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  • 1985-1989  (1,612)
  • 1965-1969  (4,020)
  • 1986  (1,612)
  • 1969  (1,926)
  • 1968  (2,094)
  • General Chemistry  (3,198)
  • Inorganic Chemistry  (2,359)
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  • 1985-1989  (1,612)
  • 1965-1969  (4,020)
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  • 1
    Electronic Resource
    Electronic Resource
    Regional morphology and biochemistry in experimental brain abscesses (1986)
    Springer
    Acta neuropathologica 69 (1986), S. 17-22 
    Details
    ISSN: 1432-0533
    Keywords: Brain abscess ; Cat ; Energy state ; Substrate mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Brain abscesses were induced experimentally in six cats by stereotactic inoculation ofStaphylococcus aureus A8 into the white matter of the left cerebral hemisphere. Seven days later, the brains were frozen in situ with liquid nitrogen and subsequently sawn into coronal sections of 5 mm thickness, while being cooled with liquid nitrogen. Thin slices were taken from those sections containing the largest expanse of abscess: slices of 5 μm thickness were stained histologically, and in adjacent 20 μm slices the regional distribution of ATP and glucose was mapped using substrate-specific bioluminescence methods. Furthermore, the NADH fluorescence from the surface of the tissue section was recorded. Six layers could be distinguished histologically in the abscess capsule, five of which showed different substrate patterns. Only in two layers a low metabolic activity could be observed, as shown by slight ATP bioluminescence. The pattern of the biochemical substrates in the white matter surrounding the abscess indicated a reduction in the cellular oxygen availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687033
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  • 2
    Electronic Resource
    Electronic Resource
    Topographic distribution of callosal neurons and terminals in the cerebral cortex of the cat (1986)
    Springer
    Anatomy and embryology 173 (1986), S. 323-342 
    Details
    ISSN: 1432-0568
    Keywords: Cerebral cortex ; Corpus callosum ; Anterior commissure ; Columns ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This investigation had four goals: First, to study the general topography of the corpus callosum (CC) of the cat. Second, to study the columnar organization of CC terminals and map their banding pattern in the cortex. Third, to examine the relation between CC neuron density and the presence of CC terminal columns. Fourth, to determine whether CC and anterior commissure (AC) neuron distributions are intermixed. Eight adult cats were subjected to partial commissurotomies, and then to large injections of horseradish peroxidase to one cerebral hemisphere. Processing with tetramethyl benzidine revealed retrogradely labelled cells and anterogradely labelled terminals in the cortex of the uninjected hemisphere. The distributions of these cells and terminals were examined by light microscopy and analyzed by computer microscopic methods. The genu of the CC interconnects frontal portions of the cortex, the body interconnects mostly dorsal portions of the cortex, while the splenium interconnects the temporal and occipital cortices. Reconstructions of the CC terminal columns reveal intricate banding patterns in several non-primary areas of the cortex. CC cell density is greater within than outside the terminal columns. CC and AC neurons intermix in the infragranular lavers of the neocortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318916
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  • 3
    Electronic Resource
    Electronic Resource
    Is motilin a cerebellar peptide in the rat? (1986)
    Springer
    Anatomy and embryology 173 (1986), S. 371-376 
    Details
    ISSN: 1432-0568
    Keywords: Motilin-like immunoreactivity ; RIA ; HPLC ; Cat ; Intestine ; Rat ; Cerebellum ; Purkinje cells ; Dendrites ; Neocortex ; Pyramidal cells ; Hippocampus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Motilin was demonstrated by the immunoperoxidase technique in endocrine cells of the gastrointestinal tract using several specific antisera. Motilin-like immunoreactivity could only be demonstrated with one of these antisera and was observed in Purkinje cells and dendrites of the cerebellum, in pyramidal cells and dendrites of the cerebral cortex and in dendrites of the CA3 field of the hippocampus of the rat. Very low motilin-like immunoreactivity was found in cerebellum as well as in cerebral cortex using radioimmunoassay. However, using reverse phase liquid chromatography combined with UV-detection and radioimmunoassay, no peak of a peptide corresponding to synthetic motilin was detectable in rat cerebellar extracts, in contrast to findings in rat duodenum. The results do not suggest that motilin is an intrinsic neuroactive substance of the cerebellum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318921
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  • 4
    Electronic Resource
    Electronic Resource
    Afferents to the lateral reticular nucleus from the oculomotor region (1986)
    Springer
    Anatomy and embryology 175 (1986), S. 261-269 
    Details
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Edinger-Westphal nucleus ; Retrograde transport of WGA-HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By means of retrograde axonal transport of the wheat germ agglutinin — horseradish peroxidase complex, a projection from the Edinger-Westphal nucleus to the lateral reticular nucleus was demonstrated in the cat. Following small tracer ejections in the main part of the lateral reticular nucleus, a significant number of labelled neurons were found bilaterally throughout the Edinger-Westphal nucleus. Most of the labelled cells were located on the ipsilateral side. The projecting neurons are spindle-shaped to round with a maximum diameter of the cell body between 15 and 30 μm. The findings are discussed in relation to other Edinger-Westphal efferent projections, and some comments are made concerning the cytoarchitecture and delineation of the feline Edinger-Westphal nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389604
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  • 5
    Electronic Resource
    Electronic Resource
    Fluorescent double-labelling study of ascending and descending neurones in the feline lateral cervical nucleus (1986)
    Springer
    Experimental brain research 62 (1986), S. 479-485 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Double labelling ; Fluorescent tracing ; Lateral cervical nucleus ; Ascending and descending neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The organization of ascending and descending neurones of the lateral cervical nucleus (LCN) was investigated in 10 adult cats after injections of the fluorescent tracers Fast Blue and Nuclear Yellow. Injections into the thalamus and tectum resulted in up to 3000 labelled cell profiles within the contralateral LCN. This corresponded to a calculated number of 4500 labelled LCN neurones. The greatest diameter of the labelled cell profiles was about 30 μm. They were located throughout the nucleus, but were less numerous in its medial portion. Injections mainly into the dorsal horn of different pairs of cervical and lumbar segments of the spinal cord resulted in a calculated number of up to 305 labelled LCN cells. The diameter of these cell profiles was about 25 μm and they were mainly situated in the rostro-ventral and medial parts of the LCN. Doublelabelled cells with ascending and descending projections were not encountered after injections into the thalamus-tectum and spinal segments C5-6. About 15% of the descending LCN cells were doublelabelled by pairs of spinal injections separated by intervals of one segment. It is concluded that the neurones descending down the spinal cord and ascending to the thalamus-tectum constitute different subpopulations of cells within the LCN and that a minor proportion of the descending cells seem to project to at least three adjacent segments of the spinal cord.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236026
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  • 6
    Electronic Resource
    Electronic Resource
    Short latency inputs to phrenic motoneurones from the sensorimotor cortex in the cat (1986)
    Springer
    Experimental brain research 61 (1986), S. 280-290 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Phrenic nerve ; Phrenic motoneurones ; Medullary pyramids ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Short latency responses were recorded from C5 phrenic roots and intracellularly from phrenic motoneurones following stimulation of the pericruciate cortex or medullary pyramids in cats anaesthetized with Nembutal or chloralose-urethane. Focal stimulation of the cortical surface (single pulses, 0.5–2 ms, 0.3–8 mA) during inspiration evoked EPSPs (latency 4.7 ± 1.7 ms, rise time 1.9 ± 1.1 ms, amplitude 0.22 to 3.94 mV) in 42% of motoneurones studied (n = 107). The EPSPs were absent, or on average 60% smaller, following stimulation during expiration. In all but two motoneurones, during both inspiration and expiration, hyperpolarizing potentials were observed either following the initial depolarization or alone. They could be reversed by hyperpolarizing current or chloride injection. Stimulation of the pyramidal tract at mid medullary level (1 to 3 pulses, 0.2 ms) evoked short latency excitation in phrenic motoneurones only with currents of more than 200 μA. Smaller stimuli applied to the medial reticular formation above the pyramidal tract evoked excitation (onset latency 1.5–3.2 ms) in which the earliest part was probably monosynaptic. These results show that the corticospinal responses in phrenic motoneurones are both excitatory and inhibitory. They are not transmitted through the pyramidal tract and are at least disynaptic. Excitation evoked from the medullary pyramidal tract can be explained by current spread beyond the pyramidal tract fibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239518
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  • 7
    Electronic Resource
    Electronic Resource
    Development of horizontal intrinsic connections in cat striate cortex (1986)
    Springer
    Experimental brain research 63 (1986), S. 443-448 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex (area 17) ; Intrinsic connections ; Visual deprivation ; Development ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracortical injections of horseradish peroxidase conjugated with wheat-germ agglutinin (WGA-HRP) reveal a characteristic patchy staining pattern within the superficial layers of cat striate cortex. The patches consist of a dense accumulation of labeled neurons and axonal arborizations. We have investigated the tangential organization and the development of these intrinsic cortical connections by using a flat-mount preparation of area 17. The diameter of the patches varied from 200 to 400 μm, the center-to-center distance ranged from 400 to 800 μm, and the spread of patches extended further in the anterior-posterior than in the medial-lateral direction. The expression of these horizontal patchy connections is age- and experience-dependent. From ten days to six weeks of age patches are exuberant and on occasion fuse to beaded bands extending radially from the injection site. From 6 weeks onwards the number and the tangential spread of the patches decreases to one or two rows of isolated clusters. Long-term binocular deprivation disrupts this pattern of intrinsic connections nearly completely. We infer from these results that there is an inborn pattern of discrete horizontal connections in striate cortex which is shaped by visual experience and requires contour vision for its maintenance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236865
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  • 8
    Electronic Resource
    Electronic Resource
    Excitatory interactions between phrenic motoneurons in the cat (1986)
    Springer
    Experimental brain research 62 (1986), S. 273-280 
    Details
    ISSN: 1432-1106
    Keywords: Motoneurons ; Interactions ; Cholinergic synapses ; Phrenic nerve ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Interactions between phrenic motoneurons have been analysed in anaesthetized, paralyzed cats after C3 to C7 deafferentation. Effects of electrical stimulation of the C5 phrenic axons have been studied on thin filaments dissected from the stimulated nerve. Repetitive stimulation could elicit, after the primary direct response of the stimulated axons, a secondary response named Recurrent Response, RR. 2. RRs have been obtained in 117/186 phrenic axons. They appear sporadically (mean occurrence: 3.75 RRs elicited by 100 shocks of stimulation) at a constant latency. They originate from a spinal mechanism since they persist after C2 transection and disappear after section of the ventral roots. 3. The mechanism responsible for RR shows spatial and temporal facilitation. The RR probability increases with the number of antidromically invaded motoneurons as revealed by changes either of stimulation intensity or of central respiratory drive. However, RR could be evoked in a motoneuron without an antidromic volley in its axon. 4. Systemic injections of nicotinic blocking drugs such as dihydro-β-erytroidin or mecamylamine decrease or suppress the occurrence of RR; therefore, cholinergic synapses are involved in the RR generating process. 5. RR are assumed to be due to direct excitatory interactions between homonymous motoneurons. Recurrent axon collaterals impinging directly on neighbouring motoneurons would link together the different motoneurons of the phrenic pool. The functional significance of this phenomenon is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238846
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  • 9
    Electronic Resource
    Electronic Resource
    Dual mode of projections from the parietal to the motor cortex in the cat (1986)
    Springer
    Experimental brain research 62 (1986), S. 281-292 
    Details
    ISSN: 1432-1106
    Keywords: PT cell ; Areas 4γ and 5 ; Intracortical microstimulation ; HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The cortico-cortical projection from area 5 to area 4 γ was studied in anesthetized cats. 2. Intracortical microstimulation of area 5 produced EPSPs in pyramidal tract (PT) cells in area 4 γ. Such EPSPs were analysed in a total of 54 fast PT cells. The rising phase of these EPSPs was often composed of fast and slow components. 3. Fast-rising EPSPs (fast component) were produced predominantly by stimulation within layer III of area 5 while slow-rising EPSPs (slow component) were evoked predominantly by stimulation within layer V of area 5. 4. The amplitudes of the fast and slow components of EPSPs produced during repetitive stimulation within layers III and V of area 5 decreased and increased, respectively, with an increase in the stimulus frequency without any appreciable changes in their latency and time-to-peak. The slow component was much less influenced by membrane hyperpolarization than the fast component. 5. Retrogradely labeled neurons were found not only in layer III but also in layer V of area 5 following HRP injection centered on superficial layers (I–III) of area 4γ. 6. It is suggested that there are two groups of cortico-cortical neurons in layers III and V of area 5, which may make monosynaptic contact with the proximal and distal sites of fast PT cells in area 4γ, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238847
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  • 10
    Electronic Resource
    Electronic Resource
    Pattern of pyramidal tract collateralization to medial thalamus, lateral hypothalamus and red nucleus in the cat (1986)
    Springer
    Experimental brain research 61 (1986), S. 585-596 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Chloralose ; Motor cortex ; PT collaterals ; Macro- and microstimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stimulating electrodes were placed in the red nucleus, lateral hypothalamus and medial thalamus in order to determine whether pyramidal tract (PT) neurons send collaterals to those sites. The red nucleus projections are well-known, but it was discovered that PT neurons also project into the other two sites. All of the fibers that sent collaterals to all three sites originated from fast PT neurons. Those that responded to stimulation of the skin and that sent collaterals to two or three sites were predominantly fast PT neurons. Those neurons that responded only to cerebral peduncle stimulation were predominantly slowly-conducting, when compared with the set of PT neurons in response to cerebral peduncle stimulation. The patterns of collateral branching to red nucleus and to lateral hypothalamus were similar, suggestimg a similar synaptic effect of the pyramidal system in the two sites. Measurement of the speed of conduction from three sites along the length of corticospinal fibers revealed large changes on some, but not all, fibers; there was no evident pattern to these changes that might be associated with collateral branching. A new hypothesis concerning the functional role of fast PT neurons in regulating movement is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237585
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  • 11
    Electronic Resource
    Electronic Resource
    An electrophysiological investigation of propriospinal inspiratory neurons in the upper cervical cord of the cat (1986)
    Springer
    Experimental brain research 61 (1986), S. 625-637 
    Details
    ISSN: 1432-1106
    Keywords: Respiratory neurons ; Cervical spinal cord ; Axonal projection ; Phrenic motoneurons ; Intercostal motoneurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was performed in order to describe the location, axonal projection and possible synaptic action of the inspiratory neurons recently described in the upper cervical cord. In 26 cats anaesthetized with Nembutal, extracellular recordings were made from 224 cervical inspiratory units which were found near the lateral border of lamina VII and formed a column extending from the caudal end of the nucleus retroambigualis at the C1 segment to the rostral half of the C3 segment. Most of the units (approximately 85%) could be excited antidromically from the thoracic cord. Antidromic mapping showed collateral branches to the C5 segment in the vicinity of the phrenic nucleus, occasionally crossing the midline. No synaptic connections with phrenic motoneurones could be revealed either by cross-correlation of the activity of the cervical units with the discharge of C5 phrenic root, or by spike-triggered averaging (STA) of the post-synaptic noise recorded intracellularly from phrenic motoneurons. Extensive branching was found in the examined T3–T5 segments with arborizations near the ipsilateral intercostal motor nuclei and often extending across the midline. Cross-correlation experiments did not show clear monosynaptic connections to the inspiratory intercostal motoneurons. Intracellular recording from intercostal motoneurons and STA resulted in a few (2 out of 37) small, probably disynaptic, e.p.s.p.s. It is concluded that the upper cervical neurons are involved in the control of phrenic and intercostal motoneurons, probably through a disynaptic pathway involving segmental interneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237589
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  • 12
    Electronic Resource
    Electronic Resource
    Anti-5-hydroxytryptamine antibodies: studies on their cross-reactivity in vitro and their immunohistochemical specificity (1986)
    Springer
    Experimental brain research 63 (1986), S. 627-638 
    Details
    ISSN: 1432-1106
    Keywords: Antibodies to serotonin ; Immunocytochemistry ; Radioimmunoassay ; Antibodies specificity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Antibodies to 5-hydroxytryptamine (5-HT) were obtained from 4 rabbits after injections of 5-HT coupled to bovine serum albumin by means of paraformaldehyde (PF). Two methods were used to monitor the developement of antibodies (AB): the one based on the “in vitro” competitive binding properties of the antibodies with3(H)5-HT, the other, on their “in situ” binding properties to endogenous 5-HT, using the peroxidase-anti-peroxidase immunohistochemical technique, applied to paraffin embedded sections of cat brainstem. No pharmacological processing, detergents or proteolytic enzymes were used. The specificity of the antiserum was tested by competitive procedures with 20 analogs using the “in vitro” and “in situ” techniques. “In vitro” studies were performed with 5-HT free analogs and with analogs previously coupled with PF to lysine. Radioimmunological tests showed that the antibodies recognize mainly the ethylamine (CH2-CH2-NH2)-cham of the free analogs and that the best specificity was obtained with the 5-HT conjugate (5-HT-lysine-PF). The results suggest that the hapten is coupled through the phenolic positions C4 or C5. The “in situ” immunohistochemical extinction assays also revealed a distinct specificity for 5-HT. Possible optical and ultrastructural applications are illustrated in the raphé nuclei of the cat. These results confirm the reliability of radioimmunological tests for studying the specificity of AB directed against haptens, provided that haptens and analogs tested were first chemically transformed to resemble the immunogen (herewith lysine-PF coupling) with regard to its antigenic structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237485
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  • 13
    Electronic Resource
    Electronic Resource
    Liminal and supraliminal response characteristics of mechanoreceptive neurons in the cuneate nucleus of cat (1986)
    Springer
    Experimental brain research 62 (1986), S. 486-494 
    Details
    ISSN: 1432-1106
    Keywords: Mechanoreceptors ; Thresholds ; Stimulus-response functions ; Cuneatus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response characteristics of mechanoreceptive neurons (RA, SA, and PC) innervating the foot pad of cat were determined in the cuneate nucleus. The mechanical stimuli were single sinusoidal pulses of varying frequency (20, 60, 150, and 240 Hz), and vibratory trains of varying frequency (80 and 240 Hz) and duration (50, 100, and 400 ms). Thresholds and stimulus-response functions were determined with single pulses. Absolute thresholds (1 impulse/train), tuning thresholds (1 impulse/cycle), and atonal intervals (the range between absolute and tuning thresholds) were determined with vibratory stimulus trains. When tested with single pulses the thresholds resembled those of primary afferents in all unit populations. The stimulus-response function of PC units but not of all RA units were comparable to those of primary afferents. Noxious conditioning stimulation did not influence the thresholds of cuneate mechanoreceptors in the tested sample (N = 6). Mostly PC units were tested with vibratory trains. Absolute thresholds were not dependent on stimulus duration, which is a consistent finding with peripheral units. In contrast to peripheral units, the tuning thresholds in most PC units were elevated with increasing stimulus duration. The variability in the range of atonal intervals was much larger than in the periphery. Thus, it seems that both the type of the tactile signal and the type of the studied mechanoreceptive neuron are critical parameters in determining whether the response characteristics of neurons in the cuneate and in the periphery are identical or not.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236027
