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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 27 (1977), S. 61-70 
    ISSN: 1432-1106
    Keywords: Amygdala ; Commissural fibers of the fimbria ; Electrophysiology ; Lesions ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single shock stimulations have been applied stereotaxically and bilaterally in the region of the caudo-thalamic groove of the cat. These stimulations elicit diphasic potentials in the amygdala. Using combined methods of stimulation and lesion, it has been demonstrated that these electrical responses are due to the excitation of fibers projecting rostrally in the lateral border of the contralateral fimbria and caudally in the homologous part of the homolateral fimbria. A commissural path has been identified in the rostral part of the fimbria-fornix. Analysis of the experimental data has shown that the projection system consists of a discrete bundle of fibers which probably reaches the amygdala directly, in the dorsal part of the basal nucleus. The length of the explored portion of this pathway has been measured. The calculated conduction velocity of this amygdalopetal commissural component of the fimbria is 4.5 m/sec.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 27 (1977), S. 131-141 
    ISSN: 1432-1106
    Keywords: Colliculus superior ; Single neurons ; Eye movements ; Head movements ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 452 single neurons from the superior colliculus were recorded in awake and non-paralysed cats. 75 neurons were obtained from cats with unrestrained horizontal head movements. 228 neurons remained unaffected by saccadic eye movements. Eye movement related discharge followed the onset of saccades in 156 neurons either only in the presence of a visual pattern (92 neurons) or in darkness, too (64 neurons). The latter reaction type probably depends on eye muscle afferents. In 48 neurons eye movement related activity preceded the onset of eye movements. 12 neurons fired in synchrony with eye movements of any direction (type I). 30 neurons were excited during contralaterally directed eye versions within or into the contralateral head related hemifield. They were inhibited when the eyes moved within or into the ipsilateral head related hemifield (type II). 6 neurons with constant maintained activity during fixation were inhibited by ipsilaterally directed saccades, but remained unaffected by contralateral eye movements. Head movement related discharge followed the onset of head movements in 20 neurons only in presence of a visual pattern and also in darkness in 6 neurons. Ipsilateral head movements or postures strongly suppressed maintained activity and visual responsiveness of some neurons. 15 neurons discharged in synchrony with and prior to contralateral head movements. Ipsilateral head movements inhibited these neurons. Activation or inhibition were usually related to movement and to posture, exceptionally to movement or to posture. Electrical stimulation of recording sites of these neurons through the recording microelectrode elicits contralateral head movements.
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  • 3
    ISSN: 1432-1106
    Keywords: Descending auditory pathways ; Superior olivary complex ; Cochlear nuclear complex ; Axoplasmic flow ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The descending pathways from the superior olivary complex (SO) to the cochlear nuclear complex (CN) were investigated in 58 cats using labelled aminoacid and horseradish peroxidase transport techniques. Descending connections were found coursing bilaterally through the trapezoid body (TB) and ipsilaterally in the intermediate and dorsal acoustic striae. The dorsolateral periolivary nucleus (DLPO) sends fibres through both the intermediate and dorsal striae, which are joined by others from the lateral preolivary nucleus (LPO). Both the latter nucleus and the medial preolivary nucleus (MPO) give rise to a bilateral descending projection which traverses TB. The distribution of these descending pathways within CN is described (although the technique did not permit precise synaptic identification). The possible implications of these pathways for response patterns at the level of CN are discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 153-166 
    ISSN: 1432-1106
    Keywords: Cat ; Spinal cord ; Dorsal horn ; Dendritic fields ; Golgi stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Observations of neurons in dorsal horn laminae IV–VI of the lumbosacral segments of Golgi-stained spinal cords in kittens and adult cats revealed laminar differences in dendritic architecture. Many neurons in lamina IV had dense, bushy dendritic fields. Lamina V contained, in addition to bushy cells similar in appearance to those of lamina IV, increasing numbers of neurons with radiating dendritic fields. Lamina VI was composed almost exclusively of neurons with radiating dendritic fields. These qualitative differences among laminae were accompanied by systematic variations in mean dendritic spread, which increased more than two-fold in adult cats between laminae IV and VI. A second gradient of dendritic spread was found within individual laminae: dendritic spread, particularly medial to lateral spread, increased for successively more lateral cells within a lamina. These differences in the spread of dendrites for neurons in different regions of the dorsal horn may be related to variations in the areas of peripheral receptive fields of dorsal horn neurons.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 325-333 
    ISSN: 1432-1106
    Keywords: Spatial contrast sensitivity ; Cat ; Grating pattern ; Flicker ; X- and Y-cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using behavioral techniques, contrast sensitivity for flickering and stationary gratings was measured in ordinary cats. Gratings of low spatial frequency were more easily detected by the cat when temporal modulation was present, but at high spatial frequencies temporal modulation reduced grating visibility. These psychophysical results are consistent with neurophysiological evidence for the existence of two classes of visual cells in the cat, which are distinguishable in terms of their spatio-temporal response properties.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 29 (1977), S. 107-122 
    ISSN: 1432-1106
    Keywords: Area 17 ; Lateral suprasylvian area ; Remote visual stimuli ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single units were recorded extracellularly from area 17 and lateral suprasylvian area (LSSA) in curarized cats. Visual stimuli, usually a 10 ° black spot, were introduced abruptly in the visual field remote from the discharge area of a neuron's receptive field and moved at a speed of about 30 °/sec. The effect of these remote stimuli (S2) on the response to a restricted visual stimulus (S1) crossing the discharge area was studied. It was found that most units in area 17 were not affected by the presentation of remote stimuli, the remainder being either slightly facilitated or slightly inhibited. In contrast the LSSA neurons were usually inhibited by the presentation of S2: this effect was strong, was present in all classes of LSSA neurons and was independent of the relative directions of movement of S1 and S2. On the basis of these data and those previously obtained from the superior colliculus it is concluded that the way the extrageniculate centres respond to a stimulus abruptly introduced in the visual field is substantially different from that of the striate cortex. Only in the extrageniculate centres a new stimulus, besides exciting the neurons which correspond to the position of the stimulus in the field, concomitantly decreases the responses of neurons located in positions of the visual field remote from that stimulus. Possible behavioral implications of the findings are discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 30 (1977), S. 89-105 
    ISSN: 1432-1106
    Keywords: Extrageniculate visual system ; Pretectum ; Efferent connections ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Direct projections from the pretectum in the cat were investigated by means of the Nauta-Gygax and the Fink-Heimer method in an attempt to identify the morphological substrates subserving possible neural mechanisms involved in visual behaviour and reflexes. Degeneration in the diencephalon was found ipsilaterally in the nucleus limitans, lateral pulvinar nucleus, lateral posterior nucleus, lateral dorsal nucleus, dorsal and ventral lateral geniculate nuclei, centre medianparafascicular complex, central medial nucleus, paracentral nucleus, central lateral nucleus, ventroanterior and ventrolateral nuclear complex, zona incerta, H field of Forel and the reticular nucleus. The pretectal fibers projecting to the ventral lateral geniculate nucleus appeared to be topically organized. In the midbrain, the pretectal fibers were observed to terminate ipsilaterally within the superior colliculus, nucleus of Darkschewitsch, dorsolateral portion of the red nucleus, lateral terminal nucleus of the accessory optic tract and the reticular formation, and bilaterally within the central gray, interstitial nucleus of Cajal and the rostral portion of the nucleus of Edinger-Westphal. Degeneration in the superior colliculus was marked in laminae II, III and IV. The fibers arising from more anterior part of the pretectum appeared to be distributed more medially in laminae II and III. The pretectopontine fibers terminated ipsilaterally in the paramedial and the dorsolateral pontine nuclei as well as the reticular formation. In the inferior olivary complex, degeneration was found in caudal levels of the dorsal cap and β-nucleus, and additionally in the rostral portion of the dorsal accessory olive.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 30 (1977), S. 155-160 
    ISSN: 1432-1106
    Keywords: Cat ; Postural reflexes ; Visual and vestibular reflex modulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The excitability of hindlimb extensor and flexor motoneurons is tonically modulated by animal tilt and a large visual stimulus rotating about the animal's line of sight. This direction-specific modulation is opposite for extensor and flexor motoneurons and opposite for optokinetic and vestibular stimuli, thus combining to a functionally significant pattern of postural reflexes.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 30 (1977), S. 275-296 
    ISSN: 1432-1106
    Keywords: Striate cortex ; Simple and complex cells ; Visual texture ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The responsiveness of 254 simple and complex striate cortical cells to various forms of static and dynamic textured visual stimuli was studied in cats, lightly anaesthetised with N2O/O2 mixtures supplemented with pentobarbitone. Simple cells were unresponsive to all forms of visual noise presented alone, although about 70% showed a change in responsiveness to conventional bar stimuli when these were presented on moving, rather than stationary, static-noise backgrounds. Bar responses were depressed by background texture motion in a majority of cells (54%), but were actually enhanced in a few instances (16%). In contrast, all complex cells were to some extent responsive to bars of static visual noise moving over stationary backgrounds of similar texture, or to motion of a whole field of static noise. The optimal velocity for noise was generally lower than for bar stimuli. Since moving noise backgrounds were excitatory for complex cells, they tended to reduce specific responses to bar stimulation; in addition, directional bias could be modified by direction and velocity of background motion. Complex cells fell into two overlapping groups as regards their relative sensitivity to light or dark bars and visual noise. Extreme examples were insensitive to conventional bar or edge stimuli while responding briskly to moving noise. In many complex cells, the preferred directions for motion of noise and of an optimally oriented black/white bar were dissimilar. The ocular dominance and the degree of binocular facilitation of some complex cells differed for bar stimuli and visual texture. Preliminary evidence suggests that the deep-layer complex cells (those tolerant of misalignment of line elements; Hammond and MacKay, 1976) were most sensitive to visual noise. Superficial-layer complex cells (those preferring alignment) were less responsive to noise. Only ‘complex-type’ hypercomplex cells showed any response to visual noise. We conclude that, since simple cells are unresponsive to noise, they cannot provide the sole input to complex cells. The differences in the response of some complex cells to rectilinear and textured stimuli throw a new light on their rôle in cortical information-processing. In particular, it tells against the hypothesis that they act as a second stage in the abstraction of edge-orientation.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 30 (1977), S. 353-368 
    ISSN: 1432-1106
    Keywords: Visual deprivation ; Cat ; Behavior ; Perimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Visual fields of 15 monocularly deprived (MD) cats and 2 monocularly tested normal adult cats, were measured using stationary stimuli at fixed distances in the horizontal plane. Compared to the visual fields of monocularly tested normal cats, those of the deprived eyes of MD cats were found to be restricted to the ipsilateral hemifield up to the midline. This finding appeared to be permanent since it was measured both in cats tested early (4 cases) and late (11 cases) after deprivation. In addition, it seemed to be independent whether the nondeprived eye was closed by reverse suturing (13 cases), or was left open after deprivation and closed only temporarily during testing (2 cases). Visual fields were also found to be restricted to the ipsilateral hemifield, if MD cats were tested at several levels above the horizontal plane or in a hemisphere (23 cm radius) in which the superior and inferior segment of the visual space could be tested (6 cases). The results are controversial to those of Sherman (1973) who described the visual fields of MD cats to be restricted to the monocular (60–90 ° ipsilateral) segment. The differences observed in our results compared to those of Sherman could not be explained by experimental factors, since testing MD cats by the method employed by Sherman (8 cases) also resulted in visual fields covering the monocular as well as the binocular part of the ipsilateral side. Consequently, Sherman's hypothesis (1974b), that for MD cats the geniculocortical pathways dominate in the visual behavior and that retinotectal pathways are somehow suppressed, could not be confirmed by our results. In our experiments the visual behavior demonstrated by MD cats seemed to be developed mainly through retinotectal pathways. In MD cats in which after the deprivation period the non-deprived eye remained open, the monocular part seemed to be of more importance than the binocular segment; permanent closure of the normal eye seemed to lead to a further shift towards the binocular segment. Therefore, in non-reverse sutured MD cats some suppression of retinotectal pathways by imbalanced corticotectal pathways may be present, but not as elaborate as described by Sherman. This slight suppression is overcome by reverse suturing. The mechanism of release from suppression of retinotectal pathways is unknown, its possible localisation is discussed.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 259-278 
    ISSN: 1432-1106
    Keywords: Cat ; Lateral geniculate nucleus ; X- and Y-cells ; Visual deprivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Retrograde axonal transport of horseradish peroxidase (HRP) was used to identify two populations of cells in the lateral geniculate nucleus (LGN) of the cat. HRP was injected into area 17 and 18 separately in the same animal, and the neuronal somata giving rise to thalamo-cortical axons, identified by the presence of granular HRP reaction product within them, were measured. The mean size of LGN neurones labelled by injections in area 17 (“17-relay” cells) was less than of neurones filled from area 18 (“18-relay” cells). Similar separate injections into area 17 and 18 of monocularly deprived kittens also showed that in non-deprived LGN laminae 17-relay cells were, on average, smaller than 18-relay cells. In deprived laminae, 17-relay cells were some 20% smaller than in nondeprived laminae, but deprived 18-relay cells were 50–60% smaller than normal, being on average, actually smaller than deprived 17-relay cells. We conclude that the population of large LGN neurones projecting to area 18 is more severely affected by monocular deprivation than the smaller neurones projecting to area 17, and discuss the relationship of the morphological results to physiologically defined X and Y cells in the LGN.
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  • 12
    ISSN: 1432-1106
    Keywords: Pons ; Cerebellum ; Pontocerebellar projection ; HRP method ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By use of the retrograde axonal transport of horseradish peroxidase (HRP) the projection to the anterior lobe from the pontine nuclei was mapped in detail. In 18 cats 0.1–0.5 gml of a,50% suspension of Sigma VI or Serva HRP was injected in the anterior lobe under visual guidance or stereotactically. The main findings are as follows: 1. The projection to the vermis of the anterior lobe is bilateral with a contralateral preponderance (about 3/4). 2. The vermis of the anterior lobe receives afferents from a restricted, laterally located region in the caudal part of the pons. Dorsal parts of this region project anteriorly (lobules I–III), ventral parts posteriorly (lobulus V). 3. The projection to the intermediate-lateral part is almost exclusively contralateral and is considerably heavier than the projection to the vermis. 4. The intermediate-lateral part receives afferents from two pontine regions. One is located laterally and coincides caudally with the region projecting to the vermis. The other is located medially and projects only sparsely to the vermis. 5. Within the projection from the lateral pontine region to the intermediate part there is a somatotopical pattern corresponding to that within the projection to the vermis. Within the medial pontine region the somatotopical pattern is less clear, but there is a tendency for cells projecting to lobules III–IV to be located more ventrolaterally than those sending their fibres to lobulus V. 6. The pontine regions projecting to the anterior lobe seem to coincide closely with those receiving fibres from the primary sensorimotor cortex, particularly the lateral part of the anterior sigmoid gyrus and medial part of the posterior sigmoid gyrus, as determined previously (P. Brodal, 1968a).
