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  • Articles: DFG German National Licenses  (1,527)
  • 2020-2022
  • 1985-1989  (682)
  • 1965-1969  (845)
  • 1890-1899
  • 1987  (682)
  • 1966  (845)
  • Inorganic Chemistry  (1,493)
  • Cerebellum
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  • Articles: DFG German National Licenses  (1,527)
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  • 2020-2022
  • 1985-1989  (682)
  • 1965-1969  (845)
  • 1890-1899
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  • 1
    Electronic Resource
    Electronic Resource
    The timing of granule cell differentiation and mossy fiber morphogenesis in the opossum (1987)
    Springer
    Anatomy and embryology 175 (1987), S. 341-354 
    Details
    ISSN: 1432-0568
    Keywords: Growth cones ; Granule cells ; Cerebellum ; Neonatal ; Mossy fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The timing of developmental events may be important for the orderly formation of neuronal interconnections. In the present study, the timing of granule cell migration is compared with the arrival and maturation of mossy fiber projections. The opossum was chosen as the experimental animal because its protracted postnatal development enables the examination of developmental sequences not as easily recognized in other more commonly used mammalian species. It is shown that all areas that project to the cerebellum as mossy fibers in the adult opossum do so by postnatal day (PD) 30. Their major target, the granule cells begin inward migration from the external germinal layer (EGL) prior to PD 30, but do not form a distinct internal granular layer (IGL) until PD 35. Migrating granule cells penetrate into the IGL deep to granule cells that have begun dendritic differentiation. By PD 50, Golgi impregnations reveal that many granule cells have numerous immature processes, somal spines and dendritic growth cones. After this age these structures are rare and the vast majority of granule cells exhibit short dendrites with digiform endings. Dendritic differentiation subsequent to PD 54 involves an increase in the length of the shaft and the further maturation of terminal digits. Also from Golgi material, immature mossy fiber endings can be identified in the IGL by PD 35 and exhibit mature characteristics at PD 73. Thus, the formation and maturation of granule cell dendrites and their afferents (mossy fibers) occur over an extended period of time (PD 35–73). Moreover, granule cells exhibit a sequence of development similar to that of Purkinje cells: 1) early arrival of their primary afferent projections in the cerebellar anlage: 2) a period of exuberant dendritic growth; and 3) a protracted and overlapping period for dendritic and synaptic maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309847
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  • 2
    Electronic Resource
    Electronic Resource
    Development of the basilar pons in the North American opossum: dendrogenesis and maturation of afferent and efferent connections (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 191-202 
    Details
    ISSN: 1432-0568
    Keywords: Basilar pons ; Dendrogenesis ; Neonatal ; Axon growth ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study provides data on temporal factors that may play a role in the development of precerebellar-cerebellar circuits in the North American opossum. In this study the basilar pons and cerebellum are analyzed from birth, 12–13 days after conception, to approximately postnatal day (PD) 80 at which time the brainstem and cerebellum have a mature histological appearance. In Nissl preparations, the basilar pons was first seen at PD 7 as a small cluster of tightly packed cells. Analysis of Golgi impregnations revealed that dendritic growth occurred between PD 25–80. During this period, dendrites gradually increased in length and in the complexity of their branching pattern. Horseradish peroxidase (HRP) was placed into the cerebellar and cerebral cortices in order to examine the development of efferent and afferent projections of the basilar pons, respectively. Evidence for the growth of pontine axons into the cerebellum was first detected on PD 17. Neurons located dorsally within the basilar pons appear to be the first neurons retrogradely labeled with horseradish peroxidase. By PD 27 retrogradely labeled neurons are found throughout the basilar pons. Afferent fibers from the cerebral cortex are not seen within the neuropil of the nucleus until after PD 25 and by PD 29, they have greatly expanded their terminal fields. Degeneration techniques reveal that afferent fibers from the cerebellum arrive by PD 19 and increase in number until PD 30 when their adult distribution is achieved. These data suggest that the time of afferent arrival from the cerebral cortex and deep cerebellar nuclei is closely correlated in time with the initiation of dendritic maturation and the outgrowth of pontocerebellar axons. Afferent axons from the cerebral cortex and deep cerebellar nuclei reach the basilar pons and afferents from the basilar pons grow into the cerebellum when the dendrites of the respective target neurons are very immature. Thus, the time of axon arrival in these circuits may be an important factor in determining their synaptic location on individual neurons. The data derived from the present study is compared to those obtained in previous studies on the inferior olive. The results of this comparison provide evidence for a similar sequence of events, but a differential timetable for the development of specific connections within precerebellar-cerebellar circuits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310052
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  • 3
    Electronic Resource
    Electronic Resource
    Two cases of agenesis of the vermis of cerebellum, with fusion of the dentate nuclei and cerebellar hemispheres (1987)
    Springer
    Acta neuropathologica 74 (1987), S. 278-280 
    Details
    ISSN: 1432-0533
    Keywords: Embryology ; Teratology ; Cerebellum ; Hydrocephalus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two cases are reported of the rare anatomical abnormality of fusion of the cerebellar hemispheres with agenesis of the vermis. The cases are the more unusual since they show prolonged survival and the absence of other major fusion abnormalities in the nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688192
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  • 4
    Electronic Resource
    Electronic Resource
    Damage and repair of the immature rat cerebellum after cis-dichlorodiammineplatinum II (cis-DDP) treatment. An ultrastructural study (1987)
    Springer
    Acta neuropathologica 72 (1987), S. 218-228 
    Details
    ISSN: 1432-0533
    Keywords: Cerebellum ; Histogenesis ; Cisdichlorodiammineplatinum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this electron microscopy study was to further investigate the effects of cis-dichlorodiammineplatinum (cis-DDP) on the cerebellum of the immature rat. Ten-day-old animals were treated with cis-DDP subcutaneously and killed after 1, 7, 15 or 21 days. On postinjection day 1, cis-DDP effects were evident mainly in the external granular layer, with nuclear damage in many dividing cells, while their cytoplasm appeared to be less affected. Some binucleate cells were also present. On the contrary, in postmitotic or more differentiated cells, only cytoplasmic alterations were found. At later stages (postinjection day 7), the frequency of damaged cells in the external granular layer decreased, but there was a cellular deficit in the internal granular layer. Many postmitotic neurons underwent coagulative necrosis. Finally (postinjection days 15 and 21), the cellular deficit was partly compensated for by “reactive” structures, e.g., glial cell fibers, which underwent hypertrophy after initial edema. Moreover, packing densities of Bergmann astrocytes and oligodendrocytes were higher.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691093
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  • 5
    Electronic Resource
    Electronic Resource
    Non-uniform projections of granule cells to the cerebellar molecular layer (1987)
    Springer
    Anatomy and embryology 175 (1987), S. 537-544 
    Details
    ISSN: 1432-0568
    Keywords: Cerebellum ; Parallel fibers ; Autoradiographic tracing ; Turtle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Injections of radioactive amino acids and wheat germ agglutinin were made into the cerebellar cortex of the turtle, Pseudemys scripta elegans. Labeled parallel fibers were always found to project along the entire mediolateral extent of the corpus cerebelli, regardless of the location of the injection site. In fact, lateral cerebellar portions of both the ipsi- and the contralateral hemisphere often appeared more heavily labeled than intermediate regions. Particularly impressive was the differential pattern of labeling throughout the depth of the molecular layer. Projections coursing towards the midline and the contralateral side were located predominantly in the basal half of the molecular layer while those oriented laterally showed a tendency to occupy primarily superficial portions of the molecular layer. Regional variations along the rostrocaudal extent of the cerebellar plate were also noted. These findings are in an apparent conflict with the reported parallel fiber organization of mammals where granule cells are commonly thought to project to basal and superficial portions of the molecular layer respectively according to a basal-superficial gradient in their location within the granular layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309689
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative-morphometric aspects of bergmann glial (Golgi epithelial) cell development in rats (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 183-188 
    Details
    ISSN: 1432-0568
    Keywords: Glia ; Cerebellum ; Rat ; Development ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bergmann glial (Golgi epithelial) cells in the cerebella of rats of various ages were stained by the rapid Golgi technique, and their radial stem processes were measured for length and diameter. Additionally, the average number of such processes per cell was counted, and the development of bushy lateral protrusions was quantified. The length of radial processes—depending on the thickness of the molecular layer—was found to increase up to the end of the 2nd year of life. This elongation was accompanied by a reduction of the mean process diameter which was, however, not sufficient to prevent an increase in the cytoplasmic volume of the elongating cells. A marked outgrowth of lateral protrusions was observed up to at least the 5th month of life. These data are compared with earlier findings on the development of rat brain stem fetal radial glia, and of rabbit retinal Müller cells. Common mechanisms of glial cell development are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572543
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  • 7
    Electronic Resource
    Electronic Resource
    Transplantation of cerebellar anlagen to hosts with genetic cerebellocortical atrophy (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 145-154 
    Details
    ISSN: 1432-0568
    Keywords: Neurological mutant mice ; ‘Purkinje cell degeneration’ (pcd) ; Weaver ; Neural transplants ; Cerebellum ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Embryonic cerebellar grafts from genetically normal donors were implanted into the cerebellomedullary cistern of adult ‘Purkinje cell degeneration’ (pcd) and weaver mutant mice, which are respectively characterized by the selective loss of Purkinje and granule cells. Grafts placed into both mutant recipients exhibited a layered cellular organization reminiscent of the normal cerebellar cortex. Molecular, Purkinje, and granule cell layers were identifiable. Grafted Purkinje cells displayed characteristic cytological features, such as hypolemmal cisterns in association with mitochondria in the perikaryon, and lamellar structures in their axons. The cytological features of granule cell somata in the grafts appeared similar to those of mature granule cells. Electron microscopic examination of the molecular layer of the grafts revealed the presence of parallel fibers, which were not oriented in a parallel fashion; axon terminals of such fibers were often presynaptic to dendritic spines. The number of parallel fibers was markedly reduced in grafts implanted into both mutants compared to the normal cerebellar cortex; however, this phenomenon is commonly seen in cerebellum in tissue culture and in cerebellar transplants into normal hosts. It is concluded, therefore, that the environment of the mutant hosts does not affect the survival of Purkinje or granule cells and that transplantation of solid cerebellar grafts in the neurological mutants studied does not seem to pose any apparent limitations beyond those inherent to the process of cerebellar growth and differentiation outside its normal environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310047
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  • 8
    Electronic Resource
    Electronic Resource
    Observations on the development of cerebellar afferents in Xenopus laevis (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 431-439 
    Details
    ISSN: 1432-0568
    Keywords: Cerebellum ; Cerebellar afferents ; Xenopus laevis ; Development ; Retrograde labeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of cerebellar afferents has been studied in the clawed toad, Xenopus laevis, from stage 46 to 64, with the horseradish peroxidase retrograde tracer technique. Already in stage 48 tadpoles, i.e. before the formation of the limbs, a distinct set of cerebellar afferents was found. Vestibulocerebellar (mainly arising bilaterally in the nucleus vestibularis caudalis) and contralateral olivocerebellar projections dominate. Secondary trigeminocerebellar (from the descending nucleus of the trigeminal nerve) and reticulocerebellar connections were also found. At stage 50, spinocerebellar projections appear originating from cervical and lower thoracic/upper lumbar levels. The cells of origin of the spinocerebellar projection can be roughly divided in two neuronal types: ipsilaterally projecting large cells, which show a marked resemblance to primary motoneurones (‘spinal border cells’) and smaller contralaterally projecting neurons. Primary spinocerebellar projections from spinal ganglion cells could not be demonstrated. At stage 50, a possible anuran homologue of the mammalian nucleus prepositus hypoglossi was found to project to the cerebellum. In only one of the experiments labeled neurons were found in the contralateral mesencephalic tegmentum. At none of the studied stages a raphecerebellar projection could be demonstrated. It appears that already early in cerebellar development, before the formation of the limbs, most of the cerebellar afferents as found in adult Xenopus laevis are present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310084
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  • 9
    Electronic Resource
    Electronic Resource
    Primary degeneration of the granular layer of the cerebellum (Norman type) (1987)
    Springer
    Acta neuropathologica 75 (1987), S. 203-208 
    Details
    ISSN: 1432-0533
    Keywords: Granular layer ; Cerebellum ; Purkinje cells ; Golgi method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Purkinje cells, impregnated with the rapid Golgi method, in a patient with primary degeneration of the granular layer showed abnormal orientation of the perikaryon and dendrites, reduction in size of the dendritic arbor, absence of spiny branchlets, and large numbers of stubby spines and hypertrophic spines on secondary dendritic branches; stubby spines and thorn-like formations were seldom observed on the primary dendrites and perikaryon of some Purkinje cells. These findings are similar to those described in the cerebellum of the homozygous weaver mutant mouse and in the cerebella of experimentally induced agranular phenocopies, thus suggesting that similar plastic changes occur in human and animal Purkinje cells as a result of the absence of parallel fibres input in early developmental stages. In addition, Purkinje cells in this patient showed club-shaped deformities in the distal region of primary dendrites, which were filled with radially oriented, short dendrites covered with stubby spines and hypertrophic spines. These latter structures appear to be fully impregnated asteroid bodies observed in paraffin sections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687082
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  • 10
    Electronic Resource
    Electronic Resource
    Dysplastic disease of the cerebellum of an adult horse (1987)
    Springer
    Acta neuropathologica 75 (1987), S. 209-211 
    Details
    ISSN: 1432-0533
    Keywords: Cerebellum ; Dysplasia ; Lhermitte-Duclos disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 4-year-old horse was evaluated at the Colorado State University Veterinary Teaching Hospital for rapidly progressing cerebellar disease. Euthanasia was elected and at postmortem examination a proliferative mass encompassing the right side of the cerebellum was discovered. The lesion was characterized by large, convoluted, vascular folia and absence of the core of central white matter. Histologically, there was a diminution or loss of the internal granule cell layer, cavitation of the central white matter, and absence of Purkinje cells. The molecular layer was thickened with myelinated axons originating from large neurons aberrantly located in this zone. The pathology of this cerebellar mass closely resembles that seen in the cerebellum of humans with Lhermitte-Duclos disease. Mature adults are most commonly affected and clinical signs associated with this disease are often vague. The disease is thought to result from hypertrophy of granule cells possibly due to an early maturation or migration defect. Because of the late age of onset and the rarity of the disorder, its pathogenesis has been difficult to discover. Awareness that other mammalian species may be affected with a similar disorder may lead to an understanding of the causative developmental defect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687083
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  • 11
    Electronic Resource
    Electronic Resource
    Cerebellar hemispheric agenesis (1987)
    Springer
    Acta neuropathologica 74 (1987), S. 202-206 
    Details
    ISSN: 1432-0533
    Keywords: Cerebellum ; Agenesis ; Transsynaptic degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case report is reported of bilateral cerebellar hemispheric agenesis which was associated with secondary degeneration of cerebellofugal and cerebellopetal tracts. Somatotopic correlations between the cerebellar and the medullary olive lesions were obvious: preserved dorsal accessory olives pattern correlated with the spared vermis and normal medial accessory olives with the spared flocculi. Cerebellopetal degeneration was more difficult to analyse. The relation of cerebellar agenesis with basal ganglia abnormalities and microcephaly is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692854
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  • 12
    Electronic Resource
    Electronic Resource
    Glycine-like immunoreactivity in the cerebellum of rat and Senegalese baboon, Papio papio: a comparison with the distribution of GABA-like immunoreactivity and with [3H]glycine and [3H]GABA uptake (1987)
    Springer
    Experimental brain research 66 (1987), S. 211-221 
    Details
    ISSN: 1432-1106
    Keywords: Glycine ; GABA ; Immunocytochemistry ; Cerebellum ; Golgi cells ; Colocalization ; Rat ; Baboon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An antiserum against conjugated glycine was characterized and applied to cerebellar sections of rats and baboons that had been perfusion-fixed with glutaraldehyde. After immunosorbent purification the serum reacted with brain protein-glutaraldehyde-glycine conjugates, but did not stain similar test conjugates prepared from other amino acids, including GABA and β-alanine. In the rat cerebellum the glycine antiserum selectively labelled a subpopulation of Golgi neurons. Adjacent Vibratome sections treated with an antiserum against conjugated GABA revealed an about equally large subpopulation of immunopositive Golgi cells. A proportion of the Golgi cells that were cleaved by the plane of section contained both immunoreactivities. Additional evidence for a colocalization of glycine and GABA was obtained by postembedding staining of alternate semithin sections with the GABA antiserum and glycine antiserum, respectively. The ability of the antisera to distinguish between fixed glycine and GABA was corroborated by preincubation of the antisera with glutaraldehyde-amino acid fixation complexes: glycine complexes abolished staining with the glycine antiserum but had no effect on the GABA antiserum. The opposite effects were obtained with the GABA complexes. Matching the distributions of the respective immunoreactivities, [3H]glycine uptake was restricted to glomerulus-like structures in the granule cell layer whereas [3H]GABA uptake also occurred in punctate and fibrous profiles in the molecular layer. The baboon showed a distribution of glycine-like immunoreactivity similar to that in the rat, except that a few immunopositive neurons occurred in the molecular layer. The latter neurons were interpreted as outlying Golgi neurons; however, the possibility that they represent a subpopulation of basket cells could not be excluded. The Purkinje cells were negative in both species. Glial cells were weakly stained with the glycine antiserum but were strongly immunopositive after incubation with an antiserum raised against conjugates of the structurally similar amino acid β-alanine. The present data suggest that glycine and GABA occur in about equally large subpopulations of Golgi neurons. A subpopulation of the Golgi neurons appears to contain both glycine and GABA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236216
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  • 13
    Electronic Resource
    Electronic Resource
    Motor abnormalities in weaver mutant mice (1987)
    Springer
    Experimental brain research 65 (1987), S. 479-481 
    Details
    ISSN: 1432-1106
    Keywords: Weaver mutant mice ; Cerebellum ; Motor abnormalities ; Paw clasping responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Weaver mutant mice lose mainly cerebellar granule cells. Motor abnormalities included less activity in a hole-board test and a loss of balance in two equilibrium tests. It was noted that the weaver mutants also displayed paw clasping responses when held by the tail of a sort never seen in normal mice. The role of the cerebellum in these abnormalities is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236322
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  • 14
    Electronic Resource
    Electronic Resource
    Visuo-motor tracking during reversible inactivation of the cerebellum (1987)
    Springer
    Experimental brain research 65 (1987), S. 455-464 
    Details
    ISSN: 1432-1106
    Keywords: Monkey ; Cerebellum ; Cooling ; Local anaesthetic ; Visuo-motor ; Tracking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two monkeys were trained to track a continuously moving target using a joystick. One then had a cooling probe implanted in nucleus interpositus of the cerebellum ipsilateral to his tracking arm. The other had a cannula implanted in the ipsilateral cortex of the lateral cerebellum through which local anaesthetic could be infused. Both monkeys showed similar tracking deficits during temporary inactivation of the cerebellum. The main effects seen were an increase in the peak velocity of their intermittent corrective tracking movements, and a decrease in the accuracy of these movements. Linear regression analyses were undertaken of the peak velocity and amplitude of each corrective movement against a number of possible control signals (target velocity, target position, error, error velocity etc.). The initially strong correlation of the amplitude of each movement made with target velocity was severely reduced during cerebellar inactivation, and movement amplitude became better predicted by the error between target and joystick positions. The peak velocity of movements became more strongly correlated with movement amplitude and less correlated with target velocity than in the intact animal. These results are consistent with the hypothesis that intermittent tracking is achieved by the production of ‘primitive’ movements, that are then adjusted to the correct amplitude and velocity required to catch up with the moving target. Our findings suggest that the cerebellum may normally be responsible for these adjustments, using visual and memorised cues about the target. The velocity of each movement may be reduced, and its amplitude adjusted, by combining measures of the current error with estimates of target speed and direction. We conclude that the cerebellum has an inhibitory role in tuning movements during visuo-motor tasks and that optimal tuning using feedforward measurements of target motion cannot be made without it.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236319
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  • 15
    Electronic Resource
