a) adds predominantly from the equatorial direction, while allyltitanium reagents 11b and 12 show axial preference. Crotyltitanium compounds react with carbonyl compounds to afford primarily adducts having anti-configuration, a process which is of particular value in case of ketones (anti/syn ratios up to 99:1). Titanation of (trimethylsilyl)allyllithium (48) with Ti(OCHMe2)4 reverses regioselectivity in reactions with aldehydes and ketones, β-hydroxy silanes 50 being the only observed products. These have anti-configuration and can be converted either into Z- or E-dienes using the Peterson elimination under basic or acidic conditions, respectively.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180413
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  • 96
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    Chalkogen-Addukte des Bis(di-tert-butylphosphino)schwefeldiimids - Festkörperstruktur von Bis[di-tert-butyl(thiophosphinyl)]- und Bis[di-tert-butyl(selenophosphinyl)]schwefeldiimid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1476-1484 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Adducts of Chalcogens with Bis(di-tert-butylphosphino)sulfur Diimide - Solid State Structures of Bis[di-tert-butyl(thiophosphinyl)]- and Bis[di-tert-butyl(selenophosphinyl)]sulfur DiimideBis(di-tert-butylphosphino)sulfur diimide, S(N — PtBu2)2 (1), adds sulfur and selenium at both phosphorus atoms to give the new chalcophosphinyl-substituted sulfur diimides S[N — P(Y)tBu2]2 (Y = S (2a), Se (2b)). According to the single-crystal X-ray structure analyses, 2a and 2b are present in the unsymmetrical Z/E-configuration in the solid state. However, the 31P NMR spectra give no indication of non-equivalence of the two phosphorus substituents in solution.
    Notes: Bis(di-tert-butylphosphino)schwefeldiimid, S(N — PtBu2)2 (1), addiert Schwefel und Selen an beide Phosphoratome unter Bildung der neuen Chalkophosphinyl-substituierten Schwefeldiimide S[N — P(Y)tBu2]2 (Y = S (2a), Se (2b)). Nach den Einkristall-Röntgenstrukturanalysen liegen 2a und 2b im Festkörper in der unsymmetrischen Z/E-Konfiguration vor. Dagegen geben die 31P-NMR-Spektren keinen Hinweis auf eine Nichtäquivalenz der beiden Phosphorsubstituenten in Lösung.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180416
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  • 97
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    Chirale Induktion bei photochemischen Reaktionen, II. Regio- und Diastereoselektivität bei der Oxetanbildung chiraler Phenylglyoxylate mit elektronenreichen Olefinen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1485-1503 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chiral Induction in Photochemical Reactions, II. Regio- and Diastereoselectivity in the Oxetane Formation of Chiral Phenylglyoxylates with Electron Rich OlefinsIn the photochemical oxetane formation of chiral phenylglyoxylates with 3 high diastereoselectivities and lower regioselectivities are achieved with 1a and 1d. The lower regio- and diastereo-selectivities observed with 1c, 1e, and 1g can be rationalized by the influence of the chiral alcohol on the conformation of the keto ester and on the different steric hindrances of the cis (face-position) or trans (edge-position) diradicals 5 or 7. In agreement with this model the differences of activation parameters obtained for the regio- and diastereoselectivities of 5b and 7b are discussed. By variation of the starting olefins we observed an increase of the diastereoselectivity of oxetane formation in the sequence 8 ≍ 7 〈 5 〈 4, caused by increasing control of the cis-diradical (face-position).