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  • 14
    Electronic Resource
    Electronic Resource
    Auditory response properties of neurons in the claustrum and putamen of the cat (1986)
    Springer
    Experimental brain research 61 (1986), S. 432-437 
    Details
    ISSN: 1432-1106
    Keywords: Claustrum ; Putamen ; Auditory response properties ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The auditory response properties of single neurons in claustrum and putamen were studied in response to simple dichotic stimuli (viz. noise- and tone-bursts) in chloralose-anaesthetized cats. Neurons in claustrum were commonly weakly driven with long latency, were broadly tuned and were excited by stimulation of either ear (EE). Putamen neurons, in contrast, were securely driven with short latency, showed irregular tuning with a preference for low frequencies and were either EE or excited only by the contralateral ear (EO). The differences between claustrum and putamen responses can be related to differences in connections with the auditory cortical fields and with auditory thalamus. Some neurons were also tested for visual responsiveness: auditory and visual cells were intermingled in both nuclei and only a small percentage of cells were bimodal. In contrast to the visual and somatosensory input to claustrum, which are derived from primary cortical fields, the auditory input to claustrum is apparently derived from non-primary cortical regions, suggesting a fundamentally different role for processing of auditory information in claustrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239531
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  • 15
    Electronic Resource
    Electronic Resource
    Eye position signals in cat superior colliculus (1986)
    Springer
    Experimental brain research 61 (1986), S. 447-450 
    Details
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Single units ; Eye movements ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single unit activity was studied in the intermediate and deep layers of the superior colliculus in two trained cats. Eye movements were recorded with a magnetic search coil, the head being fixed. Discharge rates which varied as a function of eye position were consistently observed in 7 of 67 (about 10%) of the sample of eye movement-related units. These units showed similar changes in firing rate as a function of eye position in total darkness and during task related fixation of visual targets and thus appear to convey an “eye position” signal. Their activity may originate either from proprioception or from corollary discharge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239534
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  • 16
    Electronic Resource
    Electronic Resource
    Binocular suppression in cortical neurons (1986)
    Springer
    Experimental brain research 63 (1986), S. 581-584 
    Details
    ISSN: 1432-1106
    Keywords: Visual neurons ; Contrast ; Binocular interactions ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dichoptic presentation of patterns similar in shape but of very different contrast results in the perception of only the high contrast pattern (binocular suppression). When recording from binocular neurons of the cat visual cortex, we have found an effect which is strikingly similar to this perceptual phenomenon. If a high and a low contrast grating are presented simultaneously, one to each eye, the cell's response to the low contrast stimulus is suppressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237480
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  • 17
    Electronic Resource
    Electronic Resource
    Bulbar neurones with axonal projections to the trigeminal motor nucleus in the cat (1986)
    Springer
    Experimental brain research 65 (1986), S. 98-111 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Interneurones ; Motor control ; Jaw movements ; WGA-HRP ; Retrograde transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The location of bulbar neurones with axons projecting to the ipsi- and contralateral trigeminal motor nucleus were investigated in cats anaesthetized with sodium pentobarbital. Wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected in amounts of 5–24 nl. A volume-calibrated microelectrode was used for recording of evoked potentials and pressure injection of WGA-HRP. The injection site was guided by the position where a maximal antidromic response was evoked by electrical stimulation of the masseteric nerve. The survival time was 19–22 h. In preparations with the depot located in the masseteric subnucleus retrogradely stained neurones were found bilaterally in the borderzone of the trigeminal motor nucleus. Dense populations of stained neurones were observed ipsi- and contralaterally in the dorsal division of the main sensory trigeminal nucleus and the subnucleus-γ of the oral nucleus of the spinal trigeminal tract. Clusters of WGA-HRP-neurones were observed bilaterally in the lateral tegmental field at the level of the subnucleus-β of the oral nucleus of the spinal trigeminal tract, bilaterally dorsal to the facial nucleus and contralaterally adjacent to the hypoglossal nucleus. No stained neurones were found in the gigantocellular reticular nucleus. A group of stained neurones was located in the marginal nucleus of brachium conjunctivum and some were found in the raphé nuclei near obex. Cell profiles were of two types: medium-sized neurones with a triangular profile and 30–40 μm diameter, and fusiform neurones 10×50–70 μm. Convergence of descending cortical and trigeminal afferent inputs on interneurones located in the lateral borderzone of the trigeminal motor nucleus, i.e. the intertrigeminal area, is reported in the preceding paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243833
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  • 18
    Electronic Resource
    Electronic Resource
    Cortically and lingually induced postsynaptic potentials in trigeminal motoneurons after axotomy (1986)
    Springer
    Experimental brain research 61 (1986), S. 272-279 
    Details
    ISSN: 1432-1106
    Keywords: Membrane property ; Postsynaptic potentials ; Axotomized trigeminal motoneuron ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The membrane properties and the efficacy of excitatory and inhibitory synapses were studied in cat masseteric motoneurons (Mass Mns) after axotomy. In axotomized Mass Mns the slope of the primary range in the frequency-current relationship showed a higher gain than that of normal Mass Mns. The safety of antidromic invasion was increased and the initial segment component of antidromic action potentials could not be separated from the somadendritic component. In normal Mass Mns a single shock delivered to the orbital gyrus or the lingual nerve induced long-lasting inhibitory postsynaptic potentials (IPSPs). In two-thirds of Mass Mns explored 30 days after axotomy, a single shock delivered to the orbital gyrus or the lingual nerve evoked a mixture of inhibitory and excitatory synaptic potentials. In Mass Mns 50 days after axotomy, we have demonstrated that the major fraction of the total sample of explored Mass Mns showed long-lasting excitatory postsynaptic potentials followed by IPSPs. The results suggest that in Mass Mns, axotomy is followed by the decline of synaptic efficacy of inhibitory rather than of excitatory synapses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239517
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  • 19
    Electronic Resource
    Electronic Resource
    Pyramidal tract of the cat: axon size and morphology (1986)
    Springer
    Experimental brain research 61 (1986), S. 303-310 
    Details
    ISSN: 1432-1106
    Keywords: Pyramidal tract axons ; Cat ; Size and morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of this work was to determine the number and morphology of pyramidal tract (PT) axons in the cat, using electron microscopy, modern methods of fixation, and computer-assisted morphometric analysis. Sections taken at the level of the medullary pyramids in three animals were fixed and magnified up to 10,000 x to produce photomicrographs. Morphological data were entered into computer files for analysis by tracing axon perimeters on micrographs mounted on a digitizer tablet. The number of axons per PT averaged 415,000, of which 88% were myelinated and 12% were unmyelinated. 90% of the myelinated axons fell in the diameter range 0.5–4.5 μm. Axons larger than 9 μm diameter accounted for 1% of the total; the largest were 20–23 μm. Myelinated axon mean diameter was 1.98 μm; because of the skewed distribution, with many small axons and a few very large axons, median diameter was 1.60 μm. Size distribution was relatively uniform throughout the PT cross section, with all sizes represented in all regions. However, the more medial regions had a higher proportion of small fibers than the more lateral regions: mean medial diameter was 1.85 μm while mean lateral diameter was 2.09 μm. Myelin sheath thickness averaged 7.9% of fiber diameter for axons up to 11 μm, but was constant at 0.9 μm for larger fibers. Myelinated fibers were distorted from the circular shape in cross section, with a mean circularity index (or form factor) of 0.85, which implies that the fibers could swell about 15% without rupture of the cell membrane. Unmyelinated fibers averaged 0.18 μm diameter (range 0.05–0.6 μm); the largest unmyelinated axons were larger than the smallest myelinated axons. It is concluded that previous work greatly underestimated the number of axons in the cat pyramidal tract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239520
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  • 20
    Electronic Resource
    Electronic Resource
    Morphology of vertical canal related second order vestibular neurons in the cat (1986)
    Springer
    Experimental brain research 63 (1986), S. 35-48 
    Details
    ISSN: 1432-1106
    Keywords: Semicircular canals ; Three-neuron arc ; Vestibulo-ocular reflex ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphology of vertical canal related second order vestibular neurons in the cat was studied with the intracellular horseradish peroxidase method. Neurons were identified by their monosynaptic potentials following electrical stimulation via bipolar electrodes implanted into individual semicircular canal ampullae. Anterior and posterior canal neurons projected primarily to contralateral or ipsilateral motoneuron pools (excitatory and inhibitory pathways, respectively). The axons of contralaterally projecting neurons crossed the midline at the level of the abducens nucleus and bifurcated into an ascending and a descending main branch which travelled in the medial longitudinal fasciculus (MLF). Two types of anterior canal neurons were observed, one with unilateral and one with bilateral oculomotor projection sites. For both neuron classes, the major termination sites were in the. contralateral superior rectus and inferior oblique subdivisions of the oculomotor nucleus. In neurons which terminated bilaterally, major collaterals recrossed the midline within the oculomotor nucleus to reach the ipsilateral superior rectus motoneuron pool. Other, less extensive, termination sites of both neuron classes were in the contralateral vestibular nuclear complex, the facial nucleus, the medullary and pontine reticular formation, midline areas within and neighboring the raphé nuclei, and the trochlear nucleus. The ascending main axons continued further rostrally to reach the interstitial nucleus of Cajal and areas around the fasciculus retroflexus. The descending branches proceeded further caudal in the medial vestibulo-spinal tract but were not followed to their spinal target areas. In addition to two previously described posterior canal related neuron types (Graf et al. 1983), we found neurons with bilateral oculomotor terminals and a spinal collateral. Typical for posterior canal neurons, the major termination sites were in the trochlear nucleus (superior oblique motoneurons) and in the inferior rectus subdivision of the oculomotor nucleus. Axon collaterals recrossed the midline to reach ipsilateral inferior rectus motoneurons. The axons of ipsilaterally projecting neurons ascended through the reticular formation to join the MLF caudal to the trochlear nucleus. The main target sites of anterior canal related neurons were in the trochlear nucleus and the inferior rectus subdivision of the oculomotor nucleus. Minor collaterals reached the pontine reticular formation and areas in between the fiber bundles of the ipsilateral MLF. In some cases, small collaterals crossed the midline within the oculomotor nucleus to terminate in the inferior rectus subdivision on the contralateral side. The axon proceeded further rostral to project to the interstitial nucleus of Cajal and beyond. The main termination sites of posterior canal neurons were in the superior rectus and inferior oblique subdivisions of the oculomotor nucleus. Minor collaterals were also observed to reach the midline area within the oculomotor nucleus, however, prospective contralateral termination sites could not be identified. More rostral projections were found in the interstitial nucleus of Cajal. The described axonal arborization of second order vestibular neurons reflects the organization of intrinsic coordinate systems as exemplified by the geometry of the semicircular canal and the extraocular muscle planes. These neurons are interpreted to provide a matrix for coordinate system transformation, i.e. from vestibular into oculomotor reference frames, and to play a role in gaze control and related reflexes by distributing their signals to multiple termination sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235644
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  • 21
    Electronic Resource
    Electronic Resource
    Electrophysiological evidence for a projection from medial prefrontal and anterior limbic cortex toward the medial preoptic area in the cat (1986)
    Springer
    Experimental brain research 63 (1986), S. 205-215 
    Details
    ISSN: 1432-1106
    Keywords: Prefrontal cortex ; Limbic cortex ; Medial preoptic area ; Axonal branching ; Electrophysiology ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neurons in cat medial prefrontal cortex, anterior limbic cortex and possibly the indusium griseum were identified by antidromic invasion as having axonal projections towards the medial preoptic region, using both macro- and microstimulation techniques. These projecting axons were found to be of slow conduction velocity (0.2–4.8 m/s) and to in some cases also send branches towards the anteromedial thalamus, mediodorsal thalamus, ventromedial tegmentum, basolateral amygdala or medial forebrain bundle. Threshold-depth curves for axons excited by microstimulation in the medial preoptic region were very steep, with proportionality constants of 0.3–7.1 μm/μA. Calculations based on the threshold-depth curves confirmed that microstimulation was most probably only activating axons within the MPO, and current spread to lateral fibers of passage following macrostimulation in the MPO was not detected in the branching studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235665
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  • 22
    Electronic Resource
    Electronic Resource
    Differences of visual field representation in the medial and lateral banks of the suprasylvian cortex (PMLS/PLLS) of the cat (1986)
    Springer
    Experimental brain research 64 (1986), S. 77-93 
    Details
    ISSN: 1432-1106
    Keywords: Lateral suprasylvian cortex ; Posterior lateral suprasylvian area ; Topography ; Visual field representation ; Scatter of receptive fields ; Cat ; PMLS ; PLLS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied the orderliness of representation of visual space in the medial and lateral banks of the middle suprasylvian sulcus. Penetrations were made either parallel to the sulcus, in one bank or the other, or vertical, thus crossing the sulcus between the postero-medial (PMLS) and posterolateral (PLLS) divisions of this area. In some cases we found clear evidence for topographical order in the representation of the visual field with a tendency (greater in PMLS than in PLLS) for the receptive fields of cells recorded deeper in the walls of the sulcus to lie closer to the area centralis, but along many penetrations the receptive fields were so large and so scattered that no retinotopic arrangement could be discerned. In PMLS the receptive fields of the majority of units we studied were centred below and close to the horizontal meridian, whereas in PLLS they were distributed over both the upper and lower visual fields with an over-representation of the upper field. Receptive fields were significantly larger in PLLS (mean field area = 442.2 deg2) than in PMLS (mean area = 154.4 deg2); there was also less clear correlation between receptive field size and eccentricity in PLLS (correlation coefficient = +0.25) than in PMLS (corr. coeff. = +0.72). Analysis of the distance between the receptive field centres of consecutively recorded units demonstrated that the mean scatter in both PMLS and PLLS amounts to about half the average receptive field diameter. In summary the topographical representation of visual space is less orderly in PLLS, and may involve a wider area of the visual field. These findings may relate to the segregated visual cortical and extrageniculate thalamic connections that the medial and lateral banks of the LS receive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238203
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  • 23
    Electronic Resource
    Electronic Resource
    Evidence of rhythmic inhibitory synaptic influences in hindlimb motoneurons during fictive locomotion in the thalamic cat (1986)
    Springer
    Experimental brain research 64 (1986), S. 217-224 
    Details
    ISSN: 1432-1106
    Keywords: Locomotion ; Cat ; Hindlimb motoneurons ; Inhibition ; Excitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Intracellular recordings of various motoneurons of proximal hindlimb muscles were performed on thalamic paralyzed cats, during fictive locomotion that was either spontaneous or evoked by stimulation of the subthalamic region. 2. In motoneurons innervating sartorius (medialis and lateralis), vasti (intermedius, medialis and lateralis) and anterior biceps-semimembranous, one depolarization occurred in each locomotor cycle, alternating with a phase of repolarization that was synchronous with the activation of the antagonistic muscle nerve. This latter phase could be decreased or reversed by intracellular injection of chloride ions or current, revealing the presence of inhibitory inputs onto motoneurons. 3. The pattern of membrane potential variations was more complex in motoneurons of rectus femoris and posterior biceps-semitendinosus muscles, but phases of chloride dependent inhibition were nevertheless identified, mainly during the sartorius nerve activation in the case of rectus femoris, and during the vasti and anterior biceps-semimembranosus nerve activations in the case of posterior biceps-semitendinosus. These inhibitory influences were shown to be controlled by the level of activity in exteroceptive afferents. 4. The characteristics of the excitatory and inhibitory inputs to the hindlimb motoneurons identified here are discussed in relation with the organization of the central pattern generator for locomotion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238216
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  • 24
    Electronic Resource
    Electronic Resource
    The orientation bias of LGN neurons shows topographic relation to area centralis in the cat retina (1986)
    Springer
    Experimental brain research 64 (1986), S. 233-236 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Orientation bias ; Receptive field ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The orientation sensitivity of LGN cells to flickering square-wave gratings was measured in urethane-anaesthetized paralyzed cats. The mean ratio of the amplitude of peak responses to optimally oriented gratings to that elicited by gratings of the least effective orientation was 3.0 ± 0.3 (S.E.). 58% of the recorded neurons responded best to orientations within 30° of the meridional line joining their receptive field center with the fixation points (area centralis), implying that they were more sensitive to visual contours pointing to the center of the retina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238218
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  • 25
    Electronic Resource
    Electronic Resource
    Effect of exogenous dopamine on the hypercapnic ventilatory response in cats during normoxia (1986)
    Springer
    Pflügers Archiv 407 (1986), S. 504-509 
    Details
    ISSN: 1432-2013
    Keywords: Peripheral chemoreceptors ; Central chemoreceptors ; Control of respiration ; Dopamine ; Cat ; Hypercapnia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of exogenous dopamine on the normoxic hypercapnic ventilatory response were assessed in nine chloralose-urethane anesthetized cats using the technique of dynamic end-tidal forcing. The ventilatory responses to step changes in end-tidalP CO 2 (PETCO 2) were measured before (control), during and after intravenous infusion of dopamine (420 μg·kg−1·h−1). Each response was separated into a slow central and a fast peripheral chemoreflex loop by fitting two exponential functions to the measured ventilation. Both loops were described by a CO2 sensitivity, time constant, time delay and a single off-set B (extrapolated PETCO 2, of the steady-state response curve at zero ventilation). Dopamine infusion only caused a significant increase of B (mean 0.3 kPa,P〈0.0001) compared to control; the other model parameters were not significantly affected. After dopamine infusion B returned to significantly lower values (mean 0.2 kPa,P=0.006) than in control. In two additional cats the dopamine administered to the blood which was artificially perfusing the brainstem, did not affect ventilation. We conclude that in normoxic cats the effect of exogenous dopamine on the ventilatory response to CO2 is due to a CO2 independent inhibition of the ventilatory drive which originates outside the brainstem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00657508
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  • 26