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 27 (1977), S. 35-50 
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Cat ; Dark adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The receptive fields of LGN cells were investigated with stationary light and dark spot and annulus stimuli. Stimulus size and background intensity were varied while stimulus/background contrast was kept constant. The speed of dark adaptation varied considerably from cell to cell. Dark adaptation made responses more sustained in all neurones and eliminated the oscillatory on-responses evoked under some conditions in the light-adapted cells. Dark adaptation led also to a disappearance of early phasic inhibition in on-responses, and increased response rise time and latency. The power of surround responses to inhibit centre responses decreased slightly at low levels of light adaptation in LGN cells but much less than in retinal ganglion cells. Some other traces of changing retinal surround effects also appeared in the LGN on dark adaptation. For example, the functional size of receptive fields increased at low levels of illuminance as has been observed in retinal ganglion cells and the receptive fields as estimated from response peaks were larger than those estimated from sustained components.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 260 (1977), S. 29-38 
    ISSN: 1432-069X
    Keywords: Cat ; Epidermis ; Histochemistry ; Enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mit Hilfe von enzymhistochemischen Methoden wurden die Verteilung und die Aktivitäten verschiedener oxydativer und hydrolytischer Enzyme in der Epidermis der Hauskatze untersucht. Deutliche Aktivitäten oxydativer Enzyme konnten mit Ausnahme des Stratum corneum in allen epidermalen Zellagen beobachtet werden. Unter den nachgewiesenen hydrolytischen Enzymen zeigte besonders die unspezifische Esterase stark positive Reaktionen im Stratum granulosum und in den basalen Anteilen des Stratum corneum. Cholinesterase-Aktivitäten waren in der Epidermis der Katze nicht festzustellen. Die vorliegenden Ergebnisse von der Epidermis der dicht behaarten Hauskatze werden im Zusammenhang mit den Ergebnissen entsprechender Untersuchungen an der Epidermis spärlich behaarter Säugetierarten (z.B. Hausschwein und Mensch) diskutiert. Insgesamt weist das Enzymmuster der Katzenepidermis nur bedingt Parallelen zu demjenigen der Epidermis des Menschen auf, wobei speziell in der Verteilung und den Aktivitäten von Esterasen Abweichungen auftreten.
    Notes: Summary With the help of enzyme histochemical methods, the distribution and activities of several oxidative and hydrolytic enzymes in the epidermis of the densely-haired domestic cat have been studied. Distinct oxidative enzyme activity could be demonstrated in all epidermallayers except the stratum corneum. Among the hydrolytic enzymes investigated, strong reactions for non-specific esterases were visible especially in the str. granulosum and the basal lamellae of the str. corneum. Positive reactions for cholinesterases could not be observed in the cat epidermis. The results are discussed in relation to corresponding investigations on the epidermis of sparsely-haired mammals, e. g. the domestic pig and man. Generally the enzyme pattern of the cat epidermis only shows limited parallels to man, especially where esterase distribution is concerned.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 39 (1977), S. 231-235 
    ISSN: 1432-0533
    Keywords: Actinomyces viscosus ; Epidural space ; Spinal cord ; Cat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a 3 year old female domestic cat a suppurative, granulomatous lesion of the tail and sacral area penetrated into the epidural space, causing paraplegia. A. viscosus was isolated from the inflammatory tissues. A comparative light and electron-microscopic study of the bacterial elements and the architecture of the granules (Drusen) show that the latter are in-vivo microcolonies of the agent.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 133-139 
    ISSN: 1432-1106
    Keywords: Intralaminar nuclei ; Visual cortex ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thalamic projections to the visual cortex were investigated using the Horseradish peroxidase tracing technique. Besides confirmation of a distinct origin of thalamic projections to striate and extra-striate visual cortex, afferents of the intralaminar nuclei (ILN) to visual cortex were demonstrated. These projections of ILN were shown to be specific in that they terminate in areas 18, 19 and Clare Bishop but not area 17. The coupling of these intralaminar projections on to the extra-striate visual system is considered with respect to orientation of gaze.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 249-257 
    ISSN: 1432-1106
    Keywords: Hemilabyrinthectomy ; Compensation ; Postural deficits ; Vision ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A photographic technique was used to study the evolution of lateral head-tilt following hemilabyrinthectomy in adult cats. Animals were maintained post-operatively in normally lit conditions (LM cats), in total darkness (DM cats), or in stroboscopic light. In LM cats, the head tilt peaked at 45 degrees (with the lesionned side down) on the second post-operative day, and decreased to about 0 degree within about 10 days. This evolution was followed by rebounds of head-tilt to larger angles before a stable compensated head position could be maintained (approximately at the end of the third post-operative month). In DM cats, the head remained tilted by a large angle throughout the duration of the dark period. Re-exposure to light was followed by a rapid decrease of head-tilt. In stroboscopic light, the evolution of head-tilt was found to be closely similar to that in the normally lit condition. Finally, when put back in the dark at a late post-operative stage, already compensated animals were found to loose their symmetrical head position, and to re-acquire a strong head tilt. This effect resumed on re-exposure to light. It is inferred that static visual input is a necessary condition for compensation of the postural deficits of hemi-labyrinthectomy in the cat. Maintenance of a stable head posture also depends upon continuous availability of visual input.
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  • 18
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    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 345-361 
    ISSN: 1432-1106
    Keywords: Putamen ; Cat ; Center median parvocellular neurons ; Ultrastructure ; Degenerated boutons (type VII and IV)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cat putamen contains the identical nine types of synapses and the same proportion of axo-dendritic (or axo-somatic) synapses as described for the fundus striati. However, type III (cortico-striatal) (31∶16%) and type V (axon-collateral) (13∶1%) occur much more frequently and type I (nigro-striatal) much less frequently (14∶34%) in the putamen than in the fundus striati. Of the axo-spinous synapses only type IV, with densely arranged small round vesicles and interrupted, asymmetric contact, shows a dark degeneration after center median lesions, mainly in the parvocellular part. Of the six axo-dendritic (or axo-somatic) synapses, only type VII, with densely packed small round vesicles and asymmetric contact, is degenerated after the same lesion in the center median nucleus. However, after such lesions type VII synapses are much more frequently degenerated in the putamen than those of type IV.
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  • 19
    ISSN: 1432-1106
    Keywords: Pontine nuclei cells ; Unitary EPSPs ; Synaptic organization ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Intracellular potentials of pontine nuclei (PN) cells were recorded in cats anesthetized with pentobarbitone sodium. 2. Stimulation of the cerebellar nuclear regions or the brachium pontis induced an antidromic action potential composed of IS-SD spikes, after-depolarization and after-hyperpolarization. 3. Cerebellar stimulation produced EPSPs only in a few PN cells. 4. Activation of the corticopontine or pyramidal tract produced in all PN cells an EPSP built up from the unitary components with variable amplitudes and time courses. Paired or repetitive activation revealed a property of the frequency potentiation of the EPSP. 5. Unitary EPSPs also occurred spontaneously. A great majority of these spontaneous EPSPs were cerebral in origin, and had amplitudes and time courses comparable with those evoked by stimulation of the corticopontine or pyramidal tract. 6. The half-width versus time to peak relationship of these unitary EPSPs suggested a dendritic location of the synapses with variable distances from the soma. It is assumed that large, proximal synapses serve for efficient relay of signals while small, distal synapses for their integration.
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  • 20
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Cat ; Dark adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The responses of neurones in laminae A and A1 of the cat lateral geniculate nucleus to moving stimuli were investigated at different background luminances. Moving bright slits, dark bars and edges were employed; the contrast of stimuli against the background was held constant. Background intensities varied from 10−3 to 102 td. Responses as stimuli passed across the centres of LGN receptive fields became stronger with increasing levels of light adaptation up to 10−1–101 td and then remained constant. Responses as stimuli passed through surround regions altered qualitatively with adaptation level, generally increasing in strength and complexity with background luminance. As a bright slit for on-centre cells or dark bar for off-centre cells left the surround, in almost all units a strong secondary peak could be elicited by an appropriate selection of the adaptation conditions. Many features of the responses to moving stimuli could not be predicted from the responses to stationary stimuli under different adaptation conditions described in the previous paper.
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  • 21
    ISSN: 1432-1106
    Keywords: Cat ; Visual cortex ; Intrinsic connections ; Degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The extent of the spread of axonal degeneration was investigated in the visual cortex of the cat after making small lesions restricted to the grey matter. Two series of experiments were undertaken. In the first, normal adult cats were used, and in the second, the cortex of the postlateral gyrus was isolated from its extrinsic afferents by surgical undercutting 3 months before making the lesions. The results were similar in the two series in most respects. 1. Horizontal fibres extended in considerable numbers for some 500 μm from the lesion, mainly in layers I, III/IV and V, a few reaching 2–3 mm. These fibres were better seen in the intact than in the isolated cortex. Their spread was usually asymmetrical, being greater posteromedially than anterolaterally. 2. Oblique axons ran downwards from the middle layers into layers V and VI, or upwards into layers I and II. 3. Axons arising from layers II to VI descended vertically into the white matter. Degeneration patterns after lesions in areas 17 and 18 were compared.
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  • 22
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    Experimental brain research 28 (1977), S. 21-35 
    ISSN: 1432-1106
    Keywords: Cat ; Visual cortex ; Binocular convergence ; Ocularity stripes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The average latency of cortical neuronal responses to electrical optic nerve (ON) stimulation was 3.0±0.7 s.d. msec. No significant difference between latencies to ipsi- and contralateral ON stimulation was found. Binocularly excitable cells showed almost equal response latencies to stimulation of both nerves. The average latency of subcortically recorded geniculo-cortical fibers was 0.3 msec less, but showed the same variance as that of cortical cells, suggesting that in all cases direct monosynaptic excitation of cortical cells by fibers of either ocularity is possible. Classes of ocular dominance based on electrical stimulation were positively, but not 100% correlated with classes of ocular dominance to visual stimulation. An anatomical study revealed that in cat terminals of geniculo-cortical projection are segregated to a lesser degree into ocularity stripes than in monkey. Direct monosynaptic excitation of cells by fibers of either ocularity which was found physiologically would also on these grounds appear possible for all cells.
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  • 23
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    Experimental brain research 29 (1977), S. 429-432 
    ISSN: 1432-1106
    Keywords: Visual movement perception ; Cat ; Contrast sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Behavioral experiments show that the visual system of cat contains mechanisms which are selective for direction of stimulus movement. The cat's contrast detection threshold for a drifting grating is unaffected by the addition of a grating moving in the opposite direction; this same pattern of results is found for human observers. The convergence of cat and human psychophysical data suggests that man's brain may hold direction-specific neurons, similar to those known to exist in the cat brain.
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  • 24
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    Experimental brain research 30 (1977), S. 25-41 
    ISSN: 1432-1106
    Keywords: Cat ; Visual cortex ; Deprivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of monocular deprivation from contour vision were investigated in the striate cortex of cats. In addition to the receptive field (RF) properties of single cells responses to electrical stimulation of the deprived and the experienced optic nerve were analyzed: Evoked potentials as well as intra- and extracellularly recorded single unit responses were evaluated. The main goals were: 1. to determine to what extent the responses to electrical stimulation reflected the shift in ocular dominance apparent from the RF analysis, 2. to determine the relative effects of deprivation on excitatory and inhibitory responses and 3. to locate the site of impaired transmission in the pathway from the deprived eye. The results show that the responses to electrical stimulation reflect precisely the shift in ocular dominance apparent from the RF analysis. The evoked potentials elicited from the deprived nerve further indicate that deprivation had also affected the afferent system at the LGN level or (and) at the terminal field of the thalamo-cortical fibers. In contrast to the reduction of short latency excitatory responses to stimulation of the deprived nerve, oligosynaptic inhibition with latencies of 4–6 msec was equally well elicited by stimulation of either eye. The same was true for delayed excitatory responses which frequently occur with latencies between 40 and 80 msec after nerve stimulation. It is concluded from these results 1. that transmission between thalamic afferents and inhibitory interneurones in the cortex is less affected by deprivation than transmission in those pathways which relay cortical excitation, 2. that there is another deprivation resistant indirect pathway from the retina to the visual cortex which is probably relayed through mesencephalic structures and 3. that deprivation effects are not confined to transmission failure at the thalamo-cortical synapses but include alterations already at the presynaptic level.
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  • 25
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    Experimental brain research 27 (1977), S. 101-111 
    ISSN: 1432-1106
    Keywords: Eye muscle afferents ; Stretch receptors ; Cerebellar cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extraocular proprioceptive input to cerebellar vermis, lobule VI, was investigated in cats under N2O analgesia by recording neuronal responses to eye muscle stretch. Both optic tracts were transected and the periorbital skin and conjunctiva were locally anaesthetized. Eye rotation within the physiological range was achieved by applying a pull of predetermined length and tension to each of the eight musculi recti at their insertion to the globe. Within lobule VI, only small patches of cortex receive stretch receptor afferents. The information made available by these afferents corresponds to a change of eye position. Minimal responses were dependent upon angular deflections of a few degrees. Maximal response amplitudes were obtained within the physiological range of angular deflections and angular velocities for the units tested. Most cells responded to stretch of more than one muscle. Three types of convergence were found: (1) neurons responding according to a certain direction of a conjugated movement of both eyes, (2) neurons responding to movements in either direction of one plane, (3) more complicated response patterns.
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  • 26
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    Experimental brain research 28 (1977), S. 235-248 
    ISSN: 1432-1106
    Keywords: Vestibulo-ocular reflex ; Hemilabyrinthectomy ; Role of vision ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. A new description of vestibulo-ocular responses to angular velocity steps has been used to quantify vestibular compensation in right hemilabyrinthectomized cats. The amplitudes (VM and CM) and the times of occurrence (tM and to) from stimulus onset of the peaks of slow phase eye velocity and slow cumulative eye position were computed for velocity steps directed towards the lesioned side (clockwise, CW) and towards the intact side (counterclockwise, CCW). In addition, the values of these parameters were corrected from the effects of spontaneous nystagmus, when present. 2. In animals recovering in normal laboratory conditions, spontaneous nystagmus disappeared within 10 days after operation. In CCW responses, vm decreased by about 45% during the first 3 days and then remained stationary during the next 2 weeks. In CW responses VM showed a rapid increase during the first 3 days, and then remained stationary. After 2 weeks, VM increased in both CW and CCW responses. CM changes substantially reproduced those of VM. 3. In animals put in the dark immediately after operation, spontaneous nystagmus persisted until re-exposure to light (up to 31 days) and then disappeared rapidly. VM in both CW and CCW responses remained at a low value during the dark period and became more or less doubled after one week of exposure to light. CM also increased rapidly in CW and CCW responses, after re-exposure to light. 4. In the discussion these results are compared with those concerning activity of single vestibular neurons during compensation. It is concluded that vision is a primary factor conditioning disinhibition of vestibular nuclei spontaneous activity after the critical phase of compensation.
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  • 27
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    Experimental brain research 28 (1977), S. 421-425 
    ISSN: 1432-1106
    Keywords: Visual system ; Cat ; Proprioceptive receptors ; Extraocular muscles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrical stimulation of the intraorbital part of the motor branches of extraocular muscles, where proprioceptive fibers run, evokes responses in 25% of the units of the striate cortex of the cat. The latency ranges between 25 and 40 msec. Mechanical stretch of extraocular muscles evokes multiunit responses in the striate cortex. The response is abolished by injection of xylocaine into the stretched muscle. The suppression of the response is reversible.