    Notes: Die chiralen Phenylglyoxylate 1a und 1d induzieren bei der photochemischen Oxetanbildung mit 3 hohe Diastereoselektivitäten und geringere Regioselektivitäten. Der Regio- und Diastereoselektivitätsverlust mit 1c, 1e und 1g resultiert aus dem Einfluß des chiralen Hilfsalkohols auf die Ketoestercarbonyl-Konformation und auf die unterschiedliche sterische Hinderung der cis-(face-Position) und trans-(edge-Position) Diradikale von 5 und 7. In Übereinstimmung mit diesem Modell diskutieren wir die für 5b und 7b ermittelten Differenzen der Aktivierungsparameter für die Regio- und Diastereoselektivität. Durch Variation der Ausgangsolefine beobachteten wir einen Anstieg der Diastereoselektivität der Oxetanbildung in der Reihenfolge 8 ≍ 7 〈 5 〈 4, der durch zunehmende Kontrolle des cis-Diradikals (face-Position) bedingt ist.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180417
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    Erzeugung von Cumulenen durch Lithium-Addition an 1,3-Diine. Röntgenstruktur von [3,6-Di(lithio-THF)-2,2,7,7-tetramethyl-3,4,5-octatrien]2, einem 1,4-Dilithiobutatrien-Dimeren (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1504-1516 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Cumulenes by Lithium Metal Addition to 1,3-Diynes. X-Ray Structure of [3,6-Di(lithio-THF)-2,2,7,7-tetramethyl-3,4,5-octatriene]2, a 1,4-Dilithiobutariene DimerAddition of lithium metal to 2,2,7,7-tetramethyl-3,5-octadiyne (9) in tetrahydrofuran (THF) gave 3,6-dilithio-2,2,7,7-tetramethyl-3,4,5-octatriene (10), as a crystalline bis-THF adduct. X-ray analysis revealed the dilithiobutatriene 10 to have a dimeric cis-structure with two different kinds of lithium atoms and a true butatriene geometry (19). Model MNDO calculations (both with and without solvation) agree remarkably well with experiment and help reveal why the observed structure is preferred over alternative geometrical arrangements.
    Notes: Durch Addition von Lithium an 2,2,7,7-Tetramethyl-3,5-octadiin (9) in Tetrahydrofuran (THF) wurde 3,6-Dilithio-2,2,7,7-tetramethyl-3,4,5-octatrien (10) als Bis-THF-Addukt kristallin erhalten. Das Dilithiobutatrien 10 erwies sich bei der Röntgenstrukturanalyse als Dimeres des cis-Isomeren mit zwei unterschiedlichen Sorten von Lithiumatomen und echter Butatriengeometrie (19). MNDO-Berechungen an Modellen ohne und mit Solvensmolekülen zeigen eine bemerkenswerte Übereinstimmung mit dem Experiment und geben Aufschluß darüber, warum die beobachtete Struktur vor anderen Geometriealternativen bevorzugt ist.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180418
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    Synthesis, Thermolysis, and Photolysis of the Azoalkanes Spiro[4,5-diazatricyclo[4.3.0.03,7]non-4-ene-8,2′-[1.3]dioxolane] and 4,5-Diazatricyclo[4.3.0.03,7]non-4-en-8-one: On the Mechanism of the Oxadi-π-methane Rearrangement of 5-Norbornen-2-one (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3070-3088 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese, Thermolyse und Photolyse der Azoalkane Spiro[4,5-diazatricyclo[4.3.0.03,7]non-4-en-8,2′-[1,3]dioxolan] und 4,5-Diazatricyclo[4.3.0.03,7]non-4-en-8-on. Über den Mechanismus der Oxadi-π-methan-Umlagerung von 5-Norbornen-2-on4,5-Diazatricyclo[4.3.0.03,7]non-4-en-8-on (4) und Spiro[4,5-diazatricyclo[4.3.0.03,7]non-4-en-8,2′-[1,3]dioxolan] (5) wurden ausgehend von Bicyclo[2.2.1]hept-5-en-2-on (1) synthetisiert, indem das entsprechende Urazol 7 durch Cycloaddition von 4-Phenyl-4H-1,2,4-triazol-3,5-dion (PTAD) erhalten wurde. Acetalisierung zum Urazol 9 und anschließende Hydrolyse und Oxidation führten zu den Azoalkanen 4 und 5. Die Regioselektivität der PTAD-Cycloaddition zum Urazol 7 wurde röntgenographisch bewiesen. Direkte und benzophenonsensibilisierte Photolysen des Azoalkans 5 führten zum Tricycloalkan 13, während Thermolyse auch das Pyrazol 12 ergab. Bei der direkten und benzophenonsensibilisierten Photolyse des Azoalkans 4 entstanden Bicyclo[2.2.1]hept-5-en-2-on (1), Tricyclo-[3.2.0.02.7]heptan-3-on (2) und Bicyclo[3.2.0]hept-3-en-6-on (3). Bie der Thermolyse wurden nur die bicyclischen Ketone 1 und 3 erhalten. Es wird postuliert, daß die Photolyse und Thermolyse des Azoalkans 4 primär zu den Diazenyl-Diradikalen 19a, b führt, deren unterschiedliches chemisches Verhalten auf Spinmultiplizität (Singulett- bzw. Triplettzustände) und Elektronenkonfiguration (Dσ,σ- bzw. Dσ,π-Konfiguration) zurückzuführen ist. Die Bildung des Oxadi-π-methan-Diradikals 20 während der Stickstoffabspaltung durch Doppelbruch der C - N-Bindungen entspricht einem untergeordneten Reaktionsweg.