    Electronic Resource
    Human fetal tissues grafted to rodent hosts: structural and functional observations of brain, adrenal and heart tissues in oculo (1987)
    Springer
    Experimental brain research 67 (1987), S. 163-178 
    Details
    ISSN: 1432-1106
    Keywords: Human brain development ; Xenografts ; Monoamine neurons ; Cerebellum ; Cortex cerebri ; Adrenal medulla ; Ganglia ; Heart ; Intraocular transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The potential for growth and development of human tissue grafts was explored by transplantation to the anterior chamber of the eye of rats and mice. Tissues were obtained from therapeutic abortions, performed in the eighth to twelfth week of gestation, using a slight modification of routine vacuum aspirations. Recipients were either adult rats immunosuppressed with cyclosporin A and protected with antibiotics, or nude immunodeficient Balb C mice. Catecholamine-rich tissues such as chromaffin cells from the adrenal medulla, sympathetic ganglia, central dopamine neuroblasts from the substantia nigra, and noradrenaline neuroblasts from the locus coeruleus all survived grafting, and in many cases formed nerve fibers that invaded the host iris. Similarly, central serotonin neurons from developing raphe nuclei grafts were able to innervate host irides. Human fetal cerebellar and cerebral cortical transplants continued their development in rat host eyes. Extracellular recordings from such cerebellar and cortical grafts revealed spontaneously active cells with immature action potential waveforms. Spinal cord grafts also survived and contained substance P-immunoreactive neurons. Dorsal root ganglia were able to form nerve fibers invading the host iris, as evidenced by neurofilament immunohistochemistry. Heart tissue survived and manifested spontaneous rhythmic contractions in oculo. Both human cortex cerebri and heart tissue grafts became innervated by sympathetic adrenergic nerve fibers from the rat host iris. Thus both graft-to-host and host-to-graft neuronal connections may be established between man and rat. Taken together, these data suggest that transplantation of human fetal nervous tissues to the anterior chamber of immunosuppressed or immunodeficient rodent hosts yields a unique model system for studies of human brain development, developmental disturbances, connectivity, and the action of drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269464
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  • 16
    Electronic Resource
    Electronic Resource
    The role of the monkey sensory cortex in the recovery from cerebellar injury (1987)
    Springer
    Experimental brain research 66 (1987), S. 638-652 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Sensory cortex ; Compensation ; Motor performance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the study was to investigate the contribution of the primary sensory cortex in the compensation of cerebellar deficits during self-paced movements. For this purpose, monkeys were trained on motor tasks which required goal-reaching and independent finger movements. The intermediate and lateral deep cerebellar nuclei and the sensory cortex were lesioned in isolation and in sequence and the course of motor recovery was studied on the test performances. The deep nuclei were lesioned by kainic acid injections, the sensory cortex was removed by ablation. Cerebellar lesions in isolation produced obvious deficits at proximal and distal joints, affecting both slow and fast motor adjustments. Only lesions of the anterior portions of the intermediate and lateral deep nuclear complexes produced deficiencies in voluntary movements. Lesions of the posterior portions produced postural disturbances. The process of recovery following cerebellar lesions was slow and, depending on the nature of the task, was found to be differentially disruptive for motor performances requiring fast and slow motor adjustments. The deficits at distal joints appeared to be more enduring than those at proximal joints. Sensory cortical lesions in isolation produced much less severe and more transient motor deficits. They consisted of hand clumsiness and their recovery was fast and reached higher levels of performance than following cerebellar lesions. When the sensory cortex was removed secondarily to a cerebellar lesion and after recovery from the cerebellar deficits, the initially recovered motor performance became much worse again (decompensation). Removal of the sensory cortex prior to a cerebellar lesion exaggerated the cerebellar deficits and severely limited their recovery. Slow and fast motor performances were completely abolished for three weeks following sequential lesions. Signs of recovery subsequently appeared and stabilized at low levels of performance by five to seven weeks. The effects of combined, sequential cerebellar and sensory cortical lesions were much worse than expected if the effects from the two lesions were merely additive. This indicates that there is some functional interrelationship between the sensory cortex and the cerebellum, which promotes compensation. The somatosensory cortex appears to play a crucial role in the process of recovery from cerebellar motor deficits and it is likely that sensation is an important component in the process of recovery. It is suggested that the sensory cortex exerts its compensatory actions via a structure or structures which receives convergent cerebellar and sensory cortical inputs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270696
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  • 17
    Electronic Resource
    Electronic Resource
    Responses of interposed and dentate neurons to perturbations of the locomotor cycle (1987)
    Springer
    Experimental brain research 67 (1987), S. 323-338 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Dentate nucleus ; Interposed nuclei ; Locomotion ; Single-unit activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study examined the relationship of antidromically identified neurons in the dentate and interposed nuclei to perturbed and unperturbed locomotion in the pre-collicular, mid-mamillary, decerebrate cat. During treadmill locomotion two methods were used to perturb the step cycle. In the first, the treadmill was braked in different phases of the step cycle, the “treadmill” perturbation. In the second, the motion of the ipsilateral forelimb was interrupted by a rod placed transiently in the limb's path, the “single limb” perturbation. Most interposed cells were modulated during locomotion, their discharge being highly correlated with the EMG of the ipsilateral biceps or triceps. When the locomotion was perturbed, the modulation ceased for the duration of the perturbation. A few interposed cells displayed activity patterns unrelated to the EMG but were responsive to perturbations of a single limb. These responses may be explained by the putative activation of peripheral afferents produced by the perturbation. Most dentate cells were not modulated during unperturbed locomotion but did respond to features of the treadmill perturbation. Usually the response was coupled to the resumption of treadmill motion. A minority of dentate neurons was modulated slightly during unperturbed locomotion. Their modulation was less dramatic than that of interposed cells and was only weakly related to limb movement or EMG activity. Like the interposed neurons, these dentate cells responded to the treadmill perturbation with a cessation of modulation. All dentate cells were unresponsive to single limb perturbations. In a preparation lacking cerebral cortical input, the findings show that neurons of the interposed and dentate nuclei are modulated differently during perturbed and unperturbed treadmill walking in the decerebrate cat. The activity of interposed neurons is related to specific features of EMG activity recorded from muscles in the ipsilateral forelimb. Although some dentate cells were weakly modulated during unperturbed locomotion, the majority of these neurons responded most dramatically to the occurrence of a perturbation which completely stopped the walking behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248553
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    Electronic Resource
    Inferior olive excitability after high frequency climbing fibre activation in the cat (1987)
    Springer
    Experimental brain research 67 (1987), S. 523-532 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Inferior olive ; Interposito-olivary pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Climbing fibre responses (CFRs) were evoked by limb nerve stimulation and recorded from the cerebellar surface in barbiturate anaesthetized cats. Climbing fibres were activated at frequencies of usually 2.5–7.5 Hz for periods of 15–30 s, after which the stimulation frequency was reduced to below 1 Hz. 2. The high-frequency stimulation induced a strong depression of CFR-amplitude, lasting up to 60 s. The magnitude of this depression was dependent on both the frequency and the duration of the high-frequency stimulation. 3. The depression occurred in the c1, c2 and c3 zones of the pars intermedia and in the x zone in the vermis but not in the b zone in the vermis. 4. Recordings of olivary reflex responses demonstrated that the depression occurred in the inferior olive. 5. It is suggested that the inhibition of the inferior olive occurs because the high-frequency stimulation leads to a disinhibition of neurones in the interpositus nucleus which inhibit the olivary neurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247285
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  • 19
    Electronic Resource
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    Postembedding light- and electron microscopic immunocytochemistry of amino acids: description of a new model system allowing identical conditions for specificity testing and tissue processing (1987)
    Springer
    Experimental brain research 69 (1987), S. 167-174 
    Details
    ISSN: 1432-1106
    Keywords: Amino acids ; Immunocytochemistry ; Specificity testing ; Cerebellum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Specificity testing should be performed under conditions identical to or closely similar to those of the immunocytochemical procedure. This paper describes a new model system that meets this requirement for postembedding immunocytochemistry of amino acids at the light- and electron microscopic levels. Test conjugates, obtained by reacting different amino acids with brain macromolecules in the presence of glutaraldehyde, were freeze-dried and embedded in an epoxy resin (Durcupan) exactly as for brain tissue. One section from each of the embedded amino acid conjugates and from a brain protein-glutaraldehyde conjugate (without amino acid) were piled on top of each other and embedded anew. Transverse semithin (0.5 μm) and ultrathin sections were cut through the stack. These test sections, in which all the different conjugates were represented, were then processed in the same drops of sera as the tissue sections to permit identical conditions for testing and immunocytochemistry. After immunogold labelling for electron microscopy, a quantitative expression of crossreactivity was obtained by computer-assisted calculation of gold particle densities over the different conjugates. The antisera used in the present study (glutamate anti-serum 13, taurine antiserum 20, and GABA antiserum 26) showed highly selective labelling of the respective amino acid conjugates and produced distinct labelling patterns in simultaneously processed cerebellar sections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247039
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  • 20
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    Locomotor deficits in the mutant mouse, Lurcher (1987)
    Springer
    Experimental brain research 66 (1987), S. 271-286 
    Details
    ISSN: 1432-1106
    Keywords: Neurological mutant mouse ; Lurcher ; Cerebellum ; Purkinje cell degeneration ; Locomotion ; Swimming ; Scratching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of total Purkinje cell degeneration on treadmill locomotion was studied in the cerebellar mutant mouse Lurcher. Other movements such as swimming and scratchting were also studied in order to evaluate the cerebellar control of rhythmic actions. Cinematographic and electromyographic recordings were taken from normal and Lurcher mice that were subsequently perfused to obtain a Purkinje cell count. Walking deteriorated progressively and was clearly abnormal in 30 day old Lurchers with 90% Purkinje cell degeneration. In adult Lurcher mice in which Purkinje cells were totally absent, walking was characterized by short steps with exaggerated hindlimb flexion in the swing phase. Also, both the interlimb step ratio, defined as the step length of the reference limb divided by the step length of the opposite limb, and the interlimb coupling, defined as the temporal relation of one footfall with respect to the footfall of another limb, varied more than in normal mice. Furthermore, the locomotion of Lurcher mice displayed increased vertical displacement of the hip and an inability to produce continuous step cycles without stumbling. Both the EMG onset relative to foot contact and the EMG burst duration were highly variable, and a greater overlap in the activities of antagonist muscles at the transition from ankle extension to flexion was evident. Although both walking and swimming involve cyclical limb movements, the disorganization of the cycle and the irregular EMG pattern seen in the Lurcher during walking were not observed during swimming. Furthermore, scratching was well executed in the Lurcher mice. However, a consistently higher tonic extensor activity at the ankle appeared during walking, swimming and scratching. These results suggest that, in contrast to swimming and scratching, the requirements of walking depend to a greater degree on a functional cerebellar cortex for successful performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243304
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    Eye movements evoked by microstimulation in the flocculus of the alert macaque (1987)
    Springer
    Experimental brain research 67 (1987), S. 352-362 
    Details
    ISSN: 1432-1106
    Keywords: Flocculus ; Microstimulation ; Cerebellum ; Oculomotor system ; Pursuit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have used microstimulation in the floccular cortex of alert monkeys to study the role of the cerebellar flocculus in the control of slow eye movements and the representation of eye movement direction in the flocculus. Eye movements having peak velocities of less than 15 deg/s, sometimes accompanied by rapid eye movements, were evoked using trains of current pulses (22 μA or less). The initial slow eye movement was designated Phase I. By restricting current spread to specific layers of the flocculus, evidence was obtained that Phase I was caused by the activation of molecular layer elements; it appeared to reflect the suppression of Purkinje cell activity. Phase I, therefore, probably represents the best estimate of the effect of changing Purkinje cell activity in a limited region. Phase I ended either during the pulse train or after the end of the pulse train; following the end of Phase I, the eye movement reversed its direction. Again by stimulating various layers, the eye movement following the reversal (Phase II and the off-response) was attributed to activation of Purkinje cell axons and other elements, including floccular afferents, in the granular layer and white matter. Phase I eye movements in all directions were evoked from the flocculus. Homogeneous zones with respect to eye movement direction were approximately 300 μm in diameter. When the cortex was represented as a two-dimensional sheet, a large number of zones corresponding to different directions of Phase I were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248555
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    Activity of Purkinje cells and interpositus neurones during and after periods of high frequency climbing fibre activation in the cat (1987)
    Springer
    Experimental brain research 67 (1987), S. 533-542 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Inferior olive ; Purkinje cells ; Interposito-olivary neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The activity of cerebellar Purkinje cells and interpositus neurones was recorded during and after periods of high frequency (2.5–7.5 Hz) climbing fibre activation in barbiturate-anaesthetized cats. 1. During the high frequency conditioning stimulation, the Purkinje cell simple spike (SS) firing was initially silenced in all zones studied. After a few seconds, the SS reappeared and the frequency increased to well above that of the control level after approximately 10 s. Thereafter, the SS rate started to decline so that, after 15–20 s, the Purkinje cells fired no more SS. This SS silence lasted up to 60 s, whether or not the stimulation was continued. 2. The Purkinje cells responded with a complex spike (CS) to every stimulus. If the high-frequency stimulation lasted for at least 15 s, the spontaneous CS discharge of the Purkinje cells in the c1, c2, and c3 zones was suppressed after the conditioning stimulation had ended. This suppression lasted for approximately the same length of time as the SS silence. In the b zone, however, no CS suppression was observed. 3. Interpositus neurones displayed an increased discharge rate after periods of conditioning stimulation, thus displaying a mirror image of the Purkinje cell SS firing. 4. The behaviour of the neurones agrees well with the behaviour predicted by an hypothesis of the olivo-cerebello-olivary loop (Andersson and Hesslow 1987). 5. The results suggest that the cerebello-olivary projection is topographically organized and matches the microzonal organization in the olivo-cerebellar projection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247286
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    Motor abnormalities in staggerer mutant mice (1987)
    Springer
    Experimental brain research 68 (1987), S. 417-420 
    Details
    ISSN: 1432-1106
    Keywords: Staggerer mutant mice ; Cerebellum ; Motor abnormalities ; Paw clasping responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Staggerer mutant mice spontaneously lose both Purkinje and granule cells of the cerebellum. Motor abnormalities included less activity for an exploratory task and loss of balance in two equilibrium tests. It was observed that staggerer mutants exhibited paw clasping and limb crossing responses when held in the air by the tail, of a sort never seen in normal adult mice. The role of the cerebellum in these abnormalities is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248807
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  • 24
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    The cytoskeleton of cryofixed Purkinje cells of the chicken cerebellum (1987)
    Springer
    Cell & tissue research 247 (1987), S. 155-165 
    Details
    ISSN: 1432-0878
    Keywords: Cryofixation ; Freeze-etching ; Cytoskeleton ; Purkinje cell ; Cerebellum ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cerebella of 3- to 6-week-old chickens were cryofixed in a nitrogen-cooled propane jet, deep-etched and rotary-shadowed. The use of a brief perfusion of 0.32 M sucrose improved the quality of the cryofixation and allowed the study of the deeper layers of the cerebellar cortex. It is reported that the cytoskeleton of the Purkinje cells (PC) shows distinct domains and composition of filamentous structures in the different regions of the cell cytoplasm, such as the perikaryon, the cytoplasm of dendrites and the axoplasm. The perikaryon is occupied by a meshwork of fine filaments, 4–7 nm in diameter, that extends from the nuclear outer membrane to the cell membrane. In this zone the cell organelles (e.g., endoplasmic reticulum, mitochondria) adopt a circular arrangement around the nucleus. All structures are anchored by microfilaments to the cytoplasmic network. The dendrites show a dense cytoplasmic network including bundles of microtubules, neurofilaments and microfilaments. Numerous aggregated globular components are attached to this cytoskeleton. The cytoskeleton of the dendritic spines shows axially oriented 10-nm bundles of filaments, which are interconnected and anchored also to the cell membrane and the components of the agranular endoplasmic reticulum by cross-linkers. As described in peripheral nerves, the axoplasm of axons in the central nervous system exhibits predominantly neurofilaments and microtubules aligned along the axis of the neuntes in a three-dimensional arrangement and interconnected by cross-linker filaments and filamentous structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216558
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    Nucleophile Addition von Triorganozinn-Anionen an Kohlenstoffdisulfid, IX1) Synthese und Komplexierung neuer Triphenylstannandithioester (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1099-1104 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleophile Addition von Triorganotin-Anionen on Carbon Disulfide, IX1 - Synthesis and Complexation of Novel Triphenylstannane DithioestersThe known alkyl esters Ph3SnC(S)SR (1: R=Me, 2: R=CH2Ph) and the novel stannyl(methyl) esters (3: R=SnPh3, 4: R=CH2SnPh3) were obtained by the reaction of the dioxane adduct Ph3SnCS2Li · 2 C4H8O2 with appropriate organo(element) halides. As the first derivative of a homologous stannylalkanedithiocarboxylic acid, the 3-(triphenylstannyl)propane dithioester Ph3Sn[CH2]3C(S)SMe (5) was synthesized by Grignard reaction of (3-chloropropyl)triphenylstannane with activated magnesium (addition of anthracene, ultrasound). The new η1-coordinated pentacarbonylchromium and -tungsten complexes LM(CO)5 (1a: L=1, M=Cr; 2a: L=2, M=Cr; 2b: L=2, M=W; 3b: L=3, M=W; 5b: L=5, M=W) were prepared by modification of previously reported methods.
    Notes: Durch Umsetzen des Dioxan-Addukts Ph3SnCS2Li · 2 C4H8O2 mit geeigneten Organo(element)-halogeniden entstehen die bekannten Alkylester Ph3SnC(S)SR (1: R=Me, 2: R=CH2Ph) sowie die neuartigen Stannyl(methyl)ester (3: R=SnPh3, 4: R=CH2SnPh3). Als erstes Derivat einer homologen Stannylalkandithiocarbonsäure stellten wir den 3-(Triphenylstannyl)propandithioester Ph3Sn[CH2]3C(S)SMe (5) durch Grignard-Reaktion von (3-Chlorpropyl)triphenylstannan mit aktiviertem Magnesium (Anthracen-Zusatz, Ultraschall) dar. Durch Modifikation früher beschriebener Methoden erhielten wir die neuen, η1-koordinierten Pentacarbonylchrom- und -wolfram-Komplexe LM(CO)5 (1a: L=1, M=Cr; 2a: L=2, M=Cr; 2b: L=2, M=W; 3b: L=3, M=W; 5b: L=5, M=W).
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200706
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  • 26
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    Reaktionen des Diphenylphosphanoxids mit Organodiboranen(6) - Struktur einer zwitterionischen -POB- -Verbindung1) (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1117-1123 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Diphenylphosphane Oxide with Organodiboranes - Structure of a Zwitterionic -POB- -Compound1)(C6H5)2 (3′a), prepared from diphenylphosphane oxide (C6H5)2P(O)H (1) and activated triethylborane (2a*), reacts with tetraalkyldiboranes(6) (R2BH)2 [R=C2H5: (4a)2; R=C3H7: (4b)2] to form the BH3-addition compounds (C6H5)2P(BH3)OBR2 [R=C2H5: 3′a-BH3], [(C6H5)2P(BH3)O]2BR [R=C2H5: 5a-(BH3)2], and [(C6H5)2P(BH3)O]3B [6-(BH3)3]. The reaction of bis(9-borabicyclo[3.3.1]nonane) (4c)2 with 1 leads to (C6H5)2POBC8H14 (3′c) or 3′c-4c and (C6H5)2PH (7) or (C6H5)2PH-HBC8H14 (7-4c). The crystalline zwitterionic (C6H5)2P(H)OB[OP(BH3)(C6H5)2]3 [1-6-(BH3)3] (X-ray analysis) is isolated from the reaction of 1 with (4a)2.
    Notes: Aus Diphenylphosphanoxid (C6H5)2P(O)H (1) erhält man mit aktiviertem Triethylboran (2a*) das Derivat (C6H5)2POB(C2H5)2 (3′a). Aus 3′a sind mit Tetraalkyldiboranen(6) (R2BH)2 [R=C2H5: (4a)2; R=C3H7: (4b)2] die BH3-Additionsverbindungen (C6H5)2P(BH3)OBR2 [R=C2H5: 3′a-BH3], [(C6H5)2P(BH3)-O]2BR [R=C2H5: 5a-(BH3)2] und [(C6H5)2P(BH3)O]3B [6-(BH3)3] zugänglich. Bis(9-borabicyclo[3.3.1]nona) (4c)2 und 1 reagieren unter Bildung von (C6H5)POBC8H14 (3′c) oder 3′c-4c und (C6H5PH-HBC8H14 (7-4c). Das kristallisierte zwitterionische (C6H5)2P(H)OB[OP(BH3)-
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200708
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    Synthese und Strukturanalyse von 1,2,3,4-Tetrahydrobenzo[g]chinoxalin-5,10-chinonen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1125-1132 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure Analysis of 1,2,3,4-Tetrahydrobenzo[g]-quinoxaline-5,10-quinones2,3-Diamino-1,4-dihydroxynaphthalene reacts with different aromatic aldehydes to give 2,3-disubstituted 1,2,3,4-tetrahydrobenzo[g]quinoxaline-5,10-quinones (1-7). In the course of the reaction a new C-C bond is formed stereoselectively. The yields are in the range of 80%. The corresponding benzoquinoxalinequinone 8 with different substituents in 2- and 3-positions is formed by a two-step preparation. Oxidation of these trans products leads to the benzo[g]quinoxaline-quinones and subsequent catalytic reduction yields the cis isomers. The structures and the configuration of 1 and 9 were determined by X-ray crystallography. The conformations of the new heterocycles are discussed with respect to the results obtained in solid and liquid phase.