    Electronic Resource
    Electronic Resource
    Chemoreceptor response to hypoxia and hypercapnia in catecholamine depleted rabbit and cat carotid bodies in vitro (1986)
    Springer
    Pflügers Archiv 406 (1986), S. 419-423 
    Details
    ISSN: 1432-2013
    Keywords: Rabbit ; Cat ; Chemoreceptor ; Reserpine ; α-Methyl-p-tyrosine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The response of single chemoafferent fibres to hypoxic and hypercapnic stimulation was studied in vitro under different experimental conditions: 1. control, 2. 24 h after reserpinization (5 mg/kg iv) and 3. 18 h after iv injection of α-methyl-p-tyrosine (100 mg/kg in the rabbit, and 1. control and 2. 24 h after reserpinization (5 mg/kg ip) in the cat. The spontaneous activity was decreased by monoamine depletion. The amplitude of the response to hypoxia and to hypercapnia was decreased by reserpinization in the rabbit and in the cat, the change being less marked in the latter species. Similarly, treatment with·α-methyl-p-tyrosine decreased the ability of chemoreceptors to respond to hypoxia and hypercapnia and, in a few instances, these receptors could only be excited by superfusion of nitrogencquilibrated medium. These results emphasize to possible role of monoamine, and particularly dopamine, in modifying the sensitivity of arterial chemoreceptors to their natural stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00590946
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  • 27
    Electronic Resource
    Electronic Resource
    Functional characteristics of lumbar visceral afferent fibres from the urinary bladder and the urethra in the cat (1986)
    Springer
    Pflügers Archiv 407 (1986), S. 510-518 
    Details
    ISSN: 1432-2013
    Keywords: Lumbar visceral afferents ; Urinary bladder ; Urethra ; Functional properties ; Visceral nociception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neural activity of lumbar visceral afferents supplying the urinary bladder and urethra was analyzed systematically in the cat. The afferent fibres were isolated either from the white rami L3 and L4 in a preparation with closed peritoneal cavity, or from the lumbar splanchnic nerves in a preparation with open peritoneal cavity and investigated for various functional parameters. Seventy five single units and 9 multiunit bundles were analyzed. 1) About 50% of the afferent units had some ongoing activity (0.2 to 1 imp/s). Two thirds of the afferent axons were thin myelinated (conduction velocity 3–15 m/s), the rest were presumably unmyelinated (conduction velocity below 2 m/s). 2) The receptive fields of the afferent units consisted —with one exception — of single mechanosensitive sites on the surface of the bladder and urethra. Most receptive fields were situated on the dorsal side of the bladder. 3) Afferents with receptive fields on or in the bladder wall responded in a graded manner to passive distension and isovolumetric contraction at intravesical pressures ranging from about 10 to 70 mm Hg. The thresholds for exciting the afferent units ranged from less than 10 mm Hg to about 30 mm Hg intravesical pressure, most of them being less than 20 mm Hg. Generally, the discharge rate of the afferent units gave a reliable representation of the intravesical pressure to the lumbar spinal cord. 4) Urethral units exhibited either no responses to the graded distensions and contractions of the urinary bladder, or responded with low discharge rates at higher intravesical pressures. 5) The results do not support the notion that noxious events in the urinary bladder are encoded by “specific” nociceptive visceral afferents to the lumbar spinal cord but possibly by some other mechanism of encoding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00657509
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  • 28
    Electronic Resource
    Electronic Resource
    Distributional pattern of serotonin-immunoreactive nerve fibers in the lateral geniculate nucleus of the rat, cat and monkey (Macaca fuscata) (1986)
    Springer
    Cell & tissue research 243 (1986), S. 249-253 
    Details
    ISSN: 1432-0878
    Keywords: Serotonin-immunoreactive nerve fibers ; Lateral geniculate nucleus ; Immunohistochemistry ; Rat ; Cat ; Monkey (Macaca fuscata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of serotonin-containing nerve fibers in the lateral geniculate nucleus (LGN) of the rat, cat, and monkey (Macaca fuscata) was studied by use of the peroxidase-antiperoxidase method and an antiserum against serotonin. In all three species, the pattern of fibers was denser in the ventral portion of the LGN (LGNv) than in the dorsal nuclear portion (LGNd). In the LGNd of rat, serotonin-immunoreactive fibers were evenly distributed in the form of a dense network, but in cat and monkey there were marked regional differences. Serotonin-immunoreactive elements were most numerous in the C complex and medial interlaminal nucleus of cat, and in the S layer and interlaminar zones of Macaca fuscata.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00251038
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  • 29
    Electronic Resource
    Electronic Resource
    Observations on the primary sensory ending of tenuissimus muscle spindles in the cat (1986)
    Springer
    Cell & tissue research 246 (1986), S. 309-319 
    Details
    ISSN: 1432-0878
    Keywords: Muscle spindle ; Sensory innervation ; Mechanosensory transduction ; Morphogenesis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The arrangement of preterminal and terminal axon branches in the primary sensory endings of cat tenuissimus muscle spindles was studied using whole-mount and serial-section techniques. Although in every case one firstorder preterminal branch was supplied exclusively to the bag1 type of intrafusal muscle fibre, the preterminal branching patterns differed considerably in detail. Terminals varied widely in size and location. Their precise form varied according to their position on the intrafusal muscle fibres rather than their relationship to preterminal branches. Terminals derived from separate preterminal branches remained separate and did not fuse with themselves or each other. Individually bag1 fibres had most terminals, chain fibres least. The surface of the muscle fibres were differentially indented by the terminals, least in bag1 fibres and most in chain fibres. The results are discussed in relation to mechanosensory transduction and to the factors involved in determining the form of the primary ending.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215893
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  • 30
    Electronic Resource
    Electronic Resource
    Autoradiographic localization of transported neutral amino acids in epithelia of cat submandibular and sublingual salivary glands (1986)
    Springer
    Cell & tissue research 246 (1986), S. 353-358 
    Details
    ISSN: 1432-0878
    Keywords: Amino acid uptake ; Autoradiography ; Salivary gland ; Serine ; Phenylalanine ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light-microscopic autoradiography was used to localize the cellular sites for neutral amino acid uptake in submandibular and sublingual salivary gland epithelia. The vasculature of isolated glands was perfused for 3–5 min with either L-(3-3H)serine or L-(4-3H)phenylalanine and then fixed by perfusion with buffered glutaraldehyde. In the submandibular gland the small neutral amino acid L-serine and the aromatic amino acid L-phenylalanine were localized to central acinar cells, demilunar cells and ductal cells. In the sublingual gland silver grains associated with each of these tritiated amino acids were localized to central acinar and ductal cells. Perfusion of both submandibular and sublingual glands with unlabelled L-serine (25 mM) or L-phenylalanine (30 mM) resulted in a significant decrease in the silver grain density associated with each labelled amino acid. The absence of silver grains in the lumina of acinar and ductal cells and the presence of tight junctions near the apical surface of the epithelium strongly suggest that the initial uptake of these amino acids was mediated by basolateral plasma membrane carriers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215897
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  • 31
    Electronic Resource
    Electronic Resource
    The transverse tubular system of cat intrafusal muscle fibres (1986)
    Springer
    Cell & tissue research 244 (1986), S. 197-202 
    Details
    ISSN: 1432-0878
    Keywords: Transverse tubular system ; Sarcoplasmic reticulum ; Triads ; Intrafusal muscle fibre ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A modified staining technique for transverse tubular and sarcoplasmic reticular systems was used to investigate their occurrence in different types of intrafusal muscle fibres in cat tail spindles. Intrafusal muscle fibres can be divided into three basic regions, namely, the periaxial space (A-region), intracapsular area (B-region) and the extracapsular area (C-region); the components of these systems were seen to vary in structure and distribution. The occurrence of these systems also varied among the different types of intrafusal muscle fibres, namely, the bag1, bag2 and chain fibres. In bag1 fibres components were sparse in the A-region, increased slightly in the B-region, but were most developed in the C-region; triads were consistently located at the border between A- and I-bands. In bag2 fibres membrane components were noted in the A-region but were more abundant in the B-region where some tubular components showed transverse and longitudinal branches linked together in the form of a network; membrane systems diminished towards the C-region. The majority of triads were located within the A-bands. In chain fibres the membrane systems occurred more commonly in the A-region, while in the B- and C-regions, the transverse tubular system possessed numerous transverse and longitudinal branches forming irregularly distributed tubular networks. Some tubular branches were dilated, while other branches terminated as sacs among arrays of the sarcoplasmic reticular system in I-bands. Some transverse tubules bifurcated into two branches with numbers of dilated sarcoplasmic reticular cisternae lying on either side, or between, the branches. Triads sometimes occurred between A- and I-bands, but, generally, were situated well within A-bands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218399
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  • 32
    Electronic Resource
    Electronic Resource
    Exercise induced increases in muscle fiber number (1986)
    Springer
    European journal of applied physiology 55 (1986), S. 137-141 
    Details
    ISSN: 1439-6327
    Keywords: Weight-lifting exercise ; Cat ; Flexor carpi radialis muscle ; Nitric acid digestion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of weight-lifting, which induced muscular enlargement, on fiber number was tested in the flexor carpi radialis muscle by operantly conditioning 6 cats to flex their right wrist against increasing resistance for an average of 101 weeks. The left was used as a control. At the end of training, the cats were performing “one-arm“ lifts with an average of 57% of their body weight. There was an 11% greater muscle weight (P〈0.01) and 9% (P〈0.02) more fibers in the exercised muscles from the right limb than in the left. This study using a different method, supports our earlier observations that prolonged weight-lifting exercise significantly increases the total number of muscle fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00714995
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  • 33
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    Hauptgruppenelement-Übergangsmetall-Mehrfachbindungen, IV. Katalytische Assistenz von [Cp(CO)3Mo]2 bei der Aggregation von Metallo-arsanen über Arsen-Metall-Doppelbindungskomplexe (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 378-382 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Main Group Element Transition Metal Multiple Bonds, IV. Catalytic Assistance by [Cp(CO)3Mo]2 in the Aggregation of Metallo-arsanes via Arsenic Metal Double Bond Complexes2)The metallo-arsanes Cp(CO)3M—AsMe2 (1a, b) (M = Mo, W) are converted to the double arsenido-bridged dinuclear complexes [(μ-AsMe2)Mo(CO)2Cp]2 (3a, b) in the presence of [Cp(CO)3Mo]2. Due to the unusual mild conditions of aggregation the intermediate formation of the double bonded species Cp(CO)2M=AsMe2 (2a, b) is postulated. The crystal structure of 3a is reported, which shows mutual trans arrangement of the cyclopentadienyl and CO ligands.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190133
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  • 34
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    Aliphatische Flüssigkristalle, 7. Einige mesogene Tercyclohexylderivate (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 387-400 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aliphatic Liquid Crystals, 7. Some Mesogenic Tercyclohexyl DerivativesStarting from bicyclohexyl-4-one 1 the tercyclohexyl-3-one 6 is synthesized via the acetyl derivatives 3a,b. Methoxycarbonylation of 6 gives the keto ester 12 which on the one hand is tranformed to the esters 15a,b and 17 - 20 and the nitriles 21a,b, on the other hand to the methylated keto esters 23a,b and 24a,b. From 23a the ester 26 with an axial 1-methyl group is obtained. Nearly all the products are mesogenic.
    Notes: Aus dem Bicyclohexyl-4-on 1 wird über die Acetylderivate 3a,b das Tercyclohexyl-3-on 6 aufgebaut, daraus durch Methoxycarbonylierung der Ketoester 12, der einerseits zu den Estern 15a,b und 17 - 20 und den Nitrilen 21a,b, andererseits zu den methylierten Ketoestern 23a,b und 24a,b umgesetzt wird. Aus 23a erhält man den Ester 26 mit axialer 1-Methylgruppe. Fast alle Produkte sind mesogen.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190202
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  • 35
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    Beiträge zur Chemie des Bors, 169. Sterisch anspruchsvolle N-Lithioaminoborane: Reagentien zur Synthese symmetrisch und unsymmetrisch substituierter Diborylamine (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1361-1373 
    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, 169. Sterically Demanding N-Lithioaminoboranes: Reagents for the Synthesis of Symmetrically and Unsymmetrically Substituted DiborylaminesN-Metalation of R2BNH2 or R2BNMeH yields lithium amides R2BNR′Li with sterically demanding R groups (R = tBu, iPr). These compounds are synthons for symmetrically or unsymmetrically substituted diborylamines as well as for B-functional diborylamines. NMR data reveal the conformation of these diborylamines. Compounds of the type tBu2B—NMe—BR2 contain tBu2B groups whose BC2 plane stands nearly orthogonal to the B2NC skeleton. In contrast, the BRX group in diborylamines of the type tBu2B—NH—BRX is strongly twisted with respect to the B2NH plane.
    Notes: Durch N-Metallierung erhältliche Lithiumamide R2BNR′Li mit sperrigen Substituenten R = tBu, iPr eignen sich sowohl zur Darstellung symmetrisch und unsymmetrisch substituierter Diborylamine als auch zur Gewinnung B-funktioneller Diborylamine. Kernresonanzspektroskopische Untersuchungen zeigen, daß Diborylamine tBu2B—NMe—BR2 eine tBu2B-Gruppe enthalten, deren BC2-Ebene weitgehend orthogonal zur B2NC-Gerüstebene steht. In Diborylaminen tBu2B—NH—BRX ist hingegen die BRX-Gruppe gegen die B2NH-Ebene verdrillt.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190423
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    Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen, XXV. Aufbau und Reaktivität von Se1- und Se2-Brücken in Organochrom-Komplexen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1437-1440 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiple Bonds Between Main Group Elements and Transition Metals, XXV. Synthesis and Reactivity of Se1- and Se2-Bridges in Organochromium CompoundsReaction of the ionic complex K[(η5-C5Me5)Cr(CO)3] (1) with selenium(I) with selenium(I) chloride, Se2Cl2, yields the diselenium compounds 2 of composition (η5-C5Me5)Cr(CO)5Se2 which is converted to the Se1 derivative (μ-Se)[η5-C5Me5)Cr2(CO)2]2 (3) with triphenylphosphane. 3 exhibits a linear, multiple bonded CrSeCr core structure. Reaction of 2 with diazomethane gives the novel mononuclear, paramagnetic selenoformaldehyde complex (η5-C5Me5)-Cr(CO)2(SeCH2) (4).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190430
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    Masthead (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986) 
    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.19861190501
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  • 38
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    N-tert-Butylpivalohydroxamsäure: s-trans-Konformation und H-Brückenbindungen im Kristall (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1441-1444 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-tert-Butylpivalohydroxamic Acid: s-trans-Conformation and H-Bonding in the CrystalIt is shown by an X-ray crystal structure analysis that, in the crystal, teh title compound has the s-trans-conformation and the molecules are linked by strong intermolecular H-bonds to linear chains.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190431
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  • 39
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    Synthesen von 2,6,7-Triazabicyclo[2.2.2]oct-2-en-5,8-dionen und 4(3H)-Pyrimidinonen durch 1,4-Dipolare Cycloadditionen von Pyrimidinium-4-olaten an Nitrile (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1445-1454 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of 2,6,7-Triazabicyclo[2.2.2]oct-2-ene-5,8-diones and 4(3H)-Pyrimidinones via 1,4-Dipolar Cycloaddition Reactions of Pyrimidinium-4-olates to NitrilesThe 3,6-dihydro-6-oxo-1-pyrimidinium-4-olate 1a, which carry no substituent in the 2 position, undergoes 1,4-dipolar cycloaddition reactions with ethyl cyanoformate (2a) and benzoyl cyanide (2b) to produce novel bicyclic primary adducts 3a, b, respectively, which at higher temperature fragment into 4(3H)-pyrimidinones 4a, b with elimination of phenyl isocyanate. However, pyrimidinium-4-olates 1b - h or 5, which are substituted in the 2 position, react directly with nitriles 2a - c to form high yields of 4(3H)-pyrimidinone derivatives of type 4 or 7, respectively. Furthermore, the reactions of 1a with isocyanic acid as well as with cyan amide are described.
    Notes: Das in 2-Position unsubstituierte 3,6-Dihydro-6-oxo-1-pyrimidinium-4-olat 1a geht mit Cyanameisensäure-ethylester (2a) und Benzoylcyanid (2b) 1,4-Dipolare Cycloadditionen zu neuen bicyclischen Primäraddukten 3a bzw. b ein, die bei höherer Temperatur unter Phenylisocyanat-Abgabe in 4(3H)-Pyrimidinone 4a, b fragmentieren. Dagegen reagieren die in 2-Stellung substituierten Pyrimidinium-4-olate 1b - h oder 5 mit Nitrilen 2a - c in hohen Ausbeuten direkt zu den 4(3H)-Pyrimidinon-Derivaten vom Typ 4 bzw. 7. Weiterhin werden die Reaktionen von 1a mit Isocyansäure sowie mit Cyanamid beschrieben.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190502
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    Über sterisch gehinderte freie Radikale, XV. Das erste unsymmetrische Dimere aus zwei stabilen Radikalen: 3-(tert-Butylphenylmethylen)-6-(triphenylmethyl)-1,4-cyclohexadien aus tert-Butyldiphenylmethyl und Triphenylmethyl (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2006-2012 
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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: Sterically Hindered Free Radicals, XV. The First Unsymmetrical Dimer from Two Different Stable Radicals: 3-(tert-Butylphenylmethylene)-6-(triphenylmethyl)-1,4-cyclohexadiene from tert-Butyldiphenylmethyl and TriphenylmethylThe quinonoid title compound 6 is formed in an equilibrium to 95% and can be isolated, when the two title radicals 1 and 3 are generated in solution. The reason for this is the sterically less strained position of the bulky tBu group at the sp2-C atom of the methylene group. The structure of 6 is proved by 1,5-H migration giving 8 and autoxidation of the latter at -10°C giving tBuOH and 4-tritylbenzophenone (12). The synthesis of several analogous compounds are described.
    Notes: Die chinoide Titelverbindung 6 entsteht im Gleichgewicht zu 〉95% und kann isoliert werden, wenn die beiden Titelradikale 1 und 3 in Lösung erzeugt werden. Ursache hierfür ist die räumlich günstigere Unterbringung der sperrigen tBu-Gruppe am sp2-C-Atom der Methylengruppe. Die Struktur von 6 wird durch 1,5-H-Verschiebung zu 8 sowie dessen Autoxidation bei -10°C zu tBuOH und 4-Tritylbenzophenon (12) bewiesen. Synthesen analoger Verbindungen werden beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190621
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  • 41
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    Der Einfluß von Phenylgruppen auf die Homokonjugation im Bicyclo[3.2.1]octa-3,6-dien-2-yl-Anion. Eine 13C-NMR-Studie (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2025-2049 
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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: The Effect of Phenyl Groups on the Homoconjugation in the Bicyclo[3.2.1]octa-3,6-dien-2-yl Anion. A 13C NMR StudyThe effects of deuterium atoms in the positions 2 and 4 of exo-6-bromo- (11) and endo-6-methoxytricyclo[3.2.1.02,7]oct-3-ene (12) as well as exo-4-methoxybicyclo[3.2.1]octa-2,6-diene (13) on their 13C chemical shifts are in line with the previous interpretation of the effects in correspondingly deuterated bicyclo[3.2.1]octa-3,6-dien-2-yl anions 1, and thus provide evidence for the homoconjugative interaction in 1. 3-Phenylbicyclo[3.2.1]octa-2,6-diene (16) and endo- (19a) as well as exo-4-phenylbicyclo[3.2.1]octa-2,6-diene (19b) have been prepared from bicyclo[3.2.1]oct-6-en-3-one (14) and bicyclo[3.1.0]hex-2-ene-endo-6-carbaldehyde (17), respectively. 2,4-Diphenylbicyclo[3.2.1]octa-2,6-diene (6) and 19a, b were deprotonated by methyllithium and n-butyllithium, respectively, whereas the proton abstraction from tricyclo[6.3.1.02,7]dodeca-2,4,6,9-triene (4) and from 16 required potassium tert-butoxide/n-butyllithium. As products the corresponding bicyclo[3.2.1]octa-3,6-dien-2-yl anion derivatives have been identified. By means of potassium tert-butoxide/n-butyllithium 19a, b were converted into 21K, i.e. the anion with K+ as counterion. The NMR spectra of 21Li turned out to depend upon the temperature in the range between +45 and -30°C in contrast to those of 21K. The 13C NMR spectra of the anions and of the corresponding hydrocarbons are discussed in detail in relation to the spectra of the unsubstituted species 1 and 2. In particular, the wide variations of the chemical shifts of C-6,7 depending upon the substituents of the allylic moiety of the bicyclo[3.2.1]octa-3,6-dien-2-yl anion system give strong support for the bishomoaromatic nature of these anions.