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  • 28
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    Experimental brain research 27 (1977), S. 335-345 
    ISSN: 1432-1106
    Keywords: Spatial frequency ; Visual neurones ; Mean luminance ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experiments have been performed on unanaesthetized and paralysed cats. The tuning curves for spatial frequency of retinal, lateral geniculate and simple and complex cells of the cortex have been determined in response to sinusoidal gratings of various spatial frequencies at different levels of mean luminance. For all neurones, decreasing the mean luminance leads to a progressive loss of spatial resolution and contrast sensitivity. Retinal ganglion cells of type X show, for scotopic levels of luminance, a flattening of their spatial frequency tuning curves in the low spatial frequency range. For geniculate and cortical neurones, on the contrary, the spatial frequency characteristics at the various levels of luminance remain practically invariant in their bandwidth. On the average, complex cells still respond to mean luminances ten times lower than simple cells. The tuning curves for orientation of cortical cells maintain, to a first approximation, the same shape at the various levels of mean luminance. The results are discussed, comparing the electrophysiological with psychophysical data.
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  • 29
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    Pflügers Archiv 369 (1977), S. 27-32 
    ISSN: 1432-2013
    Keywords: Electrodermal reflexes ; Natural stimulation of skin ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Electrodermal reflexes recorded from the central pads on the hind- and forepaws were elicited by natural stimulation of skin in ketamine anaesthetised cats. 2. Stimuli which excite the Pacinian corpuscles in the paws (air jet stimuli applied to the paw, vibrational stimuli produced by tapping on the experimental frame) and the cutaneous nociceptors (mechanical and thermal noxious stimuli) elicit electrodermal reflexes. Stimuli exciting hair follicle receptors on the trunk or legs or slowly adapting receptors in the feet are without effect. 3. Electrodermal reflexes elicited by non-noxious mechanical stimulation of skin in the hindpaws have a clear-cut spatial organization. Air jet stimuli can only produce them from the distal hindpaws but not from any other skin area indicating that this reflex may be organized at the spinal level. Electrodermal reflexes on noxious stimulation too have some spatial organization.
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  • 30
    ISSN: 1432-2013
    Keywords: Vasoconstrictor neurones ; Skin ; Muscle ; Systemic hypoxia ; Systemic hypercapnia ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Reactions of cutaneous and muscle vasoconstrictor neurones to the hindlimb on systemic hypoxia and systemic hypercapnia were investigated in chloralose anaesthetized cats. Mainly four types of preparations were used: brain intact and decrebrate (pontomedullary) animals with and without cartotid sinus (CSN) and vagal nerves (VN). 2. In brain intact animals with intact CNS and VN most cutaneous vasoconstrictor neurones were depressed and most muscle vasoconstrictor neurones were excited during systemic hypoxia and hypercapnia. The responses to hypercapnia were smaller than those to hypoxia. 3. In brain intact deafferented animals and in decerebrate animals with and without intact CSN and VN systemic hypoxia and hypercapnia induced excitation in both cutaneous and muscle vasoconstrictor neurones. The responses to hypoxia were significantly smaller in deafferented preparations when compared to those in preparations with intact CSN and VN. Furthermore in muscle vasoconstrictor neurones the size of the responses was not significantly different in decerebrate preparations from that in brain intact preparations. 4. These results indicate a distinct neuronal organization of the chemoreceptor reflexes in the vasoconstrictor systems in the brain stem. Suprapontine brain structures are most important for producing the inhibition of the cutaneous vasoconstrictor neurones during hypoxia and hypercapnia.
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  • 31
    ISSN: 1432-2013
    Keywords: Vestibular nuclei ; Cat ; Somatosensory integration ; Neck movement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The vestibular nuclei of cats were explored extracellularly with micropipettes to locate units with a resting discharge rate which responded to rotation in the horizontal plane. These units were examined for somatosensory input from neck and limbs. Fewer than half responded to somatosensory stimulation. The neck region was the body area most effective in influencing unitary activity. The response pattern most often noted was an increase and decrease in discharge frequency when the body was moved towards and away from the recording electrode respectively. Change in discharge rate was observed to be primarily dependant upon neck velocity and not upon absolute neck position. Half of the somato-sensory units received input from either the forelimbs or the hindlimbs, while the remaining half responded to both.
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  • 32
    ISSN: 1432-2072
    Keywords: Amphetamine ; Para-hydroxy-amphetamine ; Distribution ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The distribution and metabolic fate of amphetamine were studied in cats. In the brain, high levels of drug were detected in the grey matter structures at short intervals after administration, while at longer intervals distribution between white and grey matter areas was more uniform. In peripheral tissues the greatest concentration of the drug was seen in the highly vascularized organs. Para-hydroxyamphetamine was found in minimal amounts in the liver and kidneys and only at trace quantities in the brain.
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  • 33
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    European archives of oto-rhino-laryngology and head & neck 217 (1977), S. 199-217 
    ISSN: 1434-4726
    Keywords: Hereditary deafness ; Cat ; Electron microscopy ; Stria vascularis ; Reissner's membrane ; Microcirculation ; Cellular metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The auditory pathway potentials have been recorded from a series of 35 cats, and the stria vascularis and Reissner's membrane examined with the electron microsope. The ages varied from the first postnatal day to at least 6 years. 30 of the animals had white coats, and 45 of the ears lacked potentials. The basal processes of the marginal cells fail to develop in pathological ears, and appear displaced towards the endolymphatic surface by a layer of grossly swollen, chromophobe cells. These features are already present at the 3-day stage, and persist until the third week. Thereafter, increasing electron density of all cell types is found, with progressive reduction in strial thickness. Swelling of the capillary endothelial cells and descent of Reissner's membrane are found in the first coil at 2 weeks. Obliteration of capillaries, and development of vacuolar cytoplasmic outgrowths from the vestibular membrane mesothelial cells occur at later stages. These findings are discussed and compared with the pathological changes produced by a variety of endogenous and exogenous factors in both man and animals.
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  • 34
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1-11 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation of Succinimide During the Synthesis of the Insulin A Chain(14-21) OctapeptideDuring the synthesis of insulin A chain (14-21) fragments it was observed that alkaline treatment of Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut and Msc-Tyr-(But)-Gln-Leu-Glu(OBut)Asn-Tyr(But)-Cys(Trt)-Asn-OBut caused quantitative formation of succinimide in position 21.
    Notes: Bei der Synthese von Teilsequenzen der Insulin-A-Kette (14-21) wurde während der alkalischen Abspaltung der Msc-Gruppe von Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys-(Trt)-Asn-OBut und Msc-Tyr-(But)-Gln-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut in allen Fällen Succinimidbildung in Position 21 beobachtet.
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  • 35
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 37-48 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, IX. On the Reaction of Amide Acetals with HeterocumulenesDeprotonation of the (dimethylamino)methoxycarbenium ion (10) by NaH liberated the carbene 2, which was trapped by aryl isocyanate to give the hydantoin 6 and by phenyl isothiocyanate to yield 8. Hence, the carbene 2 is assumed to be also an intermediate in the corresponding reactions of the amide acetal 1 which lead to the hydantoins 6 and 8. The reaction of 1 with phenyl isothiocyanate yielded the products 4, 7, 8, or 12 depending on the reaction conditions. An equilibrium between 1 and the carbene 2 is suggested by the reaction of 1 with sulfur to give 16, and is the basis for mechanistic discussions.
    Notes: Das durch Deprotonierung des (Dimethylamino)methoxy-carbenium-Ions (10) mit NaH freigesetzte Carben 2 addierte sich an-Arylisocyanat zum Hydantoin 6, an Phenylisothiocyanat zu 8. Dies legt nahe, daß auch bei der Umsetzung des Amidacetals 1 mit Heterocumulenen zu den Hydantoinen 6 bzw. 8 das Carben 2 beteiligt ist. Bei der Umsetzung von 1 mit Phenylisothiocyanat entstanden je nach Reaktionsführung die Produkte 4, 7, 8 oder 12. Für deren Bildung werden Mechanismen diskutiert, die von einer Gleichgewichtseinstellung von 1 mit dem Carben 2 ausgehen. Diese Annahme wird durch Umsetzung von 1 mit Schwefel zu 16 gestützt.
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  • 36
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 67-77 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Perhalomethylthio)heterocycles, VIII. (Perchlorofluoromethylthio)- and (Haloformylthio)-N-heteroaromaticsPyrrole reacts with Cl3-nFnC—SCl (n = 1-3) to give mixtures of 2- and 3-substituted pyrroles 1 a-c and 2a, b; CF3SCFCl—SCl and XC(O)SCl (X = F, Cl) merely yield 2-substituted derivatives 3. In the presence of excess CF3SCl also disubstituted products 4, 5 are available. Analogously pyrrole derivatives can be substituted directly, dependent on their reactivity (6-14). 1a is oxidized by 3-chloroperbenzoic acid to yield the sulfoxide 15 or the sulfone 16; the reaction with bromine and iodine results in the formation of the fully halogenated compounds 17, 18. Indole reacts with CF3SCl to give the 3-substituted 19, while carbazole yields the N-substituted product 20 in a Grignard reaction. 1H and 19F n. m. r. spectra are discussed.
    Notes: Pyrrol setzt sich mit Cl3-nFnC—SCl (n = 1-3) zu Isomerengemischen 2- und 3-substituierter Pyrrole 1a-c bzw. 2a, b, um; CF3SCFCl—SCl und XC(O)SCl (X = F, Cl) liefern lediglich 2-substituierte Derivate 3. In Gegenwart eines CF3SCl-Überschusses sind auch disubstituierte Produkte 4, 5 erhältlich. Analog sind Pyrrol-Derivate, je nach ihrer Reaktivität, einer direkten Substitution zugänglich (6-14). 1 a wird durch 3-Chlorperbenzoesäure zum Sulfoxid 15 bzw. Sulfon 16 oxidiert; die Umsetzung mit Brom bzw. Iod führt zu den vollständig halogenierten Verbindungen 17, 18. Indol reagiert mit CF3SCl zum 3-substituierten 19, während Carbazol in einer Grignard-Reaktion das N-Substitutionsprodukt 20 liefert. 1H- und 19F-NMR-Spektren werden diskutiert.
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  • 37
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 96-106 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Aldehydes and Ketones with the Makosza Dichlorocarbene ReagentPhase transfer-catalyzed reactions of aldehydes and ketones with trichloromethane and 50 per cent aqueous sodium hydroxide in the presence of benzyltriethylammonium chloride (BTEA) at low temperatures result in the formation of α-(trichloromethyl)carbinols 7; in the presence of dimethyl sulfate the corresponding methyl ethers 8 are obtained. At 56 ± 2°C the α-hydroxy-11, α-chloro- 12 and α,β-unsaturated carboxylic acids 13 are formed. In this reaction the α-(trichloromethyl)carbinols 7 can be excluded as intermediates. An alternative reaction mechanism for the formation of 11, 12, and 13 is discussed, which involves direct addition of dichlorocarbene to the C=O double bond to form the dichlorooxiranes 5 followed by rearrangement and saponification.
    Notes: Aldehyde und Ketone reagieren mit Trichlormethan im Zweiphasensystem mit 50proz. wäßrigem Natriumhydroxid unter Phasentransfer-Katalyse durch Benzyltriethylammonium-chlorid (BTEA) (1) bei tiefer Temperatur zu α-(Trichlormethyl)carbinolen 7, in Gegenwart von Dimethylsulfat zu den entsprechenden Methylethern 8. Bei 56 ± 2°C entstehen α-Hydroxy- 11, α-Chlor- 12 und α,β-ungesättigte Carbonsäuren 13, wobei die α-(Trichlormethyl)carbinole 7 als Zwischen-stufen auszuschließen sind. Als Alternativmechanismus wird die direkte Addition von Dichlor-carben an die C=O-Doppelbindung zu Dichloroxiranen 5 und deren Umlagerung und Verseifung diskutiert.
    Additional Material: 2 Tab.
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  • 38
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    Berichte der deutschen chemischen Gesellschaft 110 (1977) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 39
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 23-36 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, VIII. Selectivity of Nucleophilic Carbenes with Regard to HeterocumulenesThe selectivities of N-methylbenzothiazolinylidene (2) and 1,3-diphenylimidazolidinylidene (3) against aryl isocyanates and phenyl isothiocyanate have been determined. The selectivities increase from dimethoxycarbene (1) over 2 to 3. In contrast all three carbenes display equal selectivity with regard to different aryl isocyanates.
    Notes: Für N-Methylbenzothiazolinyliden (2) und 1,3-Diphenylimidazolidinyliden (3) wurden die Selektivitäten gegenüber verschiedenen Arylisocyanaten einerseits und Phenylisothiocyanat andererseits bestimmt. Diese nehmen vom Dimethoxycarben (1) über 2 zu 3 zu. Dagegen zeigen alle drei Carbene bei 140°C eine übereinstimmende Selektivität gegenüber Arylisocyanaten.
    Additional Material: 3 Ill.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 12-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Metabolites of Microorganisms, XII. Michigazone, a New Phenoxazone Pigment from Streptomyces michiganensis  -  Structure Determination and SynthesisBy spectroscopic methods and chemical degradation michigazone has been shown to possess structure 7. 7 and some further related phenoxazones have been synthesized by the Kehrmann-method.
    Notes: Spektroskopische Untersuchungen und chemischer Abbau führten für Michigazon zur Konstitution 7. 7 und einige weitere bisher noch nicht beschriebene Phenoxazone wurden durch Kehrmann-Synthese dargestellt.
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  • 41
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 49-52 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, X. Ionic Intermediates in the Reaction of Trimethyl Orthoformate with Aryl IsocyanatesThe ion pair 2/3 is assumed to be the crucial intermediate in the reaction of trimethyl orthoformate with aryl isocyanates. The collapse of the ion pair to 4 is a fast subsequent reaction. The acid base reaction of the ion pair to the carbene 6 proceeds with a comparable rate. Methoxyl transfer of 2/3 to form 1 is considerably slower. Transalkylation of the ion pair to 8 has not been observed.
    Notes: Bei der Umsetzung von Orthoameisensäure-trimethylester mit Phenylisocyanat wird das Ionen-paar 2/3 als zentrale Zwischenstufe angenommen. Eine rasche Folgereaktion dieses Ionenpaares ist die Kombination zu 4. Vergleichbar schnell verläuft die Säure-Basen-Reaktion im Ionenpaar zum Carben 6. Eine Methoxyl-Übertragung aus 2/3 zu 1 ist erheblich langsamer. Die Umalkylierung zu 8 konnte nicht beobachtet werden.
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  • 42
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 86-95 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Activated Ethylenes, V. Reaction of Aromatic Compounds with Derivatives of Chloromethylenemalonic Acid. A new Synthesis of Aromatic AldehydesThe derivatives of chloromethylenemalonic acid 3 and 4 react with aromatic compounds in the presence of aluminium chloride to give the arylmethylenemalonic acid derivatives 5a-i and 6a-d. By hydrolysis of the C=C double bond the corresponding dinitriles 2a-g are converted into aldehydes.
    Notes: Chlormethylenmalonsäure-Derivate 3 und 4 lassen sich in Gegenwart von Aluminiumchlorid mit Aromaten umsetzen, wobei die Arylmethylenmalonsäure-Derivate 5a-i und 6a-d entstehen. Die entsprechenden Dinitrile 2a-g lassen sich durch Hydrolyse der C=C-Doppelbindung in Aldehyde überführen.