    Notes: 2,3-Diamino-1,4-naphthohydrochinon reagiert mit Benzaldehyden unter Cyclisierung und Protonenwanderung stereoselektiv zu 2,3-disubstituierten 1,2,3,4-Tetrahydrobenzo[g]chinoxalin-5,10-chinonen (1-7) (Ausbeuten ca. 80%). Benzochinoxalin-5,10-chinon 8, das in 2- und 3-Stellung unterschiedlich substituiert ist, wird durch eine zweistufige Reaktion erhalten. Die Anordnung der Phenylreste in 2- und 3-Stellung wird für 1 und 9 durch Röntgenstrukturanalysen ermittelt; beide Spezies liegen in trans-Konfiguration vor. Durch Oxidation zu Benzo [g]chinoxalin-chinonen und anschließende katalytische Hydrierung werden cis-Isomere erhalten. Unter Berücksichtigung der Ergebnisse aus den Kristallstruktur- und NMR-Untersuchungen werden verschiedene Konformationen diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200709
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    Reaktionen von (Organo)Phosphor-Sauerstoff-Verbindungen mit Diorgano-hydro-boranen1) (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1105-1115 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of (Organo)phosphorus-Oxygen Compounds with Diorgarno-hydro-boranes1)Trialkyl phosphites P(OR)3 [R=CH3 (2a), C2H5 (2b), CH(CH3)2 (2c), C4H9 (2d)] react with tetraalkyldiboranes(6) (R′2BH)2 [R′=C2H5 (1a)2, C3H7 (1b)2] in a temperature-dependent manner between 20 and 130°C to form the trialkyl phosphite-boranes (RO)3P-BHR′2, (RO)3P-BH2R′, and (RO)3P-BH3, which have various stabilities toward alcohols. With bis(9-borabicyclo-[3.3.1]nonane) (1c)2 the easily protolyzed addition compounds are obtained [e.g. 2a-1c, 2c-1c]. - Diorgano phosphites (RO)2P(O)H [R=CH3 (3a), C4H9 (3b), C6H5 (3c), CH2C6H5 (3d)], triorgano phosphates (RO)3PO [R=CH3 (4a), C4H9 (4b), C6H5 (4c), 2-CH3C6H4 (4d)], and the monosaccharide-diphenyl phosphates 4f, 4g, and 4h are reduced by (1a)2 or (1c)2 to give H2, PH3, and insoluble yellow phosphorus compounds, respectively. Phosphoric acid (4e), their derivatives OP(OBR2)3 [R=C2H5 (4ea), R2=C8H14 (4ec)], and phenylphosphonic acid C6H5P(O)-(OH)2 (6) are not deoxygenated at 130°C by (1a)2 to (1c)2. - Diorganophosphinic acids R2P(O)OH [R=C6H5 (5a), c-C6H11 (5b)] and phenylphosphinic acid C6H5(H)P(O)OH (5c) are reduced by (1a)2-(1c)2. Reaction of 5a with (1a)2 leads to the compounds [(C6H5)2P(BH3)O]B(C2H5)2 (8a-BH3), [(C6H5)2P-(BH3)O]BC2H5 [9a-(BH3)2], and [(C6H5)2P(BH3)O]3B [10-(BH3)3]. 5a reacts with (1c)2 under simultaneous formation of (C6H5)2PH (7) or (C6H5)2PH-HBC8H14 (7-1c) and (C6H5)2-POBC8H14 (8c) or (C6H5)2P(OBC8H14)-HBC8H14 (8c-1c). - 6 reacts with tetraethyldiboroxane (11a) to form a mixture of the oligomeric compounds -P(C6H5)(O)OB(C2H5)O]n-(6′a)n.
    Notes: Trialkylphosphite P(OR)3 [R=CH3 (2a), C2H5 (2b), CH(CH3)2 (2c), C4H9 (2d)] reagieren mit Tetraalkyldiboranen(6) (R′2BH)2 [R′=C2H5 (1a)2, C3H7 (1b)2] in Abhängigkeit von der Temperatur (20 bis 130°C) unter Bildung der gegenüber Alkoholen unterschiedlich stabilen Trialkylphosphit-Borane (RO)3P-BHR′2, (RO)3P-BH2R′ und (RO)3P-BH3. Mit Bis(9-borabicyclo-[3.3.1]nonan) (1c)2 erhält man die protolytisch leicht spaltbaren Additionsverbindungen [z.B. 2a-1c, 2c-1c]. - Diorganophosphite (RO)2P(O)H [R=CH3 (3a), C4H9 (3b), C6H5 (3c), CH2C6H5 (3d)], Triorganophosphate (RO)3PO [R=CH3 (4a), C4H9 (4b), C6H5 (4c), 2-CH3C6H4 (4d)] sowie die Monosaccharid-Phosphorsäure-diphenylester 4f, 4g und 4h werden von (1b)2 bzw. (1c)2 unter Bildung von H2, PH3 und/oder unlöslichen, gelben Phosphor-Produkten reduziert. - Phosphorsäure (4e), deren Derivate OP(OBR2)3 [R=C2H5 (4ea), R2=C8H14 (4ec)] und Phenylphosphonsäure C6H5P(O)(OH)2 (6) lassen sich von (1a)2 - (1c)2 bis 130°C nicht desoxygenieren. - Diorganophosphinsäuren R2P(O)OH [R=C6H5 (5a), c-C6H11 (5b)], Phenylphosphinsäure C6H5(H)P(O)OH (5c) werden von (1a)2 bis (1c)2 reduziert. 5a und (1a)2 bilden [(C6H5)2P(BH3)O]B(C2H5)2 (8a-BH3), [(C6H5)2P(BH3)O]2BC2H5) [9a - (BH3)2] und [(C6H5)2P(BH3)O]3B [10-(BH3)3]. Mit (1c)2 reagiert 5a unter gleichzeitiger Bildung von (C6H5)2PH (7) bzw. (C6H5)2PH-HBC8H14 (7-1c) sowie von (C6H5)2POBC8H14 (8c) bzw. (C6H5)2P(OBC8H14)-HBC8H14 (8c-1c). - 6 bildet mit Tetraethyldiboroxan (11a) ein Gemisch oligomerer - [P(C6H5)(O)OB(C2H5)O]n-Verbindungen (6′a)n.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200707
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    The Vinylogous Tricarbonyl Chromophore. Violerythrine End Groups and Related Six-Membered Ring Compounds. Their synthesis, Conformation, and Investigation by Photoelectron, UV, and NMR Spectroscopy and by Crystal Structure Analysis1) (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1133-1149 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Der vinyloge Tricarbonyl-chromophor. Violerythrin-Endgruppen und verwandte Sechsringverbindungen. Synthese, Konformation, Untersuchung mit Photoelektronen-, UV-, NMR-Spektroskopie und Röntgenstrukturanalyse1)Die Synthese von ungesättigten Fünf- und Sechsringen, 3a, 4, 5b, 5c und 17a, die das Strukturelement des 3-Penten-1,2,5-trions enthalten, wird beschrieben. Diese vinylogen Tricarbonyle werden zusammen mit verwandten Verbindungen auf ihre chromophoren Eigenschaften hin untersucht. Die Konformation in Lösung, insbesondere der Torsionswinkel Ring-Seitenkette, wird mit Hilfe von 3JCH-Kopplungen, NOE-Differenzspektren und Kraftfeldrechnungen abgeleitet. Röntgenstrukturanalysen von 11a, 17a, 18a und 35 liefern die Geometrie im festen Zustand. Die Ionisierungsenergien werden photoelektronenspektroskopisch bestimmt. Zur Berechnung und Interpretation der Absorptionsspektren und der Farbe werden die CNDO/S-CI- und die HAM/3-Methode verwendet.
    Notes: The synthesis of five- and six-membered rings 3a, 4, 5b, 5c, and 17a, containing the structural moiety 3-pentene-1,2,5-trione, is described. The chromophoric properties of these vinylogous tricarbonyls together with related compounds are investigated. The conformation in solution, particularly the torsion angle ring/sidechain, can be derived from measurements of 3JCH coupling constants, NOE difference spectra, and force-field calculations. X-ray structure analyses of 11a, 17a, 18a, and 35 afford geometries in the solid state. Ionization energies are determined by means of photoelectron spectroscopy. The theoretical calculations and interpretation of absorption spectra and colour are carried out using the models CNDO/S-CI and HAM/3.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200710
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    Elementorganische Amin/Imin- Verbindungen, XXVIII1) Polycyclische Phosphor-Stickstoff-Rhenium(I)-Komplexe (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1183-1190 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Element-Organic Amine/Imine Compounds, XXVIII1). - Polycyclic Phosphorus-Nitrogen Rhenium(I) ComplexesThe thermolysis of [(OC)4RE - NR - P(Cl)(NR2) - NR](2), R = SiMe3 affords the tricyclic phosphorus dispiro compound 3, the cubanelike rhenium complex [Re2(CO)6(μ3-NR)4(μ3 -PNR)2] (4) as well as the tetracyclic rhenium complex 5. The attempt to synthesize 3 from RN-P(NR)(NR2)-NR- P(NR)(NR2 (7), R=SiMe3, and [Re(CO)5X] or [(OC)4ReX]2 (X=Cl, Br), gave the ionic species [RN-(RN)(RHN)P-NR-P- NR-SiMe2-NR]⊕ [Re2(CO)6(μX)3]⊖ (6a, X=Cl; 6b, X=Br). 3, 5, and 6a have been characterized by an X-ray structure analysis.
    Notes: Die Thermolyse von [(OC)4Re-NR -P(Cl)(NR2)-NR] (2), R = SiMe3 ergibt die tricyclische Phosphor-Dispiroverbindung 3, den cubanartigen Rheniumkomplex [Re2(CO)6(μ3-PNR)2] (4) sowie den tetracyclischen Rheniumkomplex 5. Beim Versuch, 3 aus RN-P(NR)(NR2)-NR -P(NR)(NR2) (7), R = SiMe3 und [Re(CO)5X] bzw. [(OC)4ReX]2 (X=Cl, Br) herzustellen, bildeten sich die Komplexsalze [RN- (RN)(RHN)P-NR-SiMe2-NR[⊕ [Re2(CO)6(μX)]⊖ (6a, X = Cl; 6b, X = Br). 3, 5 und 6a wurden durch eine Röntgenstrukturanalyse charakterisiert.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200713
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    Dibenzocycloocten-, Dibenzochalcocin- und Diarenochalconindione (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1151-1173 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dibenzocyclooctene-, Dibenzochalcocine- and Diarenochalconinediones2,2′-Oxybis-, -thiobis-, and -methylenebisbenzoic esters 2a-c react with methyllithium in ether to give low yields of 5H-dibenzo[b,g]chalcocine-5,7(6H)-diones 6a, 7a, and dibenzo[a,d]cyclooctene-5,7(6H,12H)-dione (8), respectively. Very good yields of such heterocycles with oxygen (6a-h, 37), sulfur (7a-h, 38) and selenium (36) as key atom are obtained when diaryl ethers (21, 22, 25), -sulfides (27, 29, 30), and -selenides (33) that contain 2′ -acetyl- (or -propionyl-) and 2-methoxycarbonyl groups are treated with sodium hydride in boiling toluene. Analogously are prepared the dibenz[b,g]oxonine-11,13(6H,12H)-diones 62a-c and 7H-benzo[h]naphtho[1,8-bc]thionine-7,9-(8H)-dione (65) which are expanded by one ring member. In the analogous reaction of a corresponding benzophenone derivative 35, spiro[1H-indene-1,1′(3′H)-isobenzofuran]-3(2H),3′- dione (41) is formed in a tandem reaction. - Under phase transfer conditions the dibenzochalcocinediones 6, 7, 36 and also the corresponding nitrogen cycles 5 react to give mixtures of C-(42-45) and O-alkyl derivatives (46-49). Methyllithium and diisobutylaluminium hydride provide the carbinols 50-54. With bromine and SO2Cl2, respectively, the methylene group is mono- or dihalogenated to the products 56, 57; defined nitration was only possible for the oxacycle 6a.
    Notes: Die 2,2′-Oxybis-, -Thiobis- und -Methylenbisbenzoesäureester 2a-c reagieren mit Methyllithium in Ether in schlechten Ausbeuten zu den 5H-Dibenzo[b,g]chalcocin-5,7(6H)-dionen 6a, 7a bzw. Dibenzo[a,d]cycloocten-5,7(6H,12H)-dion (8). Sehr gute Ausbeuten an derartigen Heterocyclen mit Sauerstoff (6a-h, 37), Schwefel (7a-h, 38) und Selen (36) als Schlüsselatom erhält man bei der Umsetzung von mit 2′-Acetyl- (bzw. -Propionyl-) und 2-Methoxycarbonyl-Gruppen versehenen Diarylethern (21, 22, 25), -sulfiden (27, 29, 30) und -seleniden (33) mit Natriumhydrid in siedendem Toluol. In analoger Weise lassen sich die um ein Ringglied erweiterten Dibenz[b,g]oxonin-11,13(6H,12H)-dion 62a-c und das 7H-Benzo[h]naphtho[1,8-bc]thionin-7,9(8H)-dion (65) herstellen. Bei der analogen Umsetzung eines vergleichbaren Benzophenonderivates 35 wird in einer Tandemreaktion Spiro[1H-inden-1,1′(3′H)-isobenzofuran]-3(2H),3′-dion (41) gebildet. - Unter Phasentransfer-Bedingungen lassen sich die Dibenzochalcocindione 6, 7, 36 sowie die entsprechenden Stickstoffcyclen 5 zu Gemischen von C-(42-45) und O-Alkylderivaten (46-49) umsetzen. Methyllithium bzw. Diisobutylaluminiumhydrid liefern die Carbinole 50-54. Mit Brom bzw. SO2Cl2 werden die an der Methylengruppe mono- oder dihalogenierten Produkte 56, 57 erhalten; definiert nitrieren ließ sich nur der Oxacyclus 6a.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200711
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    Thiastannacyclohexane (R2SnS)3 und -adamantane (RSn)4S6 Synthesen, Eigenschaften und Strukturen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1175-1182 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiastannacyclohexanes (R2SnS)3 and -adamantanes (RSn)4S5: Synthese, Properties, and StructuresCyclotristannathianes (4) are obtained from R2SnCl2 (1) and Na2S · 9H2O or (CH3)3SiSSi(CH3)3. Analogously, hexathiatetrastannaadamantanes are prepared from RSnCl3 (2) and the sulfenylating agents mentioned before. The reaction between dimesityltin dichloride (1a) and Na2S · 9H2O depending on the reaction conditions yields either the corresponding dithiadistannacyclobutane (3) or cyclotristannathiane 4a. The structure of the cyclostannathianes 3, 4, and 5 are elucidated by determining the intensity ratio of geminal 119Sn-117Sn couplings. Calculated data are confirmed by experimental values. Additional proof is provided by measuring the change of intensity ratio in the 117Sn-NMR spectrum of 4c. X-ray structure determination proved for (C6F5Sn)4S6 (5g) to have the same geometry as in solution.
    Notes: Cyclotristannathiane (4) werden durch Umsetzung von R2SnCl2 (1) mit Na2S · 9H2O bzw. (CH3)3 erhalten. Analog werden Hexathiatetrastannaadamantane (5) aus RSnCl3 (2) und obigen Sulfenylierungsagentien synthetisiert. Die Reaktion zwischen Dimesitylzinndichlorid (1a) und Na2S · 9H2O führt je nach Reaktionsbedingungen entweder zum entsprechenden Dithiadistannacyclobutan (3) oder zu Cyclotristannathian 4a. Die Konstitutionen der Cyclostannathiane 3, 4 und 5 wurden durch Intensitätsmessungen der geminalen 119Sn-117Sn-Kopplung ermittelt. Berechnete Werte ließen sich experimentell bestätigen. Die Beweisführung wird im Fall von 4c durch die im 117Sn-NMR-Spektrum aufgezeigte Intensitätsveränderung ergänzt. Die an (C6F5Sn)4S6 (5g) durchgeführte Röntgenstrukturanalyse belegt die in Lösung aufgezeigte Geometrie.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200712
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    Zur Synthese perfluorierter Sulfimide, RfN=SO2, und deren Stabilisierung durch tertiäre Amine (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1183-1190 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Element-Orgainc Amine/Imine compounds, XXVII1). - Polycyclic Phosphorus-Nitrogen Rhenium(I) ComplexesThe amine-stabilized sulfimides RN=SO2 Ň7H13 8, 9, and 10 could be obtained by reaction of sulfamoyl chlorides RNH-SO2Cl [R=C6F5 4, (CF3)2CH 5, (CF3)2CHOCO 6] with quinuclidine (7). A direct approach to 8 and 15 was found by oxidation of N-sulfinylamines RN=SO [R=C6F5 12, (CF3)2CF 14] with quinuclidine N-oxide or trimethylamine N-oxide, respectively. The X-ray structure analysis of 8 indicates a doublebond in the N=SO2 group, while the amine is tetrahedrally coordinated in a distance to the sulfur atom longer than a single bond. Additional reaction of N-sulfinylamines or sulfamoyl chlorides are reported.
    Notes: Die aminstabilisierten Sulfimide RN=SO2Ň7H13 8, 9 und 10 konnten durch Reaktion der Sulfamoylchloride RNH-SO2Cl [R=C6F5 4, (CF3)2CH 5, (CF3)2CHOCO 6] mit Chinuclidin (7) erhalten werden. Ein direkter Zugang zu 8 und 15 wurde durch Oxidation der N-Sulfinylamine RN=SO [R=C6F5 12, (CF3)2CF 14] mit Chinuclidin-N-oxid bzw. Trimethylamin-N-oxid gefunden. Die Röntgenstrukturanalyse an 8 weist auf eine Doppelbindung in der N=SO2-Gruppe hin, während das Amin tetraedrisch in einem Abstand zum Schwefelatom koordiniert ist, der länger als einer Einfachbindung entsprechend ist. Weitere Reaktionen von N-Sulfinylaminen bzw. Sulfamoylchloriden werden beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200714
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    Aminosäuren, 10 Zur Reaktion von Pyroglutaminsäure-Derivaten mit Thionyl- und Oxalylchlorid (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 55-59 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of N-methyl- and N-benzyl-substituted 5-oxoproline methylesters (1a, b) with thionyl or oxalyl chloride yield N-substituted 5-chloro-2,3-dihydro-1H-pyrrole-2-carboxylic esters. These esters, as α-chloro enamines, undergo further electrophilic reaction in the ß-position by thionyl or oxalyl chloride. Thus, N-substituted bis(pyrrolyl) thioethers 2, bis(pyrrolyl) disulfides 3, and their oxidation products 4,5, and 6 are formed with excess thionyl chloride. N-substituted 5-chloro-4-[chloro(chlorocarbonyl)methyl]-1H-pyrrole-2-carboxylic esters 12 are obtained with oxalyl chloride. Reaction of L-1-benzhydryl-5-oxoproline methylester (L-1c) with thionyl chloride results in the formation of N-unsubstituted bis(pyrrolyl) thioether 9 under comparable conditions.
    Notes: N-Methyl- und N-Benzyl-substituierte 5-Oxoprolin-methylester (1a, b) bilden mit Thionyl- bzw. Oxalychlorid N-substituierte 5-Chlor-2,3-dihydro-1H-pyrrolcarbonsäureester, die als α-Chlor-enamine in ß-Position elektrophil mit Thionylchlorid bzw. Oxalylchlorid weiterreagieren: mit Thionylchlorid zu N-substituierten Bis(pyrrolyl)thioethern 2 und Bis(pyrrolyl)disulfiden 3 sowie deren Oxidationsprodukten 4, 5 und 6, mit Oxalylchlorid zu N-substituierten 5-Chlor-4-[chlor(chlorcarbonyl)methyl]-1H-pyrrol-2-carbonsäureestern 12. Die Umsetzung von L-1-Benzhydryl-5-oxo-prolin-methylester (L-1c) mit Thionylchlorid führt unter vergleichbaren Bedingungen zum N-unsubstituierten Bis(pyrrolyl)thioether 9.
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    URL: http://dx.doi.org/10.1002/cber.19871200110
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    Elektroreduktion organischer Verbindungen, 7 Bildung von Monothioacetalen bei der Elektroreduktion von Thioketonen in Alkoholen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 67-70 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thioethers 3 and monothioacetals 4 are obtained on cathodic reduction of thiopivalophenone (2) in alcohols as solvents in the presence of alkylating agents.
    Notes: Bei der kathodischen Reduktion von Thiopivalophenon (2) in Alkoholen als Lösungsmittel in Gegenwart von Alkylierungsmitteln erhält man neben den Thioethern 3 die Monothioacetale 4.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200112
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  • 36
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    Zum Norcaradien-Cycloheptatrien-Strukturproblem (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 79-80 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: LiAlH4 reduction of ketone 1 which adopts a norcaradiene form leads to the alcohol 2. Ketone 1 may also be converted into the alkene 3 using McMurry conditions. Both reactions are accompanied by valence isomerisations to a bi- or tetracycloheptatriene
    Notes: Das als Norcaradien-Isomere vorliegende Keton 1 läßt sich durch Reduktion mit LiAlH4 in den Alkohol 2 und unter McMurry-Bedingungen in das Alken 3 überführen dabei beobachteten wir Valenzisomerisierung zu einem Bi- bzw. Tetra(cycloheptatrein)-System.
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    URL: http://dx.doi.org/10.1002/cber.19871200114
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    9,12,22,25-Tetramethoxy[7.7]paracyclophan-4,17-dion:Synthese und Molekülstruktur (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 89-91 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Starting from 1,4-bis-(3-iodopropyl)-2,5-dimethoxybenzene (3) via the reaction to the corresponding bis(1,3-dithian-2-yl) compound 4 and its double alkylation by 3 the 22-membered ring system of 5 was obtained from which 9,12,22,25-tetramethoxy[7.7]paracyclophane-4,17-dione (1) was prepared. The molecular structure of 1 is discussed on the basis of an X-ray analysis.
    Notes: Ausgehend von 1,4-Bis(3-iodpropyl)-2,5-dimethoxybenzol (3) wurde über die Reaktion zu der entsprechenden Bis(1,3-dithian-2-yl)-Verbindung 4 und deren erneute doppelte alkylierung durch 3 das 22-gliedrige Ringsystem von 5 aufgebaut, aus dem 9,12,22,25-Tetramethoxy[7.7]paracyclophan-4,17-dion (1) erhalten wurde. Die Molekülstruktur von 1 wird auf der Grundlage einer Röntgen-Strukturanalyse diskutiert.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200116
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    Synthese, Reaktivität und Struktur von Kupfer-, Silber- und Gold-Komplexen des Typs (C5Me5CS2)M(PR3)n mit einzähnig und zweizähnig gebundenem Dithiocarboxylat-Ligand (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 97-104 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The reactions of (η5-C5Me5)Cu(PR3) (1a - c) and (η1-C5Me5)-Au(PR3) (2a,c) with CS2 lead to insertion of carbon disulfide into the C5Me5 - M bond to the formation of the dithiocarboxyalto complexes (C5Me5CS2)M(PR3)n (3a - c, 4a, c). The silver compound (C5Me5CS2)Ag(PPh3)2 (5) is directly obtained from [AgCl(PPh3)]4, C5Me5Li, and excess CS2. The synthesis of 3 - 5 and (C5Me5CS2)Cu(PMe3)3 (6) can also be achieved almost quantitatively from C5Me5CS2Li, formed in situ from C5Me5Li and CS2 and MCl(PR3)n. By use of methyl iodide instead of MCl-(PR3)n, the ester C5Me5CS2Me (7). is obtained. The results of the X-ray structural analyses of (C5Me5CS2)Cu(PPh3)2 (3a) and (C5Me5CS2)Au(PiPr3) (4c) confirm that the dithiocarboxylato ligand to coordinated via both sulfur atoms to copper but only via one sulfur atom to gold. In solution, compound 6 undergoes a fast PMe3 ligand exchange which has been studied by NMR spectroscopy. The sign of J(PH) of 6 has been determined.
