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  • 1975-1979  (3,904)
  • 1965-1969  (4,289)
  • Inorganic Chemistry  (7,960)
  • Cat
  • Psychopharmacology
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Year
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  • 1
    Electronic Resource
    Electronic Resource
    Effects of cerebellectomy on the cat's vertical vestibuloocular reflex (1979)
    Springer
    Pflügers Archiv 382 (1979), S. 51-55 
    Details
    ISSN: 1432-2013
    Keywords: Cerebellectomy ; Vestibuloocular reflex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of cerebellectomy on the semi-circular canal evoked responses recorded from individual vertical and oblique eye muscles were studied in cats anesthetized with Ketamine. The phase lag relative angular acceleration of the electromyographic response was consistantly smaller over the frequency range tested (0.02–1.0 Hz) in cerebellectomized than in intact animals. This finding indicates that the time constant of the central, neural integrator was shifted towards smaller values by the lesion. This was also suggested when the vertical eye movements generated by rotation about the pitch axis were recorded in the fully alert animal. In addition, the EOG data show that the phase of the VOR in the low frequency range was not altered following cerebellectomy suggesting that the macular influences were still present. When the EMG responses of the superior oblique (SO) and superior rectus (SR) muscles were studied in their presumed main mode, i.e. roll-canal and pitch-canal, respectively, no difference was noted in hemicerebellectomized animals when compared to intact control animals. However, when SO and SR were studied in pitch-canal and roll-canal rotation, respectively, dramatic changes in the response pattern were noted in lesioned animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585903
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  • 2
    Electronic Resource
    Electronic Resource
    On the central generation of locomotion in the low spinal cat (1979)
    Springer
    Experimental brain research 34 (1979), S. 241-261 
    Details
    ISSN: 1432-1106
    Keywords: Locomotion ; Central generator ; Cat ; Deafferentation ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A central network of neurones in the spinal cord has been shown to produce a rhythmic motor output similar to locomotion after suppression of all afferent inflow. The experiments were performed mainly in acute spinal cats (th. 12), which had received DOPA i.v. and the monoamine oxidase inhibitor Nialamide. In some preparations all dorsal roots supplying the spinal cord were transected, in others phasic afferent activity was suppressed by curarization. The activity was recorded as neurograms from nerve filaments or as electromyograms. It is concluded that: 1. alternating activity between flexors and extensors of foot, ankle, knee, and hip of one limb can still occur 2. the duration of the flexor discharges vary less with the cycle duration than the extensor discharges 3. different flexor muscles may retain individual patterns 4. the activity at different joints can be dissociated 5. there is at least one network for each limb 6. the coordination between the two hindlimbs can be alternating as in walking or be more closely spaced as in galloping 7. alternating activity in the ankle remains even when only segments L6, L7 and S1 are intact.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235671
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  • 3
    Electronic Resource
    Electronic Resource
    SEM study of the choroid plexus of the lateral ventricle in the cat (1979)
    Springer
    Anatomy and embryology 155 (1979), S. 323-331 
    Details
    ISSN: 1432-0568
    Keywords: Telencephalon ; Choroid plexus ; Lateral ventricle ; Blood vessels ; Micro Corrosion cast ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Corrosion casts of the complete vascular network of the choroid plexus of the lateral ventricle in the cat brain were studied in SEM using the injection-replication method. The villi of this plexus are located only on its supero-anterior and infero-posterior parts, being most densely packed in the former region, close to the interventricular foramen. The capillaries of the villi display small nodular thickenings, which suggest the presence of small, sinusoidal dilatations. The main vessel supplying the plexus with blood is the anterior choroidal artery. The plexus is also characterized by a particularly rich venous network, which is drained by a prominent (main) choroid vein. The vascular organization of the choroid plexus of the lateral ventricle in cat is compared to that of the corresponding plexuses in other mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317645
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  • 4
    Electronic Resource
    Electronic Resource
    Primary vestibular afferent projections to the ipsilateral abducens nucleus in cats (1979)
    Springer
    Experimental brain research 37 (1979), S. 177-181 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Autoradiography ; Abducens nucleus ; Primary vestibular fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Primary vestibular projections to the ipsilateral abducens nucleus were found in cats by injecting anterograde tracer substances (radioactive proline and fucose) into Scarpa's ganglion. Labelling was observed in the rostral and middle portion of the abducens nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01474263
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  • 5
    Electronic Resource
    Electronic Resource
    Effets de la stimulation des mécanorécepteurs splanchniques sur l'activité des cellules cérébelleuses de Purkinje (1979)
    Springer
    Experimental brain research 37 (1979), S. 405-416 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Purkinje Cells ; Splanchnic mechanoreceptors ; Cat ; Cervelet ; Cellules Purkinje ; Mécanorécepteurs splanchniques ; Chat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les activités simple et complexe de cellules de Purkinje du cervelet du Chat (zone vermienne des lobules V et VI) ont été enregistrées au moyen de microélectrodes extracellulaires. Ces réponses étaient obtenues par stimulation de différents types de mécanorécepteurs du tractus gastro-intestinal: récepteurs musculaires connectés à des fibres C, récepteurs péritonéaux de mouvement connectés à des fibres Aγδ ou B, corpuscules de Pacini connectés à des fibres Aβ. Les caractéristiques des fibres splanchniques projetant sur cette aire cérébelleuse ont été définies. Des convergences splanchno-somatiques, splanchno-viscérales et splanchno-corticales ont été mises en évidence.
    Notes: Summary Climbing and mossy fibre activity in Purkinje cells of cat cerebellum (vermis part of lobules V and VI) were recorded by means of extracellular microelectrodes. Responses were obtained by stimulation of different types of mechanoreceptors in the gastro-intestinal tract: muscular receptors connected with C fibres, peritoneal movement receptors connected with Aγδ or B fibres, Pacinian corpuscules connected with Aβ fibres. The characteristics of the splanchnic fibre projections on this cerebellar area were defined. Splanchno-somatic, splanchno-visceral, and splanchno-cortical convergences were demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236814
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  • 6
    Electronic Resource
    Electronic Resource
    Identification of the projection from the visual cortex to the claustrum by anterograde axonal transport in the cat (1979)
    Springer
    Experimental brain research 34 (1979), S. 197-200 
    Details
    ISSN: 1432-1106
    Keywords: Claustrum ; Visual cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Visual cortex, including areas 17, 18, and sometimes 19, was injected with tritiated leucine. Terminal labelling could be detected by autoradiography in the dorsocaudal part of the ipsilateral claustrum in all cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238353
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  • 7
    Electronic Resource
    Electronic Resource
    Discriminative stimulus properties of psychomotor stimulants in the cat (1979)
    Springer
    Psychopharmacology 63 (1979), S. 151-153 
    Details
    ISSN: 1432-2072
    Keywords: Discriminative stimulus properties ; Psychomotor stimulants ; Cat ; d-Amphetamine ; Clozapine ; Cocaine ; Morphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cats were trained to choose between two levers of an operant chamber using interoceptive cues provided by d-amphetamine or saline as the discriminative stimuli. Following training, stimulus generalization was observed to additional doses of d-amphetamine and cocaine, but not to morphine. Clozapine blocked the generalization of the drug discrimination response to d-amphetamine, but had no effect on generalization to cocaine. These data indicate that discriminative stimulus properties of psychomotor stimulants, previously described in rats, are similar in cats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429694
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  • 8
    Electronic Resource
    Electronic Resource
    Lafora-like bodies in a cat (1979)
    Springer
    Acta neuropathologica 48 (1979), S. 55-58 
    Details
    ISSN: 1432-0533
    Keywords: Lafora-like bodies ; Morphogenesis ; Glycogen metabolism ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lafora-like bodies in an 8-year-old cat were studied light and electron microscopically and histochemically. In addition to Lafora-like bodies composed of branching filaments, glycogen granules and electron-dense materials, abnormal accumulations of glycogen granules attracted attention. The most remarkable features were the developmental processes of the branching filaments originating directly from glycogen granules. Lafora-like bodies in the present study showed ultrastructural, histochemical, and enzymatic similarities to those described in the previous reports in Lafora's disease, glycogenosis and other cases. From these results, a certain disturbance of the glycogen metabolism is considered to be probably related to the productive mechanism of Lafora-like bodies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691791
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  • 9
    Electronic Resource
    Electronic Resource
    Responses of single cells in cat's lateral geniculate nucleus and area 17 to the velocity of moving visual stimuli (1979)
    Springer
    Experimental brain research 34 (1979), S. 273-286 
    Details
    ISSN: 1432-1106
    Keywords: Stimulus velocity ; Single cell responses ; LGN ; Area 17 ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal responses to moving visual stimuli were recorded in the lateral geniculate nucleus (LGN) and area 17 of cats. Response duration (DE), number of spikes (NT), and mean frequency (FM) were estimated from the response histograms and analysed for their dependence on stimulus velocity. In the LGN, for about 2/3 of cells these response parameters changed monotonically with velocity up to about 100 °/s. In 1/3 of the cells, the response frequency was tuned to velocity. The speed at which individual cells reached a peak or plateau firing rate was correlated with their receptive field size. In area 17, most neurones were tuned to velocity. Nine out of 59 cells were insensitive to stimulus speed in that they responded equally well at stimulus velocities up to about 10 °/s. The results suggest that at higher levels in the nervous system information about velocity is represented in discrete groups of neurones. It is pointed out that different response parameters may be relevant for different perceptual phenomena associated with movement. The significance of integrational properties and lateral inhibition of nerve cells for the development of complex response properties is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235673
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  • 10
    Electronic Resource
    Electronic Resource
    Mise en evidence electrophysiologique des thermorécepteurs vagaux dans la région gastro-intestinale. Leur rôle dans la régulation de la motricité digestive (1979)
    Springer
    Experimental brain research 34 (1979), S. 419-434 
    Details
    ISSN: 1432-1106
    Keywords: Thermoreceptors ; Gastro-intestinal tract ; Vagal nerve ; C Fibres ; Cat ; Thermorecepteurs ; Tractus gastro ; Intestinal ; Nerf vague ; Fibres amyéliniques ; Chat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Chez des chats anesthésiés, des décharges sensitives vagales ont été enregistrées dans le ganglion plexiforme à l'aide d'électrodes extracellulaires en verre. Nous avons trouvé au niveau de l'antre et du duodénum, des récepteurs toniques, activés par des solutions chaudes (38–51 ° C avec un optimum à 46–49 ° C) ou froides (36–10 ° C avec un optimum à 12–10 ° C). Ces récepteurs ne répondent ni aux stimulus mécaniques (compression et distension des viscères), ni aux stimulus chimiques (perfusion avec des solutions glucosées ou acides). Ces récepteurs n'appartiennent donc pas au groupe des récepteurs polymodaux, mais ils doivent être considérés comme de véritables thermorécepteurs spécifiquement sensibles au chaud ou au froid. Les thermorécepteurs de la région gastro-duodénale sont connectés à des fibres vagales amyéliniques (vitesse de conduction: 0,8–1,4 m/s). Par ailleurs, le rôle éventuel des thermorécepteurs vagaux de la région gastro-duodénale dans la régulation de la motilité digestive a été recherché. En dérivant simultanément l'EMG en plusieurs points du tractus gastro-duodénal, il a été possible de démontrer que les stimulations froides et chaudes du duodénum, qui mettent en jeu les thermorécepteurs, provoquent une inhibition de l'activité électrique de l'antre. Les modifications persistent apèrs bisplanchnectomie, mais disparaissent complètement après bivagotomie. A partir de ces faits, nous en avons conclu que les thermorécepteurs vagaux sont impliqués dans la régulation nerveuse de la motilité gastro-duodénale.
    Notes: Summary In anaesthetized cats, sensory vagal units were recorded in the nodose ganglion by means of extracellular glass microelectrodes. In the antrum and the duodenum we have found receptors tonically activated by warm (38–51 ° C with an optimum at 46–49 ° C) or cold (36–10 ° C with an optimum at 12–10 ° C) solutions. These receptors did not respond to mechanical stimuli (compression and distension of the viscera) and to chemical ones (perfusion with glucose and acid solutions). Thus they did not belong to polymodal type, but they must be considered as true thermoreceptors, specifically sensitive to warm or cold stimulations. The gastro-duodenal thermoreceptors were connected to non-medullated vagal fibres (conduction velocity: 0.8–1.4 m/s). On the other hand, the role of the gastro-duodenal vagal thermoreceptors in the regulation of the digestive motility was studied. By using several electromyographic recordings, it was possible to show that the cold and warm stimulations of the duodenum which elicited thermoreceptor responses, induced an inhibition of the electrical activity of the antrum. The changes persisted after bisplanchnectomy, but disappeared completely after bivagotomy. From these facts it was concluded that the vagal thermoreceptors were involved in the nervous regulations of the gastro-duodenal motility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239140
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  • 11
    Electronic Resource
    Electronic Resource
    Effects of ventrolateral thalamic nucleus cooling on initiation of forelimb ballistic flexion movements by conditioned cats (1979)
    Springer
    Experimental brain research 34 (1979), S. 435-452 
    Details
    ISSN: 1432-1106
    Keywords: Cooling ; Ventrolateral thalamic nucleus ; Pyramidal system ; Reaction time ; Ballistic movement ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five cats were trained to perform a forelimb ballistic flexion on a reaction time paradigm including an upper limit of about 400 ms for reinforcement (food pellets). They were implanted with a cyrogenic probe thermically insulated, except at the tip, by a vacuum jacket (outer diameter, 1.1 mm). Four cats had the probe inserted into the ventrolateral thalamic nucleus (VL), contralateral to the moving limb. During cooling they showed increased reaction times, which remained constant throughout daily sessions performed during many weeks, independent of the foreperiod but varying from 25 to 100 ms according to the subject. The temperatures used to upset the reaction times varied from +10 ° C to −8 ° C, depending on the localisation of the probe and on the insulation of the silver tip used to prevent nervous tissue reaction, but for each subject the reaction times always increased when the temperature was lowered. The fifth cat, with a probe inserted between VL and the Centre Median, showed a decrease of reaction times on cooling to 0 ° C and an increase of the reaction times for a cooling at −10 ° C. For one of the four cats with a probe properly inserted into the VL, strain-gauges were stuck on the lever to measure the latency of the decrease of the pressure exerted by the subject when the subject initiated the forelimb flexion in response to the CS. Reaction times and latencies of pressure changes were closely correlated with the movement onset, and they were equally delayed during cooling. This result demonstrates that it is not by slowing down movement velocity that reaction times are upset during VL cooling but by delaying the movement onset.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239141
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  • 12
    Electronic Resource
    Electronic Resource
    Anatomical and electrophysiological identification of motoneurones supplying the cat retractor bulbi muscle (1979)
    Springer
    Experimental brain research 34 (1979), S. 541-550 
    Details
    ISSN: 1432-1106
    Keywords: Retractor bulbi motoneurones ; Accessory abducens nucleus ; 6th nerve ; Oculomotricity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Motoneurones innervating the retractor bulbi muscle in the cat have been identified by retrograde labelling with horseradish peroxidase, by intracellular recording and by intracellular staining with horseradish peroxidase. Their somata are found in an accessory abducens nucleus, analogous to that described in some other species, which consists of a narrow column of cells situated in the lateral tegmental reticular field, above the superior olive and medial to the facial nerve. This column of cells extends over approximately 1.5 mm from P 5.5 to P 7. The retractor bulbi motoneurones number from 80 to 120 and have large, elongated somata which give rise to five or six major dendrites. Their axons cross the reticular formation in a dorso-medial direction to pass through the principal abducens nucleus before turning to leave the brain stem in the 6th nerve. Antidromic latencies ranged from 0.4 to 0.7 ms. Some retractor bulbi motoneurones could also be activated antidromically by stimulation of the lateral rectus muscle nerve.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239148
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  • 13
    Electronic Resource
    Electronic Resource
    Classification of cat retinal ganglion cells into X- and Y-cells with a contrast reversal stimulus (1979)
    Springer
    Experimental brain research 35 (1979), S. 25-36 
    Details
    ISSN: 1432-1106
    Keywords: Retinal ganglion cells ; Cat ; Contrast reversal stimulus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A contrast reversal (alternating phase) stimulus was used to study the responses of 150 retinal ganglion cells from 15 adult cats. Because the majority of the cells did not show perfect linear spatial summation, a ratio of the firing rates at two time periods was used to express the degree of nonlinearity. Y-cells showed a high degree of nonlinearity, and their mean null ratio was significantly lower than that of X-cells. With the stimulus at the null position, X-cells had an unmodulated discharge rate which was significantly higher than maintained activity, while the firing rate of Y-cells was lower than maintained activity. With the stimulus placed at an eccentric position in the receptive field, X-cells responded in a sustained manner, while Y-cells respond transiently. Because of these observations, we conclude that X-cells correspond to the sustained cells, while Y-cells correspond to the transient cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236782
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  • 14
    Electronic Resource
    Electronic Resource
    Various types of corticotectal neurons of cats as demonstrated by means of retrograde axonal transport of horseradish peroxidase (1979)
    Springer
    Experimental brain research 35 (1979), S. 161-175 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Superior colliculus ; Cat ; Horseradish peroxidase method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The retrograde labeling of cortical neurons with horseradish peroxidase (HRP) was used to investigate the morphological features of neurons in various cortical areas projecting to the superior colliculus in the cat. Corticotectal cells were found to be labeled in layer V of the entire cerebral cortex. The number of labeled cells and their locations varied according to the sites of injections of HRP in the colliculus. Most of the Corticotectal cells identified in the present study were small (9–20 μm in diameter, 66%) and medium (20–40 urn, 30%) pyramidal neurons and only 4% of them were large (more than 40 μm). The labeled cells, 261 in total number, had somal diameters of 20.8±8.0 μm (mean and SD). The range of sizes of the labeled neurons was different in different cortical areas. For example, the labeled neurons in the Clare-Bishop area had a greater proportion of large diameter cells than in other areas. The present findings are largely in agreement with the previous data of anterograde degeneration methods with respect to the topographical correlation of the Corticotectal projections. However, in some cortical areas, e.g., the sensorimotor and the first visual (area 17) cortex of the lateral surface of the hemisphere, relatively small numbers of Corticotectal neurons appear to have been labeled by retrogradely transported HRP. The sparsity of the labeled neurons in certain cortical areas may reflect the existence of Corticotectal neurons with axon collaterals supplying brain structures other than the superior colliculus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236792