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  • 43
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 107-123 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry of the Norcaradiene-Norcaradiene Rearrangement, I. The Synthesis of Optically Active [Norcaradiene ⇌ Cycloheptatriene] DerivativesAnion 14 derived from treatment of 1,3,5-cycloheptatriene-7-carbonitrile (13) with n-butyllithium or lithium diisopropyl reacts with methyl iodide, deuterium oxide, and carbon dioxide to give the corresponding 7,7-disubstituted derivatives 2, 13-D, and 16. By a sequence of reactions 2 was transformed into the optically pure [norcaradiene ⇌ cycloheptatriene] systems 4 and 10. The equilibrium concentrations of the [norcaradiene ⇌ cycloheptatriene] systems 2-12 were determined by 1H n.m.r. mesurements at low temperatures.
    Notes: Das aus 1,3,5-Cycloheptatrien-7-carbonitril (13) mit n-Butyllithium oder Lithium-diisopropylamid erzeugte Anion 14 reagiert mit Methyliodid, Deuteriumoxid und Kohlendioxid ausschließlich zu den entsprechenden 7,7-disubstituierten Derivaten 2, 13-D, und 16. Aus 2 lassen sich durch eine Folge von Reaktionen die optisch reinen [Norcaradien ⇌ Cycloheptatrien]-Systeme 4 und 10 synthetisieren. Mit Hilfe der Tieftemperatur-1H-NMR-Spektroskopie wurden die Gleichgewichtskonzentrationen der [Norcaradien ⇌ Cycloheptatrien]-Systeme 2-12 ermittelt.
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  • 44
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 146-153 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 4-Acetoxy-2-cyclopenten-1-oneBy using 4-acetoxy-2-cyclopenten-1-one (8) as a synthone for the non-existent cyclopentadienone (5), Michael additions are performed that give rise to trans-disubstituted cyclopentanone derivatives (11,12). In the case of tert-butyl acetoacetate as Michael donator the addition to 11 is followed by an aldol-cyclisation to the trans-perhydroazulene system 22.
    Notes: Unter Verwendung von 4-Acetoxy-2-cyclopenten-1-on (8) als Synthon für das nicht existenzfähige Cyclopentadienon (5) wurden Michael-Additionen durchgeführt, die zu trans-disubstituierten Cyclopentanon-Derivaten (11, 12) führen. Bei Verwendung von tert-Butyl-acetacetat als Michael-Donator schließt sich an die Addition zu 11 eine Aldolcyclisierung zum trans-Perhydroazulensystem 22 an.
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  • 45
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 605-610 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 3,3-Bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. Trapping Reactions of Nitrile Ylides with NitrosobenzeneTrapping reactions of bis(trifluoromethyl)-substituted nitrile ylides 2, generated by thermolysis of 3,3-bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. 1, with nitrosobenzene yield 5,5-bis-(trifluoromethyl)-Δ3-1,2,4-oxadiazolines 3, 3,3-bis(trifluoromethyl)-Δ4-1,2,4-oxadiazolines 4, and 4,4-bis(trifluoromethyl)-1,4-dihydro-1-quinazolinols 5. The compounds 5 are products of a thermal rearrangement of first formed [3 + 2]-cycloadducts. I. r., 1H n. m. r., 19F n. m. r., and mass spectra of the new compounds are described.
    Notes: Abfangreaktionen von bis(trifluormethyl)-substituierten Nitril-yliden 2, die durch Thermolyse aus 3,3-Bis(trifluormethyl)-Δ4-1,4,2λ5-oxazaphospholinen 1 erzeugt werden, mit Nitrosobenzol liefern 5,5-Bis(trifluormethyl)-Δ3-1,2,4-oxadiazoline 3, 3,3-Bis(trifluormethyl)-Δ4-1,2,4-oxadiazoline 4 und 4,4-Bis(trifluormethyl)-1,4-dihydro-1-chinazolinole 5. Die Verbindungen 5 sind das Resultat einer thermisch ausgelösten Umlagerung primär erhaltener [3 + 2]-Cycloaddukte. IR-, 1H-NMR-, 19F-NMR- und Massenspektren der neuen Verbindungen werden beschrieben.
    Additional Material: 4 Tab.
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  • 46
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 619-630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXIV. Benzo[12]annulenes: On the Annulene Character of Dibenzo- and Tribenzo[12]annulenesAs a contribution to the controversial discussion about the antiaromaticity of the [12]annulene system in the di- and tribenzo[12]annulenes 3 and 4 the compounds 5, 8, and 18 were prepared for comparison. The discussion of the 1H n. m. r. spectra with consideration of the anisotropy effect of the triple bonds led to the conclusion that in contrast to earlier assumptions the [12]annulene system in 3 and 4 in spite of the benzo-anellation is paratropic.
    Notes: Als Beitrag zu der kontroversen Diskussion über die Antiaromatizität des [12]Annulen-Systems in den Di- und Tribenzo[12]annulenen 3 und 4 wurden die Vergleichsverbindungen 5, 8 und 18 dargestellt. Die Diskussion der 1H-NMR-Spektren unter Berücksichtigung des Anisotropieeffektes der Dreifachbindungen ergab, daß entgegen früherer Auffassung das [12]Annulen-System in 3 und 4 trotz der Benzo-Anellierung paratrop ist.
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  • 47
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 631-637 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXV. Benzo[12]annulenes: Synthesis and Properties of a Benzo-naphtho[12]annuleneThe benzo-naphtho[12]annulene 4, where in contrast to 1, 2, and 3 a planar twelve-membered ring is present, has been synthesized via 6-9. 1H n. m. r. absorption of the internal hydrogen is observed at δ = 13.13 ppm. The allotment of this considerable down-field shift to the paratropic effect of the annulene system and the anisotropy of the triple bonds is discussed. For this purpose, the twelve-ring system 5 in which the macrocyclic conjugation is interrupted has been synthesized from 9 via 10 and 11.
    Notes: Das Benzo-naphtho[12]annulen 4, bei dem im Gegensatz zu den Verbindungen 1, 2 und 3 eine ebene Zwölfring-Struktur fixiert ist, wurde über 6-9 synthetisiert. Die 1H-NMR-Absorption des inneren Wasserstoffatoms wird bei δ = 13.13 ppm beobachtet. Die Aufteilung dieser beträchtlichen Tieffeld-Verschiebung in den Paratropie-Effekt des Annulen-Systems und den Anisotropie-Effekt der Dreifachbindungen wird diskutiert. Hierzu wurde das Zwölfring-System 5, bei dem die makrocyclische Konjugation unterbrochen ist, von 9 über 10 und 11 synthetisiert.
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  • 48
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 651-655 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XV. Reactions of trans,trans-1,3-Diphenyl-2-azaallyllithium with Heterocumulenestrans,trans-1,3-Diphenyl-2-azaallyllithium (1) reacts with phenylisocyanate, phenylisothiocyanate, and methylisothiocyanate to give an imidazolidine-4-one (2a) or imidazolidine-4-thione (2b, c), respectively. When reacting with carbon disulfide or dicyclohexylcarbodiimide (symmetrical heterocumulenes) the cycloaddition is followed by a fast secondary reaction (→ 4, 7).
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich regiospezifisch an die CN-Doppel-bindung des Phenylisocyanats sowie Phenyl- und Methylisothiocyanats unter Bildung eines Imidazolidin-4-ons (2a) bzw. -4-thions (2b, c). Bei entsprechenden Umsetzungen mit den symmetrischen Heterokumulenen Schwefelkohlenstoff und Dicyclohexylcarbodiimid folgt der Cycloaddition jeweils eine schnelle Sekundärreaktion (→4, 7).
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  • 49
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 667-676 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of trans-[Pt(CO2R)(CO)(PPh3)2]+BF4- with Alkynes: Formation of Alkynyl- and Alkenylplatinum(II) ComplexesThe alkoxycarbonyl complexes [Pt(CO2R)(CO)(PPh3)2]+ BF4- 1 react with alkynes HC≡CR to give the acetylides 2a-c. On the other hand, cationic β-methoxyvinyl 3 or β-hydroxyvinyl complexes 4, respectively, are obtained from the reactions of 1 with disubstituted acetylenes R1C≡CR2 under participation of the nucleophiles methanol and water. Compounds 3 and 4 are converted into neutral derivatives (5, 6, 8) by methoxide or azide ions. The synthesis of Ir(CO2CH3)(CO)(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 is described. Bonding is discussed for the new complexes by means of n. m. r. and i. r. data.
    Notes: Die Alkoxycarbonyl-Komplexe [Pt(CO2R)(CO)(PPh3)2]+BF4- 1 setzen sich mit Alkinen HC ≡ CR zu den Acetyliden 2a-c um. Dagegen entstehen aus 1 und disubstituierten Acetylenen R1C≡CR2 unter Beteiligung der Nucleophile Methanol und Wasser kationische β-Methoxyvinyl- 3, bzw. β-Hydroxyvinyl-Komplexe 4. Die Verbindungen 3 und 4 werden mit Methylat- oder Azid-Ionen in neutrale Derivate (5, 6, 8) umgewandelt. Ferner wird die Synthese von Ir(CO2CH3)(CO)-(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 beschrieben. Die Bindungsverhältnisse werden mit Hilfe von NMR- und IR-Daten diskutiert.
    Additional Material: 3 Tab.
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  • 50
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 703-716 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Bridged 5,6-Diamino-4,7-dialkyl-1,3-benzodioxoles as Intermediates for the Synthesis of Molecules with Knot StructureIn a reaction sequence involving metalation with butyllithium followed by alkylation. cyclohexanone pyrocatechol acetal 4 is converted to the 3,6-dialkylpyrocatechol 11. By subsequent acetalisation with 1,25-dichloro-13-pentacosanone (14), followed by nitration (19), reduction (20), acylation (26), renewed reduction (27), and cyclization, the double bridged benzodioxole 28 is obtained. The compound represents an intermediate in the projected synthesis of a molecule with knot structure.
    Notes: Ausgehend vom Cyclohexanon-brenzcatechinacetal 4 wird durch Metallierung mit Butyllithium und nachfolgende Alkylierung in einer mehrstufigen Reaktionsfolge das 3,6-Dialkylbrenzcatechin 11 synthetisiert. Durch nachfolgende Acetalisierung mit 1,25-Dichlor-13-pentacosanon (14), gefolgt von Nitrierung (19), Reduktion (20), Acylierung (26), erneuter Reduktion (27) und Cyclisierung wird das zweifach überbrückte Benzodioxol 28 erhalten. Es stellt ein Zwischenprodukt in der geplanten Synthese eines Moleküls mit Knotenstruktur dar.
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  • 51
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 463-467 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XIV Sulfinato-O,S Complexes of Palladium(II) and Rhodium(III)The directed preparation of the sulfinato-O,S complexes {R(O)OS}nM (2a, b; 5a, b) was successful for the first time by elimination of coordinated water from the sulfinato-S complexes {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] by 2,2-dimethoxypropane. The O,S-linkage is unequivocally shown from their chemical behaviour and the i. r. spectra. The criteria necessary for the formation of sulfinato-O,S complexes are discussed.
    Notes: Durch Abspaltung von koordiniertem Wasser aus den Sulfinato-S-Komplexen {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] mit 2,2-Dimethoxypropan gelang erstmals die gezielte Darstellung der Sulfinato-O,S-Komplexe {R(O)OS}nM (2a, b; 5a, b). Die O,S-Verknüpfung ergibt sich eindeutig aus dem chemischen Verhalten und den IR-Spektren. Die für die Bildung von Sulfinato-O,S-Komplexen notwendigen Kriterien werden diskutiert.
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  • 52
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 474-486 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 78 Further Constituents of South African Senecio SpeciesFrom representatives of the section Rigidi besides already known compounds four new benzofurans (3, 5, 6, and 10) as well as six new furanoeremophilanes (13, 15, 19-21, and 23) are isolated. From Senecio pterophorus a new type of a pyrrolizidine derivative (25) is isolated. Senecio cissampelinus contains similar compounds (34-37). The structures are elucidated by spectroscopic methods as well as by some chemical reactions. The chemotaxonomical aspects are discussed.
    Notes: Aus Vertretern der Sektion Rigidi werden neben bereits bekannten Verbindungen vier neue Benzofurane (3, 5, 6 und 10) sowie sechs neue Furanoeremophilane (13, 15, 19-21 und 23) isoliert. Aus Senecio pterophorus wird ein neuer Typ eines Pyrrolizidin-Derivats (25) isoliert. Ähnliche Verbindungen (34-37) enthält Senecio cissampelinus. Die Konstitutionen werden durch spektroskopische Methoden sowie durch einige chemische Reaktionen geklärt. Die chemotaxonomischen Aspekte werden diskutiert.
    Additional Material: 6 Tab.
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  • 53
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 491-499 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Monohydrazones of Dicarbonyl Compounds, IV. New Syntheses of Pyrroles and PyrrolinesKetones and aldehydes with an active methylene group condense easily with monohydrazones of glyoxal (1 + 2 → 3). The hydrazonoethylidene derivatives thus obtained can be reduced to give pyrroles, pyrrolines, pyrrolidines, or N-aminopyrroles.
    Notes: Methylenaktive Ketone und Aldehyde lassen sich mit Monohydrazonen des Glyoxals zu Hydrazonoethyliden-Derivaten umsetzen (1 + 2 → 3). Durch Reduktion dieser Produkte sind Pyrrole, Pyrroline, Pyrrolidine sowie N-Aminopyrrole darstellbar.
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  • 54
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 522-539 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 78. Additions of C-(2,2′-Biphenylylene)-Nα-(4-chlorophenyl)-Nβ-cyano-azomethine Imine to Styrene, Alkenes, Enol Ethers and EnaminesThe cycloaddition of the title compound 1 to styrene at 70°C produces 95% of a pyrazolidine; the hydrogenolytic degradation to 9-phenethylfluorene as well as the n. m. r. spectrum reveal the addition direction. The 1-cyanopyrazolidine derivative shows reactions typical for cyanamides. - The azomethine imine 1 likewise accepts many nonconjugated alkenes, cycloalkenes and derivatives of styrene in high yield. The cycloadducts of butyl vinyl ether, cis- and trans-propenyl propyl ether, β-methoxystyrene and vinyl acetate suffer with dilute acids elimination of alkoxide or acetate, respectively, and of the N-cyano group to yield 2-pyrazolines. The electrophilicity of the azomethine imine carbon center determines the addition direction; substituents on the ethylenic dipolarophile which stabilize positive charge in the transition state of cycloaddition show up in position 5 of the pyrazolidine.
    Notes: Die Cycloaddition der Titelverbindung 1 an Styrol bei 70°C ergibt 95% eines Pyrazolidins; die Additionsrichtung geht aus der Hydrogenolyse zu 9-Phenethylfluoren ebenso wie aus dem NMR-Spektrum hervor. Das 1-Cyanpyrazolidin zeigt für Cyanamide typische Reaktionen. - Das Azomethin-imin 1 addiert viele nichtkonjugierte Alkene, Cycloalkene und Derivate des Styrols in hoher Ausbeute, wobei spektroskopische Daten die Addukt-Strukturen sichern. Die Cycloaddukte des Butylvinylethers, cis- und trans-Propenylpropylethers, β-Methoxystyrols und Vinylacetats erleiden schon mit verdünnter Säure eine Eliminierung des Alkoxyls bzw. Acetats und des N-Cyans unter Bildung von 2-Pyrazolinen. Die Additionsrichtung des 1,3-Dipols wird von der Elektrophilie des Azomethin-imin-Kohlenstoffs bestimmt; Substituenten am ethylenischen Dipolarophil, die positive Ladung im Übergangszustand der Cycloaddition zu stabilisieren vermögen, erscheinen in 5-Stellung des Pyrazolidins.