    Notes: Die Reaktionen von (η5-C5Me5)Cu(PR3) (1a - c) und (η1-C5Me5)-Au(PR3) (2a,c) mit CS2 führen zu einer Insertion des Schwefelkohlenstoffs in die C5Me5-Metall-Bindung und zur Bildung der Dithiocarboxylat-Komplexe (C5Me5CS2)M(PR3)n (3a - c, 4a, c). Die Silberverbindung (C5Me5CS2)Ag(PPh3)2 (5) ist direkt aus [AgCl(PPh3)]4, C5Me5Li und überschüssigem CS2 erhältlich. Die Synthese von 3 - 5 und (C5Me5CS2)Cu(PMe3)3 (6) gelingt praktisch quantitativ auch durch Umsetzung von in situ aus C5Me5Li und CS2 gebildetem C5Me5CS2Li und MCl(PR3)n. Bei Verwendung von Methyliodid an Stelle von MCl(PR3)n) entsteht der Ester C5Me5CS2Me (7). Die Ergebnisse der Röntgenstrukturanalysen von (C5Me5CS2)Cu(PPh3)2 (3a) und (C5Me5CS2)Au(PiPr3) (4c) bestätigen, daß der Dithiocarboxylat-Ligand über beide Schwefelatome am Kupfer, jedoch nur über ein Schwefelatome am Gold koordiniert ist. Verbindung 6 unterliegt in Lösung einem raschen PMe3-Ligandenaustausch, der NMR-spektroskopisch untersucht worden ist. Das Vorzeichen der PH-Kopplung von 6 wurde bestimmt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200118
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    Synthese von 2,6-Diazabicyclo[2.2.2]octan-3,5-dion-Abkömmlingen und 2(1H)-Pyridinonen. - Ein Beitrag zur Regiochemie und Stereospezifität 1,4-Dipolarer Cycloadditionen von Pyridmidinium-4-olaten an elektronenreiche und elektronenarme Alkene (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 109-114 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The pyrimidinium-4-olates of type 1 combine with enol ethers, enamines, ketene acetals, 1,4-dihydro-1,4-epoxynaphtalene, dimethyl fumarate, or dimethyl maleate to produce 2,6-diazabicyclo[2.2.2]octane-3,5-diones 2,3,5,7,9,17 - 19, whereas the reaction of the pyrimide[2.1-b]benzothiazolium-4-olate 13 with 8b or 1,1-bis(dimethylamino)ethene proceeds with formation of the 2(1H)-pyridinone derivative 15. The primary adducts 9a,b fragment thermally into 2(1H)-pyridinones 11a, b. In the example of the reaction of 1a with dimethyl maleate, the stereospecificity is determined.
    Notes: Die Pyrimidinium-4-olate von Typ 1 vereinigen sich mit Enolethern, Enaminen, Keten-acetalen, 1,4-Dihydro-1,4-epoxynaphthalin, Fumarsäure-dimethylester oder Maleinsäure-dimethyl-ester zu 2,6-Diazabicyclo[2.2.2]octan-3,5-dionen 2, 3, 5, 7, 9, 17-19, während das Pyrimido[2,1-b]benzothiazolium-4-olat 13 mit 8b oder 1,1-Bis(dimethylamino)ethen das 2(1H)-Pyridinon-Derivat 15 liefert. Die Primäraddukte 9a, b spalten thermisch in die 2(1H)-Pyridinone 11a, b. Am Beispiel der Umsetzung von 1a mit Maleinsäure-dimethylester wird die Stereospezifität ermittelt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200120
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    Titanium-Mediated Stereoselective Knoevenagel Condensation of Ethyl (Diethoxyphosphoryl)acetate with Aldehydes (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 121-122 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The titanation of the sodium salt of ethyl (diethoxyphosphoryl)-acetate (1) results in a reagent which undergoes a stereoselctive Knoevenagel condensation with aldehydes to form the corresponding trisubstituted olefins 3 having the Z-configuration.
    Additional Material: 1 Tab.
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    Direct Geminal Dimethylation of Aromatic Aldehydes with Dichlorodimethyltitanium (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 123-123 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic aldehydes react specifically with (CH3)2TiCl2 to form the geminal dimethylated products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200124
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    Niederkoordinierte Phosphorverbindungen, 54 Phosphaalkene durch Cope-Umlagerung (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 125-129 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The styryl-substituted diphosphanes 2a, b are prepared by the reaction of the chlorophosphanes 1a, b with magnesium or tert-butyllithium, respectively. Compound 2b, substituted with bulky residues, gives the racemic form of the phosphaalkene 5 by Cope rearrangement, which is slowly and irreversibly converted into the meso-form.
    Notes: Aus den Chlorphosphanen 1a, b wurden die Styryl-substituierten Diphosphane 2a, b hergestellt. An der mit sperrigen Resten substituierten Verbindung 2b konnte erstmals die Cope-Umlagerung eines Diphosphans zu einem Phosphaalken 5-rac beobachtet werden. Die Racemform wandelt sich irreversibel in die Mesoform von 5 um.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200202
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    Organische Synthesen mit übergangsmetall-Komplexen, 20 Lineare C-Kettenverlängerung von Allenen durch metallinduzierte Allen/Vinylcarben-Umlagerung und regiospezifische Insertion von CO in die M - C-Bindung einer zweikernigen Carbonyleisen-Matrix (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 105-107 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Binuclear carbonyl(1-propene-2,3-diyl)iron complexes 4, regioselectively derived from 1,2-propadienes 1, can be stepwise isomerized at 60°C to give binuclear 1-ferra-1,3-diene complexes 6, which at 130°C further rearrange to give ferracyclopentadienes 7 under formation of a C=C bond by a regiospecific insertion of CO at the higher substituted terminal carbon (but not at the Fe=C bond) of the ferradiene unit.
    Notes: Die von 1,2-Propadienen 1 regioselektiv erhältlichen zweikernigen Carbonyl(1-propen-2,3-diyl)eisen-Komplexe 4 isomerisieren stufenweise bei 60°C unter metallinduzierter 1,2-Wasserstoff-Wanderung zu zweikernigen 1-Ferra-1,3-dienen 6, und diese wiederum bei 130°C zu Ferracyclopentadienen 7 unter Aufbau einer C=C-Bindung durch regiospezifische Insertion von CO am höher substituierten terminalen C-Atom (nicht an der Fe=C-Bindung) der Ferradien-Einheit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200119
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  • 44
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    (Trimethylsiloxy)maleinsäureanhydrid (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 119-120 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Trimethylsioxy)maleic anhydride (2) can easily be prepared from pyridinium salt 1 and chlorotrimethylsilane. Reaction of 2 with acetone or acetaldehyde affords the diols 3a and 3b.
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    URL: http://dx.doi.org/10.1002/cber.19871200122
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    Masthead (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200201
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  • 46
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    1,3-Dithienium- und 1,3-Dithioleniumsalze, VI N,N-Disubstituierte 4-Aminobenzophenone aus 1,3-Dithian- bzw. 1,3-Dithiolan-2-ylium-tetrafluoroboraten (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 135-139 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The 1,3-dithienium- and 1,3-dithiolenium tetrafluoroborates 3 (n=3, 2), respectively, react in good yields with the N,N-dialkylarylamines 4 to give the 2,2-disubstituted cyclic dithio acetals 5, which can be converted after dethioacetalization with HgCl2/HgO into the ketones 7.
    Notes: Die 1,3-Dithienium- bzw. 1,3-Dithiolenium-tetrafluoroborate 3 (n=3, 2) reagieren in guten Ausbeuten mit den N,N-Dialkylarylaminen 4 zu den 2,2-disubstituierten cyclischen Dithioacetalen 5, die sich nach Dethioacetalisierung mit HgCl2/HgO in die Ketone 7 überführen lassen.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200204
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    Niederkoordinierte Phosphorverbindungen, 55 Zur Cope-Umlagerung an 1,3-Diphospha-1,5-hexadienen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 131-134 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chlorophosphane 1 reacts with substituted allyl-Grignard reagents 2a, b to yield the 1,3-diphospha-1,5-hexadienes 3a, 4b. 31P-NMR temperature run of 3a shows dynamic processes, which can be explained by inversion of the trivalent P-atom. Above 40°C 3a undergoes a [3,3′]-phospha-carbon Cope rearrangement to give the thermodynamically stable product 4a. The structures of 3a and 4a are confirmed by X-ray structure analysis.
    Notes: Das Chlorphosphan 1 reagiert mit den substituierten Allyl-Grignard-Reagenzien 2a, b zu 1,3-Diphospha-1,5-hexadienen 3a, 4b. Bei 3a lassen sich 31P-NMR-spektroskopisch temperaturabhängige dynamische Phänomene beobachten, die auf Inversion am Phosphan-Phosphor zurückgeführt werden. Oberhalb von 40°C unterliegt 3a einer [3,3′]-Phospha-Kohlenstoff-Cope-Umlagerung zum thermodynamisch stabileren Produkt 4a. Die Molekülstrukturen von 3a und 4a wurden röntgenographisch bestimmt.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200203
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  • 48
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    Chirale Cluster mit μ3-Alkin- und μ3-Vinyliden-Liganden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 141-151 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: By reaction of alkyne-bridged dicobalt complexes with Fe2(CO)9 or Fe3(CO)12 alkyne- and vinylidene-bridged clusters of the general type FeCo2(CO)9(μ3-L) were accessible. These and the homologous RuCo2 clusters could be subjected to the reaction types metal exchange and alkyne-vinylidene rearrangement. Combination of both reaction types in the appropriate sequence yielded altogether 16 new hetero trinuclear clusters with μ3-vinylidene ligands. Internal alkynes R2C2 with R=Me, Et, Ph and terminal alkynes HC2R with R=H, Me, t-Bu, Ph were used; the latter were also the precursors of the corresponding vinylidene ligands. The resulting metal frameworks were of the FeCoNi, FeCoMo, FeCoW, RuCoNi, RuCoMo, RuCoW, FeNi2, and FeCo2 types. The alkyne-vinylidene rearrangements on the chiral clusters showed diastereoselectivities between 0 and 100%. The crystallographically determined molecular structure of RuCoWCp(CO)8(μ3-CCH-t-Bu) allows to interprete the diastereoselectivity as not resulting from steric effects.
    Notes: Durch Umsetzung von alkinverbrückten Dicobalt-Komplexen mit Fe2(CO)9 bzw. Fe3(CO)12 wurden alkin- und vinylidenverbrückte Cluster des allgemeinen Typs FeCo2(CO)9(μ3-L) zugänglich. Auf diese und die homologen RuCo2-Cluster ließen sich die Reaktionstypen Metallaustausch und Alkin-Vinyliden-Umlagerung anwenden. Kombination beider Reaktionstypen in der geeigneten Reihenfolge lieferte insgesamt 16 neue Hetero-Dreikerncluster mit μ3-Alkin-Liganden und 29 entsprechende Verbindungen mit μ3-Vinyliden-Liganden. Es kamen interne Alkine R2C2 mit R=Me, Et, Ph und terminale Alkine HC2R mit R=H, Me, t-Bu, Ph zum Einsatz; letztere waren auch die Vorläufer der entsprechenden Vinyliden-Liganden C2HR. Die entstehenden Metallgerüste waren vom FeCoNi-, FeCoMo-, FeCoW-, RuCoNi-, RuCoMo-, RuCoW-, FeNi2- und FeCo2-Typ. Die Alkin-Vinyliden-Umlagerungen auf den chiralen Clustern zeigten Diastereoselektivitäten zwischen 0 und 100%. Die kristallographisch bestimmte Molekülstruktur von RuCoWCp(CO)8(μ3-CCH-t-Bu) läßt sich so interpretieren, daß die Diastereoselektivität nicht auf sterischen Effekten beruht.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200205
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    1,3-Dipolare Cycloadditionen, 92 Reaktionen aliphatischer Diazoverbindungen mit vierfach Acceptorsubstituierten Ethylenen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 153-158 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: In contrast to a literature report, diazomethane and diazoaceticester add to the CC double bond of tetracyanoethylene and ethylenetetracarboxylic ester. The behavior of the 1- and 2-pyrazolines deviates from the rule.
    Notes: Entgegen einem Literaturbericht finden die Cycloadditionen des Diazomethans und Diazoessigsäureesters an die CC-Doppelbindung des Tetracyanethylens und des Ethylentetracarbonsäureesters statt. Das Verhalten der 1- and 2-Pyrazoline zeigt Abweichungen von der Norm.
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    URL: http://dx.doi.org/10.1002/cber.19871200206
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    1,3-Dipolare Cycloadditionen, 93 Überraschungen bei der Umsetzung des 2,3-Dicyanfumarsäure-dimethylesters mit Diazomethan (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 159-169 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The reaction with excess of diazomethane furnished methyl 4-cyano-1-methylpyrazole-5- and-3-carboxylate (2 and 3) as well as the three N-methyl-1,2,3-triazolecarboxylic esters 4-6. A mechanistic study revealed a poly-step sequence. The initial formation of the pyrazoline 8 proceeded normal. Base catalysis effected an equilibration of trans- and cis-2-pyrazoline, 8⇌12, followed by a fragmentation into methyl 4-cyano-3-pyrazolecarboxylate (26) and methyl cyanoformate (32); a 4H-pyrazole is supposed to be the key intermediate. The final products mentioned above emerged from further reaction of 26 and 32 with diazomethane.
    Notes: Die Reaktion mit überschüssigem Diazomethan lieferte 4-Cyan-1-methylpyrazol-5- und-3-carbonsäure-methylester (2 und 3) sowie die drei N-Methyl-1,2,3-triazolcarbonsäure-methylester 4-6. Eine mechanistische Studie brachte eine vielstufige Reaktionsfolge an den Tag. Die einleitende Bildung des Pyrazolins 8 vollzog sich normal. Unter Baseneinwirkung kam es zur Äquilibrierung von trans-2-Pyrazolin 8 mit cis-2-Pyrazolin 12, gefolgt von einer Spaltung in 4-Cyan-3-pyrazolcarbonsäureester (26) und Cyanameisensäureester (32); ein 4H-Pyrazol wird als Zwischenstufe vermutet. Die oben erwähnten Endprodukte entsprangen der Weiterreaktion von 26 und 32 mit Diazomethan.
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    URL: http://dx.doi.org/10.1002/cber.19871200207
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    Phosphorverbindungen ungewöhnlicher Koordination, 171) über die Abfangreaktion von Phenylthioxophosphan mit Hexacarbonylbis(cyclopentadienyl)dimolybdän (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1263-1267 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphorus compounds with Unusual Cooradination, 171). - On the Trapping Reaction Of Phenylthioxophosphane with Hexacarbonylbnis(cyclopentadienyl)dimolybdenumPhenylthioxophosphane (6) - generated in boiling toluene from endo/exo-10 - reacts under these conditions with hexacarbonylbis(cyclopentadienyl)dimolybdenum (12) to yield the two binuclear molybdenum complexes 13a and 14a. A crystal structural analysis has been performed for 13a. Lawesson's reagent (17) leads under the same conditions with 12 to the analogous complexes 13b and 14b.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200727
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    Masthead (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200801
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    Synthesen, Struktur und Eigenschaften von 1,1-Dialkoxy-2-azapropenylium-Salzen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1271-1279 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses, Structures, and Properties of 1,1-Dialkoxy-2-azapropenylium Salts1,1-Dialkoxy-2-azapropenylium salts 1 were synthesized by alkylation at the oxygen atom of N-methylenecarbamates 4 with trialkyloxonium salts 5, in cases, where steric hindrance makes N-alkylation difficult (4a); otherwise the iminium salts 6 are formed preferentially. A more general synthetic route to the salts 1 is based on the reaction of N-(alkoxymethyl)imidocarbonates 8 with acylium ions (acyl cleavage reaction). The salts are thermally not very stable; phenyl ester derivatives are easily converted into 4H-1,3-benzoxazine derivatives 11. - An X-ray analysis of 1aa shows an allenic structure with orthogonal π systems; for steric reasons the C-N-C bond angle is reduced to ca. 150°. - Quantum mechanical ab initio calculations predict high steric flexibility for the salts 1; in the parent compound (16a) an allenic structure is slightly (2-3 kcal/mol) favored over allylic forms (16d). Thermodynamically more stable are the isomeric iminium salts 6 and 17, respectively. - Depending on the substitution pattern in solution (IR, dynamic NMR spectroscopy) allenic (1a) or allylic (1b) structures are observed.
    Notes: 1,1-Dialkoxy-2-azapropenylium Salze 1 können durch O-Alkylierung am Carbonylkohlenstoff von N-Methylencarbamidsäureestern 4 mit Trialkyloxonium-Salzen 5 erhalten werden, falls eine N-Alkylierung sterisch erschwert ist (4a); andernfalls werden die Iminium-Salze 6 gebildet. Eine allgemeinere Darstellungsmethode für die Salze 1 beruht auf der Umsetzung von N-(Alkoxymethyl)-imidokohlensäureestern 8 mit Acylium-Ionen (Acylspaltung). Die Salze 1 sind thermische nicht sehr beständig Phenylester-Derivate gehen leicht in 4H-1,3-Benzoxazin-Derivate 11 über. - Die Kristallstrukturanalyse von 1aa ergibt eine allenische Struktur mit orthogonalen π-Systemen, wobei der C-N-C-Bindungswinkel auf ca. 150° reduziert ist (sterische Effekte). - Quantenmechanische Ab-initio-Berechnungen sagen hohe sterische Flexibilität der Salze 1 voraus, wobei beim Grundkörper allenische Strukturen (16a) geringfügig (ca. 2-3 kcal/mol) gegenüber allylischen Formen (16d) bevorzugt sind. Thermodynamisch günstiger als die Salze 1 (bzw. 16) sind die isomeren Iminium-Salze 6 bzw. 17. - Je nach Substitutionsmuster beobachtet man in Lösung (IR-, dynamische NMR-Spektroskopie) allenische (1a) oder allylische Strukturen (1b).
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    URL: http://dx.doi.org/10.1002/cber.19871200802
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    Organische Synthesen mit Übergangsmetallkomplexen, 231) Bicyclische 3-Imidazoline aus primären Isocyaniden und Alkenylcarben-Komplexen durch metallinduzierte anomale Insertion einer C=N- in eine α-CH-Bindung des Isocyanids (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1287-1291 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Syntheses via Transition Metal Complexes, 231). - Bicyclic 3-Imidazolines from Primary Isocyanides and Alkenylcarbene Complexes by a Metal-Induced Anomalous Insertion of a C=N- into an α-CH Bond of the IsocyanideAlkenylcarbene complexes 1 react smoothly with one equivalent of methyl- and primary isocyanides 2 to give 1:1 adducts 3, which contain C-alkenyl ketenimine ligands. To these a second molecule of 2 may be added in a [4 + 1] fashion with formation of bis-(imino)cyclopentene complexes 6 or - in a competing reaction path - with induction of a second spontaneous ring closure to 3-imidazoline complexes 4/5 by an insertion of 2 into the α-CH bond of 3. Complexes 4-6 were characterized spectroscopically, the 3-imidazoline complex 4a also by an X-ray analysis. In competition with the addition of 2c to 3c an isomerisation of 3c to the α-alkoxycyanide complex 9a is observed involving an N/Cmigration of the N-allyl group. Steric factors exhibit strong influences on the course of the different competition reactions.
    Notes: Alkenylcarben-Komplexe 1 bilden mit Methyl- bzw. einem primären Isocyanid 2 1:1-Addukte 3, die einen C-Alkenylketenimin-Ligand enthalten. An diesen läßt sich ein zweites Molekül 2 addieren unter [4 + 1]-Cycloaddition zu Bis(imino)cyclopenten- 6 bzw. unter weiterem Ringschluß zu 3-Imidazolin-Komplexen 4/5 durch metallinduzierte Insertion von 2 in eine α-CH2N-Bindung von 3. Die Komplexe 4-6 wurden spektroskopisch, der 3-Imidazolin-Komplex 4a zusätzlich durch eine Kristallstrukturanalyse charakterisiert. Neben einer Addition von 2c an 3c wird eine Isomerisierung von 3c zum α-Alkoxycyanid-Komplex 9a unter N/C-Wanderung des N-Allylrests beobachtet. Sterische Faktoren beeinflussen entscheidend das Zusammenspiel sämtlicher Konkurrenzreaktionen.