    Notes: 4,5-Diazatricyclo[4.3.0.03,7]non-4-en-8-one (4) and spiro[4,5-diazatricyclo[4.3.0.03,7]non-4-ene-8,2′-[1,3]dioxolane] (5) were prepared starting from bicyclo[2.2.1]hept-5-en-2-one (1) by cycloaddition with 4-phenyl-4H-1,2,4-triazole-3,5-dione (PTAD) to the corresponding urazole 7, followed with acetalization to the urazole 9 and subsequent hydrolysis and oxidation. The regioselectivity of the PTAD-cycloaddition leading to urazole 7 was confirmed by an X-ray analysis. Direct and benzophenone-sensitized photolyses of azoalkane 5 gave the tricycloalkane 13, while in the thermolysis also the pyrazole 12 was formed. Direct and benzophenone-sensitized photolyses of azoalkane 4 yielded bicyclo[2.2.1]hept-5-en-2-one (1), tricyclo[3.2.0.02,7]heptan-3-one (2), and bicyclo[3.2.0]hept-3-en-6-one (3). Thermolysis gave only the bicyclic ketones 1 and 3. It is postulated that the photolysis and thermolysis of azoalkane 4 first lead to diazenyl diradicals 19a, b, which are differentiated in their chemical behavior on account of spin state multiplicities (singlet versus triplet) and electronic configurations (Dσ,σ versus Dσ,π). Formation of the oxadi-π-methane-type 1,3-diradical 20 by denitrogenation involving double C - N cleavage represents a minor product channel.
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    URL: http://dx.doi.org/10.1002/cber.19851180807
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    Olefin- und Cyclopropan-Aktivierung durch geminale Phosphonium-Zentren (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3105-3113 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Olefin and Cyclopropane Activation Through Geminal Phosphonium CentresComplete quaternization of vinylidenebis(diphenylphosphane) (1) with CH3I or CH3OSO2F yields the diquaternary salts 2a,b, whose olefinic double bond is strongly electrophilic through the activation by two geminal phosphonium centres. Accordingly, addition of methanol or ethanol to 2a,b leads to β-alkoxy-substituted double phosphonium salts 9a-i. The structure of one of these products (9a: X=I, R=CH3) was elucidated by single crystal X-ray diffraction analysis. Spectroscopic data are provided for the remaining compounds. - Treatment of triphenylphosphonium cyclopropylide (5) with chlorodiphenylphosphane gives the gem-phosphinosubstituted salt 6, which can be quaternized with CH3OSO2F to yield a bis-phosphonium salt (7a,b). A symmetrical homologue 7c is formed from cyclopropylidenebis(diphenylphosphane) (8) and CH3OSO2F. In 7a-i the cyclopropane cycle is also clearly activated. Ring cleavage occurs with alcohols leading to γ-alkoxylated salts 10a,b.
    Notes: Die erschöpfende Quartärisierung von Vinylidenbis(diphenylphosphan) (1) mit CH3I oder CH3OSO2F liefert Diquartärsalze 2a,b, deren olefinische Doppelbindung durch die beiden Phosphonium-Zentren stark elektrophil aktiviert ist. Die Addition von Methanol oder Ethanol an 2a,b liefert entsprechend die β-alkoxysubstituierten Doppelphosphonium-Salze 9a-i. Die Struktur eines dieser Produkte (9a: X=I, R=CH3) wurde durch eine Einkristall-Röntgenbeugungsanalyse gesichert, für die übrigen liegen spektroskopische Daten vor. - Triphenylphosphoniumcyclopropylid (5) ergibt mit (C6H5)2PCl das geminal phosphinosubstituierte Salz 6, das durch CH3OSO2F zum Bisphosphonium-Salz quartärisiert werden kann (7a,b). Ein symmetrisches Homologes 7 c entsteht aus Cyclopropylidenbis(diphenylphosphan) (8) und CH3OSO2F. In 7a-i ist der Cyclopropan-Cyclus ebenfalls deutlich elektrophil aktiviert. Mit Alkoholen tritt Ringspaltung ein, die hier zu γ-alkoxylierten Salzen 10a,b führt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180809
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