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  • 15
    Electronic Resource
    Electronic Resource
    Cortical neurons projecting to the pontine nuclei in the cat. An experimental study with the horseradish peroxidase technique (1979)
    Springer
    Experimental brain research 35 (1979), S. 269-285 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Pontine nuclei ; Cat ; Horseradish peroxidase method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Horseradish peroxidase (HRP) injections in various portions of the cat pontine nuclei resulted in retrograde labeling of neurons in layer V of the ipsilateral cerebral cortex. Corticopontine neurons, pyramidal in type, have been found to be labeled in the entire cortex, confirming the previous findings of anterograde degeneration studies. Most (91%) of the labeled cells were 14–26 μm in diameter (mean 19.4±4.5 μm SD). Small (10–20 μm) and medium (20–40 μm) cells represent 51.5% and 47.7%, respectively, of the total number of the labeled neurons. The populations of the neurons of various sizes were almost identical in different cortical areas, and were different from the populations of corticoreticular and corticospinal cells. Corticopontine cells were well labeled in experimental cases of 3-days' survival time, confirming the topographical organization established previously by degeneration studies for this projection system. However, in cases of shorter survival time (20–27 h), the number of labeled neurons was very small. The relative paucity of labeled Corticopontine neurons in the sigmoid and lateral gyri is discussed with reference to other cortical descending neurons (e.g., the corticotectal, corticoreticular and corticospinal) which have hitherto been identified morphologically as well as physiologically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236615
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  • 16
    Electronic Resource
    Electronic Resource
    Cat phrenic nucleus architecture as revealed by horseradish peroxidase mapping (1979)
    Springer
    Experimental brain research 35 (1979), S. 395-406 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Spinal cord ; Phrenic motoneurons ; Neuron geometry ; Horseradish peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cat phrenic motoneurons, labeled by intradiaphragmatic injection of horseradish peroxidase, formed a tight cluster in the most ventral portion of the ventral horn in lamina IX of the lower cervical cord. Cell counts were symmetrically distributed for 17 to 21 mm along the longitudinal axis of the cord with a unimodal peak at the junction of segments C5 and C6. The phrenic nucleus was bilaterally organized on either side of the cord with anatomical symmetry and in no case was there evidence for the crossing of phrenic axons in the cord. Assessment of cellular geometry and intercellular relationships demonstrated that phrenic cell diameters approximated a normal distribution with a single peak at 26 μm while longitudinal cell lengths averaged 76 μm. Cells of different size were mixed randomly at all levels of the nucleus. The minimum distance between cells was about 10 μm and the maximum cell packing density approached 2 cells per 106 μm3. The results confirm the location of the cat phrenic nucleus, extend the knowledge of phrenic motoneuronal geometry, and provide an anatomical basis for the understanding of recruitment and synchronization phenomena within the phrenic nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236759
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  • 17
    Electronic Resource
    Electronic Resource
    Visual suppression from nondominant eye in the lateral geniculate nucleus: A comparison of cat and monkey (1979)
    Springer
    Experimental brain research 35 (1979), S. 465-477 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Monkey ; Lateral geniculate nucleus ; Visual nondominant suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied the suppression of firing in single LGN cells of cat and monkey in response to visual stimulation of the nondominant eye. In the cat LGN most of the cells of each of the main laminae show this nondominat suppression. X cells having their dominant input from the ipsilateral eye were suppressed to a significantly greater degree than any other cell type in the cat LGN. In the monkey LGN nondominant suppression was absent in all 19 X-like cells studied, whereas 6 of 21 Y-like cells showed nondominant suppression. Thus nondominant suppression is present in the magnocellular laminae of the monkey LGN, where the Y-like cells are found, but appears to be absent from the parvocellular laminae, where the X-like cells are found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236765
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  • 18
    Electronic Resource
    Electronic Resource
    Thermosensory defects after cervical spinal cord lesions in the cat (1979)
    Springer
    Experimental brain research 35 (1979), S. 479-494 
    Details
    ISSN: 1432-1106
    Keywords: Thermosensitivity ; Lesions ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The behavioural thermosensitivity of cat paws was examined before and/or after restricted uni- and/or bilateral lesions had been made in the spinal cord between the first and fifth cervical segments. Unilateral lesions of the lateral funiculus, which involved at least its whole width at the level of the central canal, reproducibly were found to interfere with the contralateral sensitivity for temperature increases and/or decreases. No corresponding thermosensory deficiencies were found after unilateral lesions involving the ventral spinal quadrant or the dorsal funiculus. Various bilateral and combined lesions were made, but no cat ever developed thermoanaesthesia. The bilateral lesions included bilateral transections of: the middle parts of the lateral funiculi, the dorsal halves of the lateral funiculi, the dorsal funiculi, and the ventral spinal half. Most of our knowledge about peripheral behavioural thermosensitivity after spinal cord injury is based on observations of human patients, especially after anterolateral chordotomies. The present finding of contralateral thermosensory deficiencies after lesions of the middle part of the lateral funiculus fits with some of the clinical reports. The present failure to cause thermoanaesthesia, on the other hand, is inconsistent with the theory of a single ascending spinal pathway for behavioural thermo-sensitivity, which has emanated mainly from the clinical observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236766
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  • 19
    Electronic Resource
    Electronic Resource
    A comparison of visual responses in two pretectal nuclei and in the superior colliculus of the cat (1979)
    Springer
    Experimental brain research 35 (1979), S. 495-510 
    Details
    ISSN: 1432-1106
    Keywords: Pretectal nuclei ; Superior colliculus ; Visual response pattern ; Retinal input types ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single unit recordings from 220 units were obtained from the nuclei praetectalis anterior (NPA) and posterior (NPP) of 30 immobilized, anesthetized cats. Quantitative analysis of pretectal (PT) visual activity was mainly based on recordings from the NPP. For comparison, 160 collicular (CS) neurons were studied. A strong sensitivity for moving objects was evident in both samples. The following main types of PT activity were categorized: (A) slow movement, direction-selective units (21%); (B) slow movement, nondirection-selective units (19%); (C) units nonselective for stimulus velocity and direction (24%); (D) jerk movement selective, nondirection-selective units (36%). Latency measurements following single shocks to optic chiasm (OX) and tract (OT) showed mainly slow conducting fiber input to the PT and CS which can be divided into two different groups by conduction properties and synaptic delay: direct W-input and delayed W-input. Fast Y-fiber input of both types, direct and indirect, was recorded at both sites, PT and CS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236767
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  • 20
    Electronic Resource
    Electronic Resource
    Hypercomplex cell types in area 18 of the cat (1979)
    Springer
    Experimental brain research 36 (1979), S. 191-194 
    Details
    ISSN: 1432-1106
    Keywords: Hypercomplex cells ; Area 18 ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single unit recording has revealed the same orientation sensitive cell classes in cat area 18 as are to be found in area 17. These include particularly the various types of hypercomplex cell belonging to the S, C, and B cell families.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238477
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  • 21
    Electronic Resource
    Electronic Resource
    Activity of ventrolateral thalamic neurons in relation to a simple reaction time task in the cat (1979)
    Springer
    Experimental brain research 36 (1979), S. 285-300 
    Details
    ISSN: 1432-1106
    Keywords: VL nucleus ; Single units ; Reaction time ; Movement initiation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Unrestrained cats performed ballistic forelimb flexion movements triggered by an auditory stimulus (CS) on a simple reaction time (RT) paradigm. During the variable foreperiod the subject was required to hold down a lever and to release it on presentation of the CS. The RTs ranged from 200 to 300 ms. The activity of single neurons of the ventrolateral nucleus of the thalamus (VL) was recorded bilaterally. More than 40% of the 166 units recorded in the VL contralateral to the performing limb presented, after the CS, changes of activity with a latency less than 100 ms and were classified into three types: (1) Twenty-five units had a short latency transient increase of activity 10 to 30 ms after the CS, followed by a longer increase or decrease in activity. Short latency increase as well as subsequent increase of the firing rate were not correlated to the RTs. (2) Twenty-nine units showed a 40–60 ms latency increase of activity which lasted long enough to continue during the forelimb movement. These units displayed a correlation between the RTs and the mean firing rate measured in the 40–100 ms period after the CS. The more the cells were activated, the shorter the RTs. (3) Fifteen units presented a reciprocal pattern of discharge with respect to the type (2) units. The firing rate decreased with latencies ranging from 20 to 90 ms after the CS. Only 14,5% of the 96 units recorded in the VL ipsilateral to the performing limb presented changes of activity starting in the 100 ms period following the CS. Background firing levels as well as phasic activity were rather low compared to those observed contralaterally. Sixteen units showed burst activity while the cat was performing but burst pattern was not time-related to the task. In an unconditioned animal, a very low level of activity and an absence of modulations were observed in both VLs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238912
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  • 22
    Electronic Resource
    Electronic Resource
    The role of maturation and visual experience in the development of eye alignment in cats (1979)
    Springer
    Experimental brain research 37 (1979), S. 41-47 
    Details
    ISSN: 1432-1106
    Keywords: Eye alignment ; Cat ; Visual experience ; Maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the developing kitten, the alignment of the pupils changes from strongly divergent to almost parallel. The visual axes, however, seem to stay almost parallel throughout this period. The influence of early visual experience on this development is examined in the present study. The results suggest that the development of eye alignment is not controlled by visual experience, but depends on maturational processes, and that normal visual input serves only to halt these processes at the appropriate time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01474252
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  • 23
    Electronic Resource
    Electronic Resource
    14C-Deoxyglucose mapping of orientation subunits in the cats visual cortical areas (1979)
    Springer
    Experimental brain research 37 (1979), S. 609-613 
    Details
    ISSN: 1432-1106
    Keywords: Orientation subunits ; Visual cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The orientation domain in the cortical visual areas of anesthetized cats has been investigated by employing the 14C-Deoxyglucose technique (Sokoloff et al., 1977). Orientation subunits (OS) are seen in the first (V1), the second (V2) and the third visual area (V3) as well as in the visual areas of the suprasylvian sulcus. In the latter regions OS are less elaborated than in V1, V2, and V3. The OS are continuous through all cortical layers; in V1 however, only weak label is detected in layer 4C. In V1, V2, and V3 the width of the OS is about 0.4 mm and the average distance between two OS centers is 0.9 mm. The spatial pattern of the OS seems to be more regular in the visual field periphery than in regions representing the vertical meridian.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236828
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  • 24
    Electronic Resource
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    The effects of splanchnic nerve stimulation on the plasma levels of serotonin and substance P in the portal vein of the cat (1979)
    Springer
    Journal of neural transmission 46 (1979), S. 105-112 
    Details
    ISSN: 1435-1463
    Keywords: Cat ; electrical stimulation ; serotonin ; splanchnic nerves ; substance P
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The blood levels of serotonin (5-HT) and substance P (SP) in the portal vein were studied after splanchnic nerve stimulation in the cat. The portal levels of both substances were studied before, during and after splanchnic nerve stimulation. There was a twofold increase in 5-HT during stimulation whilst the SP concentration remained unchanged. These results suggest that the nervous control of the amine release into the portal stream and the mechanism that regulates the release of the polypeptide is not the same.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01250332
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  • 25
    Electronic Resource
    Electronic Resource
    Brain-stem responses of the cat and interaural attenuation (1979)
    Springer
    European archives of oto-rhino-laryngology and head & neck 222 (1979), S. 113-118 
    Details
    ISSN: 1434-4726
    Keywords: Brain-stem electric response (BSER) ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The early auditory evoked responses have been studied in bilaterally hearing cats, and in animals with hereditary unilateral anacusis. Cross-over stimulation of the hearing ear occurs at an interaural attenuation of 50-50 dB, and all six waves of the responsare present at supra-threshold stimulus levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00469750
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  • 26
    Electronic Resource
    Electronic Resource
    Types of thalamo-cortical relay neurons in the anteroventral nucleus of the cat (1979)
    Springer
    Cell & tissue research 196 (1979), S. 175-179 
    Details
    ISSN: 1432-0878
    Keywords: Thalamo-cortical projection ; Anteroventral nucleus ; HRP retrograde transport ; Golgi impregnation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neurons displaying a thalamo-cortical projection were marked by means of the retrograde transport of horseradish peroxidase (HRP), and the labeled elements were compared with neurons impregnated by the Golgi technique. Injections of HRP into the posterior area of the limbic cortex resulted in its uptake by various anterior thalamic nuclei, especially the anteroventral nucleus. HRP-positive cells are characterized by their position, dendritic orientation, and the shape and size of their somata. On the basis of the combined HRP- and Golgi-analysis three different types of thalamo-cortical relay neurons can be distinguished.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236358
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  • 27
    Electronic Resource
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    A combined horseradish peroxidase and Golgi study on the afferent connections of the ventrobasal complex of the thalamus in the cat (1979)
    Springer
    Cell & tissue research 199 (1979), S. 529-538 
    Details
    ISSN: 1432-0878
    Keywords: Thalamus ; Horseradish peroxidase ; Golgi-impregnation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Afferent connections to the ventrobasal complex (VB) of the thalamus were studied by means of retrograde transport of horseradish peroxidase (HRP) and by the Golgi-method. After HRP-injection into the VB, peroxidase-positive cells were observed contralaterally in the dorsal column nuclei (DCN), in the trigeminal nuclei and in the lateral cervical nucleus (LCN), and ipsilaterally in the somatosensory I (SI) and II (SII) cortical areas. Labeled cells of different shape and size were compared with neurons impregnated by the Golgi-technique. On the basis of HRP-labeling it is concluded that cells projecting to the VB are different in size and shape even within one region and that they correspond to the relay or efferent neurons observed in the Golgimaterial.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236088
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  • 28
    Electronic Resource
    Electronic Resource
    Immunocytochemical identification of vasopressinergic and oxytocinergic neurons in the hypothalamus of the cat (1979)
    Springer
    Cell & tissue research 196 (1979), S. 117-122 
    Details
    ISSN: 1432-0878
    Keywords: Vasopressin neurons ; Oxytocin neurons ; Immunocytochemistry ; Magnocellular neuroendocrine system ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Our immunocytochemical investigation of the magnocellular neuroendocrine cells in the cat hypothalamus reveals a mixture of vasopressin (VP)- and oxytocin (OT)-containing neurons in the supraoptic (NSO), the paraventricular (NPV) and in five accessory nuclei (NAC). We describe the lateral hypothalamic nucleus (NLH), a new accessory nucleus, lying at the junction of the internal capsule and pallidum, and possibly involved in drinking behavior. Previously characterized incompletely in mammals, the four other accessory nuclei consist of the circularis (NC), anterior fornical (NAF), posterior fornical (NPF) and retrochiasmatic (NRC). The two peptidergic cell types, VP and OT, are equally mixed in the NPV and the NAC, but in the NSO VP neurons predominate. The perikarya of these VP and OT neurons do not show distinct morphological differences at the level of light microscopy. The organization of magnocellular neurosecretory neurons in the cat hypothalamus closely resembles that described in other mammals with the exception of the unique presence of the lateral hypothalamic accessory nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236352
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  • 29
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    Electronic Resource
    Elektrophile aromatische Substitutionsreaktionen mit protonierten 1,3-Diazinen, I. Darstellung und Eigenschaften 4-arylsubstituierter 3,4-Dihydropyrimidin-Derivate (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1-15 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electrophilic Aromatic Substitution Reactions with Protonated 1,3-Diazines, I. Preparation and Properties of 4-Aryl-substituted 3,4-Dihydropyrimidine DerivativesIn the presence of trifluoroacetic acid, pyrimidine and 5-methylpyrimidine react with active aromatic compounds to form stable 4-aryl-substituted 3,4-dihydropyrimidinium salts, e.g. 1, 2, 6. From these, the dihydro bases 7 or 8 can be obtained which are readily oxidized to 4-aryl-substituted pyrimidines 9. 2- and/or 4-substituted pyrimidines as well as 2-amino- and 2-mercaptopyrimidines react with phenols to form benz[g][1,3,5]oxadiazocines 3 and 10. The mechanism of this novel reaction is apparently best described as an aromatic electrophilic substitution by the protonated pyrimidine derivative. The observed reactivity of different diazines is in accordance with frontier orbital arguments, using HMO-coefficients.
    Notes: Bei Gegenwart von Trifluoressigsäure reagieren Pyrimidin und 5-Methylpyrimidin mit aktiven aromatischen Verbindungen zu stabilen 4-arylsubstituierten 3,4-Dihydropyrimidinium-Salzen, z. B. 1, 2, 6, aus denen sich die zugrunde liegende Dihydrobase 7 bzw. 8 erhalten läßt, die ihrerseits leicht zu 4-arylsubstituierten Pyrimidinen 9 oxidiert werden kann. 2- und/oder 4-substituierte Pyrimidine sowie 2-Amino- und 2-Mercaptopyrimidine bilden mit Phenolen Benz[g][1,3,5]oxadiazocine der (Konstitution 3a - f und 10. Als Reaktionsmechanismus wird eine elektrophile Substitutionsreaktion durch das protonierte Pyrimidinderivat vorgeschlagen. Die beobachtete Reaktivität der verschiedenen Diazine steht im Einklang mit dem Grenzorbital-Modell auf der Basis der HMO-Koeffizienten.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120102
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    Umlagerungen freier Radikale, VII. Elektrocyclische und sigmatrope Umlagerungen des Bicyclo[3.1.0]hexenyl-Radikals (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 42-56 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangements of Free Radicals, VII. Electrocyclic and Sigmatropic Rearrangements of Bicyclo[3.1.0]hexenyl RadicalAbstraction of an allylic hydrogen from bicyclo[3.1.0]hex-2-ene (1) leads to the bicyclic allyl radical 2. Electrocyclic ring opening to the cyclohexadienyl radical 3 could not be observed in solution up to + 70°C. Only the product analysis of a thermolysis (130°C) of di-tert-butylperoxide in presence of 1 evidenced the possibility of ring opening with the formation benzene. In adamantane matrix 2 rearranges at -50°C in 3 (ΔG≠ = 68.6 ± 2.0 kJ/mol). In matrix bimolecular termination reactions are prohibited. Therefore rearrangements with activation barriers greater than those of diffusion controlled reactions can easily be observed. By this method a degenerate 1,4-sigmatropic rearrangement of the methylene bridge in 2 could be proven. For this purpose specifically in 2- and 3-position deuterated derivatives of 1 were synthesized. The sigmatropic reaction follows from the statistical distribution of deuterium in the cyclohexadienyl radical over the carbon atoms of the former five-membered ring.