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    URL: http://dx.doi.org/10.1002/cber.19871200804
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    Arsen als Funktionszentrum und Substituent von Yliden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1281-1285 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arsenic as a Functional Center and as a Substituent in YlidesBis(dimethylarsino)-, bis(diethylarsino)-, and bis(diphenylarsino)-methane (1-3) are obtained from Cl2AsCH2AsCl2 and the corresponding Grignard reagents. Through the reaction with MeI or EtI, respectively, 1 and 2 give mono- and bis-quarternary salts 4-7. The former (4, 6) when treated with NaNH2 in liquid ammonia, yield the ylides R3As=CH-AsR2 (R=Me: 8; R=Et: 9), while the latter (5, 7) could not be converted into double-ylides R3As=C=AsR3. 3 affords the ylide MePh2As=CH-AsPh2 (11) via the arsonium salt 10. Treatment of 11 with Ph2AsCl gives MePh2As=C(AsPh2)2 (13) as the product of a transylidation reaction. With MeI only C-alkylation of 11 takes place (to give 14). - Ph2PCH2AsPh2 is the starting material for the synthesis of the (arsinomethyl)phosphonium salt 17 and the ylide MePh2-P=CH-AsPh2 (15). This ylide is also exclusively C-alkylated by MeI (to give 16). Methylation of Ph2PCH2AsPh2 by MeOSO2F yields the diquaternary salt 18, which on reaction with NaNH2/NH3 (liq.) affords the first mixed P/As double-ylide MePh2-P=C=AsPh2Me (19). The ylide Ph3P=C(AsPh2)2)2 (20) is converted into semi-ylidic quaternary salts [Ph3PC(AsPh2)-AsPh2Me]I (21) and [Ph3PC(AsPh2Me)2]I2 (22) by MeI, which are analogues of the tris(phosphonio)methanide salts [(R3P)3C]X2.
    Notes: Bis(dimethylarsino)-, Bis(diethylarsino)- und Bis(diphenylarsino)-methan (1-3) wurden aus Cl2AsCH2AsCl2 und den entsprechenden Grignard-Reagenzien dargestellt. 1 und 2 ergeben mit MeI bzw. EtI die Mono- und Bisquartärsalze 4-7. Aus ersteren (4, 6) entstehen bei Einwirkung von NaNH2 die Arsen-Ylide R3As=CH-AsR2 (R=Me: 8, R=Et: 9). Die Isolierung von Doppel-yliden R3As=C=AsR3 aus 5 und 7 gelang dagegen nicht. Aus 3 ist über das Monoquartärsalz 10 analog das Ylid MePh2-As=CH -AsPh2 (11) zugänglich, aus dem mit Ph2AsCl unter Umylidierung das erste Arsonium-bis(arsino)methylid, MePh2-As=C(AsPh2)2 (13), hervorgeht. 11 wird von MeI am ylidischen C-Atom methyliert (zu 14). - Von Ph2PCH2AsPh2 aus gelangt man mit MeI zum (Arsinomethyl)phosphoniumsalz 17, das mit NaNH2 das Ylid MePh2P=CH - AsPh2 (15) liefert. Auch dieses Ylid wird von MeI nur C-alkyliert (zu 16). Die Quartärisierung von Ph2PCH2AsPh2 mit MeOSO2F führt zum Diquartärsalz 18, aus dem das erste gemischte P/As-Doppel-ylid, MePh2-P=C=AsPh2Me (19), entsteht. Das Ylid Ph3P=C(AsPh2)2 (20) kann mit MeI in die Semi-ylid-Quartärsalze [Ph3PC(AsPh2)-AsPh2Me]I (21) und [Ph3PC(AsPh2Me)2]I2 (22) übergeführt werden, die den Tris(phosphonio)methanid-Salzen [(R3P)3C]X2 entsprechen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200803
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    Organische Synthesen mit Übergangsmetallkomplexen, 251) Cyanoallylierung von Carbenliganden mit Allylisocyaniden durch metallinduzierte N/C-Allylumlagerung intermediärer 3-Aza-1,2,5-hexatrien-Komplexe (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1293-1296 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Syntheses via Transition Metal Complexes, 251). - Cyanoallylation of Carbene Ligands with Ally Isocyanides via Metal-Induced N/C-Allylic Rearrangement of intermediate 3-Aza-1,2,5-hexatriene ComplexesAllyl isocyanides 2 react with (CO)5M=C(OEt)C6H5 (1, M=Cr, W) to give N-allylketenimine/(3-aza-1,2,5-hexatriene) complexes 3 in high yields. In absence of suitable reactants compounds 3 isomerise spontaneously and smoothly already at 0°C via a metalinduced N/C-migration of the allyl group to give 4-pentenenitrile complexes 5, from which the ligand can be disengaged by substitution with pyridine. The regiochemistry of the rearrangement corresponds to the [3,3] type as has been proven by a labeling experiment with α,α-dideuterioallyl isocyanide. In the presence of an alcohol, the reaction of 1 with 2 leads to the formation of competition products resulting from an N/C-rearrangement or the addition of the alcohol to 3, respectively. The competition ratio strongly depends on the type of metal used. The tungsten complex 3b, e.g., at 0°C adds one equivalent of an alcohol to give up to 97% yields of (allylamino)carbene complexes 8b-c, while the corresponding chromium complex 3a rearranges smoothly under these conditions to give 5a only. The addition of alcohols to 3b is reversible: on thermolysis of 8c at 70°C the products of thermal isomerisation of 3b together with a chelate complex 9 are obtained.
    Notes: Durch Addition von Allylisocyaniden 2 an (CO)5M=C(OEt)C6H5 (1, M=Cr, W) erhält man in hohen Ausbeuten N-Allylketenimin-/(3-Aza-1,2,5-hexatrien)-Komplexe 3. Diese isomerisieren in Abwesenheit geeigneter Reaktionspartner spontan und glatt schon bei 0°C unter metallinduzierter N/C-Wanderung des Allylrestes zu 4-Pentennitril-Komplexen 5. Anhand von Markierungsexperimenten mit α,α-Dideuterioallylisocyanid wurde hierfür die Regiochemie einer [3,3]-Umlagerung nachgewiesen. Aus 5 kann der Ligand durch Verdrängung mit Pyridin freigesetzt werden. Bei der Umsetzung von 1 mit 2 in Gegenwart von Alkoholen beobachtet man in Konkurrenz zur N/C-Umlagerung eine Addition des Alkohols an 3. Abhängig vom Metall ergeben sich dabei erhebliche Reaktivitätsunterschiede: der Wolframkomplex 3b z. B. addiert bei 0°C rasch ein äquivalent des Alkohols unter (fast) ausschließlicher Bildung von (Allylamino)carben-Komplexen 8b, c, wohingegen der entsprechende Chromkomplex 3a unter gleichen Reaktionsbedingungen glatt zu 5a isomerisiert. Die Addition von Alkoholen an 3b ist reversibel: bei der Thermolyse (70°C) von 8c erhält man neben einem Chelatkomplex 9 das thermische Isomerisierungsprodukt von 3b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200805
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    Trimethylsilylcyanid als Umpolungsreagens, XV Intramolekulare Diels-Alder-Reaktion mit Vinylfuranen über die Umpolung von 3-(2-Furyl)acrolein (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 325-329 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: With 3-(2-furyl)acrolein (17) as an example it is demonstrated that umpolung of aldehydes with trimethylsilyl cyanide allows the synthesis of diene-dienophiles (19, 21) for intramolecular Diels-Alder reactions introducing the required protecting group at the same time. In this novel model reaction thermal [4 + 2] cycloaddition finally affords so far unknown tricyclic ketones with one furan ring (25 and 26). This reaction sequence should be useful in natural product synthesis.
    Notes: Am Beispiel von 3-(2-Furyl)acrolein (17) wird gezeigt, daß die Umpolung von Aldehyden mit Trimethylsilylcyanid eine Synthese von Dien-Dienophilen (19, 21) für die intramolekulare Diels-Al-der-Reaktion erlaubt, bei der zugleich die erforderliche Carbonylschutzgruppe eingeführt wird. Thermische [4 + 2]-Cycloaddition erzeugt in dieser neuen Modellreaktion schließlich bisher unbekannte tricyclische Ketone mit einem Furanring (25 und 26). Die Reaktionsfolge dürfte für Naturstoffsynthesen einsetzbar sein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200312
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    Diagnostic OH 1H-NMR shift differences in syn and anti ß-Hydroxy Ethers (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 331-333 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die relative chemische Verschiebung des OH-Protonen-Signals in den 1H-NMR-Spektren eines Paares diastereomerer ß-Hydroxyether erlaubt eine syn/anti-Zuordnung der relativen Konfiguration. Dies basiert vermutlich auf der Bildung von Strukturen mit intramolekularer Wasserstoff-Brücke. Insofern ist diese Regel auf solche ß-Hydroxyether beschränkt, bei denen nur dieser Typ von intramolekularer H-Brücke ausgebildet werden kann.
    Notes: In a pair of diastereomeric ß-hydroxy ethers the relative 1H-NMR chemical shift of the OH proton is diagnostic for the syn or anti stereostructure. This is probably based on the presence of internally hydrogen-bonded structures. The rule is therefore restricted to those compounds for which only this type of internal hydrogen bonding is accessible.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200313
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    Photoreactions of biacetyl with electron-rich olefins. An extended mechanism (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 307-318 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Photoreaktionen von Biacetyl (1) mit verschiedenen elektronenreichen Olefinen wurden untersucht. Im allgemeinen bilden sich bei der Bestrahlung mit λ=400-480 nm (nπ*-Anregung von Biacetyl) in Abhängigkeit von der Olefin-Struktur Oxetane und Allylalkohole. Hinweise auf die primäre Bildung eines Exciplexes liefert die ungewöhnliche Abhängigkeit der Geschwindigketiskonstanten der Lumineszenzlöschung von Biacetyl durch die Olefine (log kq) von der freien Bildungsenthalpie des Elektronentransfers (ΔG2). Ein Mechanismus mit einer Exciplex-Zwischenstufe und einem ionischen Photodissoziationsweg gestattet es nach Anpassung der Parameter, die experimentellen Daten gut zu simulieren (log kq/ΔG2-Korrelation). Vollständiger Elektronentransfer wurde als Folgeprozeß bei einigen besonders elektronenreichen Olefinen mit Hilfe der ESR-Spektroskopie bzw. durch Abfangen der Radikalkationen bewiesen. Die Abhängigkeit der Produktquantenausbeuten von der Lösungsmittelpolarität bestätigt die Konkurrenz zwischen Produktbildung und ionischer Photodissoziation. Die bevorzugte Bildung von Allylalkoholen (Reduktionsprodukte) mit starken Donor-Olefinen und die regioselektiv ablaufende Oxetanbildung mit Ketenacetal werden auf der Basis von stark polaren Exciplexen bzw. Kontaktionenpaaren und Zwitterionen als Zwischenstufen diskutiert.
    Notes: The photoreactions of biacetyl (1) with various electron-rich olefins have been investigated. Oxetanes and allyl alcohols are formed upon irradiation with λ=400-480 nm (nπ* excitation of biacetyl) depending on the nature of the olefin. An unusual relationship between the rate constants of luminescence quenching of biacetyl by olefins (log kq) and the free enthalpies of electron transfer (ΔG2) indicate formation of an exciplex first. A reasonable good fit between experimental results of log kq and ΔG2 has been obtained on the basis of a mechanistic model which includes the exciplex intermediate as well as an ionic photodissociation pathway and some empirical adjustment of the parameters. Complete electron transfer as a consecutive process has been proven for some strong electron-donating olefins by means of ESR spectroscopy and scavenging of the radical cations. The solvent dependence of the product quantum yields further confirms the competition between ionic photodissociation and product formation. The preferred formation of allyl alcohols (reduction products) with strong electron-donating olefins and the highly regioselective oxetane formation with ketene acetal are discussed in terms of exciplexes of strong CT character or even contact ion pairs and dipolar intermediates.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200310
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    Das Hydrolyseverhalten zwei- und dreifach mesylierter Hydroxylamine und ihrer Derivate (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 351-354 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mesylhydroxylamines (CH3SO2)2NOH, (CH3SO2)2NOCH3, CH3SO2N(H)OSO2CH3, CH3SO2N(CH3)OSO2CH3 (1-4) and (CH3SO2)2NOSO2CH3 (5) were treated with basic, neutral, and acidic aqueous solutions. The reaction products were identified. Possible decomposition mechanisms were discussed.
    Notes: Die Mesylhydroxylamine (CH3SO2)2NOH, (CH3SO2)2NOCH3, CH3SO2N(H)OSO2CH3, CH3SO2N(CH3)OSO2CH3 (1-4) und (CH3SO2)2NOSO2CH3 (5) wurden in alkalischer, neutraler und saurer Lösung hydrolysiert. Die Zersetzungsprodukte wurden identifiziert und mögliche Reaktionswege ihrer Entstehung diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200317
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    Alkyl Shifts in 1,4-Dipoles from Tosyl Iso(thio)cyanate and Imido(thio)carbonates or Isoureas (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 339-344 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Dipole 3, 13 aus Tosylisocyanat (2a) und Imido(thio)kohlensäureestern 1 (12) geben O → N-Alkyl-Verschiebungen zu (Thio)Allophansäureestern 5 (14). ähnlich führt die Addition von Tosylisothiocyanat (2b) an den Isoharnstoff 24a zum Produkt 28 einer O→S-Methyl-Verschiebung. Ausgehend von 2a und den Imidothiokohlensäureestern 12b,c ergab ein Kreuzungsversuch die vier Produkte 14a-d und bewies so den intermolekularen Verlauf der Umlagerung. Beim Zusammengeben des Isothiocyanats 2b und der Imido(thio)kohlensäureester 1 (12) oder von 2a und der Isoharnstoffe 24a,b bleibt die Reaktion jedoch auf der Stufe der Dipole 8, 19, 25a, b stehen.
    Notes: O→N alkyl shifts are observed in the dipoles 3, 13 from tosyl isocyanate (2a) and imido(thio)carbonates 1 (12) to give (thio)allophanates 5 (14). Similarly, addition of tosyl isothiocyanate (2b) to isourea 24a leads to the product 28 of an O → S methyl shift. A cross-over experiment involving 2a and imidothiocarbonates 12b,c gives the four products 14a-d proving the intermolecular nature of the rearrangement. However, on mixing 2a and isoureas 24a,b or 2b and imido(thio)carbonates 1 (12), the reaction stops at the stage of dipoles 8, 19, 25a,b.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200315
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    PMO Analysis of Cycloadditions, I Diels-Alder Reactions of 2,3-Bis(methylene)norbornane (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1323-1330 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: PMO-Analyse von Cycloadditionen, I. - Diels-Adler-Reaktionen von 2,3-Bis(methylen)norbornanEine störungstheoretische Methode (PMO) zur Berechnung der Wechselwirkung von Molekülen auf der Basis des semiempirischen MINDO/3-Verfahrens wird auf die Cycloadditionen von 2,3-Bis(methylen)norbornan (1) mit den elektronenarmen Olefinen 2-5 angewendet. Verschiedene Anteile der Wechselwirkungsenergie, von sterischen Effekten, polaren Beiträgen und Orbitalwechselwirkungen stammend, werden analysiert. Die Ergebnisse werden mit dem Programmpaket PERVAL, das für einen IBM AT Personal Computer entwickelt wurde, berechnet und graphisch ausgewertet. Die Reaktivitätssequenz 2 〈 3 〈 4 〈 5 wird auf die dominante HOMODien-LUMODienophil-Wechselwirkung zurückgeführt. Es werden verschiedene Möglichkeiten der Anwendung des Programms PERVAL aufgezeigt.
    Notes: A perturbational molecular orbital (PMO) treatment within the semiempirical MINDO/3 approximation is applied to the cycloadditions of 2,3-bis(methylene)norbornane (1) to electron-deficient olefins (2-5). Different contributions to the interaction energy deriving from steric effects, polar effects, and orbital interactions are analysed. The results, obtained by the program package PERVAL, which is developed for an IBM AT personal computer, are evaluated graphically. The origin of the reactivity sequence 2 〈 3 〈 4 〈 5 is traced back to the HOMOdiene-LUMOdienophile interaction. Various possibilities to interpret the results of PMO calculations are demonstrated.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200810
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    Diels-Alder-Reaktionen mit 2H-Pyran-2-onen: Reaktivität und Selektivität (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1339-1346 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diels-Alder Reactions with 2H-Pyran-2-ones: Reactivity and Selectivity2H-Pyran-2-ones 1 react with maleic anhydride (2) in a double Diels-Alder reaction to give bicyclo[2.2.2]oct-2-ene-5,6:7,8-tetracarboxylic dianhydrides 5; the syn/syn structure was established. As expected, the reactivity of 1 was increased by electron donor substituents (OR, alkyl) and diminished by electron withdrawing substituents (CO2R). The steric influence of substituents at C-6 also decrease the reactivity of 1. - Methyl propiolate (6) and phenylacetylene (9) react with 1 to form the Diels-Alder products 7 which suffer CO2 elimination to yield methyl benzoates 8 with low and biphenyls 10 with high regioselectivity, respectively.
    Notes: 2H-Pyran-2-one 1 gehen mit Maleinsäureanhydrid (2) eine zweifache Diels-Alder-Reaktion zu Bicyclo[2.2.2]oct-2-en-5,6:7,8-tetracarbonsäure-dianhydriden 5 ein, deren syn/syn-Struktur nachgewiesen wurde. Die Reaktivität von 1 wird erwartungsgemäß durch Donor-Substituenten (OR, Alkyl) erhöht und durch Acceptor-Substituenten (CO2R) verringert; Substituenten in 6-Stellung der α-Pyrone 1 führen infolge ihres sterischen Einflusses zu einer deutlichen Reaktivitätsverminderung. - Aus 1 und Propiolsäuremethylester (6) bzw. Phenylaceylen (9) entstehen über die primären Diels-Alder-Cycloadditionsprodukte 7 unter CO2-Abspaltung isomere Benzoesäure-methylester 8 mit geringer bzw. Biphenyle 10 mit hoher Regioselektivität.
    Additional Material: 11 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200812
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    Darstellung hochsubstituierter Aromaten über Diels-Alder-Reaktionen mit 2H-Pyran-2-onen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1347-1355 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Highly Substitued Benzenes via Diels-Alder Reactions with 2H-Pyran-2-onesThe 2H-pyran-2-ones (α-pyrones) 1 react as dienes in Diels-Alder reactions with acetylene derivatives. The primarely formed cycloadducts immediately aromatize to benzenes by CO2 elimination. Thus, methyl acetylenedicarboxylate (2a) gives dimethylphthalates 3, and methyl acetylenediphosphonate (2b) gives dimethyl 1,2-phenylenediphosphonates 8. The reactions of 1-(dimethylamino)-1-methoxyethene (9) with 1 regioselectively produce N,N-dimethylanilines 10 and isomeric homophthalate derivatives 12. Naphthoquinones 14 could be generated from 1,4-benzoquinone (13) and 1 in the presence of acetic anhydride and Pd/C. Hydroxy-2H-pyran-2-ones 4 react via their trimethylsilyl ether 6 analogously with 2a to give dimethyl (trimethylsiloxy)-phthalates 7 which are easily converted to phenols 5 by acidcatalyzed hydrolysis.
    Notes: Acetylenderivate reagieren mit 2H-Pyran-2-onen (α-Pyronen) 1 als Dien-Komponenten primär zu Diels-Alder-Cycloadditionsprodukten, die sofort unter CO2-Abspaltung zu Benzolderivaten aromatisieren. So werden mit Acetylendicarbonsäure-dimethylester (2a) Phthalsäure-dimethylester 3 und mit Acetylenbis(phosphonsäure-dimethylester) (2b) 1,2-Phenylenbis(phosphonsäure-dimethylester) 8 erhalten. 1-(Dimethylamino)-1-methoxyethen (9) sowie 2,3-Pentadiendisäure-dimethylester (11) bilden mit 1 regioselektiv N,N-Dimethylaniline 10 sowie isomere Homophthalsäure-Derivate 12. Aus 1,4-Benzochinon (13) und 1 entstehen in Gegenwart von Acetanhydrid und Pd/C Naphthochinone 14. Hydroxy-2H-pyran-2-one 4 lassen sich über ihre Trimethylsilylether 6 mit 2a zu den (Trimethylsiloxy)phthalsäure-dimethylestern 7 umsetzen, deren säurekatalysierte Hydrolyse glatt zu den Phenolen 5 führt.
    Additional Material: 13 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200813
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    Blitzvakuumpyrolyse von o-Alkylaryl- und Arylalkylchlorboranen Synthese benzoanellierter Boracycloalkene (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1331-1338 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Flash Vacuum Pyrolysis Of o-Alkyaryl- and Arylalkylchloroboranes. - Synthesis of Benzoannutated Boracycloalkenes The dichloroorganylboranes chosen as pyrolytic starting materials were synthesized upon treatment of the corresponding triorganylboroxines and aryltrimethylsilanes (giving 3, 4) or the tetraorganylstannanes (giving 9-12, 17-20) with boron trichloride. At 700°C the flash vacuum pyrolysis of the dichloro(2-ethylphenyl)boranes 10 and 4 led to 1-boraindanes 21 and 22 selectively. The dichloro-2-tolylborane (9), the B-dimethylamino derivative, and mesitylboranes like 3 were completely stable upon pyrolysis. Pyrolyzing the isopropylphenylborane 12 1,5-elimination exclusively took place yielding 26, while pyrolysis of propylphenylborane 11 led to a mixture of boraindane 29 and boratetraline 30. To exclude such competitive reactions, some arylalkyldichloroboranes were pyrolyzed. At 750°C dichloro(2-methylbenzyl)borane (18) exclusively yielded oligomeric 2-chloro-2-boraindane (31). At 950°C even the pyrolysis of benzyldichloroborane (17) succeeded in a 1,4-elimination reaction yielding the eight-membered 2H-benzoborete dimer 34. The inversion barrier of 34 is ΔG228=10.3 kcal mol-1, determined by NMR spectroscopy. The pyrolysis of the next-higher homologous dichloroorganylborane 19 yielded a boraindane 21 and a noncyclic diorganylborane 38 by a dehydroboration/hydroboration pathway. Both reaction types also took place when pyrolyzing dichloro[2-(2-tolyl)ethyl]borane (20): cyclization under formation of a five-membered ring system 39, formed upon attack of an aromatic C-H bond exclusively, and formation of an open-chain chlorodiorganylborane 40.