    Notes: Die Effekte von Deuteriumatomen in den Positionen 1 und 4 von exo-6-Brom- (11) und endo-6-Methoxytricyclo[3.2.1.02,7]oct-3-en (12) sowie exo-4-Methoxybicyclo[3.2.1]octa-2,6-dien (13) auf deren 13C-chemische Verschiebungen stützen die frühere Interpretation der Effekte bei entsprechend deuterierten Bicyclo[3.2.1]octa-3,6-dien-2-yl-Anionen 1 und belegen so die homokonjugative Wechselwirkung in 1.  -  Ausgehend von Bicyclo[3.2.1]oct-6-en-3-on (14) und Bicyclo[3.1.0]hex-2-en-endo-6-carbaldehyd (17) stellte man 3-Phenyl- (16) bzw. endo-4-Phenyl-(19a) und exo-4-Phenylbicyclo[3.2.1]octa-2,6-dien (19b) dar. 2,4-Diphenylbicyclo[3.2.1]octa-2,6-dien (6) und 19a, b wurden mit Methyllithium bzw. n-Butyllithium, Tricyclo[6.3.1.02,7]dodeca-2,4,6,9-tetraen (4) sowie 16 mit Kalium-tert-butoxid/n-Butyllithium deprotoniert, wobei die entsprechenden Bicyclo[3.2.1]octa-3,6-dien-2-yl-Anionderivate 7, 21Li, 5 und 22 entstanden. Aus 19a, b wurde mit Kalium-tert-butoxid/n-Butyllithium auch 21K, d. h. das zugehörige Anion mit K+ als Gegenion erhalten. Die NMR-Spektren von 21Li erwiesen sich im Gegensatz zu jenen von 21K im Bereich von +45 bis -30°C als temperaturabhängig. Die 13C-NMR-Spektren der Anionen und der zugehörigen Kohlenwasserstoffe werden im Vergleich mit den Spektren der unsubstituierten Verbindungen 1 und 2 ausführlich diskutiert. Insbesondere die starken Variationen der chemischen Verschiebungen von C-6,7 in Abhängigkeit von den Substitutenten am Allylteil des Bicyclo[3.2.1]octa-3,6-dien-2-yl-Anionsystems bieten ein starkes Argument für die bishomoaromatische Natur dieser Anionen.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190623
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    Synthese und physikalische Eigenschaften neuer 1,3-Dithiolylium-4-methanide und 1,3-Thiazolium-5-methanide (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2094-2103 
    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 Physical Properties of Novel 1,3-Dithiolylium-4-methanides and 1,3-Thiazolium-5-methanidesThe synthesis and physical properties of the novel title compounds of type 9 from carboxylic acid derivatives 3 and CH acidic compounds 4 are described.
    Notes: Die Synthese und physikalischen Eigenschaften der neuen Titelverbindungen vom Typ 9 aus Carbonsäure-Derivaten 3 und CH-aciden Verbindungen 4 werden beschrieben.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190704
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    Metallaheterocumulene, IV. 2-Azaallyliden-Komplexe  -  neuartige Verbindungen mit einem gewinkelten CNCR2-Fragment als Komplexligand (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2080-2093 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metallaheterocumulenes, IV. 2-Azaallylidene Complexes  -  Novel Compounds with a Bent CNCR2 Fragment as Complex Ligand(2-Azoniaallenylidene)pentacarbonyltungsten tetrabromoaluminate complexes [(CO)5W(CNCR2)]+AlBr4- (2-AlBr4) (CR2=C(C6H4Br-4)2 (a), CPh2 (b), C(C6H4OMe-4)2 (c), C(C6H4)2O (d), C(2,4,6-C6H2Me3)2 (e)) Which are synthesized by the reaction of (CO)5W[C(OEt)N=CR2] (1) with AlBr3, react with freshly distilled tetrahydrofuran to give neural trans-bromo(2-azaallylidene) complexes trans-Br(CO)4W(CNCR2) (3) and small amounts of (CO)5W—C≡N—[CR2]2—N≡C—W(CO)5 (4). The compounds 4 correspond to the product of a reductive dimerization of two cations 2. If 1b (or the corresponding methoxy compound 5) reacts with BBr3 instead of AlBr3/THF 4b is the main product. The spectroscopic data of 3 and the results of an X-ray analysis of 3b show that the replacement of a CO ligand in the cations 2 by Br- with formation of 3 results in a drastic change of the bonding situation within the CNCR2 ligand. 3a-e are the first compounds in which a strongly bent CNCR2 fragment functions as a complex ligand. The aminocarbyne complex trans-Br(CO)4W≡CNPh2 (7) was synthesized by BBr3-induced fragmentation of (CO)5W[C(NPh2)N=C(Ph)OMe] (6).
    Notes: (2-Azoniaallenyliden)pentacarbonylwolfram-tetrabromoaluminat-Komplexe [(CO)5W(CNCR2)]+AlBr4- (2-AlBr4) (CR2=C(C6H4Br-4)2 (a), CPh2 (b), C(C6H4OMe-4)2 (c), C(C6H4)2O (d), C(2,4,6-C6H2Me3)2 (e))  -  darstellbar durch Umsetzung von (CO)5W[C(OEt)N=CR2] (1) mit Albr3  -  reagieren mit frisch destillierten Tetrahydrofuran zu neutralen trans-Bromo(2-azaallyliden)-Komplexen trans-Br(CO)4W(CNCR2) (3) und wenig (CO)5W—C≡N—[CR2]2—N≡C—W(CO)5 (4). Die Verbindungen 4. entsprechen dem Produkt einer reduktiven Dimerisierung zweier Kationen 2. 4b wird zum Hauptprodukt der Umsetzung, wenn 1b (oder der entsprechende Methoxy-Komplex 5) mit BBr3 anstatt AlBr3/THF umgesetzt wird. Wie die spektroskopischen Daten von 3 sowie die Ergebnisse der an 3b durchgeführten Röntgenstrukturanalyse zeigen, führt der Austausch eines CO-Liganden in den Kationen 2 gegen Br- unter Bildung von 3 zu einer drastischen Veränderung der Bindungsverhältnisse im CNCR2-Liganden. 3a-e sind die ersten Verbindungen, in denen ein stark gewinkeltes CNCR2-Fragment als Komplexligand fungiert. Durch BBr3-induzierte Fragmentierung von (CO)5W[C(NPh2)N=C(Ph)OMe] (6) wurde der Aminocarbin-Komplex trans-Br(CO)4W≡CNPh2 (7) dargestellt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190703
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    Heterocyclische β-Enaminoester, 41. Vinylogieprinzip bei 6,7-Dihydro-1H-azepinen; Cycloaddition und neuartige Umlagerung zu 2,3,3a,7a-Tetrahydroindolen.  -  Thermische [2 + 2]-Cycloadditionen mit 4-R-TAD (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2114-2126 
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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: Heterocyclic β-Enamino Esters, 41. Vinylogeous Principle on 6,7-Dihydro-1H-azepines; Cycloaddition and Novel Rearrangement to 2,3,3a,7a-Tetrahydroindoles.  -  Thermal [2 + 2]-Cycloadditions with 4-R-TADThe conjugated π-Systems of 6,7-dihydrooxepines, -thiepines, and -azepines (1-5) show a remarkable alternance of their 13C NMR shifts. In a cycloaddition-ring enlargement sequence the 6,7-dihydroazepine 3 reacts with acetylenedicarboxylates at the 4,5-double bond to afford first the intermediary 8,9-dihydro-1H-azonines 6B. These give in turn the indoles 7a,b via thermal 6π-electron cyclization. Under subsequent rearrangement 2,3,3a,7a-tetrahydroindoles 8a,b are formed. The structure of 8a is established by X-ray diffraction. In a polar [2 + 2]-cycloaddition 4-R-1,2,4-triazoline-3,5-dione (4-R-TAD) gives with 3 and 5 the [1,2,4]triazolo[1′,2′:1,2]diazet-[3,4-d]azepines 10a-d and 11a,b resp., and with the bis-TAD 12 the 2:1-adduct 13. Treatment of 10a with phenyl isocyanate originates the carbodiimide 14 which is converted with basic ring closure into the pyrimido[4,5-b]azepine 15.
    Notes: 6,7-Dihydrooxepine, -thiepine und -azepine (1-5) zeigen eine ausgeprägte Alternanz ihrer 13C-NMR-Verschiebungen im konjugierten π-System. Das 6,7-Dihydroazepin 3 reagiert mit Acetylendicarbonsäureestern zunächst unter Cycloaddition-Ringerweiterung an der 4,5-Doppelbindung zu den intermediären 8,9-Dihydro-1H-azoninen 6b. Diese ergeben sogleich unter thermischem 6π-Elektronenringschluß die Indole 7a,b. Nach erneuter Umlagerung entstehen 2,3,3a,7a-Tetrahydroindole 8a,b; die Konstitution von 8a wird durch Röntgenstrukturanalyse ermittelt. Mit 4-R-1,2,4-Triazolin-3,5-dionen (4-R-TAD) entstehen aus 3 und 5 in polarer [2 + 2]-Cycloaddition die [1,2,4]Triazolo[1′,2′:1,2]diazet[3,4-d]azepine 10a-d und 11a,b mit dem Bis-TAD 12 das 2:1-Addukt 13. 10a ergibt mit Phenylisocyanat das Carbodiimid 14 und beim basischen Ringschluß das Pyrimido[4,5-b]azepin 15.
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    Neue Reagenzien, XXXVII. (α-Lithioalkyl)diphenylarsanoxide: Synthese und Anwendung zur indirekten nucleophilen Haloalkylierung (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2135-2142 
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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: New Reagents, XXXVII. (α-Lithioalkyl)diphenylarsane Oxides: Synthesis and Application for the Indirect Nucleophilic HaloalkylationDue to ready accessibility and high nucleophilicity (α-lithioalkyl)diphenylarsane oxides (2) are favorable reagents for the synthesis of many organoarsenic compounds. In organic synthesis they are recommendable as reagents for indirect nucleophilic haloalkylation reactions (Hal=Cl, Br, I).
    Notes: (α-Lithioalkyl)diphenylarsanoxide (2) sind wegen ihrer bequemen Zugänglichkeit und hohen Nucleophilie günstige Reagenzien zur Darstellung zahlreicher Organoarsenverbindungen. In der organischen Synthese sind sie als Reagenzien für indirekte nucleophile Haloalkylierungen (Hal=Cl, Br, I) empfehlenswert.
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    URL: http://dx.doi.org/10.1002/cber.19861190708
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    Synthesen mit Cyclobutadienen, 13. Azapentafulvene aus 2,3,4-Tri-tert-butylcyclobutadien-1-carbonsäureestern und Isonitrilen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2159-2172 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese with Cyclobutadienes, 13. Azapentafulvenes from 2,3,4-Tri-tert-butylcyclobutadiene-1-carboxylic Esters and IsonitrilesFrom kinetically stabilized cyclobutadienes 6a and b and isonitriles 7a-c the azapentafulvenes 9a-d are obtained. In contrast, 6a reacts with 7d exclusively to form the constitution isomeric azapentafulvene 11e. Both isomers (9f and 11f) are realized in the reaction of 6a with 7e. The structural assignment of the isomers 9 and 11 is based on 13C NMR investigations as well as on an X-ray analysis performed for 9a. Hydrolysis of 9 and 11 yields the tri-tert-butyl substituted cyclopentadienones 20a,b and 21. By photochemical means 21 is transformed into the isomer 20a, which can also be obtained directly from the cyclobutadiene 6a and carbon monoxide.
    Notes: Aus den kinetisch stabilisierten Cyclobutadienen 6a bzw. b und den Isonitrilen 7a-c erhält man die Azapentafulvene 9a-d. Im Gegensatz dazu reagiert 6a mit 7d ausschließlich unter Bildung des konstitutionsisomeren Azapentafulvens 11e. Beide Möglichkeiten (9f und 11f) werden bei der Umsetzung von 6a mit 7e wahrgenommen. Die Strukturzuordnung der Isomeren 9 und 11 beruht auf 13C-NMR-Untersuchungen sowie auf der Röntgenstrukturanalyse für 9a. Hydrolyse von 9 und 11 macht die tri-tert-butylsubstituierten Cyclopentadienone 20a,b und 21 zugänglich. Photochemisch läßt sich 21 in das Isomere 20a umwandeln, das auch unmittelbar aus dem Cyclobutadien 6a und Kohlenmonoxid erhalten werden kann.
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    URL: http://dx.doi.org/10.1002/cber.19861190711
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  • 47
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    Enantioselective diastereospecific synthesis of anti-α-alkyl-β-hydroxy esters through cuprate opening of glycidic esters (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2178-2190 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enantioselektive diastereospezifische Synthese von anti-α-Alkyl-β-hydroxycarbonsäureestern durch Cuprat-Ringöffnung von GlycidesternEine über die Zwischenglieder 4-7 ablaufende diastereospezifische Kettenverlängerung von Aldehyden 1 zu anti-α-Alkyl-β-hydroxyestern 2 wird beschrieben. Durch Verwendung der Sharpless-Epoxidierung kann 2 mit Enantiomerenüberschüssen von 〉90% in Form beider Antipoden erhalten werden.
    Notes: A diastereospecific chain elongation of the aldehydes 1 of anti-α-alkyl-β-hydroxy esters 2 via the intermediates 4-7 is described. By means of the Sharpless epoxidation, 2 may be obtained with 〉90% ee in either enantiomer.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190713
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  • 48
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    Stereoselektive Aldolreaktion mit chiralen sekundären Acetamiden (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2191-2207 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselective Aldol Reaction with Chiral Secondary AcetamidesThe deprotonated acetamides 4a-c und 5a-c are added to prochiral carbonyl compounds. The influence of the solvent, of the reaction temperature, and of the enolate gegenion on the ratio of the isomeric products 8/9, 18/19, and 26/27, respectively, are studied. The highest degrees of diastereoselectivity are observed, when the titanium enolate of the acetamide 4a or the threefold deprotonated N-acetyl-α-phenylglycinol (5a) is used. The diastereomers 18a-d, formed in excess in the addition of 5a to aldehydes, are isolated in a pure form by a single recrystallization, and afford the enantiomerically pure β-hydroxy carboxylic acids 3a-d. Thereby, the chiral auxiliary, α-phenylglycinol (14), is recovered.
    Notes: Die deprotonierten Acetamide 4a-c und 5a-c werden an prochirale Carbonylverbindungen addiert. Dabei wird der Einfluß von Lösungsmittel, Temperatur und Enolat-Gegenion auf das jeweilige Verhältnis der isomeren Produkte 8/9, 18/19 und 26/27 untersucht. Die höchsten Diastereoselektivitäten lassen sich mit dem Titan-enolat des Amids 4a und dem dreifach deprotonierten N-Acetyl-α-phenylglycinol (5a) erzielen. Die bei der Addition von 5a an Aldehyde im Überschuß gebildeten Diastereomeren 18a-d können durch einmaliges Umkristallisieren rein erhalten werden und liefern nach alkalischer Hydrolyse die enantiomerenreinen β-Hydroxycarbonsäuren 3a-d. Dabei wird der chirale Hilfsstoff, α-Phenylglycinol (14), zurückgewonnen.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190714
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    Synthesis of ketene aminals with an imidazolidine ring by condensation of 4,5-dihydro-2-(methylithio)-1H-imidazoles with active methylene compounds and some addition and cyclocondensation reactions (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2208-2219 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese von Ketenaminalen mit Imidazolidinring durch Kondensation von 4,5-Dihydro-2-(methylthio)-1H-imidazolen mit CH-aciden Methylenverbindungen und einige Additions-und Cyclokondensations-Reaktionen4,5-Dihydro-2-(methylthio)-1H-imidazole 1a, b reagieren mit aktiven Methylenverbindungen 2a-f unter Eliminierung von Methanthiol zu den entsprechend substituierten Methylenimidazolidinen 3a-f und 4c-f. Die Verbindungen 2g-j, die eine aktivere Carbonylgruppe enthalten, ergeben mit 1a unter Eliminierung einer Methylthio- und Acylgruppe 3g-i. 3a, g-i reagieren mit Estern ungesättigter Säuren in einer Additions- und Cyclokondensations-Sequenz zu den entsprechenden Imidazo[1,2-a]pyridinen 5,6 und 7, ergeben aber mit Azodicarbonsäure-diethylester nur die Additionsprodukte 8.
    Notes: The 4,5-dihydro-2-(methylthio)-1H-imidazoles 1a,b react with active methylene compounds 2a-f to afford the corresponding substituted methyleneimidazolidines 3a-f and 4c-f by elimination of methanethiol. The reaction of compounds 2g-j, which contain a more active carbonyl group, with 1a gives 3g-i by elimination of a methylthio group as well as an acyl group, too. 3a,g-i react with esters of α,β-unsaturated acids to afford the corresponding imidazo[1,2-a]pyridines 5,6, and 7 in an addition and cyclocondensation reaction sequence, but with diethyl azodicarboxylate only to give the addition product 8.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190715
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  • 50
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    Desaminierungsreaktionen, 43. Zum Einfluß von Trifluormethylgruppen auf die Reaktionen aliphatischer Diazonium-Ionen und Carbokationen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2233-2248 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, 43. The Effect of Trifluoromethyl Groups on the Reactivity of Aliphatic Diazonium Ions and CarbocationsVarious trifluoroalkanamines (9, 26, 35, 38, 45, 56, and 67) have been prepared and diazotized (water, pH 3.5) to probe the effect of trifluoromethyl groups on the reactivity of aliphatic diazonium ions. The product distributions reveal that α-CF3 groups enhance inverting displacement and enforce rearrangements (hydride shifts) separating the positive charge from CF3. Migrations of the positive charge from the β- to the γ-position are less strongly promoted than those from α to β. Enhancement factors of ca. 15 (α → β) and 4 (β → γ) may be derived by comparison with analogous alkanediazonium ions. The positive charge does not migrate in the reverse direction (β → α) except for minor amounts of a pinacolic rearrangement (68 → 7). A migration of the positive charge from γ to β has been detected with 36 but a tenfold decrease as compared to the analogous butanediazonium ion 37 is indicated. All observations are reasonably explained in terms of the relative stabilites of the intermediate trifluoroalkyl cations.
    Notes: Eine Reihe von Trifluoralkanaminen (9, 26, 35, 38, 45, 56 und 67) wurde dargestellt und diazotiert (Wasser, pH 3.5), um den Einfluß von Trifluormethylgruppen auf die Reaktionsweise aliphatischer Diazonium-Ionen zu untersuchen. Die Produktverteilungen zeigen, daß α-CF3-Gruppen die invertierende Substitution verstärken und Umlagerungen (Wasserstoffverschiebungen) fördern, welche die positive Ladung von der CF3-Gruppe trennen. Die Wanderung der positiven Ladung von der β- zur γ-Position wird weniger stark gefördert als die von α nach β. Aus dem Vergleich mit analogen Alkandiazonium-Ionen lassen sich Beschleunigungsfaktoren von ca. 15 (α → β) und 4 (β → γ) ableiten. In umgekehrter Richtung (β → α) wandert die positive Ladung nicht, abgesehen von einem kleinen Anteil Pinakol-Umlagerung (68 → 7). Eine Ladungsverschiebung von der γ- zur β-Position wurde bei 36 gefunden; im Vergleich zum analogen Butandiazonium-Ion 37 ist sie um den Faktor 10 verringert. Alle Beobachtungen sind im Einklang mit der relativen Stabilität der intermediären Trifluoralkyl-Kationen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190717
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    Neuartige 2,6-disubstituierte Azulene (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2272-2288 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel 2,6-Disubstituted AzulenesMethods are described to introduce varying residues into 2- and 6-positions of azulene, starting from diethyl 6-bromo-2-methoxy-1,3-azulenedicarboxylate (1). 2-Substitution is achieved by Grignard reaction or exchange of the alkoxy group and by aldol condensation of 2-methyl compounds whereas 6-substitution is conducted by nucleophilic displacement and by homo- and hetero-aromatic coupling. Consecutive dealkoxycarbonylation yields azulenes 20 with free 1,3-positions. Biazulenes 9a-c and 201, 20m, styryl- and bis(styryl)-azulenes 15-18 and 20i-k, and finally the azulenedialdehyde 19 are novel compounds which were difficult to prepare or were inaccessible so far.