    Notes: Durch Abstraktion eines allylischen Wasserstoffatoms aus Bicyclo[3.1.0]hex-2-en (1) läßt sich das bicyclische Allylradikal 2 erzeugen. Eine Ringöffnung zum Cyclohexadienylradikal 3 konnte in Lösung ESR-spektroskopisch bis + 70°C nicht beobachtet werden. Die Produktanalyse einer Thermolyse (130°C) von Di-tert-butylperoxid in Gegenwart von 1 erwies mit dem Auftreten von Benzol die grundsätzliche Möglichkeit zur elektrocyclischen Ringöffnung. In Adamantanmatrix lagert das durch Röntgenbestrahlung aus 1 erzeugte 2 bereits bei -50°C in 3 um (ΔG≠ = 68.6 ± 2.0 kj/mol). Die Matrixmethode macht durch die Unterdrückung bimolekularer Abreaktionen von 2 auch den Nachweis einer degenerierten sigmatropen 1,4- Verschiebung der Methylenbrücke möglich. Hierzu wurden in 2- bzw. 3-Stellung deuterierte Derivate von 1 dargestellt. Der Nachweis der sigmatropen Wanderung ergibt sich aus der statistischen Verteilung des Deuteriums im Cyclohexadienylradikal über die C-Atome. des ehemals fünfgliedrigen Ringes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120105
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  • 31
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    Protonenresonanz-Spektroskopie ungesättigter Ringsysteme, XXVII. Der Benzolkern als Sonde für die π-Elektronenstruktur von Annulenen; Teil IV: Dehydrobenzoannulene (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 71-83 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Proton Resonance Spectroscopy of Unsaturated Ring Systems, XXVII. The Benzene Nucleus as a Probe for the π-Electronic Structure of Annulenes; Part IV: DehydrobenzoannulenesThe 1H NMR Spectra of 6,9-dimethyl-7-monodehydrobenzo[12]annulene (1), 7,9-bisdehydrobenzo[14]annulene (2a), 6,11-dimethyl-7,9-bisdehydrobenzo[14]annulene (2a), 6,11-dimethyl-7,9-bisdehydrobenzo[16]annulene (3), and 9,11-bisdehydrobenzo[18]annulene (4) have been analyzed with respect to chemical shifts and H,H coupling constants. The electronic ground state properties of the annulene rings have been investigated using the Q-value method2). On the basis of the chemical shifts it was found that, compared to the free bisdehydroannulenes, the diatropic behaviour of 2a and 4 is reduced by ca. 70-80%, whereas the paratropic nature of 3 is diminished by less than 50%. Strong π-bond fixation exists in the annulene rings of 1-4.The conformations of the systems are discussed.
    Notes: Die 1H-NMR-Spektren von 6,9-Dimethyl-7-monodehydrobenzo[12]annulen (1), 7,9-Bisdehydrobenzo[14]annulen (2), 6,11-Dimethyl-7,9-bisdehydrobenzo[14]annulen (2a), 6,11-Dimethyl-7,9-bisdehydrobenzo[16]annulen (3) und 9,11-Bisdehydrobenzo[18]annulen (4) wurden hinsichtlich chemischer Verschiebungen und H,H-Kopplungskonstanten analysiert. Die elektronischen Eigenschaften des Grundzustandes der Annulenringe wurden mit Hilfe der Q-Wert-Methode2) untersucht. Aus den chemischen Verschiebungen wurde abgeleitet, daß das diatrope verhalten von 2a und 4 im Vergleich zu dem der freien Bisdehydroannulene um ca. 70-80% reduziert ist, während das paratrope Verhalten von 3 um weniger als 50% abgenommen hat. In den Annulenringen von 1-4 liegt eine starke π-Bindungsfixierung vor. Die Konformationen der Systeme werden diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120107
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    Darstellung und Molekülstruktur von μ-1,2-Dithiooxalato (S,S′)-bis[pentacarbonylmangan(I)] (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 95-98 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Molecular Structure of μ-1,2-Dithiooxalato(S S′)-bis [pentacarbonylamanganese(I)]The structure of the binuclear title compound 2 has been determined from X - ray data. 2 is formed by reaction of Cs2(OSC — CSO) with Mn(CO)5Br. The thiooxalato ligand has a transplanar conformation and connects the two Mn atoms through dative Mn — S — bonds.
    Notes: Die Struktur der zweikernigen Titelverbindung 2 wurde röntgendiffraktometrisch bestimmt. 2 entsteht durch Reaktion von Cs2(OSC — CSO) mit Mn(CO)5Br. Der Thiooxalato-Ligand besitzt transplanare Konformation und verknüpft über koordinative Mn— S — Bindungen die beiden Molekülhälften.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120109
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    Über Aminosäuren und Peptide, XXVIII. Über Dehydroaminosäuren, XIV. Schiffsche Basen von Dehydroaminosäuren aus 2-Aryl-4-thiazolidincarbonsäuren.  -  Erste Synthese eines N-Aryliden-dehydroalaninesters (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 107-115 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XXVIII. On Dehydro Amino Acids, XIV. Schiff Bases of Dehydro Amino Acids from 2-Aryl-4-thiazolidinecarboxylic Acids.  -  First Synthesis of an N-Arylidene-dehydroalanine Esteron treatment with Ag2CO3 in aprotic solvents the 4-thiazolidinecarboxylic acid esters 1-4 afford the N-arylidene-dehydrovaline derivatives 5-8 in excellent yields. The dehydro peptides land 9 and 10 are obtained from the N-arylidene-dehydrovaline N-hydroxysuccinimide esters 7 and 8 by the reaction with amino acid amides. Methyl 2-phenyl-4-thiazolidinecarboxylate (12) reacts with Ag2CO3/DBU to yield the unstable N-benzylidene-aminoacrylic acid derivative 14, which On treatment with methanethiol yields the cysteine ester (RS)-13. Treatment of 12 with Ag2CO3/ CH3Br and without DBU-catalysis affords the optically active derivative (S)-13.
    Notes: Die 4-Thiazolidincarbonsäureester 1-4 reagieren mit Ag2CO3 in aprotischen Lösungsmitteln in ausgezeichneten Ausbeuten zu den N-Aryliden-dehydrovalin-Derivaten 5-8. Die N-Aryliden-dehydrovalin-N-hydroxysuccinimidester 7 und 8 können mit Aminosäureamiden zu den Dehydropeptiden 9 und 10 umgesetzt werden. 2-Phenyl-4-thiazolidincarbonsäure-methylester (12) bildet mit Ag2CO3 unter DBU-Katalyse den instabilen N-Benzyliden-aminoacrylsäureester 14, der mit Methanthiol zum Cysteinderivat (RS)-13 reagiert. Ohne DBU erhält man aus 12 mit Ag2CO3 und Methylbromid das optisch aktive (S)-13.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120111
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    Syntheses of DL-Serine and of Precursors thereof (Glycolaldehyde and “Masked” Glycolaldehydes) (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 148-160 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesen von DL-Serin Vorläufern (Glycolaldehyd und „maskierte“ Glycolaldehyde)Bei Behandlung von Vinylchloridepoxid (4) mit Wasser, von Chlorethylencarbonat (9) mit wäßrigen Basen, von Vinylacetat (1) oder Ethylvinylether (6) mit wäßrigem Kaliumchlorat und einer katalytischen Menge Osmiumtetroxid bildete sich Glycolaldehyd (5) (Schema 1). Der nicht isolierte Aldehyd 5 lieferte bei der Zelinsky-Stadnikoff-Aminosäure-Synthese DL-Serin mit 70% Ausbeute. Diese Methode ergab, direkt von den „maskierten“ Glycolaldehyden 2, 7, 9, 10, Vinylencarbonat (11), 13 oder 14 ausgehend, ebenfalls DL-Serin (Ausbeuten 35-70%), wogegen ausgehend von 4 kein Serin nachgewiesen werden konnte.
    Notes: On treatment of vinyl chloride epoxide (4) with water, of chloroethylene carbonate (9) with aqueous bases, of vinyl acetate (1) or ethyl vinyl ether (6) with aqueous potassium chlorate and catalytic amounts of osmium tetroxide, glycolaldehyde (5) was formed (scheme 1). The not isolated aldehyde 5, when submitted to the Zelinsky-Stadnikoff amino acid synthesis, afforded DL-serine in 70% yield. The latter method, when applied directly to the “masked” glycolaldehydes 2, 7, 9, 10, vinylene carbonate (11), 13 or 14, also gave DL-serine (yields 35-70%), whereas with 4 no serine formation could be detected (scheme 1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120115
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    Die Umlagerung des 9-Cyan-cis-bicyclo[6.1.0]nona-2,4,6-trien-9-yl-Anions in das 9-Cyanbicyclo[4.2.1] nona-2,4,7-trien-9-yl-Anion Zur Frage der Bicycloaromatizität (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 175-195 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangement of the 9-Cyano-cis-bicyclo [6.1.0]nona-2,4,6-trien-9-yl Anion to the 9-Cyanobicyclo[4.2.1]nona-2,4,7-trien-9-yl Anion On the Problem of BicycloaromaticityReaction of methyl cis-bicyclo[6.1.0]nona-2,4,6-triene-9-anti-carboxylate (5b) with lithiumdiisopropylamide does not lead to deprotonation at C9 of 5b. Instead, a bridgehead cyclopropyl anion is formed which opens to give the allyl anion 12b.  -  In contrast, cis-bicyclo[6.1.0]nona-2,4,6-triene-9-anti-carbonitrile (5c) is also deprotonated at C9 leading to the 9-cyano-cis-bicyclo-[6.1.0]nona-2,4,6-trien-9-yl anion (1c), which rearranges comparatively fast (ΔG≠-43°C = 16.5 kcal · mol-1) to the 9-cyanobicyclo[4.2.1]nona-2,4,7-trien-9-yl anion (4c). Applying qualitative MO arguments of Goldstein and Hoffmann 4) one could explain the facile formation of the „bicyclo-aromatic“ 4c on the basis of ground state destabilization of 1c and stabilization of 4c. H/D-Exchange experiments, however, are at variance with this interpretation.  -  An additional stabilization of the transition state in the anionic sigmatropic rearrangement 1c → 4c as well as the opening the C1 — C9 bond instead of the central C1 — C8 bond are in agreement with HOMO-LUMO interactions.
    Notes: Die Umsetzung von cis-Bicyclo[6.I.0]nona-2,4,6-trien-9-anti-carbonsäure-methylester (5b) mit Lithiumdiisopropylamid führt nicht zu Deprotonierung an C9 von 5b. Statt dessen wird das Brückenkopfproton Hl abgespalten. Anionische Ringöffnung ergibt das Allyl-Anion 12b.  -  Im Gegensatz dazu wird das entsprechende 9-anti-Carbonitril 5c auch an C9 zum 9-Cyan-cis-bicyclo[6.1.0]nona-2,4,6-trien-9-yl-Anion (lc) deprotoniert, das vergleichsweise rasch (ΔG≠-43°C = 16.5 kcal · mo1) in das 9-Cyanbicyclo[4.2.1]nona-2,4,7-trien-9-yl-Anion (4c) umlagert. Qualitative MO-Überlegungen nach Goldstein und Hoffmann4) lassen vermuten, daß die leichte 1,5-Umlagerung auf Grundzustands-Destabilisierung von lc bzw. -Stabilisierung von 4c, mithin auf „Bicycloaromatizität“ von 4c, zurückzuführen ist. H/D-Austauschversuche zur Bestimmung von Anion-Stabilitäten stehen jedoch zu dieser Erklärung im Widerspruch.  -  Eine zusätzliche Stabilisierung des Übergangszustandes der anionischen sigmatropen Umlagerung 1c → 4c wie auch die seitliche statt der zentralen Bindungslösung im cyan-substituierten Anion 1c sind mit HOMO-LUMO-Wechselwirkungen zu verstehen.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120117
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    Thieno[3,4-c]isothiazol. Synthese und Eigenschaften eines neuen nichtklassisch kondensierten Thiophens (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 260-265 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thieno[3,4-cisothiazole]. Synthesis and Properties of a New Nonclassical Condensed ThiopheneThe triphenylthieno[3,4-c]isothiazole 3 is a new 10 π heteroarene containing two different masked 1,3-dipolar systems. Its synthesis from 4-phenyl-1,3.2-oxathiazolylium-5-olate (1) and dibenzoyl-acetylene via the direct precursor 2 as well as its photoelectronic and electronic spectra are desribed. The observed electronic transitions of 3 are compared with the results of a PPP-CI calculation
    Notes: Das Triphenylthieno[3,4-c]isothiazol 3 ist ein neuer 10 π-Heteroaromat, der zwei verschiedene maskierte 1,3-dipolare Systeme beinhaltet. Seine Synthese aus 4-Phenyl-1,3,2-oxathiazolylium-5-olat (1) und Dibenzoylacetylen über die direkte Vorstufe 2 sowie sein Photoelektronen- und Elektronenspektrum werden beschrieben. Die an 3 beobachteten Elektronenübergänge werden mit den Ergebnissen einer PPP-CI-Rechnung verglichen.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120123
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    Transanulare Wechselwirkungen bei [3.3]Phanen, III. [3.3]Paracyclophan, neue Synthesen, Sessel- und Wannen-Konformation (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 249-259 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transanular Interactions in [3.3]Phanes, III. [3.3]Paracyclophane, New Syntheses, Chair and Boat Conformation[3.3]Paracyclophane (1) was synthesized via the 2,13-dithia[4.4]paracyclophane (2) by vapor phase pyrolysis of the disulfone 3 obtained from 2. Reaction of 2 with benzyne gave trans- and cis-2,1 l-bis(phenylthio)[3.3]paracyclophane (4 and 5) by Stevens rearrangement. Oxidation to the sulfoxides 6 and 7 and pyrolysis yielded the [3.3]paracyclophanedienes (12/13) giving 1 on catalytic hydrogenation. Large substituents in the 2,11-positions of the bridges stabilize the two conformers of 1, based on 1H-NMR spectra the trans-isomer 4 has the chair, the cis-isomer 5 the boat conformation.
    Notes: [3.3]Paracyclophan (1) wurde über 2,13-Dithia[4.4]paracyclophan (2) durch Gasphasen-Pyrolyse des aus 2 erhaltenen Disulfons 3 synthetisiert. Reaktion von Dehydrobenzol mit 2 ergab durch Stevens-Umlagerung trans- und cis-2,11-Bis(phenylthio)[3.3]paracyclophan (4 und 5); durch Oxidation zu den Sulfoxiden 6 und 7 und Pyrolyse wurden die [3.3]Paracyclophandiene (12/13) erhalten, die bei katalytischer Hydrierung 1 ergaben. Große Substituenten in den 2,11-Positionen der Brücken stabilisieren die beiden Konformere von 1, laut 1H-NMR-Spektren liegt das trans-Isomere 4 in der Sessel-, das cis-Isomere 5 in der Wannen-Konformation vor.
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    Die Racemisierung spirocyclischer Pentaarylderivate von Elementen der V. Hauptgruppe, I. 1H-NMR-Untersuchungen mit sterisch überbesetzten asymmetrischen Phosphoranen, Arsoranen und Stiboranen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 281-291 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Racemization of Spirocyclic Pentaaryl Derivatives of Group 5 A Elements. I H NMR Investigations with Overcrowded Asymmetric Phosphoranes, Arsoranes, and StiboranesThe two different methyl positions of bis-2,2′-biarylylenephosphorane 7, the corresponding arsoranes 8a, b, and the analogous stiborane 9 are reversibly equilibrated at elevated temperatures with free enthalpies of activation of 18.2 (76.0), 17.2 (72.2), ≈ 22.5 (94.2), and 15.4 (64.6) kcal(kJ)/mol. Starting with the trigonal bipyramidal ground state conformations C and ∪ (fig. 2) these ligand exchange phenomena can be interpreted in the framework of the pseudorotation process on the basis of trigonal bipyramidal transition states of type A with diequatorial biarylylene groups.
    Notes: Die beiden unterschiedlichen Methyl-Positionen des Bis-2,2′-biarylylenphosphorans 7, der entsprechenden Arsorane 8a, b und des analogen Stiborans 9 werden bei erhöhten Temperaturen mit freien Aktivierungsenthalpien von 18.2 (76.0), 17.2 (72.2). ≈ 22.5 (94.2) und 15.4 (64.6) kcal(kJ)/mol reversibel äquilibriert. Ausgehend von den trigonal-bipyramidalen Grundzustandskonformationen C und ∪ (Abb. 2) lassen sich diese Ligandenaustauschphänomene im Rahmen des Pseudorotationsprozesses auf der Basis trigonal-bipyramidaler Übergangszustände des Typs A (Abb. 2) mit diäquatorialen Biarylylen-Gruppen interpretieren.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120125
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    Lichtinduzierte Reaktionen, XIII. Über das seco-isomere Dienylketen aus 2,4-Androstadien-l-on (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 310-348 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Light-induced Reactions, XIII. On the Seco-isomeric Dienylketene Related to 2,4-Androstadien-1-oneThe steroidal 2.4-cyclohexadienone 3 photochemically affords the diastereomer 4. Both the configurational isomers differ exceedingly in their chiroptical properties. Their respective contribution to the photostationary state depends on the wave-length of the light and the solvent utilized. The dienylketene 5 can be determined spectroscopically as a transient. It is not trapped by 2,2,2-trifluoroethanol; cyclohexylamine, however, furnishes the 1,6-adduct 7a and/or the 1,2-adduct 6 a owing to the concentration and wave-length (365 or 313 nm) used.
    Notes: Das steroidale 2,4-Cyclohexadienon 3 geht photochemisch in das Diastereomere 4 über. Beide Konfigurationsisomere unterscheiden sich deutlich in ihren chiroptischen Eigenschaften. Ihr jeweiliger Anteil im photostationären Zustand hängt von der Wellenlänge des Lichts und dem Lösungsmittel ab. Das Dienylketen 5 läßt sich als Transient spektroskopisch nachweisen. Es wird von 2,2,2-Trifluorethanol nicht, von Cyclohexylamin je nach Konzentration und Wellenlänge (365 oder 313 nm) als 1,6-Addukt 7a und/oder als 1,2-Addukt 6a abgefangen.
    Additional Material: 21 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120129
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    Cyclisierungsprodukte aus N-arylsubstituierten Propiolamidinen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 384-388 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Substances from N-Aryl-substituted PropiolamidinesThe chloroformamidines 4a-c react with lithium phenylacetylide to form the propiolamidines 5a-c. 5a and 5b cyclize upon treatment with polyphosphoric acid to give the 2-aminoquinolines 6 and 7,8, respectively; 5c yields only the spiro compound 9.
    Notes: Die Chlorformamidine 4a-c reagieren mit Lithium-phenylacetylid zu den Propiolamidinen 5a-c. 5a bzw. 5b cyclisieren in Polyphosphorsäure (PPS) zu den 2-Aminochinolinen 6 bzw. 7 und 8, während 5c als einziges Produkt die Spiroverbindung 9 ergibt.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120134
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    Konstitutionsaufklärung des Melochinins, eines Pyridon-Alkaloids neuen Typus aus Melochia pyramidata L. (Sterculiaceae) (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 376-383 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure of Melochinine, a New Type of a Pyridone Alkaloid from Melochia pyramidata L. (Sterculiaceae)Melochinine, isolated from leafs of Melochia pyramidata L., is the first representative of a so far unknown class of pyridone alkaloids. Its structure was determined by spectroscopic methods in combination with microchemical degradation reactions to be 3.