    Notes: Die als Pyrolyse-Edukte eingesetzten Dichlororganylborane wurden durch Umsetzung der entsprechenden Triorganylboroxine und Aryltrimethylsilane (zu 3, 4) oder der Tetraorganylstannane (zu 9-12, 17-20) mit Bortrichlorid gewonnen. Die Blitzvakuumpyrolyse der Dichlor(2-ethylphenyl)borane 10 und 4 führte bei 700°C selektiv zu den 1-Boraindanen 21 und 22. Das Dichlor-2-tolylboran (9) war thermisch ebenso stabil wie das B-Dimethylamino-Derivat und Mesitylborane wie 3. Auch bei der Pyrolyse des Isopropylphenylborans 12 trat ausschließlich 1,5-Eliminierung unter Bildung von 26 ein, während die Pyrolyse des Propylphenylborans 11 zu einem Gemisch aus Boraindan 29 und Boratetralin 30 führte. Um derartige intramolekulare Konkurrenzsituationen auszuschließen, wurden Arylalkyldichlorborane pyrolysiert. Dichlor(2-methylbenzyl)boran (18) lieferte bei 750°C ausschließlich oligomeres 2-Chlor-2-boraindan (31). Bei 950°C reagierte sogar Benzyldichlorboran (17) unter 1,4-Eliminierung zu dem achtgliedrigen 2H-Benzoboret-Dimeren 34. Die Inversionsbarriere von 34 wurde NMR-spektroskopisch zu ΔG228=10.3 kcal mol-1 bestimmt. Die Pyrolyse des nächsthöheren homologen Dichlororganylborans 19 lieferte ein Boraindan (21) und ein nichtcyclisches Diorganylboran 38 über eine Dehydroborierungs-/Hydroborierungsreaktion. Beide Reaktionstypen wurden auch bei der Pyrolyse von Dichlor[2-(2-tolyl)ethyl]boran (20) beobachtet: Cyclisierung ausschließlich unter Fünfringbildung (39) durch Angriff einer aromatischen C-H-Bindung und Bildung eines offenkettigen Chlordiorganylborans (40).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200811
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    Reaktivität von Silan- und Germaniminen Me2E=NR (E=Si, Ge)1) (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1357-1368 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Adduct Formation and Reactivity Of Silane- and Germaneimines Me2E=NR (E=Si, Ge)1)Silane- and Germaneimines Me2E= NR (E=Si, Ge; R=silyl), generated as reactive intermediates by thermal [2+3] cycloreversion from [2+3] cycloadducts of Me2E=C(SiMe3)2 or Me2E=NR with silyl azides RN3, combine with reactants a (e. g. NEtMe2) under addition (formation of adducts 7), with a - b [e. g. RO - H, RHN - H, X - SiMe3 (X=Cl, N3, MeO, Me2N), Cl - GeMe3, Cl - SnMe3] under insertion into the a - b bond (formation 13-16), with a=b (e.g. RN=EMe2, O=CPh2) under [2+2] cycloaddition (e. g. formation of 17, 18), with a=b=c (e.g. R′N=N=N) under [2+3] cycloaddition (formation of 19, 20), and with a=b - c - H (e.g. CH2=CR - CH2 - H, O=CMe - CH2 - H) under ene reaction (formation of 21-24). [2+4] cycloaddition of Me2Si=NR with organic 1,3-dienes (e. g. CH2=CR - CR=CH2, cyclopentadiene) is not observed. By comparison with ethenes Me2E=C(SiMe3)2, imines Me2E=NR have greater tendency for insertion and lesser tendency for cycloaddition; by comparison with silaneimines Me2Si=NR, germaneimines Me2Ge=NR are possibly less Lewis acidic.
    Notes: Silan- und Germanimine Me2E=NR (E=Si, Ge; R=Silyl), erzeugt als Zwischenstufen durch thermische [2+3]-Cycloreversion aus den [2+3]-Cycloaddukten von Me2E=C(SiMe3)2 bzw. Me2E=NR mit Silylaziden RN3, reagieren mit Reaktanden a (z. B. NEtMe2) unter Addition (Bildung von Addukten 7), mit a-b [z. B. RO - H, RHN - H, X - SiMe3 (X=Cl, N3, MeO, Me2N), Cl - GeMe3] unter Insertion in die a - b-Bindung (Bildung von 13-16), mit a=b (z. B. RN=EMe2, O=Cph2) unter [2+2]-Cycloaddition (z. B. Bildung von 17, 18), mit a=b=c (z. B. R′N=N=N) unter [2+3]-Cycloaddition (Bildung von 19, 20) und mit a=b - c - H (z. B. CH2=CR - CH2 - H, O=CMe - CH2 - H) unter En-Reaktion (Bildung von 21-24). [2+4]-Cycloaddition von Me2Si=NR mit organischen 1,3-Dienen (z. B. CH2=CR - CR=CH2, Cyclopentadien) wird nicht beobachtet. Verglichen mit den Ethenen Me2E=C(SiMe3)2 zeigen die Imine Me2E=NSiMe3 eine größere Tendenz zur Insertion und kleinere Tendenz zur Cycloaddition; verglichen mit den Silaniminen Me2Si=NR sind die Germanimine Me2Ge=NR wohl weniger Lewis-sauer
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200814
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    Reaktionen mit Diazoazolen, VIII1) Synthesen von Azolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-onen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1375-1395 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Diazoazoles, VIII1). - Syntheses of Azolo [5,1-d]-1,2,3,5,-tetrazin-4(3H-onesAzolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-ones 4 and 5 are formed by cycloaddition reactions of α-diazoazoles 2 with aryl or alkyl isocyanates 3a-p, respectively, as well as with diisocyanates 3q, r (Method A). Alternative syntheses for 4 are presented by diazotization of N-alkyl(aryl)-5-amino-1H-pyrazole-1-carboxamides (6) and subsequent intramolecular coupling (Method B), by coupling of 3-diazo-5-methyl-4-phenyl-3H-pyrazole (2A) with primary amines 11 to give pyrazolyltriazenes 12A, and by their carbonylation reaction (Method C). The lability of azolotetrazinones against bases is exemplified with-methyl-3,8-diphenylpyrazolo-[5,1-d]-1,2,3,5-tetrazine-4(3H)-one (4Aa) in its reaction with hydroxide ions or morpholine.
    Notes: Azolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one 4 und 5 entstehen durch Cycloaddition von α-Diazoazolen 2 an Aryl- oder Alkylisocyanate 3a-p bzw. an Diisocyanate 3q, r (Methode A). Alternativsynthesen für 4 werden durch Diazotierung von N-Alkyl(Aryl)-5-amino-1H-pyrazol-1-carboxamiden 6 und nachfolgende intramolekulare Kupplung (Methode B) sowie durch Kupplung von 3-Diazo-5-methyl-4-phenyl-3H-pyrazol (2A) mit primären Aminen 11 zu Pyrazolyltriazenen 12A und deren Carbonylierung (Methode C) vorgestellt. Die Basenlabilität der Azolotetrazinone wird am Beispiel des 7-Methyl-3,8-diphenylpyrazolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-ons (4Aa) in dessen Reaktion mit Hydroxidionen oder Morpholin aufgezeigt.
    Additional Material: 9 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200816
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    NMR-spektroskopische Untersuchungen zur Konstitution von Benzyl- und 1-Napthylmethyl-Verbindungen des Titaniums, Zirconiums und Hafniums (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1369-1374 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Investigations on the Constitution of Benzyl and 1- Naphthylmethyl Compounds of Titanium, Zirconium, and Hafnium1H- und 13H- spectra of tetrabenzyl compounds (C6H5CH2)4M (M=Ti, Zr, Hf; 1 - 3) and analogous 1-naphtylmethyl derivatives (1-C10H7CH2)4M (M=Ti, Zr, Hf; 4-6) do not show noticable changes in their bonding properties which were postulated on the basis of X-ray structure analyses of 1-3. On exchanging benzyl groups in 1 and 2 against halogen atoms leading to the compounds (C6H5CH2)4 - nMHaln (M=Ti, Zr, Hf; Hal=Cl, Br, I; n=1 - 3; 7-21) the δCH2 values indicate sensitively the alternation of electron density at the metal atoms. In contrast, no alternation of the benzyl group-metal bonds is indicated by the chemical shifts of the phenyl group C and H atoms, but it becomes evident when benzyl groups are substituted by Cp. Whilst in 1 - 3 a η4-coordination of the benzyl groups can be assumed, these groups are η1-bonded in Cp2Ti(CH2C6H5)2 (23) and Cp2Zr(CH2C6H5)2 (25). Furthermore, an alternation of the coordination systems could be proved in case of 3 and 6 in the presence of donor molecules (THF, pyridine).
    Notes: Die 1H- und 13C-NMR-Spektren (T 298 K, C6D6) der Tetrabenzylverbindungen (C6H5CH2)4M (M=Ti, Zr, Hf; 1-3) und der benzylanalogen 1-Napthylmethyl-Derivate (1-C10H7CH2)4M (M=Ti, Zr, Hf; 4-6) lassen keine besonderen Bindungsverhältnisse erkennen, die aufgrund von Röntgenstrukturuntersuchungen bei 1-3 vermutet wurden. Bei einem Austausch von Benzylgruppen in 1 und 2 gegen Halogenatome, d.h. in Verbindungen des Typs (C6H5CH2)4 - nMHaln (M=Ti, Zr, Hal=Cl, Br, I; n=1 - 3; 7-21), zeigt δCH2 empfindlich die veränderte Elektronendichte an den Metallatomen an. Demgegenüber werden aus den chemischen Verschiebungen der Phenyl-C- und -H-Atome keine Veränderungen der Art der Benzyl-Metall-Bindung sichtbar. Diese zeigen sich jedoch beim schrittweisen Austausch von Benzylgruppen gegen Cp-Reste. Während in 1-3 eine η4- Koordination der Benzylreste anzunehmen ist, liegen in Cp2Ti(CH2C6H5)2 (23) und Cp2Zr(CH2C6H5)2 (25) η1-gebundene Benzylgruppen vor. - In Gegenwart von Donorliganden (THF, Pyridin) wird für 3 und 613C-NMR-spektroskopisch ebenfalls eine Änderung der Bindungsart der Organylreste an das Zentralatom nachgewiesen.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200815
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    Diazoverbindungen, 691) 2-(oder 4-)(Diazomethyl)-2-(oder 4-)H-benzopyrane - Synthese durch elektrophile Diazoalkansubstitution und katalytische Zersetzung (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1397-1402 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diazo Compounds, 691) - 2-(or 4-)(Diazomethyl)-2-(or 4-)H-benzopyrans - Synthesis by Electrophilic Diazoalkane Substitution and Catalytic DecompositionElectrophilic diazoalkane substitution of the (diazomethyl)phosphoryl compounds 9a-c with the benzopyrylium tetrafluoroborate 8 yields the 2-[diazo(phosphoryl)methyl]-2H-1-benzopyrans 10a-c and the 4-isomers 11a-c. Lithiated methyl diazoacetate reacts analogously with 8 under formation of 10d and 11d. At the μ-allylpalladium chloride catalyzed decomposition of 10a-d the benzoxepines 14a-d are formed by ring enlargement reaction; 1,2-H shift is responsible for the additional formation of the 2-methylene-2H shift is responsible for the additional formation of the 2-methylene-2H-benzopyrans 15b and c in the case of 10b and c. The catalytic decomposition of 11a-d proceeds exclusively in the sense of an intramolecular [2 + 1] cycloaddition to afford the 3,4-dihydro-2,3,4-metheno-2H-benzopyrans 18a-d. The benzoxepines 14a,d are characterized by photochemical electrocyclic reaction to 19a and b.
    Notes: Elektrophile Diazoalkansubstitution der (Diazomethyl)phosphoryl-Verbindungen 9a-c mit dem Benzopyrylium-tetrafluoroborat 8 liefert die 2-[Diazo(phosphoryl)methyl]-2H-1-benzopyrane 10a-c und die 4-Isomeren 11a-c. Lithiierter Diazoessigsäuremethylester reagiert analog mit 8 unter Bildung von 10d und 11d. Bei der μ-Allylpalladium-chlorid-katalysierten Zersetzung von 10a-d entstehen die Benzoxepine 14a-d durch Ringerweiterungsreaktion; 1,2-H-Verschiebung ist für die zusätzliche Bildung der 2-Methylen-2H-benzopyrane 15b und c im Fall von 10b und c verantwortlich. Die katalytische Zersetzung von 11a-d verläft ausschließlich im Sinne einer intramolekularen [2 + 1]-Cycloaddition zu den 3,4-Dihydro-2,3,4-metheno-2H-benzopyranen 18a-d. Die Benzoxepine 14a,d sind durch photochemische, elektrocyclische Reaktion zu 19a und b charakterisiert.
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    URL: http://dx.doi.org/10.1002/cber.19871200817
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    Übergangsmetall-substituierte Diphosphene, IX1) Synthese und Struktur von metallierten 1,3-Diphospha-2-propanonen. - Carbonylierung von Diphosphenyl-Komplexen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1421-1426 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal-Substituted Diphosphenes, IX1). - Synthesis and Structure of Metalated 1,3-Diphospha-2-propanones. - Carbonylation of Diphosphenyl ComplexesThe diphosphenyl complexes (η5-C5Me5)(CO)2M-P=P-Ar (3) (M=Fe, Ru, Os; Ar=2,4,6-t-Bu3C6H2) react with Fe2(CO)9 to yield adducts such as (η5-C5Me5)(CO)2M[Fe(CO)4]P=P-Ar(4) as well as the 1,3-diphospha-2-propanone complexes [(η5-C5Me5)-(CO)2M-P(CO)PAr]Fe2(CO)6 (5) by catalytic carbonylation of the activated P=P double bond. The structures of 4a and 5a are established by X-ray diffraction studies.
    Notes: Die Diphosphenyl-Komplexe (η5-C5Me5)(CO)2M-P=P-Ar (3) (M=Fe, Ru, Os; Ar=2,4,6-t-Bu3C6H2) reagieren mit Fe2(CO)9 zu Addukten des Typs (η5-C5Me5)(CO)2M[Fe(CO)4]P=P-Ar(4) und den 1,3-Diphospha-2-propanon-Komplexen [(η5-C5Me5)-(CO)2M-P(CO)PAr]Fe2(CO)6 (5). Offensichtlich entsteht 5 aus 3 durch katalytische Carbonylierung der aktivierten P=P-Funktion. Von 4a und 5a wurden Röntgenstrukturanalysen durchgeführt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200820
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    Synthese, Struktur und einige Reaktionen von Tris- und Tetrakis(diphenylphosphino)allen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1403-1412 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Structure, and Some Reactions of Tris- and Tetrakis(diphenylphosphino)allenesTreatment of the reagent 2, obtained from 1-(diphenylphosphino)-1-propyne (1) and n-BuLi, with Ph2PCl gives high yields of tetrakis(diphenylphosphino)allene (3). On oxidation with H2O2 or Me3SiOOSiMe3, this compound yields the tetraoxide 4a, while with sulfur or selenium the tetrachalcogenides 4b,c are obtained. The allene group is not affected in these processes. In the reaction of 3 with MeLi P - C cleavage occurs to give Ph2PMe and 1,3,3-tris(diphenylphosphino)allenyllithium (5), which is converted into tris(diphenylphosphino)allene (Ph2P)2C=C=CHPPh2 (6) upon hydrolysis. Quaternization with MeI under mild conditions leads to the monoquaternary salts 7 and 8 from 3 and 6, respectively. With excess MeI at higher temperature a phosphonioalkynyl-semiylide salt [(MePh2P)2C-C≡C-PPh2Me]2+ 2 I- (9) is formed from both 3 and 6. The by-product of the P-C cleavage in 3 by MeI is Ph2PMe2+ I-3. - The structures of the allenes 3 and 6 and of the salt 9 have been confirmed by single crystal X-ray diffraction. The Ph2P groups in 3 adopt a similar conformation as found previously for (Ph2P)2C=CH2, with an opposite orientation of the lone pairs of electrons at phosphorus relative to the allene axis. In 6 a rotamer with an approximately symmetrical (“anti”) orientation of the geminal Ph2P groups is present. 9 is found to be another example of semiylidic quaternary salts with a delocalized ylide function.
    Notes: Das aus 1-(Diphenylphosphino)-1-propin (1) mit n-BuLi erhältliche Reagens Ph2P-C≡C-CH2Li(2) ergibt bei der Behandlung mit Ph2PCl hohe Ausbeuten an Tetrakis(diphenylphosphino)allen (3). Diese Verbindung liefert nach Oxidation mit H2O2 oder Me3SiOOSiMe3 das Tetraoxid 4a, mit Schwefel oder Selen die entsprechenden Tetrachalkogenide 4b,c. Die Allengruppierung wird dabei nicht angegriffen. Durch Umsetzung von 3 mit MeLi kommt es zur Spaltung einer P-C-Bindung. Das neben Ph2PMe gebildete 1,3,3-Tris(diphenylphosphino)allenyllithium (5) kann durch Hydrolyse in (Ph2P)2C=C=CHPPh2 (6) verwandelt werden. Bei schonender Quartärisierung mit MeI entstehen aus 3 und 6 die Monoquartärsalze 7 und 8, mit überschüssigem Reagens bei erhöhter Temperatur dagegen als gemeinsames Produkt das Phosphonioalkinyl-semiylid-Salz [(MePh2P)2C-C≡C-PPh2-Me]2+ 2 I- (9). Nebenprodukt der auch hierbei in 3 eintretenden P-C-Spaltung ist Ph2PMe2+ I-3. - Die Strukturen der Allene 3 und 6 sowie des Salzes 9 wurden durch Röntgenbeugungsanalysen an Einkristallen gesichert. Die Ph2P-Gruppen in 3 besitzen ähnliche Konformationen wie im analogen (Ph2P)2C=CH2 mit jeweils entgegengesetzten Orientierungen der freien Elektronenpaare an den P-Atomen zur Allen-Achse. In 6 ist ein Rotameres mit annähernd symmetrischer (“anti”) Orientierung der geminalen Ph2P-Gruppen vorhanden. 9 ist ein weiteres Beispiel für Semiylid-Quartärsalze mit delokalisierter Ylid-Funktion.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200818
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    Alkylation of Position C-5 of Triacetic Acid Lactone by [2,3] Sigmatropic Rearrangement of Sulphonium Ylides (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1413-1419 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylierung der 5-Stellung von Triessigsäurelacton durch [2,3]-sigmatrope Umlagerung von Sulfonium-YlidenDie Reaktionen von 4-Methoxy-6-(phenylthiomethyl)-2H-pyran-2-onen 4 mit drei verschiedenen Diazoverbindungen unter Kupfer- oder Rhodium-Katalyse liefern entsprechende Sulfonium-Ylide, die durch [2,3]-sigmatrope Umlagerung und nachfolgende Prototropie die Pyrone 6, die an der schwer zugänglichen 5-Stellung funktionalisiert sind, ergeben. Entschwefelung von 6 mit desaktiviertem Raney-Nickel ergibt die Pyrone 17-19. Der Einfluß der experimentellen Bedingungen auf die Konkurrenz von [2,3]-sigmatroper und Stevens-Umlagerung wurde bei der Reaktion von 4-Methoxy-6-(phenylthiomethyl)-2H-pyran-2-on (4a) mit Diazomalonsäure-dimethylester studiert. Zusammen mit den aus [2,3]-sigmatroper und Stevens-Umlagerungen abgeleiteten Verbindungen 6d und 8 wurden noch andere Produkte (9, 10 und 11), die über Sulfonium-Ylid-Gleichgewichtseinstellung und Radikalverknüpfung entstehen, isoliert.
    Notes: Reactions of the 4-methoxy-6-(phenylthiomethyl)-2H-pyran-2-ones 4 with three different diazo compounds under copper or rhodium catalysis give the corresponding sulphonium ylides, which through [2,3] sigmatropic rearrangement and further prototropy afford the pyrones 6, functionalized at the difficutly accessible position C-5. Desulphurations of products 6 with deactivated Raney nickel give the pyrones 17-19. The influence of the experimental conditions on the competition between [2,3] sigmatropic and Stevens rearrangement has been studied for the reaction of 4-methoxy-6-(phenylthiomethyl)-2H-pyran-2-one (4a) and dimethyl diazomalonate. Several products (9, 10, and 11) arising from sulphonium ylides equilibration and radical recombination have been found in addition to the [2,3] sigmatropic and the Stevens rearrangement products 6d and 8.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200819
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    Heterocyclic β-Enamino Esters, 481) Heterocondensed Pyridines by Cycloaddition-Extrusion Sequence of Bi- and Tricyclic 1,3-Oxazinones with N,N-Diethyl-1-propynylamine (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1427-1431 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclische β-Enaminoester, 481). - Heterokondensierte Pyridine durch Cycloaddition-Extrusion-Sequenz bi- und tricyclischer 1,3-Oxazinone mit N,N-Diethyl-1-propinylaminDihalogentriphenylphosphorane überführen die N-benzoylierten 2-Amino-4,5-dihydrofuran- (5b), -pyrrol- (7b), -isoxazol- (9b) und -oxazol-3- oder-4-carbonsäure-ethylester (11b) in die heterokondensierten 1,3-Oxazinone 6, 8, 10 und 12. Mit N,N-Diethyl-1-propinylamin ergeben diese und die bereits beschriebenen 1,3-Oxazinone 1a,b, 2a,b und 3 regiospezifisch in einer Cycloadditions-Extrusions-Sequenz die entsprechenden heterokondensierten Pyridine 13a,b, 14a,b, 15a,b, 16-21, von denen 15b und die 4-Oxonaphthyridine 16, 17 Beispiele für die Insertion des Acetylen-Reagens darstellen.