    Notes: Ausgehend von 6-Brom-2-methoxy-1,3-azulendicarbonsäure-diethylester (1) werden Methoden zur Einführung unterschiedlicher Reste in 2- und 6-Position entwickelt. 2-Substitution gelingt durch Grignard-Reaktion oder Austausch der Alkoxygruppe sowie durch Aldol-Kondensation von 2-Methylverbindungen, während 6-Substitution durch nucleophilen Austausch und durch Homo- und Kreuz-Aromaten-Kupplungen erfolgt. Anschließende Dealkoxycarbonylierung erbringt Azulene 20 mit freien 1,3-Stellungen. Die Biazulene 9a-c und 201, 20m, die Styryl- und Bis(styryl)azulene 15-18 und 20i-k sowie der Azulendialdehyd 19 sind Verbindungen, die bisher schwierig oder nicht zugänglich waren.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190720
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    Zur Frage der Stellungsisomerie bei disubstituierten Bullvalenen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2339-2349 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Concerning the Question of Positional Isomerism in Disubstituted BullvalenesWe report about 15 new disubstituted bullvalenes (2, 4, 5, 11, 12, 14-20, 22-24) and discuss their substitution pattern together with 9 known species (1, 3, 6-10, 13, 21). The results which are partly unexpected are put together phenomenologically. We have no reasonable explanation for some results, i.e. only a few substituents with „complementary“ properties like the pair CH2OH/Br or CH3/CN in compounds 16 and 18, respectively, prefer a vicinal arrangement at a double bond.
    Notes: Wir berichten über 15 neue disubstituierte Bullvalene (2, 4, 5, 11, 12, 14-20, 22-24) und diskutieren ihr Substitutionsmuster gemeinsam mit dem von 9 bekannten Vertretern (1, 3, 6-10, 13, 21). Die teilweise unerwarteten Ergebnisse werden phänomenologisch geordnet. Für einige Befunde fehlen befriedigende Erklärungen. So bevorzugen z. B. nur manche Substituenten mit „komplementären“ Eigenschaften wie das Paar CH2OH/Br oder CH3/CN in den Verbindungen 16 bzw. 18 eine vicinale Anordnung an der Doppelbindung.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190724
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    Zur Regio- und Stereoselektivität neuer thermischer [3 + 2]-Cycloadditionen mesoionischer 1,3-Oxathiol-4-one an Alkine und Alkene (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2317-2338 
    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 Regio- and Stereoselectivity of Novel Thermal [3 + 2] Cycloaddition Reactions of Mesonionic 1,3-Oxathiol-4-ones to Alkynes and AlkenesAs potential carbonyl ylides, the 1,3-oxathiolyium-4-olates 1c or 1d combine with dibenzoylacetylene or 1-(diethylamino)-1-propyne via nonisolable [3 + 2] primary adducts of type 2, which release COS to give the furan derivatives 3a or b, respectively. On the other hand, some representative of 1 reacts with symmetrically and unsymmetrically substituted olefinic substrates with regio- and/or stereoselective formation of the isolable [3 + 2] primary adducts 4-16. In the example of the reactions of 1c with trans- and cis-cyclooctene, the stereospecificities and the competition constant are determined. Furthermore, the thermolyses of the cycloadducts 4b,5,6, and 7a,b are investigated. The addition directions, derived from the FMO and PMO theory, are compared with the experimentally realized regiochemistry.
    Notes: Als potentielle Carbonyl-ylide vereinigen sich die 1,3-Oxathiolylium-4-olate 1c oder 1d mit Dibenzoylacetylen oder 1-(Diethylamino)-1-propin über nicht isolierbare [3 + 2]-Primäraddukte vom Typ 2 unter COS-Abspaltung zu Furan-Derivaten 3a bzw. b. Demgegenüber reagieren einige Vertreter von 1 mit symmetrisch und unsymmetrisch substituierten olefinischen Substraten regio- und/oder stereoselektiv zu isolierbaren [3 + 2]-Primäraddukten 4-16. Am Beispiel der Umsetzung von 1c mit trans- und cis-Cycloocten werden die Stereospezifitäten und die Konkurrenzkonstante ermittelt. Weiterhin werden die Thermolysen der Cycloaddukte 4b, 5, 6 und 7a,b untersucht. Die aus der FMO- und PMO-Theorie abgeleiteten Additionsrichtungen werden mit der experimentell realisierten Regiochemie verglichen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190723
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    Synthese und Reaktion von α-(Dimethylamino)alkanaldimethylhydrazonen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2397-2413 
    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 Reaction of α-(Dimethylamino)alkanal DimethylhydrazonesSeveral α-(dimethylamino)aldehyde hydrazones of the general structure 11 have been obtained by alkylation of the lithium salt of 9 or by addition of Grignard reagents to 15 or 17. The compounds react with acyl chlorides to give hydrazones of unsaturated aldehydes. The same products 27 are obtained by thermal degradation of the ammonium salts 26. In the hydrazonoammonium salts 26a, g the trimethylammonium group can be substituted by a variety of nucleophiles (→ 34-39).
    Notes: Verschieden substituierte α-(Dimethylamino)aldehyd-hydrazone der allgemeinen Struktur 11 lassen sich aus dem Lithium-Salz des (Dimethylamino)acetaldehyd-dimethylhydrazons durch Alkylierung sowie durch Addition von Grignard-Verbindungen an das Ammoniumsalz 15 oder das N,O-Acetal 17 darstellen. Die Verbindungen 11 enthalten eine leicht eliminierbare Dimethylaminogruppe und gehen mit Säurechloriden oder nach Methylierung thermisch in Hydrazone 27 α,β-ungesättigter Aldehyde über. In den Salzen 26a, g läßt sich die Trimethylammoniumgruppe durch verschiedene Nucleophile verdrängen (→ 34-39).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190802
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    Intramolekulare Wechselwirkungen in Radikalkationen von Di- und Tetra(α-methoxy)-9,10-dihydro-9,10-ethanoanthracenen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2414-2429 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Interactions in Radical Cations of Di- and Tetra(α-methoxy)-9,10-dihydro-9,10-ethanoanthracenes[4 + 2]-Cycloaddition of maleic anhydride, 2-chloropropenoyl chloride and (E)-dichloroethene to 1,4-di- (3a) and 1,4,5,8-tetramethoxyanthracene (3b) yields the dihydroethanoanthracenes 4, 5, and 8, respectively. The predominant maleic anhydride adduct 4a is assigned the exo-configuration on the basis of the ESR spectrum of the radical cations 4a+·. The cycloadducts 5 and 8 are converted to the dihydroethanoanthracenes 10 via the ketones 6 or the dihydroethenoanthracenes 9, respectively. Aluminium chloride in nitromethane oxidizes the α-methoxydihydroethanoanthracenes 4, 6a, 8, and 10 to radical cations the ESR spectra of which are analyzed. Besides the expected proton hyperfine splittings of the 1,4-dimethoxybenzene moiety, one observes long-range transfer of spin density to the unsubstituted benzene ring [a(4H) = 0.008-0.010 mT] as well as to the syn-[10a+·: a(2H) = 0.013 mT] and anti-protons [a(2H) = 0.059-0.069 mT] of the ethano bridge. Of the radical cations possessing two 1,4-dimethoxybenzene rings, 4b and 10b do not exhibit dynamic ESR spectroscopic phenomena. On the other hand, the unpaired electron is exchanged rapidly (with respect to the hyperfine splitting time scala) between the 1,4-dimethoxybenzene rings of the radical cation 8b+·. The dependence of the exchange frequency on the temperature and the aluminium chloride concentration is indicative of ion-pair effects.
    Notes: Durch [4 + 2]-Cycloaddition von Maleinsäureanhydrid, 2-Chlorpropenoylchlorid bzw. (E)-Dichlorethen an 1,4-Di- (3a) und 1,4,5,8-Tetramethoxyanthracen (3b) entstehen die Dihydroethanoanthracene 4, 5 bzw. 8. Dem überwiegenden der Maleinsäureanhydrid-Addukte 4a wird aufgrund des ESR-Spektrums der Radikalkationen 4a+· die exo-Konfiguration zugeordnet. Die Cycloaddukte 5 und 8 werden über die Ketone 6 bzw. Dihydroethenoanthracene 9 in die Dihydroethanoanthracene 10 übergeführt. Aluminiumchlorid in Nitromethan oxidiert die α-Methoxydihydroethanoanthracene 4, 6a, 8 und 10 zu Radikalkationen, deren ESR-Spektren analysiert werden. Neben den erwarteten Protonen-Hyperfeinaufspaltungen des 1,4-Dimethoxybenzolrings beobachtet man weitreichenden Transfer von Spindichte zum unsubstituierten Benzolring [a(4H) = 0.008-0.010 mT] sowie zu den syn-[10a+·: a(2H) = 0.013 mT] und anti-Protonen [a(2H) = 0.059-0.069 mT] der Ethanobrücke. Von den Radikalkationen mit zwei 1,4-Dimethoxybenzolringen zeigen die aus 4b und 10b erhaltenen keine dynamischen ESR-spektroskopischen Phänomene. Dagegen wird in 8b+· das ungepaarte Elektron rasch bezüglich der Hyperfeinaufspaltungs-Zeitskala zwischen den 1,4-Dimethoxybenzolringen ausgetauscht. Die Abhängigkeit der Austauschfrequenz von der Temperatur und der Aluminiumchlorid-Konzentration weist auf Ionenpaar-Effekte hin.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190803
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    Synthesen, Struktur und Eigenschaften von N-(Alkoxymethylen)carbamidsäureestern (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2444-2457 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses, Structures, and Properties of N-(Alkoxymethylene)carbamatesN-(Alkoxymethylene)carbamates 1 are synthesized from the imidate hydrochlorides 7 or from the imidates 8 and formates 9 in the presence of amine bases in mostly satisfactory yields (two optimized procedures, 10 examples).—An X-ray analysis of the derivative 1dbc shows an almost planar EtO—RC=N—C skeleton with an exo-s-cis-ethoxy function; the carboxylic group is nearly perpendicular to that plane.  - Quantum mechanical ab initio optimizations (3-21 G//3-21 G) were performed for nine conformations of the model substances 11; the calculated rotational barrier around the amide type bond is estimated to be ca. 5 kcal/mol. The ground state energy of the conformers of 11 is ca. 20 kcal/mol higher than that of the model for 10, N-formylcarbamic acid (12). —IR, 1H, and 13C NMR data for solutions of 1 are discussed.
    Notes: N-(Alkoxymethylen)carbamidsäureester 1 können durch Umsetzung der Imidsäureester-hydrochloride 7 oder der Imidsäureester 8 mit Chlorameisensäureestern 9 in Gegenwart von Aminbasen in meist guten bis sehr guten Ausbeuten hergestellt werden (zwei optimierte Syntheseverfahren, 10 Beispiele). Schonende Hydrolyse der Verbindungen 1 ergibt die N-Acylcarbamidsäureester 10.  - Die Röntgenstrukturanalyse des Derivates 1dbc zeigt ein planares RO—RC=N—C-Molekülgerüst mit exo-ständiger s-cis-orientierter Ethoxygruppe; die Carboxylgruppe steht annähernd senkrecht auf dieser Ebene.  - Mit Hilfe quantenmechanischer ab-initio-Berechnungen (3-21G//3-21 G) wurden Strukturen und Energien der Modellverbindungen 11 bestimmt und deren Rotationsbarriere um die amidische -Bindung abgeschätzt (ca. 5 kcal/mol). Im Vergleich mit N-Formylcarbamidsäure (12) (Modell für 10) besitzen die Verbindungen 11 eine um ca. 20 kcal/mol höhere Grundzustandsenergie. —IR-, 1H- und 13C-NMR-Daten von Lösungen von 1 werden diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190805
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    Relative Reaktivität Alkyl-substituierter Alkene und Cycloalkene gegenüber Diarylcarbenium-Ionen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2473-2496 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Relative Reactivities of Alkyl-Substituted Alkenes and Cycloalkenes towards Diarylcarbenium IonsThe relative reactivities of alkyl-substituted alkenes 4 towards diarylmethyl cations 2 generated in situ from diarylmethyl chlorides 1 and Lewis acids were determined by competition experiments. The relative reactivities were almost independent of the nature of the Lewis acid. Eventual differences of the solvation free enthalpies of various activated complexes are, therefore, independent of the nature of the gegen ions. The rate acceleration by methyl groups - 6-50 by CH3 at the attacked vinylic position and approximately 104 at the developing carbenium centre - indicates a scarcely bridged transition state.
    Notes: Nach der Konkurrenzmethode wurden die relativen Reaktivitäten Alkyl-substituierter Alkene 4 gegenüber Diarylmethyl-Kationen 2 bestimmt, die in Gegenwart von Alken-Gemischen aus Diarylmethylchloriden 1 und Lewis-Säuren erzeugt wurden. Die Konkurrenz-konstanten werden durch die Art der Lewis-Säure nur wenig beeinflußt, so daß eine eventuelle Differenz der freien Solvatationsenthalpie verschiedener aktivierter Komplexe von der Natur des Gegenions unabhängig sein muß. Aus der 6-50fachen Reaktionsbeschleunigung durch Methylgruppen, die sich am angegriffenen Alken-Kohlenstoff befinden und der 104fachen Reaktivitätssteigerung durch Methylgruppen am neuen Carbeniumzentrum wird auf einen wenig verbrückten Übergangszustand geschlossen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190808
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    Synthese von 2,5-Diazido-3,6-dicyan- und 2,6-Diazido-3,5-dicyan-1,4-benzochinon zur Darstellung von Dicyanketen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 844-849 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of 2,5-Diazido-3,6-dicyano- and 2,6-Diazido-3,5-dicyano-1,4-benzoquinone for the Preparation of DicyanoketeneTwo short syntheses of 2,5-diazido-3,6-dicyano- (1) and 2,6-diazido-3,5-dicyano-1,4-benzo-quinone (3) as starting materials for the preparation of dicyanoketene in situ are reported; beyond that the compounds 14, 15, and 16a, b are synthesized.
    Notes: Es wird über zwei wenigstufige Synthesen von 2,5-Diazido-3,6-dicyan- (1) und 2,6-Diazido-3,5-dicyan-1,4-benzochinon (3) als Ausgangssubstanzen zur Darstellung von Dicyanketen in situ berichtet; darüber hinaus werden die Verbindungen 14, 15 und 16a, b dargestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190308
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    Ester der Ferrocendithiocarbonsäure (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 850-856 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Esters of Ferrocenedithiocarboxylic AcidTwo methods were used to prepare esters of ferrocenedithiocarboxylic acid: 1. Alkylation of the ferrocenedithiocarboxylate anion in the piperidinium salt [C5H10NH2]+[Fc—CS2]- (1) by CH3I, C2H5I, and ethylene oxide gave mononuclear esters Fc—C(S)SR (R = CH3 (2), C2H5 (3), CH2CH2OH (4)), whereas the dinuclear methylene diester [Fc—C(S)S]2CH2 (9a) was formed using either CH2Cl2 or CH2I2. 2. The reaction of ferrocenecarbonyl chloride, Fc—C(O)Cl, with methanethiol, CH3SH, to give Fc—C(O)SCH3 (7) and subsequent sulfuration by P4S10 furnished Fc—C(S)SCH3 (2). The analogous reactions with dithiols, HS[CH2]nSH (n = 2 - 4), led to the dinuclear compounds [Fc—C(S)S]2[CH2]n (n = 2 (9b), 3 (9c), 4 (9d)). All the intermediates of the composition Fc—C(O)S[CH2]nSH (11b - d), [Fc—C(O)S]2[CH2]n (12b - d), and Fc—C(S)S[CH2]nSC(O) - Fc (13b - d) could be isolated. The new compounds were characterized on the basis of their 1H and 13C NMR spectra.
    Notes: Zwei Methoden wurden zur Darstellung von Estern der Ferrocendithiocarbonsäure angewandt: 1. Die Alkylierung des Ferrocendithiocarboxylat-Anions im Piperidinium-Salz [C5H10NH2]+ [Fc—CS2]- (1) mit CH3I, C2H5I und Ethylenoxid ergab einkernige Ester, Fc—C(S)SR (R = CH3 (2), C2H5 (3), CH2CH2OH (4)), während mit CH2Cl2 oder CH2I2 der zweikernige Methylendiester [Fc—C(S)S]2CH2 (9a) entstand. 2. Die Umsetzung von Ferrocencarbonsäurechlorid, Fc—C(O)Cl, mit Methanthiol, CH3SH, zu Fc—C(O)SCH3 (7) und anschließende Sulfurierung mit P4S10 lieferte Fc—C(S)SCH3 (2). Die analoge Reaktion mit Dithiolen HS[CH2]nSH (n = 2 - 4) führte zu den Zweikernverbindungen [Fc—C(S)S]2[CH2]n (n = 2 (9b), 3 (9c), 4 (9d)); alle Zwischenstufen der Zusammensetzung Fc—C(O)S[CH2]nSH (11b - d), [Fc—C(O)S]2[CH2]n (12b - d) und Fc—C(S)S-[CH2]nSC(O) - Fc (13b - d) konnten isoliert werden. Die neuen Verbindungen wurden anhand der 1H- und 13C-NMR-Spektren charakterisiert.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190309
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    Synthese und Eigenschaften von substituierten 1-Alkoxy-2-azaallenium-Salzen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 857-871 
    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 Substituted 1-Alkoxy-2-azaallenium Salts12 novel substituted 1-alkoxy-2-azaallenium salts 1 have been prepared by reaction of the N-methyleneamides 3 with trialkyloxonium salts 4. During the alkylation reaction of the N-benzylideneamides 3m, n a formal disproportionation takes place to yield higher and lower oxidized 2-azaallenium salts (13, 14 from 3n) as the major products. The salts 1n, r, which are therefore not easily accessible by the alkylation route, can be prepared successfully by an acylation cleavage reaction of the N-(alkoxymethyl)imidates 8. The protonation of the substances 3 takes place exclusively at the nitrogen atom to give the N-acyliminium salts 19. Detailed spectroscopic data (IR, 1H, 13C NMR, MS) are included.
    Notes: Durch Umsetzung der N-Methylencarbonsäureamide 3 mit den Trialkyloxonium-Salzen 4 wurden 12 bislang nicht beschriebene substituierte 1-Alkoxy-2-azaallenium-Salze 1 hergestellt. Bei der Alkylierung der N-Benzylidencarbonsäureamide 3m, n tritt eine formale Disproportionierung zu höher und niedriger oxidierten 2-Azaallenium-Salzen (13, 14 bei 3n) als Hauptreaktion ein, deren Mechanismus untersucht wurde. Die durch Alkylierung nur schlecht zugänglichen Salze 1n, r können besser durch eine Acylspaltung von N-(Alkoxy-methyl)imidsäureestern 8 hergestellt werden. Die Protonierung der Verbindungen 3 erfolgt am Stickstoffatom unter Bildung der N-Acyliminium-Salze 19. Ausführliche spektroskopische Daten (IR, 1H- und 13C-NMR, MS) werden mitgeteilt.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190310
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    Sieben- (N2O2Si3) und achtgliedrige (N2O2Si4) Ringe aus einem (Hydroxysilyl)hydrazin und 1-Amino-3-fluorsiloxanen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 872-877 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Seven- (N2O2Si3) and Eight-membered (N2O2Si4) Rings from a (Hydroxysilyl)hydrazine and 1-Amino-3-fluorosiloxanesHalogeno-functional siloxanes [(Me3C)2SiCl—O—SiHalR2, Hal = F, R = CMe3 (2), Hal = Cl, R = Ph (3)] are obtained in the reaction of dihalogenosilanes with (Me3C)2Si(Cl)OLi (1a). (Me3C)2Si(Cl)OH reacts smoothly with ammonia to form the aminosilanol (Me3C)2Si(NH2)OH (4). With fluorosilanes its lithium salt 4a yields the amino- and fluoro-functional siloxanes 5 - 8 [(Me3C)2Si(NH2) —O—SiFRR′, R = R′ = Me (5), R = R′ = CMe3 (6), R = F, R′ = CMe3 (7), R = F, R′ = N(SiMe3)2 (8)]. Primary amines react with 1 by intermolecular HCl elimination to give the 1-chloro-3-hydroxysiloxane 9, hydrazine reacts to form the N,N′-bis(hydroxysilyl)hydrazine 10, methylhydrazine to yield the N-(hydroxysilyl)-N-methylhydrazine 11, and N,N′-dimethylhydrazine to give 9. The reaction of the dilithium salt 10a with F3SiN(SiMe3)2 leads to the formation of the seven-membered N2O2Si3 ring 12. The 1,5,3,7,2,4,6,8-dioxadiazatetrasilocanes 13 and 14 are obtained by LiF elimination from lithiated 5 and 7, respectively.