    Notes: Das aus Melochia pyramidata L. isolierte Melochinin gehört einer bisher unbekannten Klasse von Pyridon-Alkaloiden an. Seine Struktur 3 wurde mit spektroskopischen Methoden und mikrochemischen Abbaureaktionen bestimmt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120133
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    Photochemische Synthese von (η5-C5H5)2V2(CO)5 (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 392-393 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemical Synthesis of (η5-C5H5)2V2(Co)5μ-Dicarbonyl-tricarbonylbis[(η5-cyclopentadienyl)vanadium](V-V) (2) has been synthesized in 89% yield by photolysis of tetracarbonyl(η5 -cylcopentadienyl)vanadium (1) in tetrahydrofuran using a falling-film photoreactor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120136
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    Masthead (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979) 
    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.19791120201
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    Natürlich vorkommende Terpen-Derivate, 156. Über eine neue Gruppe von Sesquiterpenlactonen aus der Gattung Trixis (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 435-444 
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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: Naturally Occurring Terpene Derivatives, 156. On a New Group of Sesquiterpene Lactones from the Genus TrixisTwo species of the South American genus Trixis afforded 12 new sesquiterpenes all with a new pentacyclic ring system, named trixikingolide (3-8 and 10-24). The structures are elucidated by spectroscopic methods and chemical transformations which are in part unusual. The carbon skeleton is that of an isocedrene (1), first found in several other genera of the tribe Mutisieae. This type is probably of chemotaxonomical importance.
    Notes: Zwei Vertreter der südamerikanischen Gattung Trixi ergeben 12 neue Sesquiterpene, alle mit dem neuen pentacyclischen Ringsystem. das wir Trixikingolid genannt haben (3-8 und 19-24). Die Konstitutionen werden durch spektroskopische Methoden und chemische Umwandlungen, die zum Teil ungewöhnlich sind, geklärt. Das Kohlenstoffgerüst ist das eines Isocedrens (1), das zuerst in mehreren Gattungen der Tribus Mutisieae gefunden wurde. Dieser Typ ist wahrscheinlich von chemotaxonomischer Bedeutung.
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    Reaktionen von Azidocobalt(III)-Chelatkomplexen mit Isocyaniden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 468-479 
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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: Reactions of Azidocobalt(III) Chelate Complexes with IsocyanidesAzidochelatecobalt(III) complexes N3Co(chelate)B (la-e) [chelate = e. g. dianion of N,N′-o-phenylenebis(salicylidenimine), B = PPh3] react with organic isocyanides to give metal-carbon bonded tetrazolate complexes 3, 4. 2-Isocyanoethanol affords tetrazolato- (9, 10) or azido-oxazolidin-2-ylidene complexes (11), depending on the nature of the solvent, the trans-base B, and the chelate ligand. The mechanism of formation of C-coordinated tetrazoles from azido complexes and isonitriles is discussed.
    Notes: Azidochelatcobalt(III)-Verbindungen N3Co(chelat)B(la-e) [chelat = z. B. Dianion von N,N′-o-Phenylenbis(salicylidenimin), B = PPh3] setzen sich mit organischen Isocyaniden zu Tetrazolatokomplexen 3, 4 mit Cobalt-Kohlenstoff-Bindung um. Mit 2-Isocyanethanol entstehen in Abhängigkeit vom Lösungsmittel, der trans-ständigen Base B und dem Chelatliganden Tetrazolato-(9, 10) oder Azido-oxazolidin-2-yliden-Komplexe (11). Der Mechanismus der Bildung C-koordinierter Tetrazole aus Azidokomplexen und Isonitrilen wird diskutiert.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120209
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    Gold-Komplexe von Diphosphinomethanen, IV. AuI-Verbindungen von Diphosphinoaminen und oxidative Addition von Chlor zu AuII- und AuIII-Komplexen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 496-500 
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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: Gold Complexes of Diphosphinomethanes, IV. Au1 Compounds of Diphosphinoamines and Oxidative Addition of Chlorine Yielding AuII and AuIII ComplexesBis(diphenylphosphino)amine (DPA) reacts with two equivalents of ClAu(CO) to form a binuclear gold complex HN[P(C6H5)2AuCl]2 (1). The analogous methylamine derivative (2) is prepared more easily from the ligand bis(diphenylphosphino)methylamine (DPMA) and HAuCl4 in ethanol. Excess DPMA. in the same solvent, yields a cyclic 1:1 complex 3 which is electrolytically dissociated in acetonitrile. 2 can be oxidized using stoichiometric amounts of chlorine to form complexes with the formal oxidation states +2 (5) and +3 (6) of gold. l97Au Mößbauer spectra prove that 5 is indeed not a mixed Au1/AuIII compound but contains the structural moiety Au24⊕.  -  DPA can be metallated at the nitrogen with n-C4H9Li and transformed into [(C6H5)2P]2NSI(CH3)3 using (CH3)3SiCi, but no gold complex was obtained from this ligand.
    Notes: Bis(diphenylphosphino)amin (DPA) reagiert mit zwei Äquivalenten ClAu(CO) zum zweikernigen Goldkomplex HN[P(C6H5)2AuCl]2 (1). Das analoge Methylaminderivat (2) kann leichter aus dem Liganden Bis(diphenylphosphino)methylamin (DPMA) und HAuCl4 in Ethanol erhalten werden. Überschüssiges DPMA ergibt im gleichen Solvens den cyclischen 1 : 1-Komplex 3, der in Acetonitril elektrolytisch dissoziiert. 2 kann mit stöchiometrischen Mengen Chlor in Komplexe übergeführt werden, in denen Gold formal die Oxidationsstufen +2 (5) und +3 (6) besitzt. 197Au-Mößbauer-Spektren beweisen, daß 5 tatsächlich keine gemischte AuI/AuIII 1-Verbindung ist, sondern das Strukturelement Au24⊕ enthalten muß.  -  DPA kann mit n-C4H9Li am Stickstoff metalliert und mit (CH3)3SiCl in den Liganden [(C6H5)2P]2NSi(CH3)3 verwandelt werden, von dem jedoch noch kein Goldkomplex zu erhalten war.
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    URL: http://dx.doi.org/10.1002/cber.19791120212
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    Oxiran- und Oxetanspaltung mit Phosphor-Yliden: Ein Weg zu mono- und spirobicyclischen Phosphoranen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 501-509 
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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: Oxirane and Oxetane Cleavage with Phosphorus Ylides: A Pathway to Fluctuating Mono- and Spirobicyclic Phosphoranes1-Methyl-1-methylen-1 λ5-phospholane (1) and -phosphorinane (3) react with oxirane under mild conditions to form the spirobicyclic phosphoranes 2 and 4, resp., in high yields. Oxetane converts the same ylides into the corresponding heterocycles 6 and 7 only at elevated temperatures and under autogenic pressure in sealed tubes. Similarly, trimethylmethylenephosphorane inserts into oxetane with formation of the monocyclic 2,2,2-trimethyl-1,2λ5-oxaphosphorinane (5).  -  A detailed variable temperature NMR study leads to trigonal bipyramidal ground state geometries of the phosphoranes 2 and 4-7. Their fluctuating behaviour, for which any irregular process could be excluded, is most easily described by the turnstile model of pseudorotation. The compounds reported appear to be the most simple cyclic systems of the type R4POR′ available to date.
    Notes: 1-Methyl-1-methylen-1λ5-phospholan (1) und -phosphorinan (3) reagieren schon unter milden Bedingungen mit Oxiran in guten Ausbeuten zu den spirobicyclischen Phosphoranen 2 bzw. 4. Oxetan verwandelt die gleichen Ylide in die entsprechenden Heterocyclen 6 und 7, jedoch erst bei höherer Temperatur und unter Eigendruck im Bombenrohr. Trimethylmethylenphosphoran wird in ähnlicher Weise in den Oxetanring eingeschoben, wobei das monocyclische 2,2,2-Tri-methyl-1,2Δ5-oxaphosphorinan(5)entsteht.  -  Ein detailliertes Studium der temperaturabhängigen NMR-Spektren führte zu einer trigonal-bipyramidalen Grundzustandsgeometrie der neuen Phosphorane 2 und 4-7. Deren fluktuierendes Verhalten, für das irreguläre Prozesse ausgeschlossen werden konnten, ist am leichtesten unter Zuhilfenahme des Turnstile-Modells zu beschreiben.
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    URL: http://dx.doi.org/10.1002/cber.19791120213
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    Polycyclische Verbindungen, XII. Vicinale cis-trans-isomere Dihydrodiole in der Hexahydrophenanthren- und -benz[a]anthracen-Reihe (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 532-540 
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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: Polycyclic Compounds, XII. Vicinal cis-trans-Isomeric Dihydrodiols in the Hexahydrophenanthrene and -benz[a]anthracene SeriesThe synthesis of the Vicinal trans-dihydrodiols 3a and 1la in the hexahydrophenanthrene and -benz[a]anthracene series is described. 3a and 1la are obtained by reaction of the oxanorbornadienes 1 and 9 with acetic acid and subsequent alkaline hydrolysis of the trans-hydroxyacetates 3b and 11b. Specific reactions of the cis-trans-isomers 2a and 3a are described.
    Notes: Die Darstellung der vicinalen trans-Dihydrodiole 3a und 11a in der Hexahydrophenanthren-und -benz[a]anthracen-Reihe wird beschrieben. 3a und 11a erhält man durch Reaktion der Oxanorbornadiene 1 und 9 mit Essigsäure und anschließende alkalische Verseifung der trans-Hydroxyacetate 3b und l1b. Spezifische Reaktionen der cis-trans-Isomeren 2a und 3a werden besprochen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120216
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    Enantiomere Pentatetraene und deren thermische Racemisierungsbarrieren (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 567-576 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enantiomeric Pentatetraenes and their Thermic Racemization EnergiesPartial hydroboration of the racemic pentatetraene 4 with chiral di(3-pinanyl)borane (6) gives the olefins 7 and 8, and starting material with about 5% enrichment of one enantiomer of 4. Complete separation of the enantiomers of 4 is achieved by chromatography on microcrystalline peracetylated cellulose. ( + )-4 with [α]D22 = + 336.6° (c = 0.8; CHC1,3) most likely has (S)-configuration. The enantiomers 4 racemize thermally at 358 K with activation parameters of ΔH≠ = 109.4 ± 1 kJmol-1, ΔS≠ = -18 ± 5JK-1 mol-1. and ΔG≠ = 115.8 ± 0.1 kJmol-1, independent of the polarity of the solvent.
    Notes: Die partielle Hydroborierung des racemischen Pentatetraens 4 mit chiralem Di(3-pinanyl)boran (6) führt zu den Olefinen 7 und 8, wobei im zurückgewonnenen Ausgangsmaterial 5% eines Enantiomeren von 4 angereichert werden. Die vollständige Enantiomerentrennung von 4 gelingt durch Chromatographie an mikrokristalliner peracetylierter Cellulose. (+)-4, [α]D22 = + 336.6° (c = 0.8; CHC13), besitzt wahrscheinlich (S)-Konfiguration. Die thermische Racemisierung von 4 ist bei 358 K von der Polarität des Mediums unabhängig und ergibt ΔH≠ = 109.4 ± l kJmoI-1, ΔS≠ = -18 ± 5JK-1mol-1 und ΔG≠ = 115.8 ± 0.1 kJmol-1.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120220
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    Tautomerie von Heterocyclen, VII. Synthese und Reaktionen N-vinylsubstituierter Chlorformamidine (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 640-647 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tautomerism of Heterocyclic Compounds, VII. Synthesis and Reactions of N-Vinylsubstituted ChloroformamidinesThe ureas 1 a, b are converted into the N-vinylsubstituted chloroformamidines 2 a, b by using triphenylphosphane/carbon tetrachloride as chlorinating agent. They react with silver cyanate potassium thiocyanate, potassium selenocyanate, 4-morpholinecarbonitrile and lithium phenyl-acetylide to form the substituted heterocyclic compounds 3 a, b, 5 a, b-7 a, b, 9 a, b, and 12.
    Notes: Die Harnstoffe 1 a, b werden mit Hilfe des Chlorierungsreagenzes Triphenylphosphan/Tetrachlorkohlenstoff in N-vinylsubstituierte Chlorformamidine 2 a, b übergeführt. Ihre Umsetzung mit Silbercyanat, Kaliumthiocyanat, Kaliumselenocyanat, 4-Morpholincarbonitril und Lithiumphenylacetylid liefert die substituierten Heterocyclen 3a, b, 5a, b-7a, b, 9a, b und 12.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120225
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    Electronic Resource
    Borierungsreaktionen am Keten (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 654-662 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Boration Reactions of KeteneTwo series of products are formed by aminoboration of ketene with R2B—NMe2: BR3 and CH3CONMe2, derived from a primary CC-aminoboration product R2B—CH2 —CONMe2, and the oxaazoniaboratacyclohexanes 3 and 4, derived from a primary CO-aminoboration product CH2 = C(NMe2)—OBR2. The aminoboration of ketene with HalB(NR2)2 leads to [(R2N)HalB—CH2-CONR2]2 (6). The bromoboration of ketene with Me2B—Br yields intermediates which, by aminolysis. can be transformed into products similar to those of direct aminoboration.
    Notes: Die Aminoborierung von Keten mit R2B—NMe2 liefert nebeneinander die Produkte BR3 und CH3 CONMe2, die sich vom CC-Aminoborierungsprodukt R2B—CH2—CONMe2 herleiten, sowie die Oxaazoniaboratacyclohexan-Derivate 3 und 4. die sich aus dem CO-Aminoborierungsprodukt CH2 = C(NMe2)—OBR2 bilden. Die Aminoborierung von Keten mit HalB(NR2)2 ergibt [(R2N)HalB—CH2—CONR2]2 (6). Bei der Bromoborierung von Keten mit Me2B—Br kommt man zu instabilen Zwischenprodukten. deren Aminolyse zu ähnlichen Produkten führt wie die Aminoborierung von Keten mit Me2B—NR2.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120227
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    Darstellung und Eigenschaften von (2-Methyl-1-propenyloxy)-boranen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 663-677 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of (2-Methyl-1-propenyloxy)boranes(2-Methyl-1-propenyloxy)boranes Me2C = CY—OBXX′ (2a-o) with different groups X, X′, and Y were prepared either by the addition of boranes XX′BY to dimethylketene Me2C = C = O or by the transfer of a Me2CCYO group from BrZn(Me2CCYO) to bromoboranes XX′BBr. The products dissociate thermally into XX′BY and Me2C = C = O. No tautomerism yielding XX′B—CMe2—CY = O was observed. Addition of ketene H2C = C = O to a few of the compounds 2 and subsequent methanolysis give H3C—CO—CMe2—CO2Me. The products O = CBr—CMe2—CHR—OBMe2 can be isolated from the addition of Me2C = CBr—OBMe2 (2a) to aldehydes RCHO.
    Notes: (2-Methyl-1-propenyloxy)borane Me2C = CY—OBXX′ (2a-o) mit verschiedenen Gruppen X, X′ und Y wurden z. T. durch Addition von Boranen XX′BY an Dimethylketen Me2C = C = O, z. T. durch Übertragung des Me2CCYO-Rests von BrZn(Me2CCYO) auf Bromborane XX′BBr dargestellt. Die thermische Spaltung führt zu XX′BY und Me2C = C = O. Eine die Produkte XX′B—CMe2—CY = O ergebende Tautomerie haben wir nicht beobachtet. Die 1:1-Umsetzung einiger der Produkte 2 mit Keten H2C = C = O und die nachfolgende Methanolyse der Addukte liefern den Ester H3C—CO—CMe2—CO2Me. Durch Addition von Aldehyden RCHO an Me2C = CBr—OBMe2 (2a) gewinnt man die Produkte O = CBr—CMe2 —CHR—OBMe2.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120228
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    3-Desamino- und 3-Descarboxyderivate des Nucleosids „X“ (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 700-707 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 3-Deamino- and 3-Decarboxy-Derivatives of the Nucleoside „X“Since biosynthetic investigations have shown that the aminocarboxypropyl side chain of the nucleoside „X“ (la) comes from S-adenosyl-L-methionine (2) and that compound 2 can also function as a donor of methyl-, aminopropyl- and carboxypropyl-groups, we have synthesized the two unknown uridine derivatives l b and l c. The latter compounds were obtained via N -3-alkylation of 2′,3′-O-isopropylideneuridine followed by removal of the protecting groups and characterized by 13C NMR spectroscopy. In contrast to the UV spectra the 1 H NMR spectra of 1a - c show a strong dependence on pH.
    Notes: Da Biosyntheseuntersuchungen gezeigt haben, daß der Aminocarboxypropylrest des Nucleosids „X“ (la) von S-Adenosyl-L-methionin (2) stammt, 2 aber auch als Donor von Methyl-, Aminopropyl- und Carboxypropylresten fungieren kann, haben wir die beiden noch unbekannten Uridinderivate 1 b und 1 c über N-3-Alkylierung von 2′,3′-O-Isopropylidenuridin und anschließende Abspaltung der Schutzgruppen dargestellt. l a - c wurden durch 13C-NMR-Spektroskopie charakterisiert. Im Gegensatz zu den UV-Spektren zeigen die 1 H-NMR-Spektren dieser Verbindungen eine starke Abhängigkeit vom pH-Wert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120231
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    Pentacarbonyl{furyl[tris(trimethylsilyl)siloxy]carben}chrom(0): Ein Carben-Komplex mit bemerkenswerten chemischen und strukturellen Eigenschaften (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 708-716 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pentacarbonyl{furyl[tris(trimethylsilyl)siloxy]carbene}chromium(0): A Carbene Complex with Remarkable Chemical and Structural PropertiesThe title compound 4 reacts with an ethereal solution of lithium bromide by cleavage of the Si—O bond. 13C and 29Si NMR spectroscopic investigations as well as an X-ray structure determination show the central Si atom of 4 to have a distorted trigonal-bipyramidal configuration by interaction with the oxygen atom of the furyl moiety both in solution and in crystalline state. The Si—O bond within the carbene ligand is strongly lengthened.