    Additional Material: 3 Ill.
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  • 55
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 611-618 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 2,2,2-Trifluor-4,4,5,5-tetrakis(trifluormethyl)-1,3,2λ5-dioxaphospholanePF5 and PhPF4 react with 2-[bis(trimethylsilyl)amino]-2,2-difluoro-4,4,5,5-tetrakis (trifluoromethyl)-1,3,2λ5-dioxaphospholane (1b) to yield the trifluorophosphorane 2 or 3, respectively. 3 is the first known example of a stable fluorophosphazophosphorane. 2 reacts with methoxytrimethylsilane to give the thermally stable difluoromethoxyphosphorane4; with hexamethyldisiloxane 5 is obtained. PF5 easily converts 5 into 2. Diphenyl(trimethylsilyl)phosphine reduces 2 to the cyclic fluorophosphite 6, which displaces the coordinated cycloolefin in (C7H8)Mo(CO)4 (C7H8 = norbornadiene) with formation of the cis-complex 7. The spectroscopic data are discussed.
    Notes: Die Reaktion von PF5 bzw. PhPF4 mit 2-[Bis(trimethylsilyl)amino]-2,2-difluor-4,4,5,5-tetrakis-(trifluormethyl)-1,3,2λ5-dioxaphospholan (1b) ergibt das Trifluorphosphoran 2 bzw. 3, das erste stabile Fluorphosphazophosphoran. 2 setzt sich mit Methoxytrimethylsilan zu dem thermisch beständigen Difluormethoxyphosphoran 4 um, mit Hexamethyldisiloxan entsteht 5, das mit PF5 leicht in 2 umgewandelt werden kann. Diphenyl(trimethylsilyl)phosphin reduziert 2 zu dem cyclischen Fluorphosphit 6, das in (C7H8)Mo(CO)4 (C7H8 = Norbornadien) das Cycloolefin unter Bildung des cis-Komplexes 7 substituiert. Die spektroskopischen Daten werden diskutiert.
    Additional Material: 2 Tab.
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  • 56
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 638-644 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XIII. endo-exo-Isomeric Cycloadducts of trans,trans-1,3-Diphenyl-2-azaallyllithium and Acenaphthylenetrans,trans-1,3-Diphenyl-2-azaallyllithium adds at O or -70°C to acenaphthylene with retention of configuration to give a mixture of N-lithio-syn- and N-lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrole (3a, 4a, R = Li) (ca. 1:1). The syn-isomer (endo-cycloadduct) rearranges to the anti-isomer (exo-cycloadduct) at +35°C.
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich bei O oder -70°C unter Retention an Acenaphthylen zu einem Gemisch von N-Lithio-syn- und N-Lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrol (3a, 4a, R = Li) (ca. 1:1). Das syn-Isomere (endo-Cycloaddukt) lagert sich bei +35°C in das anti-Isomere (exo-Cycloaddukt) um.
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  • 57
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 677-682 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Simple Phosphorus and Arsenic Ylides with Methylgermanium, -tin, and -lead SubstituentsThe syntheses of the ylides (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2, and (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 are reported. The relative substituent effect of all IVb elements on the carbanionic function of ylides is discussed in the light of the 13C and 31P n. m. r. spectra of these compounds and their Si and Sn analogues.
    Notes: Die Darstellung der Ylide (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2 und (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 wird beschrieben. Der relative Substituenteneffekt aller IVb-Elemente auf die Carbanion-Funktion von Yliden wird an Hand der 13C- und 31P-NMR-Spektren dieser Verbindungen und ihrer Si- und Sn-Analoga diskutiert.
    Additional Material: 1 Ill.
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  • 58
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 717-720 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Alkyl and Aryl Compounds, XIX. Preparation and Crystal Structure of Methylrubidium and MethylcaesiumCH3Rb and CH3Cs are prepared from CH3Li and rubidium tert-butoxide or caesium 2-methyl-2-pentanolate, respectively. As shown by X-ray diffraction of the crystal powders the compounds possess a hexagonal structure of the NiAs type with isolated methyl anions and alkali cations like CH3K investigated earlier.
    Notes: CH3Rb und CH3Cs werden durch doppelte Umsetzung von CH3Li mit Rubidium-tert-butylat bzw. Caesium-2-methyl-2-pentanolat dargestellt. Nach röntgenographischen Untersuchungen der Kristallpulver besitzen die Verbindungen wie das bereits früher untersuchte CH3K eine hexagonale Struktur vom NiAs-Typ mit isolierten Methyl-Anionen und Alkali-Kationen.
    Additional Material: 3 Tab.
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 730-736 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometrical Investigations of Dicarbonyl(cyclopentadienyl)(thioamidato) Complexes of Molybdenum and TungstenThe mass spectra of several dicarbonyl(cyclopentadienyl)(thioamidato) complexes of Mo and W and of the corresponding free thioamides are reported and the fragmentation processes are discussed. The fragmentation modes of the ionized complexes reveal structural rearrangements of the organic ligands, which cannot be observed in the spectra of the free thioamides.
    Notes: Die Massenspektren einiger Dicarbonyl(cyclopentadienyl)(thioamidato)-Komplexe von Mo und W und die der zugehörigen freien Thioamide werden angegeben und die Fragmentierungsprozesse diskutiert. Der organische Ligand unterliegt im ionisierten Komplex tiefgreifenden strukturellen Umlagerungen, für die sich in den Spektren der freien Thioamide keine Parallele finden läßt.
    Additional Material: 4 Tab.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 744-748 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Interactions of Triple Bonds, XVI. The Crystal and Molecular Structure of 5,6,12,13-Tetradehydro-8,9,10,11-tetrahydro-7H-dibenzo-[a,c]cyclotrideceneThe crystal structure of the title compound was solved by direct methods and has been refined to R = 0.056. The triple bonds are crossed by an angle of 64.0°. Their centres have a distance of 3.174 Å. Because of transannular repulsion within the thirteen-membered ring system the acetylene group deviates by 4.1° and 4.6° respectively in a cisoid manner from a linear arrangement. The other angles are enlarged. In the present conformation the length of the [CH2]5-bridge corresponds the length of the CH2—S—S—CH2-group. The chiral molecule lies on a crystallographic twofold axis.
    Notes: Die Kristallstruktur der Titelverbindung wurde mit direkten Methoden gelöst und bis zu einem R-Wert von 0.056 verfeinert. Die Dreifachbindungen sind unter einem Winkel von 64.0° gekreuzt angeordnet und zeigen einen Mittelpunktsabstand von 3.174 Å. Auf Grund der transannularen Abstoßung innerhalb des dreizehngliedrigen Ringsystems ist die Acetylengruppe um 4.1° bzw. 4.6° aus der linearen Anordnung cisoid deformiert. Die übrigen Winkel sind aufgeweitet. Die Länge der [CH2]5-Brücke entspricht in der vorliegenden Konformation der einer CH2—S—S—CH2-Gruppe. Das chirale Molekül liegt auf einer zweizähligen kristallographischen Achse.
    Additional Material: 1 Ill.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 693-702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Question of Inner Hexacoordination with Pentaarylphosphoranes; Phosphorane Rearrangements at the Level of Coordination Number 5The spirocyclic pentaarylphosphoranes 13 and 18b containing hydroxy groups in the direct neighbourhood of the molecule centre, isomerize more or less readily to the oxyphosphoranes 14 and 22, resp., with retention of coordination number 5. Inner onium-ate complexations could not be detected with the starting materials.
    Notes: Die spirocyclischen Pentaarylphosphorane 13 und 18b, die in unmittelbarer Nachbarschaft zum Molekülzentrum Hydroxylgruppen aufweisen, isomerisieren mehr oder weniger leicht unter Beibehaltung des Koordinationsniveaus 5 zu den Oxyphosphoranen 14 bzw. 22. Innere Onium-At-Komplexierungen konnten bei den Ausgangsverbindungen nicht nachgewiesen werden.
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  • 62
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 683-692 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 1,3,5-Trifluoro-1,3,5-trioxo-1λ6,3λ6,5λ6,2,4,6-trithiatriazine (Sulfanuric Fluoride) with AminesWhereas the reaction of the trithiatriazine 1 with diethylamine yields only mono- and disubstituted derivatives (2b, 3), the reaction with dimethylamine results in the replacement of one, two, or three fluorine atoms (→ 2a, 3a, 4). On the other hand, only mono- or trisubstituted compounds (5a, b or 9a, b, resp.), are formed by the reactions of 1 with primary amines such as methylamine and ethylamine. Ammonia reacts with 1 to give 10·NH3. The free compound 10 is formed by treatment with HCl gas. 10 reacts with P(C6H5)4Cl to yield the ionic compound 11 and with benzaldehyde to form the Schiff base 12. With secondary diamines 1 preferentially undergoes intermolecular linkage with formation of 13, but a bicyclic compound 14 could also be prepared in low yield. 1 reacts with silylamines such as RN(SiMe3)2 (R = CH3, C2H5) only after addition of RNH(SiMe3) (→ 15a, b). Sn—N cleavage reactions with 1 occur more readily. Only monosubstituted products (e. g. 16) are formed. Reaction of 1 with phenylhydrazine results in reduction of a sulfur atom and formation of the anion 17. A substituted anion (18) was also prepared from 2a by this method. The reaction behavior of 1 is discussed in detail.
    Notes: Während das Trithiatriazin 1 mit Diethylamin nur zu Mono- und Disubstitutionsderivaten (2b, 3b) reagiert, kann Dimethylamin ein, zwei oder auch drei Fluoratome austauschen (→2a, 3a, 4). Die Reaktion von 1 mit primären Aminen wie Methylamin und Ethylamin liefert hingegen nur Mono- und Trisubstitutionsprodukte (5a, b bzw. 9a, b). Ammoniak reagiert mit 1 zu 10·NH3, die freie Verbindung 10 entsteht nach Behandeln mit HCl-Gas. Mit P(C6H5)4Cl gibt 10 die ionische Verbindung 11, mit Benzaldehyd die Schiffsche Base 12. Mit sekundären Diaminen setzt sich 1 bevorzugt unter intermolekularer Verknüpfung (13) um, aber auch eine bicyclische Verbindung 14 ist in geringer Ausbeute darzustellen. Mit Silylaminen wie RN(SiMe3)2 (R = CH3, C2H5) reagiert 1 erst nach Zusatz von RNHSiMe3 (→ 15a, b). Sn-N-Spaltungsreaktionen mit 1 verlaufen erheblich leichter, wobei ausschließlich Monosubstitutionsprodukte (z. B. 16) gebildet werden. 1 gibt mit Phenylhydrazin unter Reduktion eines Schwefelatoms das Anion 17. Auch ein substituiertes Anion (18) konnte auf diesem Wege aus 2a dargestellt werden. Das Reaktionsverhalten von 1 wird ausführlich diskutiert.
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  • 63
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the 8-, 4′-, and 7-Monomethyl Ethers of Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavone) and Structure of Ranupenin from Ranunculus repens L.By synthesis of 8-, 4′- and 7-O-monomethylgossypetin via a modified Allan-Robinson condensation as well as directly from gossypetin (3,3′,4′,5,7,8-hexahydroxyflavone), it is shown that ranupenin from Ranunculus repens L., which occurs in the plant as an O-monogalactoside, has the structure not of 8-O-monomethyl- but of 7-O-monomethylgossypetin.
    Notes: Durch die Synthese von 8-, 4′- und 7-O-Monomethylgossypetin über eine modifizierte Allan-Robinson-Kondensation bzw. direkt aus Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavon) konnte geklärt werden, daß dem als O-Monogalactosid natürlich vorliegenden Ranupenin aus Ranunculus repens L. nicht die Konstitution eines Gossypetin-8-, sondern -7-methylethers zukommt.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 773-777 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molecular Mechanics Calculations on the Stability of Bridgehead OlefinsEmpirical force field calculations were used to determine the limits of application of the rules proposed by Fawcett Wiseman and Köbrich for the stability of bridgehead olefins (Bredt compounds). The stability is ruled by the size of the trans-cycloolefin unit, whereas the sum of the number of atoms in the three bridges is of minor importance. With a given skeleton the double bond was found less favourable in the largest bridge than in the second largest in most cases studied.
    Notes: Mittels empirischer Kraftfeldrechnungen wird der Gültigkeitsbereich der Regeln von Fawcett, Wiseman und Köbrich zur Vorhersage der Stabilität von Brückenkopfolefinen (Bredt-Verbindungen) untersucht. Die Größe der trans-Cycloolefineinheit ist für die Stabilität ausschlaggebend, die Summe der Ringgliederzahl in den drei Brücken ist von untergeordneter Bedeutung. Bei gegebenem Gerüst ist in der Mehrzahl der untersuchten Moleküle die Doppelbindung in der größten Brücke weniger günstig als in der zweitgrößten.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 816-819 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Borabenzene Derivatives, IX. Paramagnetic Chromium Complexes of 1-Methylborinate and 1-Phenylborinate IonsPotassium borinates, K[C5H5B-R] (R = CH3, C6H5), react with CrCl3 or CrCl2·THF to give paramagnetic bis(borinato)chromium complexes, Cr(C5H5B-R)2 (R = CH3, C6H5). For these a sandwich structure with a 16-electron valence shell is proposed.
    Notes: Durch Umsetzung von Kaliumborinaten, K[C5H5B-R] (R = CH3, C6H5), mit CrCl3 oder CrCl2·THF werden paramagnetische Bis(borinato)chrom-Komplexe, Cr(C5H5B-R)2 (R = CH3, C6H5), erhalten. Für diese wird eine Sandwich-Struktur mit einer 16-Elektronen-Valenzschale vorgeschlagen.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 994-999 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Reactions of Hydroxy-N,N-dimethylcarboxamides3-Hydroxy-N,N-dimethyl-1-carboxamides (2, 7) are converted into the corresponding γ-butyrolactones (3, 8) by treatment with an acidic ion-exchange resin in acetone or by thermolysis. 2-Hydroxy-N,N-dimethyl-1-carboxamides (10, 12, 14, 16b, 18) on the contrary form the corresponding carbonyl compounds (9, 11, 13, 15b, 17).
    Notes: 4-Hydroxycarbonsäure-dimethylamide (2, 7) lassen sich durch Behandlung mit saurem Ionenaustauscher in Aceton oder durch Thermolyse in die entsprechenden γ-Butyrolactone(3,8) überführen. 3-Hydroxycarbonsäure-dimethylamide (10, 12, 14, 16b, 18) bilden hingegen beim Erwärmen die entsprechenden Carbonylverbindungen (9, 11, 13, 15b, 17) zurück.