    Notes: Halogenfunktionelle Siloxane [(Me3C)2SiCl - O—SiHalR2, Hal = F, R = CMe3 (2), Hal = Cl, R = Ph (3)] werden durch Reaktion der Dihalogensilane mit (Me3C)2Si(Cl)OLi (1a) erhalten. Mit Ammoniak reagiert (Me3C)2Si(Cl)OH (1) glatt unter Bildung des Aminosilanols (Me3C)2Si(NH2)OH (4), dessen Lithiumsalz 4a mit Fluorsilanen die amino- und fluorfunktionellen Siloxane 5 - 8 [(Me3C)2Si(NH2) - O—SiFRR′, R = R′ = Me (5), R = R′ = CMe3 (6), R = F, R′ = CMe3 (7), R = F, R′ = N(SiMe3)2 (8)] bildet. Primäre Amine reagieren mit 1 unter intermolekularer HCl-Abspaltung zum 1-Chlor-3-hydroxysiloxan 9, Hydrazin zum N,N′-Bis(hydroxysilyl)hydrazin 10, Methylhydrazin zum N-(Hydroxysilyl)-N′-methyl-hydrazin 11 und N,N′-Dimethylhydrazin zu 9. Die Reaktion des Dilithiumsalzes 10a mit F3SiN(SiMe3)2 führt zur Bildung des siebengliedrigen N2O2Si3-Ringes 12. Durch LiF-Eliminierung aus lithiiertem 5 und 7 entstehen die 1,5,3,7,2,4,6,8-Dioxadiazatetrasilocane 13 und 14.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190311
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    Chemie der Übergangsmetall-Heterocyclen-Komplexe, II. Synthese und Elektrochemie von Carbonylchrom-Komplexen der Bithiophen-Reihe (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 878-886 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Transition Metal Heterocyclic Complexes, II. Synthesis and Electrochemistry of Carbonyl Chromium Complexes in the Bithiophen SeriesThe (substituted) (bithiophene)tricarbonylchromium complexes 4a - g are formed in yields up to 95% upon treatment of tricarbonyltris(γ-picoline)chromium with 2,2′-bithiophene (1a) and its derivatives 1b - e and 1g, respectively, in the presence of the Lewis acid BF3. The oxidation of the new compounds, as investigated by means of cyclovoltammetry, is irreversible and effects decomposition of the complexes.
    Notes: Durch Umsetzung von Tricarbonyltris(γ-picolin)chrom (3) mit 2,2′-Bithiophen (1a) und seinen Derivaten 1b - e und 1g bilden sich in Gegenwart der Lewis-Säure BF3 die (substituierten) Bithiophen-Chromtricarbonyl-Komplexe 4a - g in Ausbeuten bis 95%. Die cyclovoltametrisch untersuchte Oxidation der neuen Verbindungen verläuft irreversibel unter Zerfall der Komplexe.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190312
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    Oxidative aminomercuration of 2-propyn-1-ols. Stereoselective syntheses and structures of cis-[1,4]oxazino[3,2-b]-1,4-oxazine derivatives (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 887-899 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Aminomercurierung von 2-Propin-1-olen. Stereoselektive Synthese und Struktur von cis-[1,4]Oxazino[3,2-b]-1,4-oxazin-DerivatenDie Reaktion von 2-Propin-1-olen 1 mit 2-Aminoalkoholen 7 in Gegenwart von Quecksilber(II)-chlorid beginnt mit einer oxidativen Aminomercurierung, gefolgt von hoch stereo-selektiven Reaktionsschritten, die zu cis-[1,4]Oxazino[3,2-b]-1,4-oxazin-Derivaten 10 führen. Nach den Röntgenstrukturanalysen von 10c,f,g zeigen diese Verbindungen die gleiche Anordnung um die zentrale Bindung, und zwar so, daß die anomere Stabilisierung ein Maximum erreicht.
    Notes: The reactions of 2-Propin-1-ols 1 with 2-amino alcohols 7 and mercury(II) chloride start with an oxidative aminomercuration step followed by a series of highly stereoselective processes leading to cis-[1,4]oxazino[3,2-b]-1,4-oxazine derivatives 10. X-Ray analyses of 10c,f,g show that these compounds have the same geometrical arrangement around their central fusion bond in such a way that anomeric stabilisation reaches a maximum.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190313
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    Decabenzylgermanocen, -stannocen und -plumbocen. Synthese und Struktur von luftstabilen Metallocenen der 4. Hauptgruppe des Periodensystems der Elemente (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2656-2667 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Decabenzylgermanocene, -stannocene and -plumbocene. Synthesis and Structure of Air-stable Metallocenes of Main Group IVGermanium diiodide, tin dichloride, or lead diacetate reacts with pentabenzylcyclopentadienyllithium (1) to give decabenzylgermanocene (2), decabenzylstannocene (3) or decabenzylplumbocene (4), respectively. The air-stable metallocenes were characterized by IR, Raman, NMR, tin-119m-Mössbauer (3), and mass spectroscopy. The X-ray structural analysis shows for all three compounds an angle of 31 to 36° between the planes of the two cyclopentadienyl rings and a shielding of the lone pair of electrons at the metal atom by three of the ten benzyl groups each.
    Notes: Germaniumdiiodid, Zinndichlorid bzw. Bleidiacetat reagiert mit Pentabenzylcyclopentadienyllithium (1) unter Bildung von Decabenzylgermanocen (2), Decabenzylstannocen (3) bzw. Decabenzylplumbocen (4). Die luftstabilen Metallocene wurden durch IR-, Raman-, NMR-, 119mSn-Mößbauer- (3) und Massenspektren charakterisiert. Die Röntgenstrukturanalyse der Verbindungen zeigt, daß die Ebenen der beiden Cyclopentadienylringe einen Winkel zwischen 31 und 36° einschließen, und daß eine Abschirmung des freien Elektronenpaares am Metallatom jeweils durch drei der zehn Benzylgruppen erfolgt.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190822
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    Asymmetrische reduktive Aminierung von Cycloalkanonen, 5. Synthese und absolute Konfiguration 2-substituierter Cyclopentanamine (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2668-2677 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric Reductive Amination of Cycloalkanones, 5. Synthesis and Absolute Configuration of 2-Substituted CyclopentanaminesIn an asymmetric synthesis 2-substituted cyclopentanamines are obtained from racemic cyclopentanones by means of reductive amination in a three-step procedure. Condensation of the ketones 3(n) with optically active 1-phenylethylamines yields imine mixtures 4(n), which are hydrogenated with Raney nickel to give the optically active, diastereomerically pure secondary amines 5(n). Hydrogenolysis with Palladium-on-charcoal leads to high grade enantiomerically pure primary amines 6(n) with good yields. The relative configuration of the amines 5(n) and 6(n) is elucidated by 1H and 13C NMR techniques. The absolute configuration is determined by X-ray analysis of the 4-bromobenzamide 8 of the primary amine (+)-6(n)e and with the help of CD of the salicylidenes 9(n). The kinetically controlled asymmetric hydrogenation with a first order transformation as proved reaction mechanism in the cyclohexanamine line is confirmed for this investigation. The hydrogenation runs like-induced to the cis-configurated amines 5(n) and 6(n), respectively.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190823
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    Electron transfer reactions. Reaction of furanones and bifurandiones with potassium and oxygen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 917-928 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Elektronen-Übertragungs-Reaktionen. Reaktion von Furanonen und Bifurandionen mit Kalium und SauerstoffBei der Behandlung von Furanonen (1a - c, 25, 34) und Bifurandionen (23, 37) mit Kalium in THF entstehen Radikalanion-Zwischenstufen, die mit Sauerstoff zu Superoxid reagieren, das seinerseits mit den Ausgangsfuranonen und -bifuranonen weiterreagiert. So ergab die Reaktion von 1a mit Kalium eine Mischung von 4-Oxo-2,2,4-triphenylbutansäure (7a), 1,3,3-Triphenyl-2-propen-1-on (11a) und Benzoesäure (12). Unter ähnlichen Bedingungen reagierte 11a selbst zu einer Mischung von Benzophenon (18a) und 12. Ähnliche Ergebnisse wurden im Falle von 1b und c erhalten. Das Bifurandion 23 ergab mit Kalium eine Mischung von 2(5H)-Furanon 25, 2,3-Diphenylpropensäure (31) und 12. 25 selbst reagierte mit Kalium unter ähnlichen Bedingungen zur selben Mischung von 31 und 12. 3-Phenyl-2(3H)-benzofuranon (34) führte mit Kalium jedoch zu keinem isolierbaren Produkt; nur Ausgangsmaterial wurde zurückgewonnen. Unter vergleichbaren Bedingungen lieferte das Bifurandion 37 das Fragmentierungsprodukt 34. Mit Hilfe der cyclischen Voltammetrie wurden die zu den Radikalanionen führenden Reduktionspotentiale gemessen. Die Radikalanion-Zwischenstufen wurden durch ihre Elektronenspektren charakterisiert.
    Notes: Treatment of furanones (1a - c, 25, 34) and bifurandiones (23, 37) with potassium in THF gave rise to radical anion intermediates, which reacted with oxygen to give superoxide and ultimately products derived through the reaction of superoxide with the starting furanones and bifurandiones. Thus, the reaction of 1a with potassium gave a mixture of 4-oxo-2,2,4-triphenylbutanoic acid (7a), 1,3,3-triphenyl-2-propen-1-one (11a), and benzoic acid (12). The reaction of 11a itself, under similar conditions, gave a mixture of benzophenone (18a) and 12. Similar reactions have been observed in the case of 1b and c. The bifurandione 23, on treatment with potassium, gave a mixture of the 2(5H)-furanone 25, 2,3-diphenylpropenoic acid (31), and 12. The reaction of 25 itself with potassium under similar conditions gave the same mixture of 31 and 12. Treatment of 3-phenyl-2(3H)-benzofuranone (34) with potassium, however, did not give any isolable product; only the starting material could be recovered. Under similar conditions, the bifurandione 37 gave the fragmentation product 34. Cyclic voltammetric studies have been employed to measure the reduction potentials, leading to radical anions, and these intermediates have been characterized through their electronic spectra.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190315
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    Reactions of uracils, 7. Synthesis and novel consecutive thermal [1,5]-sigmatropic rearrangements of 6-(alkylamino)-5-ethenyluracils (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 943-949 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen von Uracilen, 7. Synthese und eine neue Sequenz thermischer [1,5]-sigmatroper Umlagerungen von 6-(Alkylamino)-5-ethenyluracilenNeue 6-(Alkylamino)-5-ethenyluracile (2d und 7) werden dargestellt, um Substituenteneffekte bei thermischen Reaktionen zu untersuchen. Ähnlich 2a werden 2d und 7 beim Erhitzen in Dowtherm® A und nach anschließender Verseifung in die 6-Amino-5-(ethoxycarbonyl[phenyl]ethyl)uracile 4 bzw. 8 übergeführt. Erhitzen in Xylol liefert die intermediären Imine 11 und 12. Deuterierungsexperimente belegen aufeinanderfolgende thermische [1,5]-H-Wanderungen (2a-D1 → 4-D1 und 4-D2; 2a′-D2 → 4′-D1). Die Mechanismen werden diskutiert.
    Notes: Additional 6-(alkylamino)-5-ethenyluracils (2d, 7) have been prepared for investigating substituent effects in thermal reactions. Like 2a, upon heating in Dowtherm® A 2d and 7 afford after saponification 6-amino-5-(ethoxycarbonyl[phenyl]ethyl)uracils 4 and 8, respectively. After refluxing in xylene the intermediary imines 11 and 12 can be isolated. Deuteration experiments reveal consecutive thermal [1,5]H-migrations (2a - D1 → 4-D1, and 4-D2; 2a′-D2 → 4′-D1). The mechanism is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190317
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    1-Methylbenzvalen - Synthese und einige Reaktionen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 960-970 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Methylbenzvalene - Synthesis and Several Reactions1-Methylbenzvalene (1) has been obtained in preparatively useful quantities from the reaction of cyclopentadienyllithium with 1,1-dichloroethane and n-butyllithium. Hydrogenation of 1 by means of diimine afforded 1-methyltricyclo[3.1.0.02,6]hexane (3). Addition of benzonitrile oxide and 2,4,6-trimethylbenzonitrile oxide to the double bond of 1 gave rise to the formation of a mixture of the isomeric Δ2-isoxazoline derivatives 4 and 5. 4-Methyl-4H-1,2,4-triazole-3,5-dione and 1 reacted to give the rearranged adducts 6 - 8. At temperatures as low as 20°C 8 transformed slowly into the dihydrodiazasemibullvalene derivative 9. Using [6-D]-1-methylbenzvalene (1a) the mechanisms of the reactions leading to 6 - 9 have been studied.
    Notes: Aus der Reaktion von Cyclopentadienyllithium mit 1,1-Dichlorethan und n-Butyllithium ging in präparativ brauchbaren Mengen 1-Methylbenzvalen (1) hervor. Seine Hydrierung mit Diimin erbrachte 1-Methyltricyclo[3.1.0.02,6]hexan (3). Benzonitriloxid und 2,4,6-Trimethylbenzonitriloxid addierten sich an die Doppelbindung von 1 unter Bildung von Gemischen der isomeren Δ2-Isoxazolin-Derivate 4 und 5. 4-Methyl-4H-1,2,4-triazol-3,5-dion ergab mit 1 die umgelagerten Addukte 6 - 8. Schon bei 20°C wandelte sich 8 langsam in das Dihydrodiazasemibullvalen-Derivat 9 um. Durch Einsatz von [6-D]-1-Methylbenzvalen (1a) wurden die Mechanismen der zu 6 - 9 führenden Reaktionen untersucht.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190319
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    Additionen von Benzvalen an Nitriloxide. Eine Synthese für Benzvalen-3-carbonitril (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 950-959 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Additions of Benzvalene to Nitrile Oxides. A Synthesis for Benzvalene-3-carbonitrile2,4,6-Trimethylbenzonitrile oxide, benzonitrile oxide, and fulminic acid undergo cycloaddition to benzvalene (1) to give the Δ2-isoxazolines 2a - c in high yields. By means of competition experiments the ratio of the rate constants for the reactions of 1 and norbornene with benzonitrile oxide has been determined to be kbenzvalene/knorbornene ≈ 1. The adduct 2c of fulminic acid was transformed to benzvalene-3-carbonitrile (4) by the following simple sequence: ring opening by sodium methoxide to yield the β-hydroxycarbonitrile 3, tosylation of 3, and, finally, elimination of toluenesulfonic acid with potassium tert-butoxide. - From the X-ray structure analysis of 2b the dihedral angle and the length of the central bond of the bicyclo[1.1.0]butane moiety have been determined to be 111.8° and 1.464 Å, respectively.
    Notes: 2,4,6-Trimethylbenzonitriloxid, Benzonitriloxid und Knallsäure ergaben mit Benzvalen (1) in hohen Ausbeuten die Δ2-Isoxazoline 2a - c. Durch Konkurrenzexperimente wurde das Verhältnis der Geschwindigkeitskonstanten der Additionen von Benzonitriloxid an 1 und Norbornen kBenzvalen/kNorbornen ≈ 1 bestimmt. Das Knallsäure-Addukt 2c ließ sich in der folgenden einfachen Reaktionssequenz in Benzvalen-3-carbonitril (4) umwandeln: Ringöffnung durch Natrium-methoxid zum β-Hydroxynitril 3, dessen Tosylierung und schließlich Eliminierung von Toluol-sulfonsäure mit Kalium-tert-butoxid. - Mit Hilfe der Röntgenstrukturanalyse wurden für das Bicyclo[1.1.0]butan-Gerüst von 2b der Interplanarwinkel zu 111.8° und die Länge der Zentral-bindung zu 1.464 Å ermittelt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190318
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    Reaktive π-Übergangsmetallkomplexe der 8. Nebengruppe, I. (η6-Aren)(η5-2,5-dihydro-1,2,5-thiadiborol)eisen: Synthesen aus Bis(aren)eisen und Aren-bis(ethen)eisen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 971-979 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactive π-Complexes of the Group VIII Transition Metals, I. (η6-Arene)(η5-2,5-dihydro-1,2,5-thiadiborol)iron: Syntheses from Bis(arene)iron and Arene-bis(ethene)ironBis(arene)iron 1a - e, (arene = p-xylene, benzene, benzotrifluoride, 1,4-difluorobenzene) react in the temperature range of -100 to -60°C with 3,4-diethyl-2,5-dihydro-2,5-dimethyl-1,2,5-thiadiborole (thiadiborolene, 2) to form reactive intermediates which decompose at -30°C and (η6-arene)(η5-thiadiborolene)iron 3a - e are obtained. Alternatively, the synthesis is achieved via arene-bis(ethene)iron 4a,c (arene = p-xylene, benzene), which is formed from 1a,c and ethene at low temperature. Reactions, spectroscopic data, and the crystal structure of (η6-benzene)(η5-thiadiborolene)iron (3c) are reported.
    Notes: Bis(aren)eisen 1a - e (Aren = p-Xylol, Toluol, Benzol, Benzotrifluorid, 1,4-Difluorbenzol) reagieren im Temperaturbereich von - 100 bis -60°C mit 3,4-Diethyl-2,5-dihydro-2,5-di-methyl-1,2,5-thiadiborol (Thiadiborolen, 2) zu reaktiven Zwischenverbindungen, die durch Zersetzung bei -30°C (η6-Aren)(η5-thiadiborolen)eisen 3a - e ergeben. Alternativ gelingt die Synthese über Aren-bis(ethen)eisen 4a, c (Aren = p-Xylol, Benzol), welche bei tiefen Temperaturen aus 1a, c und Ethen darstellbar sind. Reaktionen, spektroskopische Daten und die Kristallstruktur von (η6-Benzol)(η5-thiadiborolen)eisen (3c) werden mitgeteilt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190320
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    Darstellung, ESR- und ENDOR-Untersuchung von Radikalkationen des Tetraphenylhydrazins, des 5,6-Dihydro-5,6-diphenylbenzo[c]cinnolins und des Benzo[c]benzo[3,4]cinnolino[1,2-a]cinnolins (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 980-990 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Generation, ESR and ENDOR Study of Radical Cations Derived from Tetraphenylhydrazine, 5,6-Dihydro-5,6-diphenylbenzo[c]cinnoline, and Benzo[c]benzo[3,4]cinnolino[1,2-a]cinnolineRadical cations of the title compounds (1a·+, 2·+, 3·+) and of a series of derivatives (1b·+, 1ċ+, 6a·+ - ċ+) representing hydrazine radical cations were generated by oxidation. ENDOR studies of the tetraarylhydrazine radical cations 1a·+ - ċ+ confirm the hindered rotation of the aryl groups and yield a partial assignment of the hyperfine splitting constants. According to the ESR-ENDOR results of 1a·+ and 3·+ linkage of the N,N′-phenyl groups through their o-positions does not considerably flatten the conjugation system.