    Notes: Die Titelverbindung 4 reagiert mit etherischer Lithiumbromid-Lösung unter Spaltung der Si—O—Bindung. 13 C- und 29Si-NMR-spektroskopische Untersuchungen sowie eine Röntgenstrukturanalyse zeigen, daß sowohl in Lösung als auch im festen Zustand das zentrale Silicium-Atom von 4 durch Wechselwirkung mit dem Sauerstoff-Atom des Furyl-Restes eine verzerrt trigonal-bipyramidale Konfiguration aufweist. Die Si—O—Bindung im Carben-Liganden ist stark aufgeweitet.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120232
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    Synthesen biologisch wichtiger Kohlenhydrate, 16. Stereoselektive Synthese der 3-Dimethylamino-2,3,6-tridesoxy-ribo-hexose (DL-Megosamin) (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 717-726 
    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 Biologically Important Carbohydrates, 16. Stereoselective Synthesis of 3-Dimethylamino-2,3,6-trideoxy-ribo-hexose (DL-Megosamine)Methyl trans-4,5-epoxy-2,3,6-trideoxy-DL-threo-hex-2-enonate (1) reacts with liquid dimethylamine at - 10°C in nearly quantitative yield with formation of the 3-dimethylamino-4,5-epoxy-2,3,6-trideoxy-DL-lyxo-/xylo-hexonates 8. Epimeric 8 is transformed in one step into the corresponding 3-dimethylamino-γ-lactone hydrochlorides 10 from which the ribo-isomer is obtained by fractional crystallization. The highly critical reduction of 10 which represents a β-dialkylaminolactone is possible with good success if diisobutylaluminium hydride (DIBAH) is used under controlled conditions. The 3-dimethylamino-2,3,6-trideoxy-DL-ribo-hexopyranose (11) is very instable. Its configuration is established by the MS- and 1H-NMR-spectra of the much more stable 1,4-di-O-acetyl derivative 12 L-11 (megosamine) is known as one of the sugar components of the megalomicin antibiotics 27.  -  This four step synthesis of DL-12 gives a total yield of 29%.
    Notes: trans-4,5-Epoxy-2,3,6-tridesoxy-DL-threo-hex-2-enonsäure-methylester (1) reagiert mit flüssigem Dimethylamin bei -10°C fast quantitativ zu den epimeren 3-Dimethylamino-4,5-epoxy-2,3,6-tridesoxy-DL-lyxo-/-xylo-hexonsäureestern 8, die in einem Schritt zu den entsprechenden 3-Dimethylamino-γ-lacton-hydrochloriden 10, umgesetzt werden. Von diesen wird das ribo-Isomere durch fraktionierende Kristallisation erhalten. Die sehr kritische Reduktion von 10, einem β-Dialkylamino-lacton gelingt glatt, wenn man mit Diisobutylaluminiumhydrid (DIBAH) unter kontrollierten Bedingungen arbeitet. Die Konstitution und Konfiguration der sehr empfindlichen 3-Dimethylamino-2,3,6-tridesoxy-DL-ribo-hexopyranose (11) werden durch MS- und 1H-NMR-Untersuchungen an dem wesentlich stabileren 1,4-Di-O-acetyl-Derivat 12 bestimmt. L-11 ist als Baustein Megosamin von Macrolid-Antibiotika27) von Interesse.  -  Die Ausbeute an DL-12 beträgt 29% über alle vier Stufen.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120233
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    Feldionenkinetik der Wassereliminierung aus den Molekül-Ionen stereoisomerer Decalin-1,4-diole (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 743-762 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Field Ion Kinetics of the Water Elimination form Molecular Ions of Stereoisomeric Decalin-1,4-diolsThe field ion kinetics (FIK) of the elimination of H2O from the molecular ions of the 6 stereoisomeric decalin-1,4-diols, of 6 stereoisomers of 2-methyldecalin- 1,4-diol, and of 3 stereoisomers of 9-methyl-trans-decalin-1,4-diol has been investigated for reaction times between 5.10-11 and 5.10-9s. Characteristic FIK-curves of normalized intensities If(t/Im of the [M — H2O]+· ions have been obtained for all compounds. The structure of the curves is mainly determined by the relative steric orientation of both hydroxy groups, in compounds with a 1,4-cis-orientation of the hydroxy groups also by the geometry of other parts of the molecules. Methyl groups, however, have no noticeable effect on the structure of the curves. The investigation of specifically deuterated derivatives reveals, that the intensity curves of the [M —H2O]+· ions are the result of a superposition of at least 4 elimination reaction: 1.) A rapid loss of water by 1,2-elimination. 2) A retarded 1,5-elimination by a reaction between hydroxy groups in a 1,4-cis-position. 3) A retarded transannular 1,4-elimination in compounds with a 1,4-trans-orientation of the hydroxy group. 4.) A retarded loss of water by H-transfer from the unsubstituted ring to one of the hydroxy groups. The retardation of the loss of water is discussed with respect to intramolecular movements of the molecular ions.
    Notes: Die Feldionenkinetik (FIK) der Wasserabspaltung aus der Molekül-Ionen der 6 stereoisomeren Decalin-1,4-diole, von 6 Stereoisomeren des 2-Methyldecalin-1,4-diols und von 3 Stereoisomeren des 9-Methyl-trans-decalin- 1,4-diols wurde Für Zerfallszeiten von 5. 10-11 bis 5. 10-9s unter-sucht. Für die normalisierten Intensitäten If(t)/IM der Ionen [M — H2O]+· wurden für alle Verbindungen charakteristische FIK-Kurven erhalten. Der Kurvenverlauf wird vorwiegend durch die relative sterische Anordnung beider Hydroxygruppen bestimmt, bei Verbindungen mit 1,4-cis-ständigen Hydroxygruppen auch durch die übrige Molekulargeometrie. Methylsubstituenten machen sich dagegen nicht im Kurvenverlauf bemerkbar. Durch Untersuchung spezifisch deuterierter Derivate wird gezeigt, daß die Intensitätskurven der [M — H2O]+·-Ionen durch eine Überlagerung von mindestens 4 Eliminierungsprozessen entstehen: 1. Eine schnelle Wasserabspaltung durch 1,2-Eliminierung. 2.Eine zeitlich verzögerte 1,5-Eliminierung durch Reaktion zwischen 1,4-cis-ständigen Hydroxygruppen. Eine zeitlich verzögerte transannulare 1,4-Eliminierung bei Verbindungen mit 1,4-trans-ständigen Hydroxygruppen. 4. Eine zeitlich verzögerte Wasserabsplatung durch H-Übertragung aus dem unsubstituierten Ring auf eine der Hydroxygruppen. Die zeitliche Verzögerung der Wasserabsplatung wird im Zusammenhang mit intramolekularen Bewegungen der Molekül-Ionen diskutiert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120236
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    Eine einfache Darstellung der binären Metall-Schwefel-Cluster [Mo3S13]2- und [Mo2S12]2- aus MoO4 2- in praktisch quantitativer Ausbeute (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 778-780 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple Preparation of the Binary Metal-Sulfur Clusters [MO3S13]2- and [Mo2SI2]2- from MoO42- in Practically Quantitative Yield(NH4)2[Mo3S(S2)6] 2 H2O (2) could be isolated by heating an aqueous solution of MoO42- with (NH4 2- Sx, for several hours. The anions of both compounds are in equilibrium under the stated conditions.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120240
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    Ambivalentes Verhalten von Acyl(diphenyl)phosphanen gegenüber molekularem Sauerstoff (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 793-798 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ambivalent Behavior of Acyl(diphenyl)phosphanes towards Molecular OxygenWhen the acylphosphanes RC(O)PPh2 (4a, b) [R = CH3 (a), CF3 (b)] are „oxidized slowly“ with molecular oxygen the trivalent phosphorus is attacked with formation of the phosphane oxides RC(O)P(O)Ph2 (la, b), which react with water to give the alcohols RC[Ph2P(O)]2OX(2)and phosphinates RC[Ph2P(O)][OP(O)Ph2]X (3). In contrast, „fast oxidation“ results in an attack on the carbonyl group of 4a b, with formation of CO2 and the radicals ·PPh2 and ·R. The combination products of these radicals and the capture reaction with water and alcohols are described.
    Notes: Bei der „langsamen Oxidation“ der Acylphosphane RC(O)PPh2 (4a, b) [R = CH3 (a), CF3, (b)] mit molekularem Sauerstoff wird der dreibindige Phosphor unter Bildung der Phosphanoxide RC(O)P(O)Ph2 (l a, b) angegriffen, welche mit Wasser zu den Alkoholen RC[Ph2P(O)]2OX (2) und Phosphinaten RC[Ph2P(O)][OP(O)Ph2]X (3) weiterreagieren. Im Gegensatz hierzu erfolgt bei der „schnellen Oxidation“ der Angriff des Sauerstoffs an der Carbonylgruppe von 4a, b unter Bildung von CO2 und der Radikale · PPh2 und · R. Die Kombinationsprodukte dieser Radikale und die Abfangreaktion mit Wasser und Alkoholen werden beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120303
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    Anodische Hydroxylierung und Acetamidierung von konjugierten Dienen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 807-817 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anodic Hydroxylation and Acetamidation of Conjugated DienesAnodic oxidation of 2,4-hexadiene (1), 1,3-butadiene (2), and 1,3-cyclohexadiene (3) in acetonitrile water/sodium perchlorate yields diols, 2-oxazolines, and 3-pyrrolines. Methyl sorbate (5) forms methyl 4,5-epoxy-(E)-2-hexenoate (26); 1,4-diphenyl-1,3-butadiene (4) is cleaved to benzaldehyde (24) and cinnamaldehyde (25). The product distribution is influenced by the supporting electrolyte. With tetrafluoroborate nearly exclusively diols are obtained, whilst in acetamide/acetonitrile 2-oxazolines and 3-pyrrolines are formed. As intermediates radical cations (31) are assumed.
    Notes: Die anodische Oxidation von 2,4-Hexadien (1), 1,3-Butadien (2) und 1,3-Cyclohexadien (3) in Acetonitril/Wasser/Natriumperchlorat führt zu einem Gemisch aus Diolen, 2-Oxazolinen und 3-Pyrrolinen. Sorbinsäure-methylester (5) liefert 4,5-Epoxy-(E)-2-hexensäure-methylester (26); 1,4-Diphenyl-1,3-butadien (4) wird zu Benzaldehyd (24) und Zimtaldehyd (25) gespalten. Die Produktverhältnisse werden vom Leitsalz beeinflußt. In Gegenwart von Tetrafluoroborat entstehen nahezu ausschließlich Diole, während die Elektrolyse in Acetamid/Acetonitril zu 2-Oxazolinen und 3-Pyrrolinen führt. Als Zwischenprodukte werden Radikalkationen (31) angenommen.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120305
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    Synthesen und Reaktionen von L-Olivomycal und L-Mycaral (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 818-822 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reaction of L-Olivomycal and L-MycaralStarting with L-rhamnal (3) the synthesis of L-olivomycal (4a) is achieved with only few steps and in high yields. Following hydrogenation of 4a and the isomeric side product L-mycaral (5), to the corresponding 1,5-anhydro derivatives 7 and 8, only 8 gave a cis-carbonate 9. This proves the configuration at the branching point C-3 in 4a and in 5. By the reaction of 4b with methanol and N-iodosuccinimide 10b is obtained, which, after subsequent reduction employing nickel boride, gave methyl α-L-olivomycoside (11) in high yield. By application of the same procedure the disaccharide derivative 13 is synthesized without problems.
    Notes: Die Synthese von L-Olivomycal (4a) gelingt in wenigen Reaktionsschritten und guten Ausbeuten ausgehend von L-Rhamnal (3). Nach Hydrierung von 4a und dem isomeren Nebenprodukt L-Mycaral (5) zu den entsprechenden 1,5-Anhydroverbindungen 7 und 8 reagiert nur 8 zu einem cis-Carbonat 9, womit die Konfiguration am Verzweigungspunkt C-3 in 4a und 5 belegt wird. Umsetzung von 4b mit Methanol und N-Iodsuccnimid zu 10b und nachfolgende Reduktion mit Nickelborid gibt Methyl-α-L-olivomycosid (11) in hoher Ausbeute. Gleichermaßen gelingt die glatte Synthese des Disaccharidderivats 13.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120306
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    Kristallstrukturen der Alkali-isopropoxide des Kaliums, Rubidiums und Caesiums (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 844-848 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structures of the Isopropoxides of Potassium, Rubidium, and CesiumPotassium-, rubidium- and cesium isopropoxide are isostructural (tetragonal space group P4/nmm-D4h7). Their cell constants have been determined. Using a single crystal the structure of cesium isopropoxide has been determined by X-ray analysis and refined to R = 0.069. The alkoxides form layer structures of the type of lithium respectively sodium methoxide. The metal atoms are arranged in one plane and are coordinated on both sides by O-atoms. each O-atom being surrounded by four metal atoms and one sec. C-atom. The methyl-C-atoms are distributed statistically between two positions differing by a 90° rotation of the (CH3)2CH-group.
    Notes: Die Isopropoxide des Kaliums, Rubidiums und Caesiums sind isostrukturell tetragonale Raum-gruppe P4/nmm-D4h7). Ihre Zellkonstanten wurden ermittelt und die Struktur des Caesium-isopropoxids anhand eines Einkristalls röntgenographisch bestimmt und bis R = 0.069 verfeinert. Die Alkoxide bilden Schichtgitter vom Typ des Lithium- bzw. Natriummethoxids. Dabei liegen die Metallatome in einer Ebene und sind beiderseits von O-Atomen koordiniert, indem jedes O-Atom von vier Metallatomen und einem sec. C-Atom umgeben ist. Die Methyl-C-Atome sind statistisch auf zwei Lagen verteilt, welche sich durch Drehung der (CH3)2CH-Gruppe um 90° unterscheiden.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120309
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    Basische Metalle, X. C5H5Co(PMe3)2 als Synthesebaustein zur Knüpfung von Metall-Metall-Bindungen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 823-833 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Basic Metals, X. C5H5Co(PMe3)2 as Building Block for the Formation of Metal-Metal BondsC5H5Co(PMe3)2 (1) reacts with equimolar amounts of ZnCl2 and PMe3 to give the complex C5H5(PMe3)2CoZnCl2(PMe3)(2). Contrary, 1, ZnCl2 and PPh3 react to give a mixture of C5H5(PMe3)2CoZnCl2 (3) and (PPh3)2ZnCl2. The reaction of 2 with PMe3 leads to cleavage of the Co—Zn bond with formation of 1 and (PMe3)2ZnCl2. - 1 reacts with [(PMe3)2CuCl]2 to give C5H5(PMe3)2CoCuCl(PMe3)2(4). In this complex and in 2, the metal atoms are probably tetrahedrally coordinated. Reaction of 4 with PMe3 leads to 1 and (PMe3)3CuCl. - Complexes having Co—Sn bonds can be synthesized through reaction of 1 with SnCl4. Me3SnCl. and Ph3SnCl. The 1:1 adducts 5, 8, and 9 that are first formed react with SnCl4 or NH4PF6 with loss of a chloride ion and formation of the cationic complexes [C5H5(PMe3)2CoSnR3]+ (R = Cl, Me, Ph) (6, 11 and 12). Electrophilic substitution of the SnMe3 group in [C5H5(PMe3)2CoSnMe3]PF6 (11) by SnCl4 or HgCl2 leads to [C5H5(PMe3)2CoSnCl3]PF6 (10) or [C5H5(PMe3)2CoHgCl]PF6 (14), respectively. - With HgCl3 1 forms both a 1:1 and a 1 :2 adduct (13 and 15). Structural suggestions for these compounds are discussed.
    Notes: C5H5Co(PMe3)2 (1) reagiert mit äquimolaren Mengen ZnCl2 und PMe3 zu dem Komplex C5H5(PMe3)2CoZnCl2(PMe3)(2). Aus 1, ZnCl2 und PPh3 entsteht dagegen ein Gemisch von C5H5 (PMe3)2CoZnCl2 (3) und (PPh3)2ZnCl2. Die Reaktion von 2 mit PMe3 führt unter Spaltung der Co—Zn-Bindung zu 1 und (PMe3)2ZnCl2. - Mit [(PMe3)2CuCl]2 reagiert 1 zu C5H5(PMe3)2CoCuCl(PMe3)2(4), in dem wahrscheinlich wie in 2 beide Metallatome tetraedrisch koordiniert sind. Bei der Umsetzung von 4 mit PMe3 bildet sich 1 und (PMe3)3CuCl. - Die Synthese von Komplexen mit Co—Sn-Bindungen gelingt durch Reaktion von 1 mit SnCl4, Me3SnCl und Ph3SnCl. Die primär gebildeten l : l-Addukte 5, 8 und 9 reagieren mit SnCl4 bzw. NH4PF6 unter Abspaltung eines Chlorid-Ions und Bildung der kationischen Komplexe [C5H5(PMe3)2CoSnR3]+(R = Cl, Me, Ph) (6, 11 und 12). Die elektrophile Substitution der SnMe3-Gruppe in [C5H5(PMe3)2CoSnMe3]PF6 (11) durch SnCl4 bzw. HgCl2 führt zu [C5H5(PMe3)2CoSnCl3]PF6 (10) bzw. [C5H5(PMe3)2CoHgCl]PF6 (14). - Mit HgCl2 bildet 1 sowohl ein 1:1- als auch ein 1:2-Addukt (13 und 15). Strukturvorschläge für diese Verbindungen werden diskutiert.
    Additional Material: 1 Tab.
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    Zur Diels-Alder-Reaktivität s-cis-fixierter 1,3-Diene (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 862-882 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Diels-Alder Reactivity of s-tis-Fixed 1,3-DienesContrary to the 1,2-dimethylenecycloalkanes 8-10 and 2,3-dimethylene-14-dioxane (6), the 4,5-dimethylene-1,3-dioxolanes 1-5 show very poor diene reactivities in the Diels-Alder reaction though possessing an s-cis-fixed diene system. This is documented by bimolecular rate constants as well as activation parameters. The influence of the ionisation potentials measured by PE spectroscopy and of the molecular geometries calculated by the MINDO/3 method on the reactivity is studied. It is shown that not the dehedral angle but the scissoring (1.4-distance) of the diene system is of decisive importance for the reactivity of the s-cis-fixed dienes.
    Notes: Die 4,5-Dimethylen-1,3-dioxolane 1-5 zeigen, obwohl sie s-cis-fixierte Diensysteme darstellen, im Vergleich zu den 1,2-Dimethylencycloalkanen 8-10 und 2,3-Dimethylen-1,4-dioxan (6) sehr geringe Dienreaktivitäten, wie durch die Geschwindigkeitskonstanten und die Aktivierungsparameter belegt wird. Der Einfluß der durch Photoelektronenspektroskopie festgelegten Ionisationspotentiale und der nach dem MINDO/3-Verfahren berechneten Molekülgeometrien auf die Reaktivität wird untersucht. Es zeigt sich, daß für die Reaktivität der s-cis-fixierten Diene nicht der Interplanarwinkel, sondern die Scherung (1,4-Abstand) des Dien-Systems von entscheidender Bedeutung ist.