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  • 67
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, XIV. The Reactions of Aliphatic Diazo Compounds with the Tricarbonyl(cyclopentadienyl) Hydrides of Molybdenum and TungstenDepending on their constitution, aliphatic diazo compounds 3 behave differently in their reactions with tricarbonyl(cyclopentadienyl)hydridomolybdenum (1) and -tungsten (2). Diazomethane (3a), diazoethane (3b), and 2-diazopropane (3c) are stabilized as alkane diazo ligands in complexes of the type C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7). Phenyl-, (4-nitrophenyl)-, (4-methoxyphenyl)diazomethane (3d, e, f), and 9-diazofluorene (3g) form in clean reactions the carbene insertion products C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), whereas ω-diazoacetophenone (3h) and diazodimedone (3i) yield the binuclear diazo complexes C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10). Diethyl diazomalonate (3h) is coordinated as an imino-amido ligand in the coordination compound 14 which arises from a 1,1-insertion of 3k into the polar tungsten-hydrogen bond of 2.
    Notes: In ihrer Reaktivität gegenüber Tricarbonyl(cyclopentadienyl)hydridomolybdän (1) und -wolfram (2) weisen Diazoalkane 3 starke konstitutionsbedingte Unterschiede auf: Diazomethan (3a), Diazoethan (3b) und 2-Diazopropan (3c) werden als Alkandiazo-Liganden in Komplexen vom Typ C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7) stabilisiert; Phenyl-, (4-Nitrophenyl)-, (4-Methoxyphenyl)diazomethan (3d, e, f) sowie 9-Diazofluoren (3g) bilden in glatten Reaktionen die Carben-Insertionsprodukte C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), während ω-Diazoacetophenon (3h) wie auch Diazodimedon (3i) die zweikernigen Diazoketon-Komplexe C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10) ergeben. Diazomalonsäure-diethylester (3k) wird im Zuge einer zur Koordinationsverbindung 14 führenden 1,1-Insertion in die polare Wolfram-Wasserstoff-Bindung von 2 als Imino-amido-Ligand komplexiert.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 948-953 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XXI. On Dehydro Amino Acids, VIII. N-Acyl-α,β-dehydro Amino Acids by Rearrangement of N-Acyl-α-imino AcidsAcetylation of 2-iminoisovaleric acid ester 1 gives the acetyl imino derivative 2. By addition of nucleophilic reagents the α-substituted valine esters 5 and 6 are obtained; base catalyzed rearrangement affords acetyl-α,β-dehydrovaline ester 7. The latter reaction opens a general approach to Boc-α,β-dehydroamino acids 11a-d and esters 9a-d.
    Notes: Durch Acetylierung von 2-Iminoisovaleriansäureester 1 wird die Acetyliminoverbindung 2 erhalten. Addition von nucleophilen Reagentien führt zu den α-substituierten Valinestern 5 und 6, basenkatalysierte Umlagerung zu Acetyl-α,β-dehydrovalinester 7. Letztere Reaktion eröffnet einen allgemeinen Weg zu Boc-α,β-Dehydroaminosäuren 11a-d und ihren Estern 9a-d.
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  • 69
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 979-984 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Natural Dibenzo-α-pyrones, II. Synthesis of Alternariol and Alternariol 9-Methyl EtherThe synthesis of 3,7,9-trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-one (alternariol, 1) and the first synthesis of its 9-methyl ether (2) as well as an extension of the Hurtley condensation to o-bromobenzamides are reported.
    Notes: Die Synthese von 3,7,9-Trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-on (Alternariol, 1), die erste Synthese von Alternariol-9-methylether (2) und eine Erweiterung der Hurtley-Kondensation auf o-Brombenzamide wird beschrieben.
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  • 70
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1020-1026 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylchlorobis(tri-tert-butylphosphine)rhodium(I)Tri-tert-butylphosphine reacts with tetracarbonyl-μ-dichlorodirhodium (1) to form carbonylchlorobis(tri-tert-butylphosphine)rhodium(I) (2), existing in an equilibrium with dicarbonyl-μ-dichlorobis(tri-tert-butylphosphine)dirhodium (3) in pentane solution, which can be seen in the i. r. and 31P-n. m. r. spectra. The crystal structure of 2 has been determined from single crystal X-ray data. The compound crystallizes with 4 molecules in a unit cell of symmetry P21/n in the monoclinic system.
    Notes: Tri-tert-butylphosphin reagiert mit Tetracarbonyl-μ-dichlorodirhodium (1) unter Bildung von Carbonylchlorobis(tri-tert-butylphosphin)rhodium(I) (2), das in Pentanlösung mit Dicarbonyl-μ-dichlorobis(tri-tert-butylphosphin)dirhodium (3) im Gleichgewicht steht, was sich im IR- und 31P-NMR-Spektrum verfolgen läßt. Die Kristallstruktur von 2 wurde röntgenographisch aus Diffraktometer-Einkristalldaten bestimmt. Die Verbindung kristallisiert mit 4 Molekülen in der Elementarzelle der Symmetrie P21/n im monoklinen System.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1042-1046 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stable Mercury(I)-Sulfur Compounds, 3. Investigations on the Donor Capacity of Sulfur at the Mercury(I) IonNew mercury(I)-sulfur compounds have been prepared by reactions between mercury(I) nitrate, perchlorate or hexafluorosilicate solutions with methanol, water/benzene or water/methylene chloride solutions of the following sulfur donor ligands: 1,3-dithiolane, 2-phenyl-1,3-dithiolane, 2,2′-trimethylenebis(1,3-dithiolane), bis(benzylthio)methane, dibenzylsulfide. With mercury(I)-dinitrate, the products are the 1:1 adducts (1a), (4a), (6a), and (11a). With mercury(I)-perchlorate the 1:2 adducts (1b),(4b),(6b) or the 1:1 adducts (5b) and (11b) have been obtained. Dibenzylsulfide forms a 1:1 adduct (11c) with dimercury(I)-hexafluorosilicate.
    Notes: Neue Quecksilber(I)-Schwefel-Verbindungen wurden durch Umsetzung von Quecksilber(I)-nitrat, -perchlorat bzw. -hexafluorosilicat-Lösungen mit folgenden Schwefel-Donor-Liganden in methanolischen Lösungen bzw. im Zweiphasensystem wäßrige Lösung/Benzol oder Methylenchlorid hergestellt: 1,3-Dithiolan, 2-Phenyl-1,3-dithiolan, 2,2′-Trimethylenbis(1,3-dithiolan), Bis-(benzylthio)methan, Dibenzylsulfid. Mit Quecksilber(I)-nitrat werden 1:1-Addukte (1a), (4a), (6a) und (11a), mit Quecksilber(I)-perchlorat 1:2-Addukte (1b), (4b) und (6b) bzw. 1:1-Addukte (5b) und (11b) erhalten. Mit Diquecksilber(I)-hexafluorosilicat bildet das Dibenzylsulfid ein 1:1-Addukt (11c).
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  • 72
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1069-1085 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of Thiacyclanone-1,1-dioxides with DiazoalkanesThiacyclanone-1,1-dioxides 1a-e, 9, 13, 15a react with diazomethane and diazoethane to give the enol ethers 2a-j, epoxides 4c, h, 10a, 14a, 17a, α-alkyl-β-ketosulfones 3d, e, j, and ring-enlarged ketosulfones 5h, i, 7h, 11b, 12b, 15b, 16b and 18a, depending on the size of the ring and the position of the carbonyl and sulfonyl group to each other. The enol ethers are easily hydrolysed with mineral acids forming the β-ketosulfones 1a-e. In the presence of lewis acids ethyl diazoacetate yields ethoxycarbonylmethoxy compounds 2k, I, and ring-enlarged β-ketoesters 5k-o, 7m, n, 15c, 16c, and 18c. Only the γ-ketosulfone 9 with ethyl diazoacetate gives, in addition to the ring-enlarged product 11c, the glycidic ester 10c. The β-ketoesters undergo hydrolysis and decarboxylation to the ketosulfones in very good yield. In the ring-expansion of ketosulfones with diazoethane and ethyl diazoacetate the preferred insertion of the diazo compound occurs between the C-3 and C-4 atoms.
    Notes: In Abhängigkeit von der Ringgliederzahl und der Lage von Carbonyl- und Sulfonylgruppe zueinander reagieren Thiacyclanon-1,1-dioxide 1a-e, 9, 13 und 15a mit Diazomethan bzw. -ethan zu Enolethern 2a-j, Epoxiden 4c, h, 10a, 14a, 17a, α-Alkyl-β-ketosulfonen 3d, e,j oder zu ringerweiterten Ketosulfonen 5h,i, 7h, 11b, 12b, 15b, 16b und 18a. Die Enolether spalten leicht mit Mineralsäure zurück zu den β-Ketosulfonen 1a-e. Mit Diazoessigester in Gegenwart von Lewis-Säuren entstehen die Ethoxycarbonylmethoxy-Verbindungen 2k, I bzw. die ringerweiterten β-Ketoester 5k-o, 7 m, n, 15c, 16c und 18c; lediglich das γ-Ketosulfon 9 gibt mit Diazoessigester neben dem Ringerweiterungsprodukt 11c den Glycidester 10c. Die β-Ketoester lassen sich in guten Ausbeuten zu den Ketosulfonen verseifend decarboxylieren. Bei den Ringerweiterungen der Ketosulfone mit Diazoethan und Diazoessigester ist eine bevorzugte Insertion des Diazoalkanrestes zwischen C-3 und C-4 festzustellen.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1124-1129 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Four- and Five-membered Phosphorus Heterocycles, 15. The Products of Carbohydrazide/Phosphonic Chloride Reaction: 2,2′-Spirobi(1,3,4,2λ5-oxadiaza-phospholines)The products of the 2:1-condensation of carbohydrazides 1 with phosphonic dichlorides 2 are not cyclic anhydrides 4 of the phosphonic bis(acylhydrazides), as has been assumed until now. Instead they possess the structure of the spirocyclic phosphoranes 9 named in the title. Their formation is due to the unusual reaction of a P = O-bond involving elimination of water. With dimethylphosphinic chloride (14) the hydrazides 1 react in quite the same sense to give the dimers 17 of oxadiazaphospholes in which the pentacoordinate phosphorus (as a bridgehead) is again part of two small rings. The phosphoranes 9 are also obtained from the reaction of 1 with tetrachloro-phosphoranes 5 or thiophosphonic dichlorides 18 or even bis(dimethylamino)phosphines 19.
    Notes: Die 2:1-Kondensationsprodukte aus Carbonsäurehydraziden 1 und Phosphonyldichloriden 2 stellen nicht - wie bisher angenommen - durch Anhydridbildung cyclisierte Phosphonsäure-bis(acylhydrazide) 4 dar, sondern die im Titel genannten spirocyclischen Phosphorane 9. Ihr Entstehen beinhaltet das „Aufrichten“ einer P = O-Bindung unter Wasserabspaltung. Mit Di-methylphosphinylchlorid (14) reagieren die Hydrazide 1 im gleichen Sinn zu Oxadiazaphosphol-Dimeren 17 mit ebenfalls bicyclisch (als Brückenkopf) eingebautem Phosphoranphosphor. Die Phosphorane 9 entstehen auch aus 1 und Tetrachlorphosphoranen 5 oder Thiophosphonyl-dichloriden 18 oder auch Bis(dimethylamino)phosphinen 19.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1684-1690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Hydronium Tetrachloroaurate(III)-2,2-dimethyl-2H-benzimidazole 1,3-Dioxide, (C9H10N2O2)H3O+ [AuCl4]-1,2-Benzoquinone dioxime (1) reacts with tetrachlorogold(III) acid-trihydrate in dialkyl ketones as solvents to yield solids 5-7 which contain H3O+ and [AuCl4]- ions and neutral 2,2-dialkyl-2H-benzimidazole 1,3-dioxides (2-4). The organic, neutral molecule can easily be isolated from this solid by means of an ion-exchanger. The structure of hydronium tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazole 1,3-dioxide (5), which can be obtained from acetone solutions, is obtained by X-ray analysis.
    Notes: Die Reaktion von 1,2-Benzochinondioxim (1) mit Tetrachlorogold(III)-säure-trihydrat in Dialkyl-ketonen als Lösungsmittel führt zu Festkörpern 5-7, die aus H3O+- und [AuCl4]--Ionen sowie aus neutralen 2,2-Dialkyl-2H-benzimidazol-1,3-dioxiden (2-4) aufgebaut sind. Daraus läßt sich das organische neutrale Molekül mittels eines Ionenaustauschers abtrennen und in Substanz isolieren. Die Struktur des aus Aceton erhältlichen Hydronium-tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazol-1,3-dioxids (5) wird durch Röntgenstrukturanalyse ermittelt.
    Additional Material: 1 Ill.
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  • 75
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1744-1747 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Photochemistry of Two Tribenzo-(CH)12-Valence IsomersA new synthesis of the tribenzo[12]annulene 1 and the photochemical transformations of 1 and of its valence isomer 2 are described. A reaction mechanism is proposed.
    Notes: Eine neue Synthese des Tribenzo[12]annulens 1 und die photochemischen Umwandlungen von 1 und seines Valenzisomeren 2 werden beschrieben. Ein Reaktionsmechanismus wird vorgeschlagen.
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  • 76
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1759-1762 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 94. New Furanoeremophilanes from Ligularia vorobierii Worosh.L. vorobierii contains besides already known five new furanoeremophilane derivatives (5 and 7-10). Their structures have been elucidated by spectroscopic methods. The constituents show again a close relationship to the neighbouring genus Senecio.
    Notes: L. vorobierii enthält neben bereits bekannten fünf neue Furanoeremophilan-Derivate (5 und 7-10), deren Konstitutionen durch spektroskopische Methoden geklärt werden. Die Inhaltsstoffe zeigen erneut eine enge Verwandtschaft zu der Nachbargattung Senecio.
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  • 77
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Reactivity of Metal π-Complexes, XXII. Sandwich-like Dinuclear (Pd-Pd)-Complexes with Bridging Cyclopentadienyl and Allyl LigandsThe reaction of C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-allyl) with tertiary phosphines or phosphites in the molar ratio of 1:1 produces in practically quantitative yields the dinuclear complexes (C5H5)(2-RC3H4)Pd2L2 (4-20) in which palladium has the oxidation state +1. The crystal structure analysis of 5 (R = CH3, L = P(C6H5)3) and 12 (R = CH3, L = P(OC6H4-o-CH3)3) shows that the cyclopentadienyl as well as the allyl ligand is bonded in a sandwich manner to the Pd-Pd unit. The Pd-Pd distance of 267.9 (in 5) or 268.9 pm (in 12) is suggestive of a metal-metal bond. It is not possible to determine whether the cyclopentadienyl ring in 4-20 exists as a pentahapto- or trihapto-bonded ligand on the basis of the 1H- and 13C n. m. r. data. The reactivity of the dinuclear complexes is in agreement with square planar coordination of the metal atoms.
    Notes: Bei den Reaktionen von C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-Allyl) mit tertiären Phosphinen oder Phosphiten im Molverhältnis 1:1 entstehen in praktisch quantitativer Ausbeute die Zweikernkomplexe (C5H5)(2-RC3H4)Pd2L2 (4-20), in denen Palladium in der Oxidationszahl +1 vorliegt. Wie die Kristallstrukturanalysen von 5 (R = CH3, L = P(C6H5)3) und 12 (R = CH3, L = P(OC6H4-o-CH3)3) zeigen, sind sowohl der Cyclopentadienyl- als auch der Allyl-Ligand sandwichartig an die Pd2-Einheit gebunden. Der Pd-Pd-Abstand von 267.9 (in 5) bzw. 268.9 pm (in 12) weist auf das Vorliegen einer Metall-Metall-Bindung hin. Aufgrund der 1H- und 13C-NMR-Daten ist nicht zu entscheiden, ob in 4-20 der Cyclopentadienylring als pentahapto-oder trihapto-gebundener Ligand vorliegt. Die Reaktivität der Zweikernkomplexe steht mit einer quadratisch-planaren Koordination der Metallatome in Einklang.