    Notes: Die Hydrazin-Radikalkationen der Titelverbindungen (1a·+, 2·+, 3·+) sowie einer Reihe von Derivaten (1b·+, 1c·+, 6a·+ - e·+) wurden durch Oxidation erzeugt. ENDOR-Untersuchungen der Tetraarylhydrazin-Radikalkationen 1a·+ - c·+ bestätigen die gehinderte Rotation der Arylreste und liefern eine partielle Zuordnung der HFS-Kopplungskonstanten. Nach den ESR- und ENDOR-Ergebnissen von 1a·+ und 3·+ führt die Verknüpfung der N,N′-Phenylreste über ihre o-Positionen zu keiner beträchtlichen Einebnung des Konjugationssystems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190321
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    Über die Konfigurations- und Substituenten-Abhängigkeit der Pt — Cl-Valenzschwingungsfrequenzen und der 31P-NMR-Parameter in substituierten cis- und trans-Dichlorobis-(triphenylphosphan)platin(II)-Verbindungen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1694-1703 
    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 Configurational and Substituent Dependence of the Pt—Cl Stretching Frequencies and of the 31P NMR Parameters in Substituted cis- and trans- Dichlorobis(triphenylphosphane)platinum(II) CompoundsCorrelations between substituent constants σ, Pt — Cl vibrational frequencies and 31P NMR parameters 1J[195Pt,31P] und δ[31P] for compounds of the type cis- and trans-{Pt-[P(aryl)(aryl′)(aryl″)]2 Cl2} (aryl, aryl′, aryl″ = substituted phenyl rings) are reported and discussed with respect to bonding properties.
    Notes: Zusammenhänge zwischen Substituenten-Konstanten σ, Pt—Cl-Valenzschwingungsfrequenzen und 31P-NMR-Parameter 1J[195Pt, 31P] und δ[31P] für die Verbindungen des Typs cis- und trans-{Pt[P(aryl)(aryl′)(aryl″)]2 Cl2} (aryl, aryl′, aryl″ = substituierte Phenyl-Ringe) werden beschrieben und im Hinblick auf die Bindungseigenschaften diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190521
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  • 73
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    Photochemie des 1,3-Distyrylbenzols  -  Ein neuer Weg zu syn-[2.2](1,3)Cyclophanen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1704-1715 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of 1,3-Distyrylbenzene  -  A New Route to syn-[2.2](1,3)CyclophanesDepending on the reaction conditions the irradiation of the title compound 1 leads to cyclodimerization 1 → 6, dehydrogenating cyclization 1 → 11, 12 or a combination of both processes 1 → 13, 14, 15. The stereoisomeric [2.2](1,3)cyclophanes 6a - c as well as the access into the pyrene series 15, 16, 18 are of special synthetic interest.
    Notes: In Abhängigkeit von den Reaktionsbedingungen beobachtet man bei der Photolyse der Titelverbindung 1 Cyclodimerisierung 1 → 6, dehydrierende Cyclisierung 1 → 11, 12 oder eine Kombination von beiden 1 → 13, 14, 15. Von besonderem synthetischem Interesse sind dabei die stereoisomeren [2.2](1,3)Cyclophane 6a - c und der Zugang in die Pyrenreihe 15, 16, 18.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19861190522
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    Reaction of trialkyl orthoformates with the aluminium derivatives of some α-unsaturated bromides. Preparation of β-unsaturated acetals (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1725-1730 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaktion von Trialkylorthoformaten mit den Aluminium-Derivaten einiger α-ungesättigter Bromide. Darstellung von β-ungesättigten AcetalenDie Aluminium-Derivate 2, 4 und 7 α-ungesättigter Bromide, dargestellt in Ether, sind sehr reaktionsfähig gegenüber Trialkylorthoformaten. Mit Hilfe dieser Reaktion, durchgeführt bei -80°C, können auf einfache Weise β-ungesättigte Acetale 3, 5 bzw. 8 dargestellt werden.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190524
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  • 75
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    Fluoreszenz-Untersuchungen an styrylsubstituierten Benzolen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1716-1724 
    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 the Fluorescence of Styryl-substituted BenzenesFluorescence decay measurements of the stilbene-like compounds 1 - 4 demonstrate that the average lifetimes of these molecules in the electronically excited singlet state are about 102 times higher than for trans-stilbene itself. According to UV absorption and excitation spectra this is due to a new S1 state, which corresponds to a forbidden S0 → S1 transition on the long-wavelength edge of the intense absorption.
    Notes: Die Fluoreszenz-Abklingzeiten der stilbenartigen Verbindungen 1 - 4 zeigen, daß die mittleren Lebensdauern dieser Moleküle im elektronisch angeregten Singulettzustand um rund zwei Zehnerpotenzen höher sind als bei trans-Stilben selbst. Anhand von UV-Absorptions-und Anregungsspektren wird das auf einen neu gefundenen S1-Zustand zurückgeführt, der einem verbotenen Übergang S0 → S1 auf der langwelligen Seite der intensiven Absorption entspricht.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190523
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  • 76
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    Enantioselektive katalytische Hydrierung von α-(Acetylamino)-zimtsäure mit einem Rhodium-Phosphankomplex in wäßriger Lösung (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1731-1733 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantioselective Catalytic Hydrogenation of α-(Acetylamino)cinnamic Acid with a Rhodium Phosphane Complex in Aqueous SolutionThe synthesis of [(3R,4R)-3,4-bis(diphenylphosphino)-1,1-dimethylpyrrolidinium-P,P′](1,5-cyclooctadiene)rhodium bis(tetrafluoroborate) (5) is described. With this water-soluble catalyst the sodium salt 6c of α-(Acetylamino)cinnamic acid (6a) is hydrogenated in aqueous solution to give (S)-N-acetylphenylalanine with 90% ee.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190525
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    McMurry-Reaktion der 2-Alkyl-3-ethoxyacroleine (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1734-1736 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: McMurry Reaction of 2-Alkyl-3-ethoxyacroleinsMcMurry reductive coupling of 2-alkyl-3-ethoxyacroleins 1 yields 2,5-dialkylhexadienedials 6. (E) Configuration at the 2,3- and 4,5-double bonds of these dialdehydes is derived from three-bond carbon-13 proton coupling. A mechanism similiar to that discussed for McMurry coupling of carbonyl compounds is proposed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190526
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    Masthead (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986) 
    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.19861190601
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    Oxopropenylierung von Alkylmagnesiumhalogeniden mit 3-(Trimethylsilyloxy)acroleinen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1737-1744 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxopropenylation of Alkylmagnesium Halides by 3-(Trimethylsilyloxy)acroleinsOxopropenylation of alkylmagnesium halides 4 by 3-(trimethylsilyloxy)acroleins 3 selectively yields the (E)-isomers of α,β-unsaturated aldehydes such as 4-phenyl-2-butenals 9, 3-cyclopropylpropenals 10, 3-cyclohexylpropenals 11, 3-(3-menthyl)propenals 12, and 2,5-hexadienals 13. 3-Hydroxyenolsilylethers 6 are isolated when allylmagnesium chloride is used as carbon nucleophile; to conclude, the reaction primarily involves nucleophilic addition of the Grignard reagent at the aldehyde carbon of the acrolein 3.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190527
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  • 80
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    Metallkomplexe mit verbrückten permethylierten Cyclopentadienylliganden (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1750-1754 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Complexes with Bridged Permethylated Cyclopentadienyl LigandsThe preparation of the permethylated silyl-bridged dicyclopentadienyl ligands Me2Si(Me4C5H)2 (1) and C2H4(Me2Si(Me4C5H))2 (2) is reported. Reaction of dimetalated 1 with TiCl4 and ZrCl4 yielded the corresponding metallocenophane dihalides 3 and 4, while treatment of the dilithio derivative of 2 with GeCl2 · dioxane, SnCl2, and FeCl2 yielded the bridged metallocenes 5, 6, and 7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190529
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    Synthese neuer 1λ6,2,6-Thiadiazine durch Kondensationsreaktion mit S,S-Dialkylschwefeldiimiden (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1745-1749 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of New 1λ6,2,6-Thiadiazines by Condensation with S,S-Dialkylsulfur DiimidesReactions of ketene mercaptals 1a, b, d with S,S-dialkylsulfur diimides 2a - c lead to colourless 1λ6,2,6-thiadiazines 4a - i; reaction of 1c with 2a - c leads to ring-open products 3a - c. 5-Methyl-substituted 1λ6,2,6-thiadiazines 6a, c, d can be prepared by condensation of S,S-dialkylsulfur diimides 2a, c, d with acrylic acid derivative 5.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190528
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    Diazoverbindungen, 68. Dibenzo[a,c]cyclooctene und Dibenzo[a,c]heptafulvene aus 5-(Diazomethyl)-5H-dibenzo[a,c]cycloheptenen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1755-1765 
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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: Diazo Compounds, 68. Dibenzo[a,c]cyclooctenes and Dibenzo[a,c]heptafulvenes from 5-(Diazomethyl)-5H-dibenzo[a,c]cycloheptenes5,6-Dichloro-5H-dibenzo[a,c]cycloheptene (11) reacts with the silver (diazomethyl)phosphoryl compounds 12a-d and the mercury bis(diazomethylcarbonyl) compounds 12e-h, respectively, by electrophilic diazoalkane substitution to yield the 5-(diazomethyl)-5H-dibenzo[a,c]cycloheptenes 14a-h. The copper(II) acetylacetonate-catalyzed decomposition of 14a, c, e and g in toluene leads to the formation of both dibenzo[a,c]cyclooctenes 16a-d and 17a, b by ring enlargement and of dibenzo[a,c]heptafulvenes 18a-d by 1,2-H-shift.
    Notes: 5,6-Dichlor-5H-dibenzo[a,c]cyclohepten (11) geht mit den Silber-(diazomethyl)phosphorylverbindungen 12a-d bzw. den Quecksilber-bis(diazomethylcarbonyl)verbindungen 12e-h elektrophile Diazoalkansubstitution zu den 5-(Diazomethyl)-5H-dibenzo[a,c]cycloheptenen 14a-h ein. Kupfer(II)-acetylacetonat-katalysierte Zersetzung von 14a,c,e und g in Toluol führt über Ringerweiterung zu den Dibenzo[a,c]cyclooctenen 16a-d und 17a,b sowie unter 1,2-H-Shift zu den Dibenzo[a,c]heptafulvenen 18a-d.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190602
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    Trimethylsilylcyanid als Umpolungsreagens, XI. Über den ambidenten Charakter substituierter Allyl-Anionen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1772-1800 
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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: Trimethylsilyl Cyanide  -  A Reagent for Umpolung, XI. On the Ambident Character of Substituted Allylic AnionsThe dependence of the α/γ-ratio of alkylation products on several factors has been determined with 1-cyano-3-aryl-1-(trimethylsiloxy)allylic anions. Increasing amounts of γ-product are found in more polar solvents, with larger alkali ions, on addition of HMPT, with smaller alkyl groups in the electrophile, and especially with p-cyanophenyl groups. In contrast, temperature and leaving groups have minor effects. On substitution of the O-silyl group by O-methyl and O-ethoxycarbonyl, α-alkylation predominates strongly. The results are compared to known allylic anions. Furthermore, the isomerisation of compounds of type C to type B is described as well as a new addition reaction of cyanoformates to aldehydes.
    Notes: An 1-Cyan-3-aryl-1-(trimethylsiloxy)allyl-Anionen (6) wird das Verhältnis der α/γ-Alkylierung in Abhängigkeit von verschiedenen Faktoren bestimmt. Dabei wird der γ-Anteil durch stärker polare Solventien, größere Alkali-Ionen, Zusatz von HMPT, kleinere Alkylreste im Elektrophil und besonders p-Cyanphenylreste erhöht, während Abgangsgruppen des Elektrophils und die Temperatur wenig Einfluß ausüben. Ersatz der O-Silylgruppe durch die O-Methyl- und O-Ethoxycarbonylgruppe bewirkt α-Alkylierung. Die Ergebnisse werden im Vergleich mit literaturbekannten Allyl-Anionen diskutiert. Außerdem werden die Isomerisierung der Verbindungen vom Typ C zu Typ B sowie eine neue Additionsreaktion von Cyanameisensäureester an Aldehyde beschrieben.
    Additional Material: 13 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861190604
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    Norpinene (Bicyclo[3.1.1]hept-2-ene) aus Homobenzvalenen (Tricyclo[4.1.0.02,7]hept-3-enen) (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3027-3044 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Norpinenes (Bicyclo[3.1.1]hept-2-enes) from Homobenzvalenes (Tricyclo[4.1.0.02,7]hept-3-enes)4,5-Dibromo-(1b) and 4,5-dichlorohomobenzvalene (1c) were converted into the tetrahalonorpinenes 2b, c by elemental bromine. In the case of unsubstituted homobenzvalene (1a) the analogous reaction could be achieved in 1% yield only by pyridinium perbromide. Treatment of 1a, b as well as of chlorohomobenzvalenyl nitrobenzoate 1d with iodine furnished the diiodonorpinenes 3a-c. However, 7,7-dibromotetracyclo[4.1.0.02,4.03,5]heptane (4) and bromine gave the tetrabromo-trans-tricyclo[4.1.0.02,4]heptane derivative 5. - On irradiation in the presence of thiophenol, the homobenzvalenes 1a, c, e, f were transformed into the 6-(phenylthio)norpinenes 6a-d. The hydroxyhomobenzvalenes 1g, h afforded the 6-(phenylthio)norpinenes 6e, g as major products, the configuration at C-4 of which is inverted as compared to that of 6b-d. By using [D2]-1a it was shown that with respect to stereochemistry the addition of thiophenol does not proceed uniformly. Without irradiation, 1a was consumed by thiophenol rather slowly at 20°C with formation of the norcarene derivatives 9 and 10 in addition to 6a. - By treatment with LiAlH4 the dichloro compound 6b gave the monochloro derivative 6h. Both 6b and 6h, however the latter one with a better yield, were converted into unsubstituted norpinene (11a) by means of sodium in liquid ammonia, thus providing a new and preparatively useful synthesis for 11a. Analogously, 6c, d furnished 4-phenylnorpinene (11b). The reaction of norpinenes 3a and 11a with N-bromosuccinimide produced the allylbromides 3d and 11c, respectively. - The 13C NMR spectra of the 4-substituted norpinenes revealed a diagnostically important γ-anti-substituent effect.
    Notes: 4,5-Dibrom-(1b) und -Dichlorhomobenzvalen (1c) wurden durch elementares Brom in die Tetrahalogennorpinene 2b, c umgewandelt. Die analoge Reaktion konnte bei unsubstituiertem Homobenzvalen (1a) mit 1% Ausbeute nur durch Pyridiniumperbromid erzielt werden. Aus 1a, b sowie dem Chlorhomobenzvalenyl-nitrobenzoat 1d und Iod gingen die Diiodnorpinene 3a-c hervor. Dagegen erbrachte 7,7-Dibromtetracyclo[4.1.0.02,4.03,5]heptan (4) mit Brom das Tetrabrom-trans-tricyclo[4.1.0.02,4]heptan-Derivat 5. - Beim Belichten in Gegenwart von Thiophenol ergaben die Homobenzvalene 1a, c, e, f die 6-(Phenylthio)norpinene 6a-d. Die Hydroxyhomobenzvalene 1g, h lieferten überwiegend die 6-(Phenylthio)-norpinene 6e, g, deren Konfiguration an C-4 im Vergleich zu derjenigen von 6b-d invertiert ist. Der Einsatz von [D2]-1a zeigte, daß die Addition von Thiophenol stereochemisch nicht einheitlich verläuft. Bei der Einwirkung von Thiophenol auf 1a bei 20°C ohne Belichtung bildeten sich in langsamer Reaktion neben 6a auch die Norcaren-Derivate 9 und 10. - Die Umsetzung der Dichlorverbindung 6b mit LiAlH4 führte zur Monochlorverbindung 6h. 6b und mit besserer Ausbeute 6h gingen mit Natrium in flüssigem Ammoniak in unsubstituiertes Norpinen (11a) über, für das somit eine ergiebige neue Synthese zur Verfügung steht. Auf diese Weise wurden auch 6c, d in 4-Phenylnorpinen (11b) umgewandelt. Die Reaktionen der Norpinene 3a und 11a mit N-Bromsuccinimid ergaben die Allylbromide 3d und 11c. - Die 13C-NMR-Spektren der 4-substituierten Norpinene brachten einen diagnostisch wichtigen γ-anti-Substituenteneffekt an den Tag.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861191011
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    Tricyclo[5.1.0.02,8]oct-3-en, -oct-4-en und -octan: Darstellung und Thermolyse der Hydroderivate des Octavalens (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3045-3058 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tricyclo[5.1.0.02,8]-oct-3-ene, -oct-4-ene, and -octane: Preparation and Thermolysis of the Hydro Derivatives of OctavaleneOn treatment of 2,3,7,8-tetrabromobicyclo[4.1.1]oct-3-ene (7) with LiAlH4 an allylic rearrangement occurred with formation of tribromide 8, which was converted into 4-bromotricyclo[5.1.0.02,8]oct-3-ene (9) by n-butyllithium. Sodium/tert-butyl alcohol and 9 reacted to give tricyclo[5.1.0.02,8]oct-3-ene (4). Hydrogenation of 4 was achieved with diimine and afforded tricyclo[5.1.0.02,8]octane (6) along with some bicyclo[5.1.0]oct-2-ene (10). Sodium iodide transformed 7 into the unrearranged iodide 12. Reduction of 7 with sodium in liquid ammonia led to bicyclo[4.2.0]octa-3,7-diene (11) in low yield. An allylic rearrangement took place when 7 was treated with AgNO3 to give nitrate 13. In another allylic rearrangement tribromide 14 was formed from 13 and LiAlH4. The reaction of 14 with n-butyllithium afforded 4-bromotricyclo[5.1.0.02,8]oct-4-ene (15), and from 15 tricyclo[5.1.0.02,8]oct-4-ene (5) was obtained by means of sodium/tert-butyl alcohol. By treatment of 4-bromooctavalene (16) with tert-butyllithium and subsequent hydrolysis, a new route to octavalene (1) was elaborated with virtually no formation of cyclooctatetraene as side product. - At 100°C 4 rearranged (t1/2 ≍ 40 min) almost quantitatively to dihydrosemibullvalene (17). The decomposition of 5 at 200°C (t1/2 ≍ 25 h) gave a complex mixture, in which only 11 has been identified. The saturated hydrocarbon 6 was converted virtually quantitatively into a 5.5:1 mixture of 3-methylenecycloheptene (18) and 1,3-cyclooctadiene (19) at 160°C (t1/2 ≍ 8 h). Possible mechanisms of these rearrangements are discussed.