    Additional Material: 9 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120312
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    Der Einfluß des Dien-1,4-Abstandes auf die Reaktivität bei Diels-Alder-Reaktionen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 883-889 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Significance of Diene-1,4-Distance on the Reactivity in Diels-Alder ReactionsThe reactivity of cyclopentadiene and di-exo-methylene compounds in Diels-Alder reactions is investigated using the frontier molecular orbital method. It is shown that besides the HOMO-LUMO energy difference the diene 1,4-distance plays an important part for the rate of reaction. The shorter this distance is the higher becomes the reactivity. Experimentally this is shown by the rates of reaction of tetracyanoethylene and maleic anhydride with cyclopentadiene and di-exo-methylene compounds 2-6. The 1,4-distance of the latter is known from force field calculations. 1,4-Distance and log k2 exhibit a linear relationship which is supported by theoretical considerations.
    Notes: Die Reaktivität von Cyclopentadien und cis-fixierten Di-exo-methylenverbindungen in Diels-Alder-Reaktionen wird im Rahmen des Grenzorbitalmodells untersucht. Es wird gezeigt, daß neben der Energiedifferenz der dominanten Grenzorbitalwechselwirkung auch der Dien-1,4-Abstand eine wichtige Funktion besitzt. Je kürzer dieser ist, umso reaktiver ist das Dien. Dies zeigt die Kinetik der Umsetzung von Tetracyanethylen und Maleinsäureanhydrid mit Cyclopentadien und den Di-exo-methylenverbindungen 2-6, deren 1,4-Abstand auf Grund von Kraftfeldrechnungen bekannt ist. Zwischen 1,4-Abstand des Diens und log k2 der Cycloaddition besteht ein linearer Zusammenhang, der sich theoretisch begründen läßt.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120313
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    Der Mechanismus der photolytischen Umsetzung von Pyridin mit Bis(trimethylsilyl)quecksilber, ein Beitrag zur metallorganischen Photochemie (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 950-956 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Mechanism of the Photolytic Reaction of Pyridine with Bis(trimethylsilyl)mercury, a Contribution to the Photochemistry with Metal AlkylsThe photolytic generation of N-(trimethylsilyl)pyridinyls 2 or. resp., their 4,4′-dimers from pyridine or its alkyl derivatives and bis(trimethylsilyl)mercury (1) involves surprisingly no free silyl radicals, but passes a long-lived, photoexcited, polar state 1a of the molecule 1. The latter is described more closely. It is complexed stepwise by two molecules of pyridine, and only in the last step free radicals are formed. The possibly more general importance of these findings for photolytic reactions with metal alkyls is pointed out.
    Notes: Die photolytische Bildung von W-(Trimethylsilyl)pyridinylen 2 bzw. ihren 4.4′-Dimeren. aus Pyridin bzw. seinen Alkylverbindungen und Bis(trimethylsilyl)quecksilber (1) verläuft überraschenderweise nicht über freie Silyl-Radikale, sondern über einen längerlebigen, photoangeregten, polaren Zustand la des Moleküls 1, über den nähere Aussagen gemacht werden. Er wird schrittweise durch zwei Moleküle Pyridin komplexiert, worauf erst im letzten Schritt freie Radikale entstehen. Auf die mögliche Bedeutung der Befunde für andere photolytische Reaktionen mit Metallalkylen wird hingewiesen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120318
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    Cyclopropyl-Nachbargruppeneinfluß auf die Brückenkopfreaktivität von Verbindungen mit Bicyclo[2.2.2]octan-Grundgerüst (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 908-935 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropyl Neighbouring Group Influence on the Bridgehead Reactivity of Compounds with a Bicyclo[2.2.2]octane SkeletonUpon photochlorination with tert-butyl hypochlorite the cyclopropane anellated bicyclo[2.2.2]-octane hydrocarbons 10a and 2a-6a give the bridgehead chlorids 10b and 2b-6b in increasing relative yields. In addition, a more efficient directed synthesis for 2b has been developed. The solvolysis reactions of 2b-6b lead to unrearranged bridgehead derivatives exclusively, the substantially increasing rates in the series 2b-6b indicating, that a cyclopropyl group can stabilize a neighbouring carbenium ion center substantially, even if the system does not possess the best bisected conformation. It is only with a perpendicular arrangement of the axis of the carbenium ion p-orbital and the Walsh orbital at the neighbouring cyclopropyl carbon atom as in 10b that the cyclopropyl group exhibits a destabilizing effect exclusively. Analysis of the kinetic parameters leads to the result, that the skeletons of the intermediate carbenium ions from 2b, 5b and 6b are twisted with respect to those of the starting materials, because this apparently enables the intermediates to gain additional stabilization. However, for 3b and 4b the twisting in the ground and the transition state has to be equally small. For 2b and 5b-6b the twist angle decreases with an increasing number of anellated cyclopropane rings. The same conclusions have been drawn from the interpretation of the 13C-chemical shifts of the free bridgehead carbenium ions 2f and 4f-6f, which have been generated by the reaction of the corresponding chlorides with antimony pentafluoride in sulfuryl chloride fluoride.
    Notes: Bei der Photochlorierung mit tert-Butylhypochlorit entstehen aus den cyclopropan-anellierten Bicyclo[2.2.2]octan-Kohlenwasserstoffen 10a und 2a-6a mit ansteigenden Relativanteilen die Brückenkopfchloride 10b und 2b-6b. Die Solvolysereaktionen von 2b-6b führen ausschließlich zu nichtumgelagerten Brückenkopfderivaten; die in dieser Reihe erheblich ansteigenden Geschwindigkeiten - relativ zum 1-Bicyclo[2.2.2]octylchlorid um bis zu 2.8·108. beweisen, daß eine Cyclopropylgruppe auch bei einer von der optimalen bisektierten Anordnung abweichenden Konformation ein benachbartes Carbeniumionzentrum beträchtlich stabilisiert. Nur bei senkrechter Anordnung der Achsen des Carbeniumion-p-Orbitals und des Walsh-Orbitals am benachbarten Dreiring-C-Atom wie in 10b wirkt die Cyclopropylgruppe ausschließlich destabilisierend. Die Auswertung der kinetischen Parameter ergibt, daß die Gerüste der intermediären Carbeniumionen aus 2b, 5b und 6b im Vergleich zu denjenigen der Ausgangsverbindungen stärker verdrillt sind, weil dies offenbar eine zusätzliche Stabilisierung der Zwischenstufen ermöglicht. Bei 3b und 4b dagegen muß die Verdrillung von Ausgangs- und Übergangszustand gleich gering sein; bei 2b, 5b und 6b wird sie mit zunehmender Zahl anellierter Cyclopropanringe geringer. Zu den gleichen Schlußfolgerungen führt die Interpretation der 13C-chemischen Verschiebungen der freien Brückenkopf-Carbeniumionen 2f und 4f-6f, die aus den entsprechenden Chloriden mit Antimonpentafluorid in Sulfurylchloridfluorid erzeugt wurden.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120316
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    Polycarbonylverbindungen, XXIV. Gemischte „Oxothioxokohlenstoffe“ aus Amiden und Thioamiden der Quadratsäure (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 990-999 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycarbonyls, XXIV. Mixed „Oxothioxocarbons“ from Amides and Thioamides of Squaric AcidHydrolysis or sulfhydrolysis of 1,2-or 1,3-Squaric acid diamides or their mono- or dithioderivatives yields sulfur analogues of squaric acid dianion, examples of mixed „oxothioxocarbons“ (5-8). Reaction with electrophiles and nucleophiles as well as spectroscopic data are reported.
    Notes: Durch Hydrolyse bzw. Sulfhydrolyse von 1,2- oder 1,3-Quadratsäurediamiden bzw. ihrer Mono- oder Dithioderivate entstehen Schwefelanaloga des Quadratsäure-Dianions, Vertreter der gemischten „Oxothioxokohlenstoffe“ (5-8). Es werden Reaktionen mit Elektrophilen und Nucleophilen beschrieben und spektroskopische Daten mitgeteilt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120321
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    Cycloadditionsreaktionen von Heterocumulenen, XVII. Über den Mechanismus der [2+2]-Cycloaddition von Thioketenen mit Azomethinen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1000-1011 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions of Heterocumulenes, XVII. On the Mechanism of the [2+2]-Cycloaddition of Thioketenes with AzomethinesThe thioketene 1 reacts with the azomethines 2a-f to give the β- thiolactames 3a-f, the structures of which were proven by methylation and oxidation leading to 7 and 8/9c Attempts to trap the potential intermediate of the cycloaddition 11 were unsuccessful. Kinetic experiments demonstrate low solvent and substituent effects on the cycloaddition rate. Starting form 1-deuterated and 1-undeuterated 2b a secondary kinetic isotope effect was measured. These results as well as the formation of the sterically disfavoured cycloadduct 3A indicate that in the rate-determining step of the cycloaddition not the „classical“ dipole 11 is formed, but with orbital symmetry -control the dipolar species 14.
    Notes: Das Thioketen 1 reagiert mit den Azomethinen 2a - zu den β-Thiolactamen 3a-f, deren Struktur durch Methylierung zu 7 und Oxidation zu 8/9c belegt wurde. Versuche, die potentielle Zwischenstufe der Cycloaddition 11 abzufangen, verliefen negativ. Nach kinetischen Untersuchungen sind Lösungsmittel-und Substituenteneinflüsse auf die Cycloadditionsgeschwindigkeit gering. Ausgehend von 1-deuteriertem und 1-undeuteriertem 2b wurde ein sekundärer Isotopeneffekt gemessen. Diese Ergebnisse wie auch die Bildung des sterisch ungünstigen Cycloaddukts 3A sprechen dafür, daß im geschwindigkeitsbestimmenden Schritt der Cycloaddition kein „klassischer“ Dipol 11 entsteht, sondern unter Orbitalsymmetrie-Kontrolle die dipolare Species 14.
    Additional Material: 4 Tab.
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    Elektronenstruktur von Alkyl-aryl- und Alkyl-vinyl-ethern (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1614-1625 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electronic Structure of Alkyl Aryl and Alkyl Vinyl EthersFor the evaluation of the interactions between π electrons of the CC double bond and lone Pairs at the 0 atom of α, β-unsaturated ethers p. e. spectra of some alkyl aryl ethers 1-3 were recorded and compared with those of alkyl vinyl ethers 5. The data could be interpreted by means of orbital correlation diagrams provided the interaction with energetically high-lying σ orbitals of the correct symmetry was taken into account. Sterically hindered alkyl aryl ethers were found to exist in a perpendicular conformation; in sterically unhindered ethers like anisole a less stable isomer having this conformation was detected. In the case of alkyl vinyl ethers non-bonding interactions favour the s-cis conformation, whereas sterically hindered molecules of this type prefer the s-trans form. From p. e. spectra at higher temperatures (up to 510 K) the relative conformational energies are estimated. The results of the p. e. analysis are used for the interpretation of some reactions of α,β-unsaturated ethers.
    Notes: Um das Ausmaß der Konjugation zwischen π-Elektronen der CC-Doppelbindung und freien Elektronenpaaren am O-Atom α, β-ungesättigter Ether zu ermitteln, wurden die Photoelektronenspektren einer Anzahl von Alkyl-aryl-ethern 1-3 aufgenommen und mit den Spektren von Alkyl-vinyl-ethern 5 verglichen. Die Ergebnisse lassen sich mit Hilfe von Orbitalkorrelationsdiagrammen vollständing interpretieren, sofern man energetisch hochliegende σ-Orbitale geeigneter Symmetrie in die Betrachtung einbezieht. Sterisch gehinderte Alkyl-aryl-ether nehmen eine perpendikuläre Konformation ein, die bei sterisch nicht gehinderten Verbindungen wie etwa Anisol als zweite weniger stabile Form gefunden wird. Im Fall der Alkyl-vinyl-ether überwiegt aufgrund einer nichtbindenden Wechselwirkung die s-cis-Konformation bei sterisch nicht gehinderten Ethern, während sonst die s-trans-Konformation bevorzugt wird. Durch die Aufnahme von Photoelektronenspektren bei Temperaturen bis 510 k lassen sich die Energieunterschiede zwischen den verschiedenen Konformeren abschätzen. Die Ergebnisse der PE-Untersuchungen Können zur Interpretation von Reaktionen α,β-ungesättigter Ether herangezogen werden.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120512
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    Beiträge zum Mechanismus der photochemischen Reaktionen von Phenylsydnonen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1635-1649 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Mechanism of the Photochemical Reactions of PhenylsydnonesThe light-induced decay of diphenylsydnone (1a in various solvents and in the presence of benzonitrile or 4-chlorobenzonitrile with evolution of carbon dioxide leads to the formation of a nitrile imine intermediate 4 a, whose products are partially isolated and identified. For example, the isomeric triazoles 5 (2.5%) and 7 (7.9%) beside the oxadiazolinone 6a (0.9%) and the phenylhydrazine 8 a (29 %) are formed during the irradiation 1a in acetone. The phenanthridinone derivative 22 and the N-phenylbenzohydrazide 24 are formed during working up of the irradiation mixture from 1a in pure acetyl chloride. Furthermore, the photolyses of 1b, c in acetone and of 1b or 6b in methanol are described. The formation of the isolated products is discussed.
    Notes: Der lichtinduzierte Zerfall des Diphenylsydnons (1a) in verschiedenen Lösungsmitteln sowie in Gegenwart von Benzonitril oder 4-Chlorbenzonitril liefert unter Kohlendioxid-Abspaltung eine Nitrilimin-Zwischenstufe 4 a, deren Folgeprodukte teilweise isoliert und identifiziert werden. Beispielsweise werden bei der Bestrahlung von 1a in Aceton die isomeren Triazole 5 (2.5%) und 7 (7.9%) neben dem Oxadiazolinon 6 a (0.9%) und dem Phenylhydrazin 8 a (29 %) gebildet. Das Phenanthridinon-Derivat 22 und das N-Phenylbenzohydrazid 24 entstehen bei der Aufarbeitung des Belichtungsansatzes aus 1a in reinem Acetylchlorid. Weiterhin werden die Photolysen von 1b, c in Aceton und von 1b oder 6 b in Methanol beschrieben. Die Bildungsweisen der isolierten Produkte werden diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120514
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    3-O-Benzyl-D-ribose (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1705-1711 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 3-O-Benzyl-D-ribose3-O-Benzyl-D-ribose (4) is synthesized from D-glucose and D-ribose via different routes; these methods were compared. For a characterization 4 is transformed into 3′-O-benzyl-adenosine (19). 1H NMR data of the synthesized compounds are compiled.
    Notes: Aus D-Glucose und aus D-Ribose wird in vergleichenden Untersuchungen auf verschiedenen Wegen 3-O-Benzyl-D-ribose (4) hergestellt. Zur Charakterisierung wird 4 in 3′-O-Benzyladenosin (19) übergeführt. 1H-NMR-Spektroskopische Daten der synthetisierten Verbindungen werden mitgeteilt.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120520
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    Komplexchemie reaktiver organischer Verbindungen, XXIV. Fünfgliedrige Cobaltacyclen durch Carben-Addition an Dicarbonyl-(η5-cyclopentadienyl)cobalt (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1731-1742 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, XXIV. Five-Membered Cobalta Cycles from Carbene Addition to Dicarbonyl (η5-cyclopentadienyl)cobaltPhotolysis of the dialkyl diazomalonates 2a-g in the presence of dicarbonyl(η5-cyclopentadienyl)cobalt (1) in tetrahydrofuran yields the cobalta cycles 3a-g. The formation of the new compounds, established by X-ray structural determination on the case of 3c, can be explained formally as a result of a [2 + 3]-cycloaddition of the carbenes derived from the diazo precursors 2a-g to the organometallic substrate 1. The cyclic cobalt compounds 3a-g are converted by a thermal reaction with 1 through opening of the metalla cyclic structural element into the dinuclear μ-methylene cobalt compounds 4a-g.
    Notes: Durch Photolyse der Diazomalonsäure-dialkylester 2a-g in Gegenwart von Dicarbonyl-(η5-cyclopentadienyl)cobalt (1) in Tetrahydrofuran sind die Cobaltacyclen 3a-g zugänglich. Die Bildung der neuen, am Beispiel von 3c auch röntgenstrukturanalytisch gesicherten Verbindungen ist formal das Ergebnis einer [2 + 3]-Cycloaddition der von den Diazo-Vorstufen 2a-g abgeleiteten Carbene an das Organometall-Substrat 1. Unter Öffnung des metallacyclischen Strukturelements sind die cyclischen Cobalt-Derivate 3a-g bei thermischer Umsetzung mit 1 in die zweikernigen μ-Methylen-Cobalt-Komplexe 4a-g überführbar.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120523
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    Trigonal planar koordinierter Schwefel(VI): Die Kristall- und Molekülstrukturen von (R3SiN)3S und (R3CN)3S (R=CH3) bei -130°C (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1751-1755 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Planar Threefold Coordination of Sulfur(VI): Crystal and Molecular Structures of (R3SiN)3S and (R3CN)3S (R=CH3) at -130°CThe crystal structures of the title compounds were determined from single crystal X-ray data (measured at -130°C) and refined to unweighted R-values of 0.034 for (R3SiN)3S (1) and 0.047 for (R3CN)3S(2). 2 crystallizes in the triclinic space group P1 and 1 in the hexagonal space group P63/m. Both structures exhibit a planar threefold nitrogen coordination of the sulfur but the large coefficients of the temperature factors perpendicular to the SN3 planes in 1 and 2 might indicate a disorder due to small deviations from planarity. The S—N bond lengths were found to be 150.4 (1) and 151.5 pm (2, mean).
    Notes: Die Strukturen der Titelverbindungen wurden aus Diffraktometer-Einkristalldaten (gemessen bei -130°C) bestimmt und zu ungewichteten R-Werten von 0.034 für (R3SiN)3S )(1) und 0.047 für (R3CN)3S (2)verfeinert. 2 kristallisiert triklin, P1. Und 1 hexagonal, P63/m. In beiden Strukturen wird eine trigonal planare Koordination des zentralen Schwefelatoms beobachtet, doch deuten die relativ großen Koeffizienten der anisotropen Temperaturfaktoren senkrecht zu den SN3-Ebenen in 1 und 2 auf eine Fehlordnung als Folge geringer Abweichungen von der Planarität in den einzelnen Molekülen hin. Die S—N-Abstände betragen 150.4 pm (1) und 151.5 pm (2, Mittelwert).
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120525
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    Das Reaktivitäts-Selektivitätsprinzip, 4. Die Selektivität von Alkyl-Radikalen im BrCCl3/CCl4-Konkurrenzsystem (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1743-1750 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Reactivity-Selectivity Principle, 4. Selectivity of Alkyl Radicals in Competition System BrCCl3/CCl4Alkyl radicals were generated from alkylmercuric salts 1 and peresters 4. Their reactions in competition system BrCCl3/CCl4 show that at 273 and 403 K the sequences of radical selectivities are completely reversed. At 273 K the methyl radical is the least selective but at 403 K it is the most selective alkyl radical of table 1. The isoselective temperature lies in the region of 340 K. The reason of this is the opposing influence on activation enthalpies and activation entropies. With increasing alkylation of the radicals, activation enthalpies enlarge but activation entropies reduce the selectivities (table 2). The differences of radical selectivities are governed below the isoselective temperature by variation of activation enthalpies and above the isoselective temperature by variation of activation entropies.