    Additional Material: 3 Ill.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1833-1851 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Metallation of Benzyl- and Allylmercaptanes; the Thiobenzaldehyde and Thioacrolein DianionsDouble deprotonation of benzyl, allyl and 2-methylallyl mercaptane furnishes thiocarbonyl dianiones 2, 12, and 15, respectively. The novel nucleophiles react with alkyl halides, epoxides, and carbonyl derivatives to give good yields of products of type 3, 13/14, and 16/17, respectively. The doubly lithiated allyl mercaptanes are preferentially attacked by all of the employed electro-philes in the γ-position (60/40-90/10 γ/α-ratio) to lead to cis-vinyl sulfides 13 and 16. These can be converted into sulfur-free propanal derivatives 22-26 in high yields. 12 resembles synthetically the otherwise not available 3-lithiopropionaldehyde (18′, homoenolate).
    Notes: Thiocarbonyl-Dianionen lassen sich quantitativ durch doppelte Deprotonierung aus Benzyl-(→2), Allyl- (→12) und 2-Methylallylmercaptan (→15) erzeugen. Die neuen Nucleophile setzen sich mit Alkylhalogeniden, Epoxiden und Carbonylverbindungen in guten Ausbeuten zu Produkten vom Typ 3, 13/14 bzw. 16/17 um. Die doppelt metallierten Allylmercaptane reagieren mit allen bisher getesteten Elektrophilen bevorzugt in γ-Stellung (60/40—90/10 für γ/α) zu cis-Vinyl-sulfiden 13 und 16, die in guten Ausbeuten in schwefelfreie Propionaldehydderivate 22-26 übergefuhrt werden konnten. 12 entspricht damit synthetisch dem nicht direkt zugänglichen 3-Lithio-propionaldehyd (18′, Homoenolat).
    Additional Material: 4 Tab.
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  • 79
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1896-1907 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched-chain Sugars, XV. Glycoside Syntheses with L-StreptoseThe halogeno derivatives of the cyclic carbonates 11 a and 11 b are most suitably used in the synthesis of L-streptose β-glycosides. α-Glycosides are obtained from the benzylidene compound 20. The benzylidene group can be subsequently removed by catalytic hydrogenation. Using the glycosyl halide 16 a also α-glycosides are formed in high yields. However, it is difficult to cleave the isopropylidene group under acidic conditions. Acetylated halides of type 4 are very labile and therefore not useful in glycoside synthesis.
    Notes: Zur Herstellung β-L-glycosidischer Verknüpfungen der L-Streptose sind die Halogenide des cyclischen Carbonats 11 a und 11 b am besten geeignet. α-L-Glycosidische Verknüpfungen der L-Streptose werden am günstigsten mit der Benzylidenverbindung 20 erhalten. Die Benzylidengruppe ist anschließend hydrogenolytisch abspaltbar. Auch das Halogenid 16 a liefert hohe Anteile an α-Glycosid. Die Isopropylidengruppe ist aber schwierig sauer abspaltbar. Acetylierte Halogenide wie 4 sind wegen ihrer Empfindlichkeit zur Glycosidsynthese weniger geeignet.
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  • 80
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1925-1930 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, VI. Synthesis of StreptobiosamineA synthesis of 5-deoxy-2-O-(2-deoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-streptobiosamine) is described. The same synthesis was repeated with the corresponding L-sugars. It leads to 5-deoxy-2-O-(2-deoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-streptobiosamine), the disaccharide portion of streptomycin.
    Notes: Eine Synthese der 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-Streptobiosamin) wird beschrieben. Die gleiche Synthese wurde auch mit den entsprechenden L-Zuckern durchgeführt. Sie lieferte 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-Streptobiosamin), das den Disaccharidbaustein des Streptomycins darstellt.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1971-1977 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XIV. The Catalysed Reaction of Aldehydes with Mannich BasesAlkali cyanide- and thiazolium salt-catalysed addition of aldehydes to Mannich bases of saturated and unsaturated ketones leads to the formation of 1,4-diketones (1-6, 9-22).
    Notes: Alkalicyanid- und thiazoliumsalz-katalysierte Additionen von Aldehyden an Mannich-Basen von gesättigten und ungesättigten Ketonen führen zu 1,4-Diketonen (1-6, 9-22).
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  • 82
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mechanism of the Aluminium Chloride-catalysed Rearrangement of 7 H-Dibenzo[c,g]carbazole to 7 H-Dibenzo[a,g]carbazole and of Related Aromatic Skeleton RearrangementsOn an experimental basis a mechanism for the aluminium chloride-catalysed rearrangement of 7 H-dibenzo[c,g]carbazole (1) to 7 H-dibenzo[a,g]carbazole (2) is derived, that involves in the first step formation of the 5,6-dihydro derivatives 3 and 9 which rearrange via a spiro cation 14. This mechanism should also be valid for topologically analogous systems.
    Notes: Für die aluminiumchlorid-katalysierte Skelettumlagerung von 7 H-Dibenzo[c,g]carbazol (1) in 7 H-Dibenzo[a,g]carbazol (2) wird aus Experimenten ein Mechanismus abgeleitet, nach dem zunächst Bildung der 5,6-Dihydro-Derivate 3 und 9 erfolgt, die über ein Spirokation 14 umlagern. Dieser Mechanismus sollte auch für topologisch analoge Systeme zutreffen.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2019-2027 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclophosphates, III. Synthesis and Properties of Uridine 3′,5′-Cyclophosphate EstersThe uridine 3L′,5′-cyclophosphate esters 4-11 were synthesized by reaction of the free acid of uridine 3′,5′-cyclophosphate (1-3) with the appropriate diazoalkane. The configuration of the isomeric 1,3,2λ5-dioxaphosphorinanes is assigned on the basis of an X-ray analysis with the aid of 31P n. m. r. The stereoselectivity was influenced in part by the degree of reactivity of the diazo compound, by steric hindrance in the 2′-position of the ribose, and by variation in the reaction temperature. The newly synthesized compounds were characterized by u. v. and 31P n. m. r. spectra.
    Notes: Die Uridin-3′,5′-cyclophosphat-ester 4-11 wurden durch Reaktion der freien Säure des Uridin-3′,5′-cyclophosphates (1-3) mit den entsprechenden Diazoalkanen erhalten. Die Zuordnung der stereoisomeren 1,3,2λ5-Dioxaphosphorinane läßt sich mit Hilfe der 31P-NMR-Spektren aufgrund einer Röntgenstrukturanalyse zeigen. Eine stereoselektive Beeinflussung durch Variation der Reaktivität der Diazokomponente oder durch sterische Hinderung an der 2′-Position der Ribose, sowie in Abhängigkeit von der Temperatur, konnte partiell erzielt werden. Sämtliche synthetisierten Verbindungen wurden durch UV- und 31P-NMR-Spektren charakterisiert.
    Additional Material: 4 Tab.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1462-1469 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mannich Reaction at 2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one, the Chromophore of the Ribonucleoside “Q”2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (6a) reacts with dimethylamine and cyclopentylamine in the presence of formaldehyde to form the Mannich bases 6c and d. From 6c the amine moiety was split off on hydrogenation under pressure. The degradation product was identical with 2-amino-6-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (6b), which was obtained by unambiguous synthesis. This shows that in contrast to 3,7-dihydropyrrolo[2,3-d]-pyrimidin-4-one, Mannich reaction involving 6a leads to substitution at C-6.
    Notes: 2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-on (6a) reagiert mit Dimethylamin und Cyclo-pentylamin in Gegenwart von Formaldehyd zu den Mannich-Basen 6c und d. Aus 6c ließ sich durch Druckhydrierung das Amin abspalten. Das Abbauprodukt war identisch mit 2-Amino-6-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-on (6b), das auf eindeutigem Syntheseweg erhalten worden war. Damit wird gezeigt, daß die Mannich-Reaktion bei 6a im Gegensatz zu 3,7-Dihydropyrrolo[2,3-d]pyrimidin-4-on zur Substitution an C-6 führt.
    Additional Material: 1 Ill.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1492-1496 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: as-Triazines and Condensed Derivatives, XVIII. Ring-Chain Tautomerism in 3-Hydroxythiazolo[3,2-b]-as-triazin-7-onesThe hydroxyl groups of the most stable conformer (y) of 3-hydroxythiazolo[3,2-b]-as-triazin-7-one (2a) as well as of the related compound 4 are axial.  -  At elevated temperatures, the AB signal of the CH2 group in the 1H-NMR spectrum of compound 2b collapses, as a result of tautomerization to 3b, into a singlet. ΔG≠ is 17.0 kcal/mole at the coalescence temperature (68°C). In agreement with the decreasing order of the +I effect in the series CH3 〉 CH2Cl 〉 H, no similar tautomerizations take place up to 130°C in the case of compounds 2a and 2c. Compound 4, however, exists at elevated temperatures as an equilibrium mixture with the corresponding “open-chain” form 5.  -  The singlet of the CH2Cl group of compound 2c is transformed, at elevated temperatures, into an AB quadruplet. An explanation for this apparent anomaly is suggested.
    Notes: Das stabilste Konformere (y) des 3-Hydroxythiazolo[3,2-b]-as-triazin-7-ons (2a) enthält eine axiale OH-Gruppe, ebenso wie das der verwandten Verbindung 4.  -  Bei Erhöhung der Temperatur fällt das AB-Signal der CH2-Gruppe im 1H-NMR-Spektrum von 2b als Folge der Tautomerisierung zu 3b in ein Singulett zusammen. Der ΔG≠-Wert bei der Koaleszenztemperatur (68°C) beträgt 17.0 kcal/mol. Im Einklang mit der Abnahme des +I-Effektes in der Reihenfolge CH3 〉 CH2Cl 〉 H erfolgt bei den Verbindungen 2a und 2c bis 130°C keine ähnliche Tautomerisierung. Die Verbindung 4 liegt jedoch bei erhöhter Temperatur im Gleichgewicht mit der „offenkettigen“ Form 5 vor.  -  Bei steigender Temperatur wandelt sich das Singulett der CH2Cl-Gruppe von 2c in ein Quadruplett um. Eine Erklärung für diese scheinbare Anomalie wird gegeben.
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  • 86
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Seven-Membered Ring Systems, XV. Organolithium Derivatives of the Conformationally Rigid Tetraphenyltribenzocycloheptariene (1,2,3,4-Tetraphenyl-9H-tribenzo[a,c,e]cycloheptene)Quasi-axial substituents (e. g. hydrogen and chlorine) at C-9 of 1,2,3,4-tetraphenyl-9H-tribenzo-[a,c,e]cycloheptene (1) are easily exchanged with formation of quasi-axial organometallic compounds. Only in the case of the 9-lithio-9-methyl derivative 17 an equilibrium 17A ⇄ 17B between a quasi-equatorial and a quasi-axial lithium compound was found. Various stereospecific reactions of the new organometallics are reported and the reactivity differences of conformational origin are discussed.
    Notes: Quasi-axiale Substituenten (z. B. Wasserstoff und Chlor) am C-9 von 1,2,3,4-Tetraphenyl-9H-tribenzo[a,c,e]cyclohepten (1) werden leicht unter Bildung quasi-axialer Organometall-Verbindungen ausgetauscht. Lediglich im Fall des 9-Lithio-9-methyl-Derivates 17 konnte ein Gleichgewicht 17A ⇄ 17B zwischen einer quasi-äquatorialen und einer quasi-axialen Lithium-Verbindung nachgewiesen werden. Zahlreiche stereospezifisch verlaufende Abwandlungen der neuen Organometalle werden beschrieben und die konformativ bedingten Reaktivitätsunterschiede diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1576-1585 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Methyl-1-methylene-1λ5-phosphorinane and Cyclopropyl(dimethyl)methylenephosphorane: Two Different Types of Ylides from an Analogous Reaction, and their ComplexesThe reaction of NaNH2 with (4-bromobutyl)- or (3-bromopropyl)-trimethylphosphonium bromide in THF under reflux yields the two title compounds 1 and 8, resp. At room temperature imide-bridged double ylides 2 and 10 are generated. The reaction path is interpreted. With copper, silver, and gold(I) chloride, the dimeric coinage metal complexes of these ylides are obtained. In the first case (with 1) the complexes are assigned a double spirocyclic structure (7a-c).
    Notes: Die Reaktion von NaNH2 mit (4-Brombutyl)- oder (3-Brompropyl)-trimethylphosphonium-bromid in siedendem THF liefert die beiden Titelverbindungen 1 bzw. 8. Bei Raumtemperatur entstehen imid-verbrückte Doppel-Ylide 2 bzw. 10. Der Reaktionsverlauf wird gedeutet. Mit Kupfer-, Silber- und Gold(I)-chlorid werden die dimeren Münzmetall-Komplexe der Ylide erhalten, denen im ersteren Fall (mit 1) eine doppelt spirocyclische Struktur zukommt (7a-c).
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1597-1600 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 820-832 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions of Heterocumulenes, IX. 1:1-, 2:1-, and 3:1-Adducts from the Reaction of Isothiocyanates with 3-Dimethylamino-2,2-dimethyl-2H-azirineTreatment of the azirine 1 with the activated isothiocyanates 2a, b leads to 1,3-cleavage of the ring and formation of the dipoles 5, which can be characterized by hydrolysis, protonation and methylation to give 6-8. In the reaction of 1 with the sterically hindered alkyl isothiocyanates 2f-i the ring of 5 is split to form the carbodiimides 10. 10f-i hydrolyze via 5 to give the thioureas 11, from which 11f, g easily cyclize to yield the 2-thiohydantoins 12. Cycloaddition reactions of 10f lead to the heterocycles 14, 15, and 17. The alkyl isothiocyanates 2c-e react with 1, depending on the reaction conditions, to give the 3:1-adducts 14 or the dipolar 2:1-adducts 21. The hydrolysis of 21e leads to the thiazolinone 26 with the acyclic product 25 as intermediate.
    Notes: Die aktivierten Isothiocyanate 2a, b reagieren mit dem Azirin 1 unter öffnung der 1,3-Bindung zu den Dipolen 5, die sich durch Hydrolyse, Protonierung und Methylierung zu 6-8 charakterisieren lassen. Im Falle der sterisch gehinderten Alkylisothiocyanate 2f-i tritt Ringöffnung von 5 zu Carbodiimiden 10 ein. 10f-i hydrolysieren über 5 zu den Thioharnstoffen 11, die für 11f, g leicht zu den 2-Thiohydantoinen 12 cyclisieren. Cycloadditionsreaktionen mit 10f führen zu den Heterocyclen 14, 15 und 17. Die Alkylisothiocyanate 2c-e bilden mit 1 je nach den Reaktionsbedingungen die 3:1-Addukte 14 oder die dipolaren 2:1-Addukte 21. Die Hydrolyse von 21e führt über das ringoffene Produkt 25 zum Thiazolinon 26.