    Notes: Dihalotriphenylphosphoranes convert the N-benzoylated ethyl 2-amino-4,5-dihydrofuran- (5b), -pyrrole- (7b), -isoxazole- (9b), and -oxazole-3- or-4-carboxylates (11b) into heterocondensed 1,3-oxazinones 6, 8, 10, and 12. Treatment with N,N-diethyl-1-propynylamine of these compounds as well as the already known 1,3-oxazinones 1a,b, 2a,b, and 3 results in a regiospecific cycloaddition-extrusion sequence to afford the corresponding heterocondensed pyridines 13a,b, 14a,b, 15a,b, and 16-21. Of these 15b and the 4-oxonaphthyridines 16, 17 represent examples of insertion of the acetylene reagent.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200821
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    Photochemistry of Heterocycles, 161) Sensitized Photorearrangement of 2,4-Dioxofuro[2,3-d]pyrimidines into 5,7-Diazaspiro[2.5]octanes (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1433-1435 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Short-wavelength triphenylene-sensitized UV irradiation of the furo[2,3-d]pyrimidines 2a-c leads to homolysis and rearrangement with formation of the 5,7-diazaspiro[2.5]octanes 3a-c. Employing the 6,6-dimehtyl derivative 2d, homolysis gives A and subsequent ∊-H abstraction (Norrish-type II) furnishes B ⇄ C; radicalic hydroxylation in 5-position (from THF peroxide) finally leads to 5-hydroxy-2,4,6-trioxo-5-propenylpyrimidine 3d.
    Notes: No Abstract
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200822
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  • 75
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    Carben-analoge Reaktionen der Dehalogenierungsprodukte von Dichlor(diisopropylamino)boran mit Aromaten und 1,2-Dimethoxyethan (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1437-1439 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbene-Analgous Reactions of the Products of Dehalogenation of Dichloro(diisopropylamino)borane with Aromatic Compounds and 1,2-DimethoxyethaneSodium complexes of aromatic compounds in 1,2-dimethoxyethane react with dichloro-diisopropylamino)borane to give compounds formed via carben(oidal) intermediates: From naphthalene 1,2-bis(diisopropylamino)-1,1a,2,8b-tetrahydroborireno[2,3-b][3]benzoborepine (1) is formed. From acenaphthylene 2-(diisopropylamino)-2,3-dihydro-1H-naphtho[1,8-cd]borine (2) and with 1-methylnaphthalene, in addition to 1,2-bis[(diisopropylamino)methoxyboryl]ethyne (3), (diisopropylamino)dimethoxyborane (4) is isolated. 1H-, 11B-, 13C-, 14N-, 15N NMR and MS data are given. For 3 the X-ray structure is reported.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200823
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  • 76
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    Photoelektronenspektrum und elektronische Struktur von 4-Butadiinylmorpholin, einem Amino-substituierten 1,3-Diin (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1441-1443 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoelectron Spectrum and Electronic Structure of 4-Butadiynylmorpholine, an Amino-Substitued 1,3-DiyneThe PE spectrum of the title compound 1 has been obtained. Based on MNDO calculations, the ionization potentials have been assigned to molecular orbitals of the amino-substituted 1,3-diyne. Besides the n orbitals of the electron lone-pairs of the morpholine ring, there are two pairs of occupied π MOs of the diyne. One pair of π MOs interacts strongly with the n(N) MO, while the other one corresponds to those of unsubstituted butadiyne. MNDO calculations indicate a pyramidal configuration of the nitrogen atom with a rather low inversion barrier.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200824
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  • 77
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    Ethylidenphosphoran-Ethenylfluorphosphoran-(λ5σ4P-λ5σ5P)-Umlagerung (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1445-1446 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ethylidenephosphorane - Ethenylfluorophosphorane (2λ5σ4P-λ5σ5P) Rearrangement2-Methoxy-1,3,2-dioxaphospholane (4) reacts with 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietane (1) to furnish 2-methoxy-2-[2,2,2,-trifluoro-1-(trifluoromethyl)ethylidene]-1,3,2λ 5σ5-dioxaphospholane (6) which rearranges upon standing at ambient temperature to form 2-[2,2-difluoro-1-(trifluoromethyl)ethenyl]-2-fluoro-2-methoxy-1,3,2λ5σ5-dioxaphospholane (7).
    Notes: No Abstract
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200825
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  • 78
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    Schwefeldiimide mit Thioarsinyl- und Selenoarsinyl-Substituenten (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1447-1448 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur Diimdides Containing Thioarsinyl and Selenoarsinyl SubstituentsWhile bis(di-tert-butylphosphino)sulfur diimide, S(N-PtBu2)2 (1a), readily adds both elemental sulfur and selenium below 0°C to give 1: 2 adducts S[N - P(Y)tBu2]2 [Y=S (1b), Se (1b), Se (1c)], the analogous bis(di-tert-butylarsino)sulfur diimide, S(N - AstBu2)2 (2a), is almost unreactive under comparable conditions. However, thioarsinyl sulfur diimide, S[N - As(S)tBu2]2 (2b), can be obtained from K2SN2 and two equivalents of tBu2As(S)Cl. In contrast to sulfur, selenium is slowly attached to the arsino centers of 2a in toluene solution at 25°C to give both the di- and the monoselenium adduct, S[N-As(Se)tBu2]2 (2c) and tBu2As(NSN)As(Se)tBu2 (2d), respectively.
    Notes: No Abstract
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200826
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  • 79
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    Reaction of Cyclic Thioureas with 2-Benzylidenecycloalkanones (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1449-1450 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: BF3. OEt2-catalyzed reaction of cyclic thioureas (1) with 2-benzylidenecycloalkanones (2) afforded tricyclic 1,3-thiazines (3, 4). The progress of the reactions was found to depend on the ring size of both 1 and 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200827
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    Katalytische Synthese von 5-Benzylidenhydantoinen aus Alkylisocyanaten und Phenylacetylen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1451-1453 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Catalytic Synthesis of 5-Benzylidenehydantoins from Alkyl Isocyanates and PhenylacetyleneNew 5-benzylidenehydantions 1-4 have been prepared from alkyl isocyanates and phenylacethylene in the presence of various ruthenium clusters as catalyst precursors. All products have been separated into the expected Z and E isomers.
    Notes: No Abstract
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200828
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    Synthese von 1λ6- und 1λ4-1,2,6-Thiadiazinen aus S,S-Dialkylschwefeldiimiden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1455-1459 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 1λ6- and 1λ4-1,2,6,-Thiadiazines from S,S-Dialkylsulfur Diimides1λ6,2,6-Thiadiazines 4a-h, 1λ4,2,6-Thiadiazines 5a-k, 6a,b, and ring-open products 3a-o are synthesized by reaction of dialkylsulfur diimides 1a-g with ethylene derivatives 2a-h. 1λ6,2,6-Thiadiazines 4h,b,c can be converted into 1λ4,2,6-Thiadiazines 5j, 6a,b under acid catalysis. The ring-open product 3n leads to 1λ6,2,6-thiadiazine 4a when heated with base.
    Notes: No Abstract
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200829
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  • 82
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    Anomer kontrollierte Substitutionsreaktionen mit verschiedenen N-Alkylpyridiniumverbindungen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 735-745 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The results of semiempirical MNDO calculations on bond lengths, heats of formation, and net atomic charges of compounds 6, 7, and 8, which all contain an N-alkylpyridinium moiety (see Table 1), allow general trends to be recognized. These trends allow the prediction of important reactivity characteristics of this series of compounds and were the reason for the synthesis of compounds 9, 24, and 26 and for tests of their usefulness. Specifically, the C1-N2 bond length serves as a useful criterion for the reactivity with nucleophilic partners, especially in combination with thermodynamic data calculated from reactions (3) and (4) (Tables 3 and 4). In 7 and 8, this bond is very long as a consequence of an extreme anomeric effect. This observation is reflected in the (experimentally tested) property of the complexes 9 to split off the pyridine moiety. The Cl atom in 6a does not influence the C1-N2 bond length but it does activate the C1 atom toward nucleophilic attack and can itself function as the leaving group [see eq. (10)]. - A remarkable example, both on the basis of the MNDO results (using the model compound 6i) and from the experimental viewpoint, was observed for the class of compounds 24a. The calculated C1-N2 bond length of 6i (1.563 Å) could be classified as adequate for nucleophilic substitution of the pyridine moiety controlled by the anomeric effect on the basis of experimental tests. Whereas “normal” N-alkylpyridinium salts (e.g. the N-methylpyridinium cation, 6b) are hardly ever attacked in the C1 position, the preparative usefulness of this structural element can now be considerably increased by use of the anomeric effect. This is demonstrated by the synthesis of compounds 5, 9h, 17, and 22 from 9, 25a and 25b from 24a as well as 27a from 26a.
    Notes: Ergebnisse aus semiempirischen (MNDO)-Berechnungen der Bindungslängen, Bildungsenergeien und Überschußladungen solcher Verbindungsklassen 6, 7 und 8, die als gemeinsames Strukturelement einen N-Alkylpyridinium-Molekülteil besitzen (vgl. Tab. 1), lassen allgemeingültige Trends erkennen, mit deren Hilfe wichtige Reaktivitätsmerkmale dieser Reihe vorhergesagt werden können und somit Anlaß zur gezielten Herstellung der Beispiele 9, 24 und 26 und deren erste Verwendungstests waren: Insbesondere die C1-N2-Bindungslänge kann bei Umsetzungen mit nucleophilen Reaktionspartnern - bei zusätzlicher Berücksichtigung der entsprechend Gl. (3) und (4) berechneten thermodynamischen Daten (Tab. 3 und Tab. 4) - als ein zuverlässiges Beurteilungskriterium dienen. Diese Bindung ist in 7 und 8 infolge eines extremen anomeren Effekts sehr lang, ein Befund, der sich in der (experimentell überprüften) Eigenschaft der Komplexe 9, den Pyridiniumteil besonders leicht abzuspalten, widerspiegelt. Das Cl-Atom in 6a ist auf die genannte Bindungslänge ohne Einfluß, es erleichtert jedoch den nucleophilen Angriff auf das C1-Zentrum und kann selbst zur Abgangsgruppe werden [vgl. Gl. (10)]. - Ein sowohl aufgrund der MNDO-Ergebnisse (Berechnung des Modells 6i) als auch aus experimenteller Sicht bemerkenswertes Beispiel manifestiert sich als Konsequenz dieser überlegungen in der Substanzklasse 24a: Die berechneten C1-N2-Bindungslänge von 6i (1.563 Å) konnte durch experimentelle Tests [G1. (9)] als hinreichend für die durch den anomeren Effekt gesteuerte nucleophile Substitution des Pyridiniumteils in 24a klassifiziert werden. Während also “normale” N-Alkyl-pyridiniumsalze (z. B. das N-Methylpyridinium-Kation 6b) kaum an der C1-Position angreifbar sind, kann durch gezielte Ausnutzung des anomeren Effekts das präparative Anwendungsspektrum dieses Strukturelements nunmehr deutlich erweitert werden (hier umrissen durch die Herstellung der Verbindungen 5, 9h, 17 und 22 aus 9, 25a und 25b aus 24a sowie 27a aus 26a).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200510
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    Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, VIII (Tetrahydrofurfuryl)phosphan-Komplexe von Rhodium(I) mit reaktiven Rhodium-Sauerstoff-Bindungen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 761-767 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The rhodium complexes SbF6 (5a, b) [R=Ph (a), c-C6H11 (b)] are obtained by Cl- abstraction from ClRh(COD)PR2CH2C4H7O (3a, b) with AgSbF6. 3a, b result from [μ-ClRh(COD)]2 (1) and the P,O ligands R2PCH2C4H7O (2a, b). Complex 5b is also formed from [Rh(COD)(THF)2]SbF6 (4) and 2b. As was demonstrated with the cis complexes PF6 (8a, b), the introduction of a second ligand 2a, b succeeds either by COD elimination from [Rh(COD)-(PPh2CH2C4H7O)2]PF6 (6a) or by an one-pot reaction of [μ-ClRh(COE)2]2 (7) with 2a, b and NaPF6. In the presence of excess COD 8a is reversibly transformed into 6a with cleavage of two Rh-O bonds. In contrast to 8a, 8b reacts with hydrogen to give the cis hydrido compound PF6 (9b) with reorientation of the P,O ligands from cis to trans, being only stable in solution under an atmosphere of hydrogen. Upon the oxidative addition of CH3I (13CH3I) to 8b, leading to cis-PF6 (10b and 10′b, respectively), also the kinetic instability of the Rh-O bond is of importance. With cleavage of the Rh-O bond 8a, b react with CO (13CO) to give the trigonal-bipyramidally configurated complexes [(OC)3Rh(PR2CH2C4H7O)2]PF6 (11a, b and 11′a, b, resp.) with trans-arranged P,O ligands. As a result of CO (13CO) elimination and reversible Rh-O bond formation 11b and 11′b (13CO enriched) are tranformed into the trans-P configurated complexes PF6 (12b and 12′b, resp.), showing fluctional behaviour at 20°C in the 31P{1H}-NMR spectrum, regarding the Rh-O bond.
    Notes: Die Rhodium-Komplexe SbF6 (5a, b) [R=Ph (a), c-C6H11 (b)] erhält man durch Cl--Abstraktion aus ClRh(COD)PR2CH2C4H7O (3a, b) mit AgSbF6. 3a, b entstehen aus [μ-ClRh(COD)]2 (1) und den P,O-Liganden R2PCH2-C4H7O (2a, b). Komplex 5b bildet sich auch aus [Rh(COD)-(THF)2]SbF6 (4) und 2b. Die Einführung eines zweiten Liganden 2a, b gelingt, wie mit den cis-Komplexen PF6 (8a, b) gezeigt wird, entweder durch COD-Abspaltung aus [Rh(COD)(PPh2CH2C4H7O)2]PF6 (6a) oder durch Eintopfreaktion von [μ-ClRh(COE)2]2 (7) mit 2a, b und NaPF6. In Gegenwart von überschüssigem COD geht 8a reversibel unter Spaltung von zwei Rh-O-Bindungen in 6a über. Im Gegensatz zu 8a reagiert 8b mit Wasserstoff unter Umorientierung der P,O-Liganden von cis nach trans zur cis-Hydrido- Verbindung PF6 (9b), die nur in Lösung unter H2- Atmosphäre beständig ist. Bei der oxidativen Addition von CH3I (13CH3I) an 8b, die zu cis-PF6 (10b bzw. 10′b) führt, spielt ebenfalls die kinetische Labilität der Rh-O-Bindung eine Rolle. Unter öffnung der Rh-O-Bindung reagieren 8a, b mit CO (13CO) zu den trigonalbipyramidal konfigurierten Komplexen [(OC)3Rh(PR2CH2-C4H7O)2]PF6 (11a, b bzw. 11′a, b) mit trans-ständigen P,O-Liganden. 11 b bzw. 11′b (13CO-angereichert) eliminiert CO (13CO) und geht dabei unter reversibler Rh-O-Knüpfung in den trans-P-konfigurierten Komplex PF6 (12b bzw. 12′b) über, der bezüglich der Rh-O-Bindung bei 20°C im 31P{1H}-NMR-Spektrum fluktuierendes Verhalten zeigt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200513
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    Reaktion von Dioxomolybdän(VI)-Komplexen mit S-Methylthiocarbazat. Darstellung und Struktur eines Diazenido-Hydrazido-Komplexes mit “side on” gebundenem Hydrazido(1 - )-Liganden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 783-787 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The reaction of NH2NHC(O)SMe with MoO2(S2CNEt2)2 and MoO2(ONEt2)2 yields the diazenido-hydrazido complexes [Mo(NNC(O)SMe)(NH2NC(O)SMe)(S2CNEt2)2] · CH2Cl2 (2) and [(μ-OMe)Mo(NNC(O)SMe)(NH2NC(O)SMe)(ONEt2)]2 (4), respectively. X-ray structure analysis shows that 2 contains the side-on hydrazido(1 - ) ligand NH2NC(O)SMe, whereas in 4 the same ligand is N,O-chelated. In 2 the Mo - N distances are 213.1(7) and 213.4(5) pm, the N - N distance is 140.4(9) pm. The nitrogen atoms are sp3 hybridized. Possible factors influencing the coordination mode of hydrazido(1 - ) ligands, i.e. side on, end on, or chelating, are discussed.
    Notes: Die Reaktion von NH2NHC(O)SMe mit MoO2(S2CNEt2)2 und MoO2(ONEt2)2 ergibt die Diazenido-Hydrazido-Komplexe [Mo(NNC(O)SMe)(NH2NC(O)SMe)(S2CNEt2)2] · CH2Cl2 (2) bzw. [(μ-OMe)Mo(NNC(O)SMe)(NH2NC(O)SMe)(ONEt2)]2 (4). Röntgenstrukturanalysen von 2 und 4 ergaben, daß der Hydrazido(1 - )-Ligand NH2NC(O)SMe in 2 symmetrisch “side on”, im dimeren 4 dagegen als N,O-Chelat gebunden ist. Die Mo-N-Abstände in 2 betragen 213.1(7) und 213.4(5) pm, der N - N-Abstand 140.4(9) pm. Die Stickstoffatome sind sp3-hybridisiert. Mögliche Faktoren für die “side-on”-, “end-on”-oder chelatartige Koordination von Hydrazido(1 - )-Liganden werden diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200516
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    Liquid Chromatography on Triacetycellulose, 14 Chromatographic Separation of Enantiomers and Barriers to Enantiomerization of Axially Chiral Aromatic Carboxamides (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 803-809 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The enantiomers (M) and (P) of a series of similar aromatic carboxamides have been, for the first time, investigated analytically and enriched preparatively by liquid chromatography on triacetylcellulose. Enantiomeric purities (7-99%), specific rotations, and barriers to rotation about the C(sp-C(sp bond (87-120 kJ/mol, Table 5) were determined. These energies are discussed in terms of the size of ortho substituents and of the buttressing effects by meta substituents.
    Notes: Die Enantiomeren (M) und (P) einer Reihe verwandter aromatischer Carbonsäureamide wurden erstmals mittels Flüssigkeits-Chromatographie an Triacetylcellulose analytisch untersucht und präparativ angereichert. Enantiomerenreinheiten (7-99%), spezifische Drehungen und Schwellen der Rotation um die C(sp-C(sp-Bindung (87-120 kJ/mol, Tab. 5) wurden ermittelt. Diese Energiebeträge werden im Hinblick auf den Raumbedarf von ortho-Substituenten und die Stützeffekte durch meta-Substituenten diskutiert.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200519
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    Metallaheterocumulene, VII α-Bromisocyanid-Komplexe durch Addition von Bromid an kationische 2-Azoniaallenyliden-Komplexe (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 811-814 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The cationic [3,3-bis(tert-butyl)-2-azoniaallenylidene]pentacarbonyl complexes [(CO)5M(CNC(tBu)2)]⊖ AlBr4⊕ (2) [M=Cr (a), W (b)] which are synthesized by the reaction of (CO)5M-[C(OEt)N=C(tBu)2] (1) with AlBr3, react with tetrahydrofuran via addition of Br⊖ to give the isocyanide complexes (CO)5M-C≡N-C(tBu)2Br (3). Under nitrogen at room temperature, 3b decomposes in solution within ca. two hours to give the binuclear diisocyanide complex [(CO)5W-C≡N]2C(tBu)2 (4b). When the same conditions are applied to solutions of 3b in the presence of oxygen or of galvinoxyl 3b is stable. The structure of 4b was confirmed by an X-ray analysis.
    Notes: Die kationischen [3,3-Bis(tert-butyl)-2-azoniaallenyliden]pentacarbonyl-Komplexe [(CO)5M(CNC(tBu)2)⊖ (2) [M=Cr (a), W (b)] - darstellbar durch Umsetzung von (CO)5M[C(OEt)- N=C(tBu)2] (1) mit AlBr3 - reagieren mit Tetrahydrofuran unter Addition von Br⊕ zu den Isocyanid-Komplexen (CO)5M - C≡N-C(tBu)2Br (3). Bei Raumtemperatur zersetzt sich 3b unter Stickstoff in Lösung innerhalb von ca. zwei Stunden zu dem zweikernigen Diisocyanid-Komplex [(CO)5W-C≡N]2C(tBu)2 (4b), in Gegenwart von Sauerstoff oder von Galvinoxyl ist 3b unter ansonsten gleichen Bedingungen stabil. Die Struktur von 4b wurde durch eine Röntgenstrukturanalyse gesichert.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200520
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    Synthesen mit Cyclobutadienen, 17 Bootförmig deformierte Arene: Die Kristall- und Molekülstruktur vic-tri-tert-butylsubstituierter Benzol-, Pyridin- und Phosphinin-Systeme (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 819-824 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The crystal structure of arene 3 and heteroarenes 4, 5 has been determined by X-ray diffraction. Steric overcrowding in the vic-tri-tert-butyl-substituted part of the molecules causes the aromatic rings to deviate strongly from planarity. Unsymmetrical boat conformations are found in all cases (bow and stern angles: 30.1 and 11.6° in 3, 25.5 and 12.9° in 4), the boat in 5 being rather twisted. Compound 3 represents the most strongly deformed non-bridged and non-condensed benzene derivative for which experimental data are available. Phosphinine 5 has the most distorted non-bridged and non-condensed 6π aromatic system known so far.