    Notes: Alkyl-Radikale wurden aus Alkylquecksilbersalzen 1 und Perestern 4 erzeugt. Ihre Reaktionen im BrCCl3/CCl4-Konkurrenzsystem zeigen, daß bei 273 und 403 K die Selektivitätsreihenfolge der Radikale einander genau entgegengesetzt ist. Während bei 273 K das Methyl-Radikal das am wenigsten selektive Radikal ist, besitzt es bei 403 K die größte Selektivität aller Alkyl-Radikale der Tab. 1. Die isoselektive Temperatur liegt im Bereich von 340 K Ursache für dieses Verhalten ist der gegenläufige Einfluß auf die Aktivierungsenthalpien und Aktivierungsentropien. Mit zunehmender Alkylierung der Radikale führen die Aktivierungsenthalpien. Zu einer Vergrößerung, die Aktivierungsentropien jedoch zu einer Verkleinerung der Radikalselektivitäten (s. Tab. 2). Unterhalb der isoselektiven Temperatur werden die Unterschiede der Radikalselektivitäten von den Änderungen der Aktivierungsenthalpien, oberhalb der isoselektiven Temperatur von den Änderungen der Aktivierungsentropien bestimmt.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120524
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    Eliminierung von Olefinen aus Iminotriorganylphosphoranen im Ammonosystem (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1756-1762 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Elimination of Olefins from Iminotriorganylphosphoranes in Liquid Ammonia SolutionIn the presence of potassium amide some iminotriorganylphosphoranes (1,2,5-7) react under elimination of olefins. The mechanism of this reaction is discussed.
    Notes: Bei Einwirkung von Kaliumamid in flüssigem Ammoniak spalten einige Iminotriorganylphosphorane (1,2,5-7) im Sinne einer Eliminierungsreaktion Olefin ab. Der Reaktionsmechanismus wird diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120526
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    Wasserstoff-Übertragungsreaktionen, III. Wasserstoffübertragungen zwischen o,o′-verknüpften Tetraarylethylenen und Diarylmethanen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1763-1768 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions involving Hydrogen Transfer, III. Hydrogen-Transfer Between o,o′-Bridged Tetraarylethylenes and DiarylmethanesThermal hydrogen transfer between o,o′-bridged diarylmethanes and o,o′-bridged tetraarylethylenes leads to reduction of the ethylenes and to dimerization and dehydrogenation of the diarylmethanes (equ. (1)-(5)). The ethylene 1 reacts with 9,10-dihydroanthracene (15) to form 3 and anthracene (16)[equ. (6)]. The principles of these reaction are discussed.
    Notes: Bei der thermischen Wasserstoffübertragung zwischen o,o′-überbrückten Diarylmethanen und o,o′-überbrückten Tetraarylethylenen werden die eingesetzten Ethylene hydriert und die Diarylmethane dehydrierend dimerisiert (Gleichungen (1)-(5)). Das Ethylen 1 und 9, 10-Dihydroanthracen (15) liefern nach (6) 3 und Anthracen (16) Die Grundlagen dieser Reaktion werden diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120527
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    Organometallphosphan-substituierte Übergangsmetallkomplexe, XXIV. Organoelement(IVb)-phosphan-Derivate von Octacarbonyldicobalt (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1779-1784 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organometalphosphine-substituted Transition Metal Complexes, XXIV. Organoelement(IVb)-phosphine Derivatives of OctacarbonyldicobaltOctacarbonyldicobalt (1) reacts with (t-C4H9)3P (2), (t-C4H9)2PH (3), [(CH3)3Si]3P (4),[(CH3)3Ge]3P (5) [(CH3)3Sn]3P (6) and (t-C4H9)2[(CH3)3Si]P (7) with displacement of two CO ligands and formation of corresponding hexacarbonyldi(organoelement)IVb)-phosphine)-cobalt complexes. The vibrational and NMR spectra of the new compounds are discussed.
    Notes: Octacarbonyldicobalt (1) reagiert mit (t-C4H9)3P (2), (t-C4H9)2PH (3), [(CH3)3Si]3P (4), [(CH3)3 Ge]3P (5), [(CH3)3Sn]3P (6) und (t-C4H9)2[(CH3)3Si]P (7) unter Abspaltung von zwei CO-Liganden und Bildung entsprechender Hexacarbonyldi(organoelement(IVb)-phosphan)-cobalt-Komplexe. Die Schwingungs- und Kernresonanzspektren der neuen Verbindungen werden diskutiert.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120529
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    Thiirene als Zwischenstufen der Thermolyse von 1,2,3-Thiadiazolen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1769-1778 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiirenes as Intermediates in the Thermolysis of 1,2,3-ThiadiazolesThermolysis of the isomeric thiadiazoles 1a or 1b in moist 2,2′-oxydiethanol (3) yields the ketone 6, the thiophene 7, the alkyne 8, and the disulfide 11, the structure of which was determined by an X-ray analysis. In the presence of diphenylacetylene (15) 1a and 1b react to give the thiophenes 16a and 16b in the same ratio. This implies that the primary products of thermolysis, the 1,3-diradicals 13, can be trapped by alkynes. The formation of identical thiophenes from isomeric thiadiazoles 1 can be understood in terms of an equilibrium between the primary fragments 13 via the thiirene 14. Similarly, the ketone 6 seems not to result from 8 but from 14.
    Notes: Bei der Thermolyse der stellungsisomeren Thiadiazole 1a oder 1b in feuchtem 2,2′-Oxydiethanol (3) entstehen das Keton 6, das Thiophen 7, das Alkin 8 und das durch eine Röntgenstrukturanalyse eindeutig aufgeklärte dimere Disulfid 11. In Gegenwart von Diphenylacetylen (15) bilden sich aus 1a und 1b die Thiophene 16a und 16b im selben Verhältnis. Die bei der Thermolyse zunächst entstehenden 1,3-Diradikale 13 können demnach durch Alkine abgefangen werden. Die Bildung identischer Thiophene aus isomeren Thiadiazolen 1 läß sich durch ein Gleichgewicht der Primärfragmente 13 verstehen, das sich über das Thiiren 14 einstellt. Auch das Keton 6 scheint nicht aus 8, sondern aus 14 zu entstehen.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120528
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    Neue helicale Kohlenwasserstoffe, III. Pentaphenylenicene (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1785-1790 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Helical Hydrocarbons, III. PentaphenylenicenesSynthesis and properties of o,p-bridged quinquephenyl compounds 5, 6 are reported. The 1H NMR highfield shift of H1 and the temperature independence of some absorptions are interpreted in terms of a more fixed helical arrangement of the o,p-compared with the m,m-bridged compound 4. p-Phenylene rotation as well as plus-minus interconversion are not observed.
    Notes: Synthese und Eigenschaften der endständig in o,p-Stellung verbrückten Quinquephenyl-Verbindungen 5, 6 werden beschrieben. Die 1H-NMR-Hochfeldverschiebungen von H1 und die Temperaturunabhängigkeit einzelner Absorptionen weisen darauf hin, daß die o,p-Verbrückung zu deutlich stärker fixierten Helices führt als die m,m-Klammer in 4. Eine p-Phenylenrotation wird ebensowenig wie eine Plus-Minus-Umwandlung beobachtet.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120530
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    Pyrane, 78. Über Reaktionen von 3-Formylchromonen mit Diphenylketen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1791-1807 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pyrans, 78. Reactions of 3-Formylchromones with DiphenylketeneThe reaction of 3-formylchromones 3a und b with diphenylketene (1) leads to 3-(diphenylvinyl)-chromones 2a and b as well as to the diphenyl-tetrahydropyrano[4,3-b]benzopyrandiones 4a and b. Treatment with base converts 4 into 2. With nucleophilic reagents 2 and 4 give rise to diphenylvinyl-substituted ketones (9), enamines (11), pyrazoles(10), pyrimidines (12), and 1,5-benzodiazepines (13) as well as to chromanonyl-diphenyl-acetic acid dervatives (16 and 18), benzopyrano[3,2-c]pyridines (21), to benzopyrano[4,3-c]pyrazole and -isoxazole derivatives (22).
    Notes: Die 3-Formylchromone 3a und b reagieren mit Diphenylketen (1) zu den 3-(Diphenylvinyl)- chromonen 2a und b sowie den Diphenyltetrahydropyrano[4,3-b]benzopyrandionen 4a und b. 4 läßt sich mit Basen in 2 überführen. Mit nucleophilen Reagenzien setzen sich 2 und 4 zu diphenylvinyl-substituirten Ketonen (9), Enaminen (11), Pyrazolen (10), Pyrimidinen (12) und 1,5-Benzodiazepinen (13) um sowie zu Chromanonyl-diphenyl-essigsäure-Derivaten (16 und 18), Benzopyrano[3,2-c]pyridinen (21), zu Benzopyrano[4,3-c]pyrazol- und -isoxazol-Derivaten (22).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120531
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    Aromatische Diazoniumsalze, IX. Zum Nα, Nβ-Austausch bei der Solvolyse aromatischer Diazoniumsalze (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1835-1840 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Diazonium Salts, IX. The Nα, Nβ-Interchange in Aromatic Diazonium Salts during SolvolysisThe Nα, Nβ-interchange during the solvolysis of [β-15N]benzenediazonium tetrafluoroborate in 2,2,2-trifluoroethanol under N2 was inhibited by less than 4% when the free radical inhibitors bromotrichloromethane, 1,1-diphenylethylene or methyl acrylate were added. Under an air atmosphere the N-inversion was increased by 8%. The main part of the N-inversion under solvolysis conditions is therefore not occurring via reversible addition of phenyl radicals to the diazonium salt.
    Notes: Der Nα, Nβ-Austausch in [β-15N] Benzoldiazonium-tetrafluoroborat bei der Solvolyse in 2,2,2-Trifluorethanol unter N2 wurde durch Zusatz der Radikalinhibitoren Bromtrichlormethan, 1,1-Diphenylethylen und Acrylsäure-methylester nur um maximal 4% erniedrigt. Unter Luftatmosphäre stieg die N-Inversion um 8% an. Eine umkehrbare Addition von Phenyl-Radikalen an das Diazoniumsalz ist daher als Hauptweg der N-Inversion unter Solvolysebedingungen ausgeschlossen.
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    URL: http://dx.doi.org/10.1002/cber.19791120533
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    Untersuchungen an Stoffwechselprodukten von Mikroorganismen, XIX. Über die Synthese einiger antibiotisch wirksamer 2,5-Dialkylresorcine  -  Synthese der Antibiotika DB 2073 und Stemphol (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1841-1848 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Metabolites of Microorganisms, XIX. The Synthesis of some Antibiotically Active 2,5-Dialkylresorcinols  -  Synthesis of the Antibiotics DB 2073 and StempholStarting from 5-alkylresorcinol dimethyl ethers stemphol (2), the antibiotic DB 2073 (3) and a series of further 2.5-dialkylated resorcinols were synthesized via the corresponding 4-alkyl-2.6-dimethoxybenzaldehydes and biologically tested.
    Notes: Ausgehend Von 5-Alkylresorcin-dimethylethern wurden über die entsprechenden 4-Alkyl-2.6-dimethoxybenzaldehyde Stemphol (2) und das Antibiotikum DB 2073 (3) sowie eine Reihe weiterer 2.5-dialkylierter Resorcine dargestellt und biologisch getestet.
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    URL: http://dx.doi.org/10.1002/cber.19791120534
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    Thermolabile Kohlenwasserstoffe, VIII. Thermolysen von 1,2-Dialkyl-1,2-diphenylethanen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1808-1834 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermolabile Hydrocarbons, VIII. Thermolyses of 1,2-Dialkyl,2-diphenylethanesA series of 1,2-dialkyl-1,2-diphenylethanes 3 was prepared by dimerisation procedures. In several cases pure diastereomers were isolated and their configuration was determined. The analyses of the thermolysis products show that bond cleavage occurs primarily at the central C—C-bond. The rates of thermolysis increase parallel with the steric substituent constants ESC and Sf of the halves of the molecules. An even better correlation is observed between rates and strain enthalpies of 3 as obtained from combustion experiments or force field calculations. A comparison of this correlation with a similar one of aliphatic hydrocarbons published recently 4) allows the separation of steric and resonance effects on the thermal stabilities of 3. It is concluded that the position of the transition state on the reaction coordinate depends strongly on group sizes.
    Notes: Eine Reihe 1,2-Dialkyl-1,2-diphenylethane 3 wurde durch Dimerisationsreaktionen dargestellt. Teilweise wurden die reinen Diastereomeren isoliert und ihre Konfigurationen aufgeklärt. Der thermische Zerfall der Kohlenwasserstoffe 3 wurde präparativ und kinetisch untersucht, er erfolgt fast ausschließlich durch primäre Spaltung der zentralen C—C-Bindung. Die Zerfallskonstanten steigen semiquantitativ parallel mit den sterischen Substitutionskonstanten ESC und Sf der Molekülhälften an. Eine bessere Korrelation geben die experimentell bzw. Durch Kraftfeldrechnungen ermittelten Spannungsenthalpien. Der Vergleich dieser Korrelation mit der entsprechenden früher4) für reine Alkane ermittelten gestattet eine Separierung von sterischen und Resonanzeffekten auf die thermische Stabilität von 3. Es wird gefolgert, daß die Lage der Übergangszustände der Thermolysen auf der Reaktionskoordinate mit der Gruppengröße stark variiert.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120532
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    Diels-Alder-Reaktionen mit Cyanthioformamiden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1867-1872 
    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 of CyanothioformamidesN-monosubstituted cyanothioformamides, 1 and their acylated derivatives 2 undergo Diels-Alder reactions with a variety of 1,3-dienes to give the adduct 3a - t and 4a - t
    Notes: Die N-monosubstituierten Cyanthioformamide 1 und ihre Acylderivate 2 gehen mit einer Reihe von 1,3-Dienen Diels-Alder-Reaktionen unter Bildung der Addukte 3a - t und 4 a - t ein.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120537
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    Synthesen biologisch wichtiger Kohlenhydrate, 18. Die vic. cis-Oxyaminierung als Schlüsselreaktion für Aminozucker-Synthesen: Methyl-N-acety-4-epi-α-garosaminid (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1849-1858 
    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 Biologically Important Carbohydrates, 18. The vic. cis-Oxyamination as the Key Reaction for Amino Sugar Syntheses: Methyl N-Acetyl-4-epi-α-garosamindeMethyl 2-O-benzyl-3,4-dideoxy-α-D-glycerol-pent-3-enopyranoside (11), easily available by Corey-Winter olefination of the 3,4-thionocarbonate 10, reacts with chloramines-T/cat. OsO4 to give the 2:1-mixture of methyl 2-O-benzyl-4-deoxy-4-tosylamino- (12) and methyl 2-O-benzyl-3-deoxy-3-tosylamino-β-L-arabinoside (15). With diazomethane 15 yields with N-methyl derivative 16 which is oxidized with cat. RuOO2/KIO4 TO FORM METHYL 2-O-BENZYL-3-DEOXY-3-(N-methyl-tosylamino)-β-L-threo-pentopyranos-4-uloside (17). Grignard reaction of 17 gives stereospecifically methyl 2-O-benzyl-3-deoxy-4-C-methyl-3-(N-methyltosyamino)-α-D-xylopyranoside (19) from which the N-tosyl group and the benzyl substituent at 2-O are split off with sodium in liquid ammonia. N-Acetylation yields methyl 3-deoxy-4-C-methyl-3-(N-methylacetylamino)-α-D-xylopyranoside (methyl N-acetyl-4-epi-α-garosaminide) (21).
    Notes: Methyl-2-O-benzyl-3,4-didesoxy-α-Dglycero-pent-3-enopyranosid (11), das gut durch Corey-Winter-Olefinierung des 3,4-Thionocarbonats 10 zugänglich ist, reagiert mit Chloramin-T/kat. OsO4 zum 2:1-Gemisch des Methyl-2-O-benzyl-4-desoxy-4-tosyalmino- (12) und Methyl-2-O-benzyl-3-desoxy-3tosylamino-β-L-arabinosids (15). 15 wird mit Diazomethan zum N-Methyl-Derivat 16 umgesetzt, das mit kat. RuO2/KIO4 zu Methyl-2-O-benzyl-3-desoxy-3-(N-methyltosylamino)-β-L-threo-pentopyranos-4-ulosid (17)oxidiert wird. Grignard-Reaktion von 17 liefert stereospezifisch Methyl-2-O-benzyl-3-desoxy-4-C-N-methyl-3-(methyltosylamino)-α-D-xylopyranosid (19), aus dem die N-Tosylgruppe und der 2-O-Benzylrest mit Natrium in flüss. Ammoniak abgespalten werden. N-Acetylierung führt zu Methyl-3-desoxy-4-C-methyl-3-(N-methylacetylamino)-α-D-xylopyranosid (Methyl-N-acetyl-4-epi-α-garosaminid) (21).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120535
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    Synthesen biologisch wichtiger Kohlenhydrate, 19. Zur Regioselektivität der vie. cis-Oxyaminierung 3,4-ungesättigter Kohlenhydrate: Gelenkte Synthese von 4-Amino-4-desoxy- und 3-Amino-3-desoxyaldosiden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1859-1866 
    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 Biologically Important Carbohydrates, 19. On the Regioselectivity of the vic. cis-Oxyamination of 3,4-Unsaturated Carbohydrates: Directed Syntheses of 4-Amino-4-deoxy- and of 3-Amino-3-deoxyaldosidesThe oxyamination of methyl 2-O-benzyl-3,4-dideoxy-α-D-glycero-pent-3-enopyranoside (1) with chloramine-T/[OsO4] yields a 2:1 mixture of methyl 2-O-benzyl-4-deoxy-4-tosylamino- (2) and of methyl 2-O-benzyl-3-deoxy-3-tosylamino-β-L-arabinoside (3). In the presence of a phase transfer catalyst the ratio is 4.5:1. In contrast benzyl 2-O-acetyl-3.4-dideoxy-α-D-glycero-pent-3-enopyrano-side (13) reacts with formation of the corresponding 4-deoxy-4-tosylamino- (14) and 3-deoxy-3-tosylamino-arabinoside 15 in the ratio 1:2. With reference to the preparative importance of this „reversal“ a hypothesis is given for the reasons of the observed regio orientation: in the reaction 1→2 + 3 through space interactions are supposed.