    Notes: 2,3,7,8-Tetrabrombicyclo[4.1.1]oct-3-en (7) ging mit LiAlH4 unter Allylumlagerung in das Tribromid 8 über, das bei der Einwirkung von n-Butyllithium 4-Bromtricyclo[5.1.0.02,8]oct-3-en (9) lieferte. Letzteres ergab mit Natrium/tert-Butylalkohol Tricyclo[5.1.0.02,8]oct-3-en (4). Die Hydrierung von 4 zu Tricyclo[5.1.0.02,8]octan (6) wurde mit Diimin ausgeführt und war von der Bildung von Bicyclo[5.1.0]oct-2-en (10) begleitet. Mit Natriumiodid brachte 7 das nicht umgelagerte Iodid 12 hervor, und die Reduktion von 7 mit Natrium in flüssigem Ammoniak führte in geringer Ausbeute zu Bicyclo[4.2.0]octa-3,7-dien (11). AgNO3 wandelte 7 unter Allylumlagerung in das Nitrat 13 um, das mit LiAlH4, wieder unter Allylumlagerung, das Tribromid 14 ergab. Bei der Behandlung von 14 mit n-Butyllithium fiel 4-Bromtricyclo[5.1.0.02,8]oct-4-en (15) an, und daraus wurde mit Natrium/tert-Butylalkohol Tricyclo[5.1.0.02,8]oct-4-en (5) gewonnen. Ein neuer Weg zu Octavalen (1), auf dem praktisch kein Cyclooctatetraen als Nebenprodukt entsteht, wurde durch Umsetzung von 4-Bromoctavalen (16) mit tert-Butyllithium und anschließende Hydrolyse gefunden. - Bei 100°C ging 4 praktisch quantitativ in Dihydrosemibullvalen (17) über (t1/2 ≍ 40 min). Der Zerfall von 5 lieferte bei 200°C (t1/2 ≍ 25 h) ein komplexes Gemisch, in dem nur 11 identifiziert wurde. Der gesättigte Kohlenwasserstoff 6 lagerte bei 160°C nahezu quantitativ in ein 5.5:1-Gemisch aus 3-Methylencyclohepten (18) und 1,3-Cyclooctadien (19) um (t1/2 ≍ 8 h). Mögliche Mechanismen dieser Thermolysen werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191012
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    Laserfarbstoffe, IV. Synthese planar fixierter Nonamethin-Cyaninfarbstoffe (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3102-3108 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Laser Dyes, IV. Synthesis of Plane Rigidized Nonamethine Cyanine DyesThe one-pot synthesis of symmetrical and unsymmetrical nonamethine cyanine dyes 2 with a plane rigidized methine chain is described.
    Notes: Es wird ein Eintopf-Verfahren zur Darstellung von symmetrischen und unsymmetrischen Nonamethin-Cyaninfarbstoffen 2 mit planar fixierter Methinkette beschrieben.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191017
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  • 87
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    Reaktionen der Cyclopropene, VII. Nickel(0)-katalysierte Cotrimerisierungen von 3,3-Dimethylcyclopropen mit Methylacrylat (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3089-3101 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Cyclopropenes, VII. Nickel(0)-catalyzed Cotrimerisation of 3,3-Dimethylcyclopropene with Methyl AcrylateThe cotrimerisation of 3,3-dimethylcyclopropene (1) with methyl acrylate is catalyzed by phosphane- or phosphite-Ni(0) compounds under mild conditions (40-50°C). Depending on the nature of the phosphane or phosphite 1 and methyl acrylate cotrimerise mainly in the ratio 2:1 or 1:2 to give cis/trans-5 or cis/trans-6 and cyclic cis/trans-7. trans-5 and trans-6 are thermally more labile than the corresponding cis compounds. Heating to 200°C for two hours induces their complete rearrangement to 12 and 13 or 14 via 1,5-homodienyl-hydrogen shift.
    Notes: Triorganylphosphan- und -phosphit-haltige Nickel(0)-Verbindungen katalysieren die Cotrimerisierung von 3,3-Dimethylcyclopropen (1) mit Methylacrylat unter milden Bedingungen (40-50°C). In Abhängigkeit von der Art des Phosphans bzw. Phosphits entstehen bevorzugt offenkettige Cotrimere aus einem Mol 1 und zwei Mol Methylacrylat (cis/trans-5) oder offenkettige und cyclische Cotrimere aus zwei Mol 1 und einem Mol Methylacrylat (cis/trans-6 und cis/trans-7). trans-5 und trans-6 sind thermisch deutlich labiler als die entsprechenden cis-Derivate. Im Zuge einer 1,5-Homodienylwasserstoffwanderung lagern sie sich bereits nach zweistündigem Erhitzen auf 200°C quantitativ in die entsprechenden 1,4-Diene um (12 und 13 aus trans-5 bzw. 14 aus trans-6).
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191016
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  • 88
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    Umlagerungen und komplexe Eliminierungen mit 1,5-Benzothiazepin-4-onen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3109-3120 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangements and Complex Eliminations with 1,5-Benzothiazepin-4-onesThe 1,5-benzothiazepin-4-ones 3, 5, and 7-10 are pyrolyzed (with proton catalysis in part). New or rarely documented rearrangements and complex eliminations occur. These are classified and mechanistically discussed. The products and by-products are spectroscopically characterized (IR, UV, NMR, MS). Their configurations are elucidated via photolysis experiments. 4 photodimerizes in solution and in the crystalline state with great ease to give 14. 11 is remarkably insensitive towards hydrolysis.
    Notes: Die 1,5-Benzothiazepin-4-one 3, 5 und 7-10 werden pyrolysiert (z. T. bei Protonenkatalyse). Es treten neue oder selten dokumentierte Umlagerungsreaktionen und komplexe Eliminierungsreaktionen auf, die klassifiziert und mechanistisch diskutiert werden. Die Produkte und Nebenprodukte werden spektroskopisch charakterisiert (IR, UV, NMR, MS) und mittels Photolyse in ihrer Konfiguration geklärt. 4 photodimerisiert sehr leicht in Lösung oder im Kristall zu 14. 11 ist erstaunlich hydrolyseunempfindlich.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191018
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    Übergangsmetall-substituierte Acylphosphane und Phosphaalkene, IX. Zur Synthese von Phosphaalkenyl-, Mono- und Diacyl- phosphidokomplexen aus [Bis(trimethylsilyl)phosphido]-dicarbonyl(pentamethylcyclopentadienyl)eisen und Carbonsäurechloriden (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1857-1867 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition-Metal-Substituted Acylphosphanes and Phosphaalkenes, IX. On the Synthesis of Phosphaalkenyl-, Mono- and Diacylphosphido Complexes from the Reaction of [Bis(trimethylsilyl)phosphido]dicarbonyl(pentamethylcyclopentadienyl)iron and Carbonyl ChloridesReaction of the title compound (η5-C5Me5)(CO)2FeP(SiMe3)2 (4) with 2,4,6-trimethylbenzoyl chloride (2a) yields the phosphaalkenyl complex (η5-C5Me5)(CO)2FeP=C(OSiMe3)(Mes) (5a). Treatment of 4 with benzoyl chloride affords the phosphaalkenyl complex 5b and (η5-C5Me5)(CO)2FeP[C(O)Ph]2 (6b), whereas with pivaloyl chloride (2c) 6c is formed as the sole product. The monoacylphosphido complexes 8a-c are generated from the reaction of 4 with acyl chlorides 2a-c in the presence of ethanol. Lithiation by LiCH3 and subsequent acylation with 2,4,6-trimethylbenzoyl chloride converts compound 8a into 6a. Similarily the lithiation product of 8 is transformed into the phosphaalkenyl complexes 5a-c by treatment with Me3SiCl.
    Notes: Die Titelverbindung (η5-C5Me5)(CO)2FeP(SiMe3)2 (4) reagiert mit 2,4,6-Trimethylbenzoylchlorid (2a) zu dem Phosphaalkenylkomplex (η5-C5Me5)(CO)2FeP=C(OSiMe3)(Mes) (5a). Demgegenüber führt die Umsetzung von 4 mit Benzoylchlorid neben dem Phosphaalkenylkomplex 5b zu (η5-C5Me5)(CO)2FeP[C(O)Ph]2 (6b). Aus 4 und Pivaloylchlorid (2c) wird nur noch der Dipivaloylphosphidokomplex 6c gebildet. Führt man die Umsetzungen von 4 mit den Säurechloriden 2a-c in Gegenwart von Ethanol durch, so erhält man die Monoacylphosphidokomplexe (η5-C5Me5)(CO)2FePH[C(O)R] (8a-c). Komplex 8a wird von Methyllithium lithiiert und durch 2,4,6-Trimethylbenzoylchlorid in 6a übergeführt. Desgleichen ergeben die Lithiierungsprodukte von 8 mit Me3SiCl die Phosphaalkenylkomplexe 5a-c.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190608
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    Additionsreaktionen von 1,1-Dicyan-2,2-bis(trifluormethyl)ethen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3150-3157 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition Reactions of 1,1-Dicyano-2,2-bis(trifluoromethyl)etheneBy the reaction of the title compound (CF3)2C=C(CN)2 with PCl5 the (phosphoranyliden-amino)ethene 1 is obtained. The phosphorane 1 reacts with Me3SiNMe2 to form 2. WCl6 and MoCl5 react with (CF3)2C=C(CN)2 to give the acyclic nitrenes 3 and 4. The X-ray structure analysis of 3a, an acetonitrile adduct of 3, is reported.
    Notes: Die Titelverbindung (CF3)2C=C(CN)2 reagiert mit PCl5 zu dem (Phosphoranylidenamino)-ethen 1. Daraus entsteht 2 durch Reaktion mit Me3SiNMe2. Umsetzungen von (CF3)2C=C(CN)2 mit WCl6 und MoCl5 ergeben die acyclischen Nitrenkomplexe 3 und 4. Von 3a, einem Acetonitriladdukt von 3, wird eine Röntgenstrukturanalyse mitgeteilt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191022
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  • 91
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    Thieno[3,4-f]-2,1-benzisothiazol.  -  Synthese und physikalische Eigenschaften eines neuen kondensierten 14π-Heteroarens sowie dessen thermisches Cycloadditions-verhalten gegenüber N,N-Doppelbindungssystemen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3158-3164 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thieno[3,4-f]-2,1-benzisothiazole.  -  Synthesis and Physical Properties of a Novel Fused 14π Heteroarene as well as its Thermal Cycloaddition Reactions with N,N-Double Bond SystemsThe synthesis of the novel condensed title compound 2, which contains three masked dipolar systems, as well as its cycloaddition reactions with 1,2,4-triazoline-3,5-diones 3a, b and azo-dicarboxylic esters 5a, b with formation of 4 and 6, respectively, are described.
    Notes: Die Darstellung der neuen kondensierten Titelverbindung 2, die drei maskierte dipolare Systeme beinhaltet, sowie deren Cycloadditionen an 1,2,4-Triazolin-3,5-dione 3a, b und Azo-dicarbonester 5a, b unter Bildung von 4 bzw. 6 werden beschrieben.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861191023
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  • 92
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    Synthesis of benzo[1,2-b′:4,5-b′]dithiophene and its 4,8-Dimethoxy and 4,8-dimethyl derivatives (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3198-3203 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthese von Benzo[1,2-b:4,5-b′]dithiophen und seinen 4,8-Dimethoxy- und 4,8-Dimethyl-DerivatenEine einfache Synthese für Benzo[1,2-b:4,5-b′]dithiophen (4) und die Synthese seines bisher unbekannten 4,8-Dimethoxy- (7) und 4,8-Dimethylderivates (13) wird beschrieben. IR-, 1H-NMR-, UV- und MS-Daten werden mitgeteilt.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861191025
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    12-Organyldibenz[b,g]azocin-5,7-dione (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3165-3197 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 12-Organyldibenz[b,g]azocine-5,7-dionesThe title compounds 10, 23 are formed in low yields on treatment of 2,2′-organyliminobisbenzoic acid esters 8 with methyllithium, but in high yields in the intramolecular ester condensation with sodium hydride of triarylamines 12, containing o-acetyl- and o′-methoxycarbonyl groups. The new heterocycles exist exclusively in the β-diketo form and react with excess sodium- or lithium hydride to give the corresponding enolates. These, on treatment with iodomethane, form mixtures of C- and O-methylated derivatives. Nucleophiles such as hydroxylamine, arylhydrazines, methyllithium and also lithium aluminium hydride condense or add to the carbonyl groups, while KOH in methanol leads to ester or acid cleavage under ring opening. Electrophiles react predominantly at the N-aryl groups but under more severe conditions also at the frame arenes. Strong acids, however, under formal ketene extrusion and ring contraction lead to acridones 31 and 33.
    Notes: Die Titelverbindungen 10, 23 entstehen in schlechten Ausbeuten bei der Umsetzung von 2,2′-Organyliminobisbenzoesäureestern 8 mit Methyllithium, hingegen in sehr guten Ausbeuten bei der intramolekularen Esterkondensation von mit o-Acetyl- und o′-Methoxycarbonyl-Gruppen versehenen Triarylaminen 12 mit Natriumhydrid. Mit überschüssigem Natrium- oder Lithiumhydrid reagieren die ausschließlich in der β-Diketoform vorliegenden Heterocyclen zu den entsprechenden Enolaten, die sich mit Iodmethan zu Gemischen von C- und O-methylierten Derivaten umsetzen lassen. Nucleophile wie Hydroxylamin, Aryl-hydrazine, Methyllithium, aber auch Lithiumaluminiumhydrid kondensieren bzw. addieren an die Carbonylgruppen, während KOH in Methanol Ester- bzw. Säurespaltung unter Ringsprengung bewirkt. Elektrophile reagieren bevorzugt an den N-Arylgruppen, unter verschärften Bedingungen aber auch an den Gerüstaromaten; starke Säuren jedoch führen unter formaler Ketenextrusion und Ringverengung zu Acridonen 31 und 33.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861191024
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    Adolf Windaus 1876 - 1959 (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. XXXI 
    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.19861191102
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    Cycloadditionen, 10. Intramolekulare Diels-Alder-Reaktion bei Allencarboxaniliden; Einbau des 1-Naphthyl-Restes an Stelle monocyclischer Aromatensysteme (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3227-3235 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions, 10. Intramolecular Diels-Alder Reaction of Allenecarboxanilides; Installation of the 1-Naphthyl Moiety Instead of Monocyclic Aromatic SystemsThe N-(1-Naphthyl)allenecarboxamides 4a-c undergo already by gentle heating a quick intramolecular Diels-Alder reaction between the terminal allenic double bond as dienophile and the naphthalene system as diene to furnish the benzo-condensated tricycles 5a-c in high yields. The rate of this isomerisation is measured and is compared with those of allenecarboxanilides.
    Notes: Die N-(1-Naphthyl)allencarboxamide 4a-c unterliegen bereits bei leichtem Erwärmen einer raschen intramolekularen Diels-Alder-Reaktion zwischen der endständigen allenischen Doppelbindung als Dienophil und dem Naphthalinsystem als Dien, wobei in hohen Ausbeuten die benzokondensierten Tricyclen 5a-c enstehen. Die Geschwindigkeit dieser Isomerisierung wird ermittelt und mit der von Allencarbox aniliden verglichen.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19861191104
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    Oxidative Addition einer C—H-Bindung an ein zweifach koordiniertes Phosphenium-Kation (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3208-3211 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative Addition of a C—H Bond at a Two-coordinated Phosphenium CationReaction of ArP(Cl)SAr (1) [Ar = 2,4,6-(t-Bu)3C6H2] with AgSbF6 in ether at 0°C affords the compound . This exists in two different forms 2a and 2b. Form 2a is a phosphonium cation. In the IR and 31P{1H} NMR spectra of 2b an interaction between the and SbF6- units is observed. 2a and 2b are in an equilibrium which depends on the temperature. 2 is formed via the unstable (arylthio)-phosphenium cation with a σ2,λ3-phosphorus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191027
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  • 97
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    Masthead (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986) 
    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.19861191101
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  • 98
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    4,6-Diamino-1,3,5-triaza-2-phosphapentalene (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3213-3226 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 4,6-Diamino-1,3,5-triaza-2-phosphapentalenesThe title compounds 5 are formed easily from the 4,6-dicyano-1,3,2-diazaphosphole derivatives 7-9 and dialkylamines. MNDO calculations, NMR and electron spectra as well as an X-ray structure investigation (5b) consistently show their pentalene π-system to divide extensively into a positively charged 2-azaallyl and a negatively charged 1,3,2-diazaphospholyl part. This is caused on the one hand by the 4,6-amino substituents and on the other hand by N-1,3 as well as by P-2. 5 is methylated in 1-position.
    Notes: Die Titelverbindungen 5 bilden sich leicht aus den 4,5-Dicyan-1,3,2-diazaphosphol-Derivaten 7-9 und Dialkylaminen. MNDO-Rechnungen, NMR- und Elektronenspektren sowie eine Röntgen-Strukturuntersuchung (5b) zeigen übereinstimmend eine weitgehende Aufgliederung des Pentalen-π-Systems in einen positiv geladenen 2-Azaallyl- und einen negativ geladenen 1,3,2-Diazaphospholyl-Teil. Dazu tragen einerseits die 4,6-Aminosubstituenten und andererseits sowohl N-1,3 wie auch P-2 bei. 5 läßt sich in 1-Stellung methylieren.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191103
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  • 99
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    Neue Reaktionen von Pyrimidinium-4- und -2-olaten mit 1-(Diethylamino)-1-propin (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3247-3252 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel Reactions of the Pyrimidinium-4- and -2-olates with 1-(Diethylamino)-1-propyneThe pyrimidinium-olates of type 1 and 9 react with 1-(diethylamino)-1-propyne (2) to form the compounds 5a, b, 8, and 10, respectively.
    Notes: Die Pyrimidinium-olate vom Typ 1 und 9 reagieren mit 1-(Diethylamino)-1-propin (2) zu 5a, b, 8 bzw. 10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191106
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  • 100
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    Beiträge zur Chemie des Bors, 179. Synthese, Konformation und Molekülstruktur sterisch anspruchsvoller Aminomethylenboran-Vorstufen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3253-3267 
    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, 179.  -  Synthesis, Conformation, and Molecular Structure of Sterically Crowded Aminomethyleneborane PrecursorsNucleophilic substitution of one halogen atom in (tetramethylpiperidino)boron dihalides, tmpBX2 (X=F, Cl, Br) by metal organyls is determined primarily by steric factors. Replacement of one F-atom by an isopropyl or a (trimethylsilyl)methyl group to yield boranes of type tmpB(F)R present no problem. However, Cl or Br atoms cannot be substituted. Similarly, LiCHPh2 reacts with tmpBX2 to produce tmpB(X)CHPh2, but LiC(SiMe3)Ph2 can substitute only one fluorine atom in tmpBF2, while the p-substituted borane 3 is obtained by using tmpBCl2. Comparable results were achieved with 9-lithiofluorene yielding the boranes 4a-c. In contrast, 9-lithio-9-(trimethylsilyl)fluorene reacts only with tmpBF2 to produce 4f. NMR data of 4a suggest an anti orientation of the F-atom and the 9H-atom of the fluorene unit, ascertained by its X-ray molecular structure. In contrast, the trimethylsilyl derivative 4f adopts a syn geometry.
    Notes: Die nucleophile Substitution eines Halogen-Atoms in (Tetramethylpiperidino)bordihalogeniden, tmpBX2 (X=F, Cl, Br) durch Metallorganyle wird vor allem durch sterische Faktoren bestimmt. Der Ersatz eines F-Atoms durch eine Isopropyl- oder (Trimethylsilyl)-methyl-Gruppe zu tmpB(F)R-Verbindungen gelingt problemlos, jedoch unterbleibt die Umsetzung bei Verwendung von tmpBCl2 oder tmpBBr2. LiCHPh2 reagiert mit tmpBX2 zu tmpB(X)CHPh2; mit LiC(SiMe3)Ph2 gelingt die Substitution aber nur mit tmpBF2. Im Fall von tmpBCl2 erhält man das p-substituierte Boran 3. Zu vergleichbaren Ergebnissen führt 9-Lithiofluoren; man erhält die Borane 4a-c. 9-Lithio-9-(trimethylsilyl)fluoren reagiert wieder nur mit tmpBF2 und liefert 4f. NMR-Daten legen für 4a eine anti-Stellung des Fluor-Atoms zum 9H-Atom der Fluorenyl-Gruppe nahe, die durch Röntgenstrukturanalyse gesichert wurde. In 4f steht die Me3Si-Gruppe jedoch syn zum Fluor-Atom.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191107
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