    Notes: Die Kristallstruktur der Arene bzw. Heteroarene 3, 4 und 5 wurde durch Röntgenbeugung bestimmt. Die mit dem vic-Tri-tert-butyl-Substitutionsmuster verbundene räumliche überfüllung führt zu einer starken Abweichung der aromatischen Ringe von der Planarität. In allen Fällen liegen unsymmetrische Bootkonformationen vor (Bug- und Heckwinkel: 30.1 und 11.6° in 3, 25.5 und 12.9° in 4), wovon die in 5 stark verdrillt ist. Die Verbindung 3 ist das am stärksten deformierte, nichtüberbrückte und nichtkondensierte Benzolderivat, für das bislang experimentelle Strukturdaten vorliegen; das Phosphinin 5 ist der am meisten verzerrte 6π-Aromat dieser Art überhaupt.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200522
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    Desaminierungsreaktionen, 47 Zerfall von 1-(3-Hydroxypropyl)cyclopropandiazonium-Ionen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 847-848 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diazonium ions 13 have been generated by alkaline cleavage of the analogous nitrosocarbamate 12. The product distribution indicates little participation of the hydroxy group (0.4% 9) while the allyl cation 14 arising from 13 undergoes intramolecular (4.3% 17) as well as intermolecular (75% 16) nucleophilic substitution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200525
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    Borylierung von Arylsilanen, I Ein allgemeiner, einfacher und selektiver Zugang zu Phenyldihalogenboranen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 853-854 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upon treatment with trihaloboranes 2b-d the phenyltrimethylsilanes 1, 6, 8, and 10 yield the corresponding phenyldihaloboranes 3, 7, 9, and 11 with high selectivity. Benzylsilanes are not attacked.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200527
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    Synthesen mit Cyclobutadienen, 18 Dewar-Benzole aus Tri-tert-butylcyclobutadiencarbonsäureestern und monoakzeptorsubstituierten Acetylenen - thermische und photochemische Folgereaktionen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 825-838 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The methyl cyclobutadienecarboxylate 1a adds methyl propiolate (2a) to the regioisomeric Dewar benzenes 3a (73%) and 4a (19%). In contrast, the corresponding tert-butyl carboxylate 1b reacts with the same dienophile as well as the acceptor-substituted olefines 2b and c exclusively by formation of the Dewar benzenes 3b-d (68-82%). - Both Dewar benzenes 3a and b are smoothly transformed into the benzenes 5a and b by thermal means. Photolyses of both aromatic compounds do not lead back to 3a and b but produce the Dewar isomers 7a and b, which finally undergo intramolecular [2+2] cycloaddition to give the prismanes 9a and b. A fundamentally comparable reaction sequence can be achieved with 4a (→ 6a → 8a → 9a). Reaction branching is observed on thermolysis of 9b: On the one hand the benzene 5b (54%) accompanied with 10% of the Dewar benzene 7b, on the other hand a 1:1 mixture of the aromatic compounds 6b and c is obtained. - Photochemically the Dewar benzenes 3a and b can directly be converted into the prismanes 10a and b (97 and 86%, respectively). Prismane/prismane isomerization (10 → 16) succeeds as a consequence of a thermal (10a,b → 12a,b) as well as of two light-induced reaction steps (12a,b → 14a,b and 14a,b → 16a,b). In an analogous way, the prismane 11 is received from 4a and then transformed into the isomer 16 via 13 and 15. As a special feature of the thermolysis of 11 the formation of 12a has to be noted, a reaction which is explained by the benzvalene intermediate 25. - The crystal structure analysis of 10b shows an evident influence of only one of both carbonyl groups (methylester) onto the prismane skeleton. This is manifested by two long, vicinal [C1-C2 1.579(3) and C1-C6 1.567(3) Å] and a short distal three-membered ring bonds [C2-C6 1.528(3) Å]. Furthermore, the C1-C4 bond [1.506(4) Å] is shortened relative to the C2-C3 distance [1.553(3) Å], whereas the C5-C6 bond [1.594(3) Å] is prolonged by the strong repulsion of both tBu groups.
    Notes: Der Cyclobutadiencarbonsäure-methylester 1a addiert Propiolsäure-methylester (2a) zu den regioisomeren Dewar-Benzolen 3a (73%) und 4a (19%). Dagegen entstehen aus dem entsprechenden tert-Butylester 1b und dem gleichen Dienophil sowie den akzeptorsubstituierten Olefinen 2b und c ausschließlich die Dewar-Benzole 3b-d (68-82%). - Thermisch gehen die beiden Dewar-Benzole 3a und b glatt in die Benzole 5a und b über. Photolysen der Aromaten führen nicht zu 3a und b zurück, sondern zu den Dewar-Isomeren 7a und b, die schließlich intramolekulare [2+2]-Cycloaddition zu den Prismanen 9a und b eingehen. Mit 4a läßt sich eine grundsätzlich vergleichbare Reaktionsfolge realisieren (→6a →8a →9a). Reaktionsverzweigung beobachtet man bei der Thermolyse von 9b: Einerseits erhält man das Benzol 5b (54%) neben 10% Dewar-Benzol 7b, andererseits ein 1:1-Gemisch aus den Aromaten 6b und c. - Photochemisch lassen sich die Dewar-Benzole 3a und b direkt in die Prismane 10a und b (97 bzw. 86%) umwandeln. Prisman/Prisman-Isomerisierung. (10 → 16) gelingt als Folge eines thermischen (10a,b → 12a,b) sowie zweier lichtinduzierter Reaktionsschritte (12a,b → 14a,b und 14a,b → 16a,b). Entsprechend läßt sich aus 4a das Prisman 11 gewinnen und dann über 13 und 15 in das Isomer 16 umwandeln. Als Besonderheit der Thermolyse von 11 ist die Bildung von 12a zu vermerken, dessen Entstehen über die Benzvalen-Zwischenstufe 25 erklärt wird. - Die Kristallstrukturanalyse von 10b zeigt einen deutlichen Einfluß nur einer der beiden Carbonylgruppen (Methylester) auf das Prismangerüst. Er äußert sich in zwei langen, vicinalen [C1-C2 (1.579(3) und C1-C6 1.567(3) Å] und einer kurzen distalen Dreiringbindung [C2-C6 1.528(3) Å]. Dar über hinaus ist die C1-C4-Bindung [1.506(4) Å] relativ zum C2-C3-Abstand [1.553(3) Å] verkürzt, während die C5-C6-Bindung[1.594(3) Å] durch die starke Abstoßung der beiden tBu-Gruppen verlängert ist.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200523
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    Silylierte Aminophosphonium-Salze und Aminophosphonium-methylide (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 789-794 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The reaction of the aminophosphonium methylides (Et2N)3P=CH2, Me(Et2N)2P=CH2, (Me2N)3P=CH2, or Me(Me2N)2P=CH2 (1a-d) with the chlorosilanes Me3SiCl and (t-Bu)2SiCl2, resp., yield silylated phosphonium salts 2a-d (Scheme 1). Treatment of these with strong base (KH/THF) or transylidation using a second equivalent of the ylide 1a-d affords the silylated ylides (Et2N)3P=CHSiMe3, Me(Et2N)2P=CHSi(t-Bu)2Cl, and Me(Me2N)2P=CHSi(t-Bu)2Cl (3a-c,c′,d). Attempts for further dehydrohalogenation of the latter to give species R3P=C=SiR′2 were unsuccessfull. Instead, treatment of 3d with t-BuLi/TMEDA yielded the cyclic ylide (4) whose structure was determined by single crystal X-ray diffraction. Addition of HCl (in Et2O) to 4 gives the corresponding phosphonium salt Cl (5). - For reason of comparison, the ylides Me3P=CH2, (i-Pr)3P=CH2, and Ph3P=CH2 (1e-g) were also converted (via silylated phosphonium salts) into ylides Me3P=CHSiR3, (i-Pr)3P=CHSiR3, and Ph3P=CHSiR3, where R3=(t-Bu)2Cl and (t-Bu)MeCl (3e-g). 3f can also be converted into an endocyclic ylide (6), whereas 3g, on standing in THF solution, yields the double ylide [Ph3P=C - Si(t-Bu)2]2 (7) with exocyclic ylide functions. NMR data are presented for all new ylides.
    Notes: Aus den Aminophosphonium-methyliden (Et2N)3P=CH2,Me(Et2N)2P=CH2, (Me2N)3P=CH2 oder Me(Me2N)2P=CH2 (1a-d) entstehen bei der Reaktion mit den Chlorsilanen Me3SiCl bzw. (t-Bu)2SiCl2 die silylierten Phosphoniumsalze 2a-d (Schema 1). Durch die Einwirkung starker Basen (KH/THF) oder durch Umylidierung mit einem weiteren äquivalent Ylid 1a-d werden daraus die silylierten Ylide (Et2N)3P=CHSiMe3, Me(Et2N)2P=CHSi(t-Bu)2Cl und Me(Me2N)2P=CHSi(t-Bu)2Cl (3a-c,c′,d). Eine weitere Dehydrohalogenierung der beiden letzteren Ylide zu den kumulierten Systemen R3P=C=SiR′2 gelingt nicht. Statt dessen wird bei der Einwirkung von t-BuLi/TMEDA auf 3d das cyclische Ylid (4) gebildet, dessen Struktur durch Einkristall-Röntgenbeugung gesichert wurde. 4 ergibt mit HCl in Et2O das korrespondierende Phosphoniumsalz (5). - Zu Vergleichszwecken wurden aus Me3P=CH2, (i-Pr)3P=CH2 und Ph3P=CH2 (1e-g) über die silylierten Phosphoniumsalze auch die Silyl-Ylide Me3P=CHSiR3, (i-Pr)3P=CHSiR3 und Ph3P=CHSiR3 mit R3=(t-Bu)2Cl und (t-Bu)MeCl (3e-g) dargestellt. Aus 3f konnte mit t-BuLi/TMEDA wieder ein endocyclisches Ylid (6) erhalten werden. 3g ergibt beim Lagern in THF-Lösung das Doppelylid [Ph3P=C - Si(t-Bu)2]2 (7) mit exocyclischen Ylidfunktionen. Für alle neuen Ylide werden NMR-spektroskopische Daten vorgelegt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200517
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    Ein weiterer erfolgloser Versuch, Tetra-tert-butylethylen herzustellen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 871-872 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rather than providing the title compound 5 the reaction of tetraacetylethene (3) with excess dimethyltitanium dichloride (4) leads to 2,2,4,4,6,6,8,8-octamethyl-3,7-dioxabicyclo[3.3.0]octl(5)-ene (10). The mechanism of formation of this tetramethylated product is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200532
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    Mono- und dimetallierte Cyclobutendione mit Molybdän-, Wolfram-, Mangan- und Rheniumcarbonylen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 889-893 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The nucleophilic substitution of chloride in dichlorocyclobutenedione by carbonylmetallates gives the μ-(3,4-dioxo-1-cyclobutene-1,2-diyl) complexes LnM(C4O2)MLn 1 [MLn=Re(CO)5, Mn(CO)5, W(CO)3(η5-C5H5)] and the μ-(2-chloro-3,4-dioxo-1-cyclobuten-1-yl) complexes LnM— [MLn = Mn(Co)5, W(CO)3(η5-C5H5), Mo(CO)3(η5-C5H5)], respectively. The structure of the dirhenium complex (OC)5Re(C4O2)Re(CO)5 (1a) was determined by X-ray diffraction. The Re-C bonds are slightly shortened with respect to single bonds, Re-C=2.18(1)/2.17(1)Å [monoclinic, P21, a=7.031(1), b=11.532(1), c=11.418(1)Å, β=105.54(1)°, V=891.95Å3, dcalc=2.727 g/cm3 for Z=2, Rw=0.031 for 252 refined parameters and 3539 observables with I ≥ 2.0σ(I)].
    Notes: Die nucleophile Substitution von Chlorid in Dichlorcyclobutendion durch Carbonylmetallate liefert die μ-(3,4-Dioxo-1-cyclobuten-1,2-diyl)-Komplexe LnM(C4O2)MLn 1 [MLn=Re(CO)5, Mn(CO)5, W(CO)3(η5-C5H5)] bzw. die μ-(2-Chlor-3,4-dioxo-1-cyclobuten-1-yl)-Komplexe LnM— [MLn = Mn(Co)5, W(CO)3(η5-C5H5), Mo(CO)3(η5-C5H5)]. Nach der Röntgenstrukturanalyse des Dirhenium-Komplexes (OC)5Re-(C4O2)Re(CO)5 (1a) sind die Re-C-Bindungen gegenüber Einfachbindungen leicht verkürzt, Re-C=2.18(1)/2.17(1)Å [monoklin, P21, a=7.031(1), b=11.532(1), c=11.418(1)Å, β=105.54(1)°, V=891.95Å3, dber=2.727 g/cm3, Z=2, Rw=0.031 für 252 verfeinerte Parameter und 3539 Observablen mit I ≥ 2.0σ(I)].
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200604
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    Übergangsmetall-Silyl-Komplexe, 18 Hydrido-Silyl- und Bissilyl-Komplexe des Eisens mit verbrückenden oder chelatisierenden Diphosphinoethan-Liganden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 879-887 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes [mer-(CO)3Fe(H)SiR3]2(dppe) (1) (dppe=Ph2PCH2-CH2PPh2), [mer-(CO)3Fe(SiR3)2]2(dppe) (2), (CO)2(dppe)Fe(H)-Sir3 (3), and (CO)2(dppe)Fe(SiR3)2 (6) are synthetized by several routes: by photochemical reaction of dppe-substituted iron carbonyls with HSiR3, by thermal reaction of (CO)4Fe(H)SiR3 or (CO)4Fe(SiR3)2 with dppe, or by exchange of the silyl groups. The dinuclear complexes 1 and 2 can be converted to the mononuclear complexes 3 and 6. The choice of the most suitable method of preparation depends essentially on the nature of the silyl ligand. Bissilyl complexes (2 or 6) are only obtained if SiR3=SiCl3 or SiMeCl2. In solution the complexes 3 are fluxional. In the crystalline state 3d (SiR3=SiMe3) shows a distorted octahedral geometry. The silyl group has trans orientation to one of the phosphorus atoms and cis to the hydride ligand, which in turn is trans to one of the carbonyls.
    Notes: Komplexe [mer-(CO)3Fe(H)SiR3]2(dppe) (1) (dppe=Ph2PCH2CH2PPh2), [mer-(CO)3Fe(SiR3)2]2(dppe) (2), (CO)2(dppe)Fe(H)-SiR3 (3) und (CO)2(dppe)Fe(SiR3)2 (6) können nach mehreren Methoden synthetisiert werden: durch photochemische Umsetzung von dppe-substituierten Eisencarbonylen mit HSiR3, durch thermische Umsetzung von (CO)4Fe(H)SiR3 oder (CO)4Fe(SiR3)2 mit dppe oder durch Silylgruppenaustausch. Die zweikernigen Komplexe 1 und 2 lassen sich in die einkernigen Komplexe 3 und 6 umwandeln. Die Wahl der jeweils günstigsten Darstellungsmethode hängt entscheidend von der Art des Silylrestes ab. Bissilyl-Komplexe (2 oder 6) werden nur mit SiR3=SiCl3 oder SiMeCl2 erhalten. Die Komplexe 3 sind in Lösung fluktuierend. Im kristallinen Zustand ist 3d (SiR3=SiMe3) verzerrt oktaedrisch koordiniert, der SiMe3-Rest steht trans zu einem der Phosphoratome und cis zum Hydrid-Liganden, welcher seinerseits trans zu einem der Carbonyle angeordnet ist.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200603
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    Komplexe mit einem pentakoordinierten Kohlenstoffatom, III Goldverbindungen von (η5 -Cyclopentadienyl)(η5-2, 3-dihydro-1H-1, 3-diborol-2-yl)metall-Komplexen (Metall=Co, Rh) (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 911-914 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: In the cobalt and rhodium sandwich complexes 2b and 3a the acidic hydrogen at C-2 is substituted by the isolobal Au-PPh3 group with formation of the dinuclear complexes 4b and 5a. Spectroscopic data and the X-ray structure determination of 4b establish the pentacoordination at the C-2 atom. In the NMR spectra of 5a3JPRh=12 Hz is observed.
    Notes: In den Cobalt- und Rhodium-Sandwichkomplexen 2b und 3a wird der acide Wasserstoff an C-2 durch die isolobale Au - PPh3-Gruppe unter Bildung der Zweikernkomplexe 4b und 5a ersetzt. Spektroskopische Daten und die Röntgenstrukturanalyse von 4b belegen die Pentakoordination am C-2-Atom. In 5a wird NMR-spektroskopisch 3JPRh=12 Hz beobachtet.
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    URL: http://dx.doi.org/10.1002/cber.19871200608
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    Reaktionen mit Aziridinen, 41 Hoch regioselektive (anomale) Ringöffnung von 1-Benzoyl-2,2-dimethylaziridin durch einfache Nitril-Anionen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 855-857 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The anions 3a-e of the acetonitriles 2a-e cleave the aziridine ring of 1-benzoyl-2,2-dimethylaziridine (1) at the tertiary Catom (abnormal opening) and provide in this way good yields of the 4-(benzoylamino)-3,3-dimethylbutyronitriles 5a-e and of the 2-(benzoylimino)pyrrolidine 7a, respectively. Positional isomers could not be detected.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19871200528
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    Beiträge zur Chemie des Bors, 185 Reaktionen von Metallcarben-Komplexen mit (tert-Butylimino)- (2,2,6,6-tetramethylpiperidino)boran (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 863-865 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [2 + 2] Cycloaddition of the aminoiminoborane 1 with Cp2-Ti=CH2 yields a blue 1-aza-2-bora-4-titanacyclobutane derivative 2. In contrast, Fischer carbenes (CO)5M = C(OMe)Me (M=Cr, W) react in a complex way to produce 1 · M(CO)5 (4), tmpB(NHCMe3)OMe (5), and the borylated acetylene derivative 6.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19871200530
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    Masthead (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200601
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  • 99
    Electronic Resource
    Electronic Resource
    1,3-Bis(2-benzoylphenyl)-1,1,3,3-tetramethyldisiloxan (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 873-878 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Attempts to prepare 9,9-dimethyl-9-sila-10(9H)-anthracenone (4a) from dimethylphenyl-2-tolylsilane (5) or 2-bromobenzoic acid as starting compounds via 2-(dimethylphenylsilyl)benzoyl chloride (11a) by condensation with tin tetrachloride resulted in high yields of the title compound 14a. Determination of its structure was only possible by X-ray analysis, determination of the course of the reaction by variation with 2-[(4-chlorophenyl)dimethylsilyl]-benzoyl chloride (11b) and mass spectroscopical investigation of the resulting isomeric mixture of bis[(chlorobenzoyl)phenyl]tetramethyldisiloxanes 14b,b′,b′.
    Notes: Versuche, von Dimethylphenyl-2-tolylsilan (5) oder 2-Brombenzoesäure ausgehend über 2-(Dimethylphenylsilyl)benzoylchlorid (11a) mit Zinntetrachlorid als Ringschlußkatalysator zu 9,9-Dimethyl-9-sila-10(9H)-anthracenon (4a) zu gelangen, führten stets in hohen Ausbeuten zur Titelverbindung 14a, deren Konstitutionsaufklärung erst durch Röntgenstrukturanalyse gelang. Der Reaktionsweg konnte durch Variation mit 2-[(4-Chlorphenyl)dimethylsilyl]benzoylchlorid (11b) und massenspektrometrische Aufklärung des dabei entstehenden Isomerengemisches von Bis[(chlorbenzoyl)phenyl]tetramethyldisiloxanen 14b, b′, b′ sichergestellt werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200602
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  • 100
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    Electronic Resource
    Metallorganische Lewis-Säuren, XXXI Reaktionen von Pentacarbonyl(tetrafluoroborato)rhenium mit neutralen und anionischen organischen Cyanverbindungen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 895-900 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (OC)5ReFBF3 reacts with ethyl thiocyanate, malononitrile, cyanamide, and dicyandiamide (L) to give the ionic complexes [(OC)5ReL]+BF-4 (1). Two or three Re(CO)-3 cations, respectively, can be added to tetracyanoethene and tetracyano-p-quinodimethane (TCNQ) to give 2, 3. With the anions of tricyanoethenolate, TCNQ-, tricyanomethanide and dicyanamide (L-) the neutral compounds (OC)5ReL (4-7) are formed. The IR spectra and the X-ray structure analyses of [(OC)5Re(NCNC(NH2)2]+BF -4 (1d), (OC)5ReNCC(CN)2 (6), and of (OC)5ReNCNCN (7) show that the ligands are coordinated in all cases via the nitrile N-atom to the metal.
    Notes: (OC)5ReFBF3 setzt mit Ethylthiocyanat, Malononitril, Cyanamid und Dicyandiamid (L) zu den ionogenen Verbindungen [(OC)5ReL]+BF-4 (1) um. An Tetracyanethen sowie an Tetracyan-p-chinodimethan lassen sich zwei bzw. drei Re(CO)-3-Kationen unter Bildung von 2 und 3 addieren. Mit den Anionen Tricyanethenolat, TCNQ-, Tricyanmethanid und Dicyanamid (L-) entstehen die Neutral-Komplexe (OC)5ReL (4-7). Die IR-Spektren sowie die Röntgenstrukturanalysen von [(OC)5Re(NCNC(NH2)2]+BF -4 (1d), (OC)5ReNCC(CN)2 (6) und (OC)5ReNCNCN (7) zeigen, daß die Liganden in allen Fällen über das Nitril-N-Atom an das Metall koordiniert sind.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200605
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