    Notes: Methyl-2-O-benzyl-3,4-didesoxy-α-D-glycero-pent-3-enopyranosid (1) reagiert mit (Chloramin-T/[OsO4 ] zu Methyl-2-O-benzyl-4-desoxy-4-tosylamino- (2) und Methyl-2-O-benzyl-3-desoxy-3-tosylamino-β-L-arabinosid (3) im Verhältnis 2:1. In Gegenwart eines Phasentransfer-Katalysators entstehen die isomeren im Verhältnis 4.5:1. Dagegen führt das Benzyl-2-O-acetyl-3,4-didesoxy-α-D-glycero-pent-3-cyanopyranosid (13) zum entsprechenden 4-Desoxy-4-tosylamino- (14) und 3-Desoxy-3-tosylamino-arabinosid 15 im Verhältnis 1:2. Auf die präparative Bedeutung dieser Umkehrung wird hingewiesen. Für ihre Ursachen wird eine Hypothese entwickelt: als Grund für die Regioorientierung bei 1→ 2 + 3 werden „through space“-Wechselwirkungen angenommen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120536
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  • 87
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    Cycloadditionen von Cyanthioformamiden mit 1,3-Dipolen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1873-1878 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions of Cyanothioformamides with 1,3-DipolesThe disubstituted cyanothioformamides 1 add to diazo compounds presumably forming the thiadiazoles 2 which decompose to give the thiiranes 3. These may be desulfurized to the ethylenes 5.1b reacts with diphenylnitrilimine to form the thiadiazoline 6. Nitrile oxides and 1 afford the oxathiazoles 7. The monosubstituted cyanothiaoformamides 8. likewise yield the oxathiazoles 9. which decompose to aryl isothiocyanates and the cyanoformamides 10. The reaction of 1 with phenylazide at 100°C produces the cyanoformamidines 14. probably via the unstable thiatriazolines 11 or 12 and the thiaziridines 13.
    Notes: Die disubstituierten Cyanthioformamide 1 addieren sich an Diazoverbindungen, vermutlich unter Bildung der Thiadiazole 2, die weiter zu den Thiiranen 3 zerfallen. Diese können zu den Ethylenen 5 entschwefelt werden. Mit Diphylnitrilimin bildet 1b das Thiadiazolin 6. Nitriloxide liefern mit 1 die Oxathiazole 7. In gleicher Weise ergeben die monosubstituierten Cyanthioformamide 8 die Oxathiazole 9, die weiter in Arylisothiocyanate und die Cyanformamide 10 zerfallen. Die Reaktion von 1 mit Phenylazid bei 100°C liefert, offenbar über die instabilen Thiatriazoline 11 oder 12 und die Thiaziridine 13, die Cyanformamidine 14.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120538
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  • 88
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    Reaktionen an Indolderivaten, XXXVIII. Dreiringreaktionen in der Indolreihe (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1889-1901 
    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 Indole Derivatives, XXXVIII. Cyclopropane Reactions in the Indole SeriesThe acid-catalyzed and the nucleophilic ring-opening of the cyclopropanelactams 1 and 2 studied and their stereospecifity is reported. The ketolactams 22 and 23 obtained via this route represent important intermediates.
    Notes: Die protonenkatalysierte und die nucleophile Ringöffnung der Cyclopropanlactame 1 und 2 werden studiert und die Stereospezifität beschrieben. Die auf diese Weise erhaltenen Ketolactame 22 und 23 sind wichtige Zwischenprodukte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120540
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  • 89
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    Reaktionen an Indolderivaten XXXVII. Stereoselektive Synthese polycyclischer Cyclopropanderivate in der Indolochinolizin-Reihe (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1879-1888 
    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 Indole Derivatives, XXXVII. Stereoselective Synthesis of Polycyclic Cyclopropane Derivatives in the Indoloquinolizine SeriesThe high yield stereoselective synthesis of the pentacyclic cyclopropanelactam 8 is reported.
    Notes: Es wird über eine in guten Ausbeuten verlaufende stereoselektive Synthese des pentacyclischen Cyclopropanlactams 8 berichtet.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120539
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  • 90
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    Reaktionen an Indolderivaten, XL. Ein einfacher Zugang zum Yohimbenon (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1913-1915 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions with Indole Derivatives, XL. Simple Access to YohimbenoneThe enolether 1, obtained by Birch reduction, easily and in high yield gives rise to yohimbenone (6) via hydrolysis followed by formaldehyde cyclization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120542
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  • 91
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    Neue μ-Hydroxo-Übergangsmetallkomplexe, II. Darstellung mehrkerniger Komplexe des Chroms(III) mit dreizähnigen Amin-Liganden. Struktur des μ[cis-Dihydroxo(O,O′)-hydroxo(l,4,7-triazacyclononan)chrom(III)]-di-μ-hydroxobis[(1,4,7-triazacyclononan)chrom(III)]-Kations (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2837-2846 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel μ-Hydroxo-Transition Metal Complexes, II. Preparation of Polynuclear Complexes of Chromium(III) Containing Tridentate Amine Ligands. The Structure of the μ-[cis-Dihydroxo(O,O′)-hydroxo(l,4,7-triazacyclononane)chromium(III)]-di-μ-hydroxo-bis[(1,4,7-triaacyziononane)chromium(III)] CationThe attempted preparation of dinuclear complexes of chromium(III) containing three μ-hydroxo bridges by a condensation reaction of triaquaaminechromium(III) complexes [amine = 1,1,1-tris(aminomethyl)ethane (l) or l,4,7-triazacyclononane (2)] in acidic media yields only di-μ-hydroxo-bis[aquaaminechromium(III)] complexes (3, 4). More drastic reaction conditions afford a trinuclear complex 7 containing four μ-hydroxo bridges and a terminal OH-ligand which is linked to one μ-hydroxo bridge via a very short hydrogen bond contributing substantially to the stability of this cation. A single-crystal X-ray analysis of [Cr3([9]aneN3)3(OH)5]I5 · 5H2O (8) exhibits two different pairs of μ-hydroxo bridges with bond angles of 98 and 126°, respectively. The synthesis of a dinuclear, triply hydroxobridged chromium(III) complex has not been successful.
    Notes: Versuche, zweikernige Komplexe des Chroms(III) mit drei μ-Hydroxobrücken durch Kondensation von Triaquaaminchrom(III)-Komplexen [Amin = 1,1,1-Tris(aminomethyl)ethan (1) Oder 1,4,7-Triazacyclononan (2)] in saurem Medium darzustellen, führen nur zu Di-μ-hydroxo-bis-[aquaaminchrom(III)]-Komplexen (3, 4). Drastischere Reaktionsbedingungen führen zur Bildung eines dreikernigen Komplexes 7 mit vier μ-Hydroxobrücken und einer terminalen OH-Gruppe, die  -  gebunden über eine starke H-Brückenbindung zu einer μ-Hydroxobrücke  -  wesentlich zur Stabilität dieses Kations beiträgt. Eine Röntgenstrukturanalyse von [Cr3([9]anN3)3(OH)5]I5. 5 H2O (8) zeigt die Existenz zweier unterschiedlicher Paare von μ-Hydroxobrücken in dem dreikernigen Kation mit -Bindungswinkeln von 98 bzw. 126°. Die Synthese eines zweikernigen Tri-μ-hydroxo-Komplexes des Chroms(III) gelang nicht.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120810
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  • 92
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    Tautomeriefähige 1-Alkyl-2-aryldiazene. Synthese und spektroskopische Untersuchungen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2913-2924 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tautomeric 1-Alkyl-2-aryldiazenes. Synthesis and Spectroscopic InvestigationsA convenient synthesis of 1-(4-hydroxyphenyl)-2-methyldiazenes 7a - h and 1-(4-hydroxynaphthyl)-2-methyldiazene 12 is reported. Evidence for a solvent and temperature dependent tautomeric equilibrium of type 1⇌2 has been found. In contrast no spectroscopic indications for type 3 tautomers have been observed. Values of the tautomeric equilibrium 12⇌13 are given for various solvents and different temperatures.
    Notes: Eine bequeme Synthese für l-(4-Hydroxyphenyl)-2-methyldiazene 7a - h und l-(4-Hydroxy-l-naphthyl)-l-methyldiazen 12 wird beschrieben. Die Existenz lösungsmittel- und temperaturabhängiger Tautomerengleichgewichte des Typs 1⇌2 wird nachgewiesen. Spektroskopische Anzeichen für Tautomere des Typs 3 ergaben sich nicht. Die Lage des Tautomerengleichgewichts 12⇌13 wird für verschiedene Temperaturen und Lösungsmittel bestimmt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120818
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  • 93
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    Schwefel-Ylide aus einem Enaminosulfonium-Salz und CH-aciden Verbindungen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3007-3012 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur Ylides by the Reaction of an Enaminosulfonium Salt with CH-acidic CompoundsMethyl 3-dimethylamino-2-(methylthio)acrylate (9) is methylated at the sulfur atom by methyl iodide to give the enaminosulfonium salt 11. The reaction of 11 with methylene active compounds leads to substitution of the amine function. The sulfur ylides of the general type 12 thus obtained are stabilized by conjugation with the activating groups of the methylene active compound.
    Notes: 3-Dimethylamino-2-(methylthio)acrylsäure-ethylester (9) wird durch Methyliodid am Schwefel methyliert. Das so gebildete Enaminosulfonium-Salz 11 reagiert mit CH-aciden Verbindungen unter Substitution der Aminfunktion durch die methylenaktive Komponente. Die so erhaltenen Schwefel-Ylide des Typs 12 sind stabilisiert durch Konjugation mit den aktivierenden Gruppen der methylenaktiven Komponente.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120823
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  • 94
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    Zur Reaktion von Pinenen mit Chlorwasserstoff (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3031-3033 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Reaction of Hydrogen Chloride with Pinenessyn-Addition of DCI to the less hindered site of α- and β-pinene (1, 2) is demonstrated by a combination of 13C- and 2H-NMR spectroscopy. The resulting tertiary chloride is configurationally pure and isomerizes to bornyl chloride only. The rapidity of the isomerization with the possible conversion of a tertiary to a secondary carbocation is rationalized by strain calculations with a molecular mechanics force field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120826
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    Masthead (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979) 
    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.19791120901
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  • 96
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    Synthese von (+)-Discadenin und seinem Desamino- und Descarboxy Derivat (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3072-3080 
    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 i.(+)-Discadenine and its Deamino and Decarboxy DerivativesThe synthesis of L.(+)-discadenine (1) and its deamino (2a) and decarboxy derivatives (2b) is described. Alkylation of N6-N(,3-dimethylallylamino)purine with the bromo compound 4. ethyl 4-bromobutyrate or N-(3-bromopropyl)phthalimide, respectively, leads to the protected purine derivatives 5a-c. The position of alkylation was confirmed by 1H/1.3C NMR spectroscopy and pH dependent UV spectra and was shown to be N-3. The phthaloyl residues of 5a and c are removed by hydrazinolysis and the cleavage of the ester group in 5a and b is accomplished by alkaline hydrolysis. The reaction products 1, 2a and b are characterised by UV, 1H/C NMR, and mass spectra. The spectroscopic data are in full agreement with those of the spore germination inhibitor from Dictyostelium discoideum.
    Notes: Die Synthese von L(+)-Discadenin (1) sowie seinem Desamino- 2a und Descarboxy-Derivat (2 b) wird beschrieben. Alkylierung von N6-(3,3-Dimethylallylamino)purin mit der Bromverbindung 4 bzw. 4-Brombuttersäure-ethylester oder N-(3-Brompropyl)phthalimid führt zu den geschützten Purin-Derivaten 5a-c, deren Substitution an N-3 mit Hilfe der 1H- bzw. 13C-NMR-Spektroskopie und der pH-abhängigen UV-Spektren gesichert wurde. Hydrazinolyse entfernt die Phthaloylreste von 5a und c, alkalische Hydrolyse spaltet den Ethoxycarbonylrest in 5a und c. Die Reaktionsprodukte 1, 2a und b wurden durch UV, 1H/13C-NMR und Massenspektren charakterisiert. Die spektroskopischen Daten von L-Discadenin zeigten dabei volle Übereinstimmung mit denen des Sporenkeimungsinhibitors aus Diciyostelium discouicum.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120905
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    Eine umkehrbare Gerüstumlagerung im trans- Erythrinan-Ringsystem, II. Neue trans- und 1(6→7)abeo-trans- Erythrinane (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3110-3125 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Reversible Rearrangement of the trans-Erythrinane Ring System, II. New trans-and 1(6→7)abeo-trans-ErythrinanesThe scope of the reversible rearrangement 1⇌2 is assessed. 1 and its monosubstituted derivatives 5-9 yield the trans-dihydroxy-1(6→7)abeo- trans-erythrinane lactams 10-23 (derivatives of “diol-A*”). Compounds such as 3/4 and 24/25 are, however, not formed under the same conditions. Under certain conditions, the reaction can be accomplished in two steps, in either direction. The rearrangement step consists of a spontaneous 1,2-shift of four reaction centres.
    Notes: Der Gültigkeitsbereich der umkehrbaren Gerüstumlagerung 1⇌2 wird abgegrenzt. Aus 1 und seinen monosubstituierten Derivate 5-9 erhält man die trans-Diol-1 (6 → 7)abeo- trans-erythrinanlactame (Diol-A*-Derivate)10 - 23, während Verbindungen vom Typus 3/4 und 24/25 unter den angewandten Bedingungen nicht darstellbar sind. Unter bestimmten Bedingungen können die Reaktionen in beiden Richtungen auch in zwei Schritten durchgeführt werden. Im Umlagerungsschritt wechseln jeweils vier Partner unter 1,2-Verschiebung spontan ihre Plätze.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120909
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    Reaktionen mit Cyclopropenen, III. tert-Butylamino-substituierte Aromaten durch Photocyclisierung von N-tert-Butyl(arylvinyl)keteniminen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3166-3170 
    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 Cyclopropenes, III. tert-Butylamino-Substitued Aromatic Compounds by Photocyclization of N-tert-Butyl(arylvinyl)ketene IminesN-tert-Butyl(arylvinyl)ketene imines 2a-g, obtained by ring-cleavage of the cyclopropenes 1a-g with tert-butyl isocyanide, cyclize on irradiation in a hexatriene-cyclohexadiene isomerisation with subsequent 1,7-hydrogen transfer to the tert-butylamino-substituted aromatic compounds 4a-f and 4g.
    Notes: Die durch Ringspaltung der Cyclopropene 1a-g mit tert-Butylisocyanid erhaltenen N-tert-Butyl-(arylvinyl)ketenimine 2a-g cyclisieren beim Bestrahlung in einer Hexatrien-Cyclohexadien-Isomerisierung mit anschließender 1,7-Wasserstoffverschiebung zu den tert-butylamino-substituierten Aromaten 4a-f und 4g.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120914
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    Bausteine von Oligosacchariden, XVII. Synthese von Trehalosamin, Mannotrehalosamin und verwandten α, α(1→1)-verknüpften Disacchariden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3203-3213 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, XVII. Synthesis of Trehalosamine, Mannotrehalosamine, and Related α,α(1→1)-Linked Disaccharides6-O-Acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-β-D-glucopyranosyl chloride (1) reacts with 2,3,4,6-tetra-O-benzyl-α-D-glucopyranose (2) in the presence of silver perchlorate and sym-collidine with good stereoselectivity to give the α,α(1→1)-linked disaccharide 3. Deblocking of 3 by sodium in liquid ammonia affords α,α-trehalosamine 5. Correspondingly, the reaction of 1 with the manno-derivative 6 affords 8, which can be converted into α,α-mannotrehalosamine 9. Several other α,α(1→1)-linked disaccharides of the trehalosamine type containing additional azido groups have been synthesized. The α,α(1→1)-linked disaccharides 21 and 23 containing 2-azido-2-deoxy-α-D-galactopyranose could be prepared, too.
    Notes: 6-O-Acetyl-2-azido-3,4-di-O-benzyl-2-desoxy-β-D-glucopyranosylchlorid (1) reagiert mit 2,3,4,6-Tetra-O-benzyl-α-D-glucopyranose (2) bei Gegenwart von AgCIO4 und sym-Collidin in guter Stereoselektivität zum α,α(1→1)-verknüpften Disaccharid 3. Entblockierung von 3 mit Natrium in flüssigem Ammoniak liefert Trehalosamin 5. Entsprechend führt die Umsetzung von 1 mit dem manno-Derivat 6 zu 8, aus dem das Mannotrehalosamin 9 freigesetzt werden kann. Eine Reihe weiterer α,α(1→1)-verknüpfter Disaccharide vom Trehalosamin-Typ, die zusätzliche Azido-Gruppen enthalten, wurden synthetisiert. Auch α,α(1→1)-verknüpfte Disaccharide 21 und 23 mit 2-Azido-2-desoxy-α-D-galactopyranose-Einheiten lieβen sich darstellen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120917
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    Electronic Resource
    Electronic Resource
    Thermische Umlagerungen von 1-Aryl-2-vinylcyclopropanen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3241-3272 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermal Rearrangements of 1-Aryl-2-vinylcyclopropanesThe 1-Aryl-2-isopropenylcyclopropanes 6a-n and 7a-n, the 1-aryl-2-vinylcyclopropanes 8/9a, h, k, l as well as 10 and 11 are prepared by cycloaddition of the carbenes 5a-n to suitable 1,3-butadienes. At temperatures of 100-200°C, rearrangement to cyclopentenes 13a-m or to benzocycloheptenes 16a-j occurs in addition to cis/trans-isomerization of the three-membered ring. Both rearrangements take place competitively with 6/7a, g, k, l and 8/9h; except for 6/7l, the amount of benzocycloheptenes can be augmented by more polar solvents. Mechanistic aspects of the 1-aryl-2-vinylcyclopropane → benzocycloheptene rearrangement are discussed. For 6/7i and n, isomerization to the pentadienes 25 and 24 is observed besides the rearrangement to cyclopentenes.
    Notes: Die 1-Aryl-2-isopropenylcyclopropane 6a-n und 7a-n, die 1-Aryl-2-vinylcyclopropane 8/9a, h, k, l sowie 10 und 11 weden durch Cycoloaddition der Carbene 5a-n an die entsprechenden 1,3-Butadiene synthetisiert. Bei Temperaturen von 100-200°C tritt neben der cis/trans-Isomerisierung am Dreiring Umlagerung zu den Cyclopentenen 13a-m oder zu den Benzocycloheptenen 16a-j ein. Für 6/7a, g, k, l und 8/9h laufen beide Umlagerungen nebeneinander ab, wobei außer im Fall von 6/71 der Anteil an Benzocyclohepten durch Übergang zu Lösungsmitteln größerer Polarität erhöht werden kann. Mechanistische Aspekte der 1-Aryl-2-vinycylclopropan → Benzocyclohepten-Umlagerung werden diskutiert. Außer der Umlagerung zum Cyclopenten wird für 6/7i und n auch Isomerisierung zu den Pentadienen 25 und 24 beobachtet.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120921
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