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  • 90
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 852-866 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Generation of and Olefination with α-S-, -Se-, -Si-, and -Sn-perheterosubstituted (Trimethylsilyl)-methyllithium DerivativesThe Peterson-olefination reaction of equation (1) is used to prepare ketenedithio- 5, ketenediseleno acetals 8, trimethylsilyl- 11, 1,1-bis(trimethylsilyl)- 12, 1-alkylthio- and 1-arylthio-1-silyl- 16, as well as 1-alkylthio- and 1-arylthio-1-stannyl olefins 19 from the α-silyllithium compounds 4, 7b, 9, 10, 15, and 18, respectively. New or improved productive methods of generation of these olefinating reagents are described. The scope and limitations of the present olefinations are discussed.
    Notes: Mit der Peterson-Olefinierungsreaktion der Gl. (1) werden aus den α-Silyllithium-Verbindungen 4, 7b, 9, 10, 15 und 18 Ketendithio- 5 bzw. Ketendiselenoacetale 8, Trimethylsilyl- 11, 1,1-Bis(trimethylsilyl)- 12, 1-Alkylthio- und 1-Arylthio-1-silyl- 16, sowie 1-Alkylthio- und 1-Arylthio-1-stannylolefine 19 hergestellt. Für die Olefinierungsreagentien 7b, 9, 10, 15 und 18 werden neue oder verbesserte, ergiebige Erzeugungsmethoden beschrieben. Die Grenzen der Anwendbarkeit der Olefinierungsreaktionen werden diskutiert.
    Additional Material: 5 Tab.
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  • 91
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 921-941 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XVII. On Dehydroamino Acids, IV. Ring Closure of DehydropeptidesSix- or five-membered cyclic compounds (amino-piperazinediones: 2, 14-19, 21, 24, or imidazolidinones 28, 29) are obtained under basic conditions from dehydropeptides by α-addition of an amide function to the acylaminoacrylic unit. Sterical conditions, scope, and limitations of this cyclisation have been investigated up to the dehydrotetrapeptide amide 20. Formation of six-membered rings is preferred. Five-membered rings only result, if reaction to six-membered rings is excluded either by the structure of the dehydropeptide (no NH-function available) or by its conformation (s-trans amide function). Ring closure to the cyclodipeptides 2a, 14, 15, 18, 19, 21, and 24 proceeds stereoselectively.
    Notes: Dehydropeptide bilden in alkalischer Lösung durch α-Addition einer Amidgruppe an das Acylaminoacrylsäuresystem sechs- oder fünfgliedrige Ringe (Amino-piperazindione: 2, 14-19, 21, 24 bzw. Imidazolidinone: 28, 29). Reaktionsbedingungen, räumlicher Ablauf und Grenzen der Cyclisierung wurden bis zum Ringschluß des Dehydrotetrapeptidamids 20 untersucht. Der Sechsring wird bevorzugt. Ein Fünfring bildet sich nur dann, wenn die Cycloaddition zum Sechsring infolge der Struktur (keine NH-Funktion zur Addition) oder der Konformation (s-trans-Fixierung einer Amidbindung) des Dehydropeptids nicht möglich ist. Der Ringschluß zu den Cyclodipeptiden 2a, 14, 15, 18, 19, 21 und 24 verläuft stereoselektiv.
    Additional Material: 2 Tab.
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  • 92
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 965-978 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dyotropic Rearrangements, XI. Mechanism of the Thermal Rearrangement of Allyl (Silymethyl) EthersThe study of the mechanism of the thermal rearrangement of allyl (silylmethyl) ethers 1a-e has been extended to include crossover and trapping experiments, secondary kinetic deuterium isotope effects, solvent influence and an investigation of the stereochemistry of the migrating silyl group. The rate determining step appears to be the coordination between the silyl group and the oxygen atom, causing the allyl-α-C-O bond to be loosened. In the following, kinetically not measurable step the allyl groups either migrate concertedly with allyl inversion or split off into radicals, depending upon the nature of the substituents R1,R2.
    Notes: Die Studie über den Mechanismus der thermischen Umlagerung von Allyl-(silymethyl)-ethern 1a-e wird mit Hilfe von Kreuzungs- und Abfangsversuchen, sekundären kinetischen Deuterium-Isotopeneffekten, Löungsmitteleinflüssen und einer Untersuchung zur Stereochemie der wandernden Silylgruppe vertieft. Danach scheint der geschwindigkeitsbestimmende Schritt die Koordinierung zwischen dem Silylrest und dem Sauerstoff zu sein, die eine Lockerung der Allyl-α-C-O-Bindung bewirkt. Im anschließenden, kinetisch nicht faßbaren Schritt lagern die Allylgruppen entweder konzertiert mit Allylumkehrung um oder zerfallen in Radikale, je nach Natur der Substituenten R1, R2.
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  • 93
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2180-2188 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of 2-Diazopropane to Allene. Asymmetric Destruction of 1-Pyrazolines with Circularly Polarized Light1,3-Dipolar cycloaddition of 2-diazopropane to allene leads to 1 and the spiropyrazoline 2. The thermal and photochemical decomposition reactions of 1 and 2 are investigated. Irradiation of 2 with circularly polarized light produces a sample which displays optical acitivity and has a strong Cotton effect in the CD. The possibility of applying circularly polarized light for the solution of mechanistic problems in the decomposition of 1-pyrazolines is discussed.
    Notes: Die 1,3-dipolare Cycloaddition von 2-Diazopropan an Allen liefert 1 und das Spiropyrazolin 2, deren thermische und photochemische Zersetzungsreaktionen untersucht werden. Die Bestrahlung von 2 mit circular polarisiertem Licht ergibt eine Anreicherung von optisch aktivem 2, das einen starken Cotton-Effekt im CD zeigt. Die Möglichkeit der Anwendung von circular polarisiertem Licht zur Lösung mechanistischer Fragen beim Zerfall von 1-Pyrazolinen wird diskutiert.
    Additional Material: 1 Ill.
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  • 94
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2222-2235 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Functional Derivatives of Trimethylphosphine, IV. Hydrido(phosphine)iron(II) ComplexesTetrakis(trimethylphosphine)iron, L4Fe (L = P(CH3)3) (3), reacts with HCl to give L2FeCl2 (1a). As an intermediate of this reaction covalent L4(H)FeCl (4a) can be isolated. Its formation by cleavage of the Fe—C bond in L3(H)[(CH3)2PCH2]Fe which is in equilibrium with 3 is established with DCl. With HX (H = NH4⊕, (CH3)3PH⊕; X = Cl⊖, Br⊖, I⊖, PF6⊖) as reagents, L4(H)FeX (X = Cl, Br, I) (4a-c) and [L5(H)Fe]⊕X⊖ (X = Cl, Br, I, PF6) (6a-d) are prepared or their formation in solution is proved. In these solutions two further species, [L4(H)Fe]⊕[X ⊖ solvent]⊕ and [L4(H)(solvent)Fe]⊖ X⊖, are characterized by spectroscopy. Substitution reactions using P(OCH3)3, CO, or isoprene yield the complexes [L5-nL′n(H)Fe]⊕PF⊖ (n = 1. L′ = CO; n = 2, L′ = CO, P(OCH3)3, ½ isoprene; n = 3, L′ = P(OCH3)3), which are also obtained by the direct reaction of the iron(0) complexes L5-nL′nFe with NH4PF6. The isoprene substituted hydridoiron complex (8c) is found to be in an equilibrium with its π-allyl form. As starting materials the tetrahedral complexes L2FeX2 (L = Cl, Br, I) (1a-c) and octahedral L4FeI2 (2c) are characterized.
    Notes: Tetrakis(trimethylphosphin)eisen, L4Fe (L = P(CH3)3) (3), reagiert mit HCl zu L2FeCl2 (1a). Dabei läßt sich kovalentes L4(H)FeCl (4a) als Zwischenstufe fassen, dessen Bildung durch Fe—C-Bindungsspaltung des mit 3 im Gleichgewicht stehenden L3(H)[(CH3)2PCH2]Fe mit DCl nachgewiesen wird. Mit HX (H = NH4⊕. (CH3)3PH⊕; X = Cl⊖, Br⊖, I⊖, PF6⊖) werden L4(H)FeX (X = Cl, Br, I)(4a-c) und [L5(H)Fe]⊕X⊖ (X = Cl, Br, I, PF6) (6a-d) dargestellt bzw. ihre Bildung in Lösung nachgewiesen. In diesen Lösungen werden daneben [L4(H)Fe]⊕[X · Solvens]⊖ und [L4(H)(Solvens)Fe]⊕ X⊖ spektroskopisch charakterisiert. Substitutionsreaktionen mit P(OCH3)3, CO oder Isopren führen zu der Komplexreihe [L5-nL′n(H)Fe]⊕ PF6⊖ (n = 1. L′ = CO; n = 2. L′ = CO, P(OCH3)3, ½ Isopren; n = 3. L′ = P(OCH3)3). Diese Komplexe werden auch durch direkte Reaktion der Eisen(0)-Komplexe L5-nL′nFe mit NH4PF6 erhalten, wobei der isoprensubstituierte Hydridoeisenkomplex (8c) ein Gleichgewicht mit einer π-Allylform erkennen läßt Als Ausgangskomplexe werden die tetraedrischen L2FeX2-Komplexe (X = Cl, Br, I) (1a-c) sowie L4FeI2 (2c) charakterisiert.
    Additional Material: 3 Ill.
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  • 95
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2254-2275 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Verdazyls, 25. N-1′-Linked Bisverdazyls with Phenylene and Naphthylene Bridges, Thermochromism and Magnetic PropertiesThe synthesis of the bisverdazyls 1a-14a starts either from a monoverdazyl and uses 1-cyano-1-methylethyl as protecting group for the free valence (1 a) or from the corresponding bisformazans. 1a with the 1,4-phenylene bridge is diamagnetic up to 300 K, J 〉 3000 cal/mol. In 6a, 2a, and 7a the thermally populated triplet state is separated from the singlet ground state by 1500, 600, or 400 cal/mol. 3a-5a and 10a-13a have almost degenerate singlet triplet states. The magnetic properties, the zero field parameters D, and the thermochromic effects of the absorption spectra are discussed with respect to the structure of 1a-14a and the distorsion around the bridge axis.
    Notes: Die Darstellung der Bisverdazyle 1a-14a entweder stufenweise aus einem Monoverdazyl unter Verwendung der 1-Cyan-1-methylethyl-Gruppe als Schutzfunktion der freien Valenz (1a) oder aus den entsprechenden Bisformazanen wird beschrieben. 1a mit der 1,4-Phenylenbrücke liegt bis 300 K diamagnetisch vor, J 〉 3000 cal/mol. In 6a, 2a und 7a ist der thermisch besetzte Triplett-zustand vom Singulett-Grundzustand durch 1500, 600 bzw. 400 cal/mol getrennt. 3a-5a und 10a-13a besitzen praktisch entartete Singulett-Triplett-Zustände. Die magnetischen Eigenschaften. die Nullfeldparameter D und die Thermochromie-Erscheinungen der Absorptions-spektren werden im Zusammenhang mit der Struktur von 1a-14a und der Verdrillung um die Brückenachse diskutiert.
    Additional Material: 6 Ill.
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  • 96
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2368-2373 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition Reaction of N,N-Dialkylsulfamides, Tertiary Amines, and Phosphines with Fluorosulfonyl IsocyanateFluorosulfonyl isocyanate (2) reacts with N,N-dialkylsulfamides 1a-c or amidosulfonic methyl ester (1d) to afford the N-fluorosulfonyl-N′-(dialkylsulfamoyl)ureas 3a-d. Thermal decomposition of 3a-c leads to the formation of sulfamidie fluorides 4a-c. With tertiary amines and phosphines fluorosulfonyl isocyanate forms 1:1 adducts. Their structure can be proved by i. r. and 13C n. m. r. analysis.
    Notes: Durch Umsetzung von Fluorsulfonylisocyanat (2) mit N,N-Dialkylsulfamiden 1a-c bzw. Amidosulfonsäure-methylester (1d) werden N-Fluorsulfonyl-N′-(dialkylsulfamoyl)harnstoffe 3a-d erhalten, die beim Erhitzen leicht in die Sulfamidsäurefluoride 4a-c zerfallen. Mit tertiären Aminen und Phosphinen bildet Fluorsulfonylisocyanat 1:1-Addukte, deren Struktur durch IR- und 13C-NMR-Untersuchungen aufgeklärt wird.
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  • 97
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2385-2387 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 98
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. XXVII 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1206-1215 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organometallic Lewis Bases, XXV. Phosphine Reactions of Heterodinuclear Complexes with Fe — Mo and Fe — W BondsThe complexes (CO)4Fe[μ-As(CH3)2]M(CO)2C5H5 (M = Mo, W) react with phosphines to form three different product types. These result from CO substitution on the iron atom, from cleavage of the metal-metal bond, or from a combination of both reactions. Investigations on the course of the reactions and independent syntheses of the products are reported.
    Notes: Die Komplexe (CO)4Fe[μ-As(CH3)2]M(CO)2C5H5 (M = Mo, W) reagieren mit Phosphinen zu drei verschiedenen Produkttypen. Diese resultieren aus einer CO-Substitution am Eisenatom, aus einer öffnung der Metall-Metall-Bindung oder aus einer Kombination beider Reaktionen. Untersuchungen zum Reaktionsverlauf und unabhängige Synthesen der Produkte werden beschrieben.
    Additional Material: 4 Tab.
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  • 100
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1246-1253 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Rotational Isomerism of Biisopropyl 1H N. M. R. Spectroscopic Investigation of 1,1,1,4,4,4-Hexadeuterio-2,3-bis(trideuteriomethyl)butaneThe conformational equilibrium in liquid biisopropyl was investigated by measuring the temperature-dependence of the vicinal coupling constant between the methine protons in 2,3-di[D3]-methyl-[1,1,1,4,4,4-D6]butane (3a) as a model compound. The change of 〈3 JHH〉 as a function of temperature shows a small stabilization of the gauche-conformer compared to the anti-conformer, which was found to be ca. 85 cal/mol by using 1H n. m. r. parameters for the pure conformers and various Karplus equations. The change of the relative stabilities of the rotamers by going from the gaseous to the liquid phase is explained on the basis of intermolecular dipolar interactions in the liquid state. The small difference in energy between the two conformers is discussed in comparison to bicyclopropyl, n-butane, and 2-methylbutane.
    Notes: Zur Untersuchung des Konformerengleichgewichtes im flüssigen Biisopropyl wurde die Temperaturabhängigkeit der vicinalen Kopplungskonstante zwischen den Methinprotonen an 2,3-Di[D3]-methyl-[1,1,1,4,4,4-D6]butan (3a) als Modellverbindung gemessen. Der Temperaturverlauf von 〈3 JHH〉 zeigt eine geringe Stabilisierung der gauche- gegenüber der anti-Form, die unter Verwendung verschiedener aus Karplus-Gleichungen ermittelter Endparameter zu ca. 85 cal/mol bestimmt wurde. Die Umkehrung der relativen Stabilität der Konformeren beim übergang von der Gasphase zur Flüssigkeit wird durch intermolekulare Dipol-Wechselwirkungen in der Flüssigkeit erklärt. Die annähernde Energiegleichheit der beiden Rotameren wird mit dem Verhalten von Bicyclopropyl, n-Butan und 2-Methylbutan verglichen.
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