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  • 1980-1984  (4,966)
  • 1965-1969  (4,735)
  • Organic Chemistry  (6,535)
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  • 1
    Electronic Resource
    Electronic Resource
    The representation of contrast and other stimulus parameters by single neurons in area 17 of the cat (1984)
    Springer
    Pflügers Archiv 401 (1984), S. 304-314 
    Details
    ISSN: 1432-2013
    Keywords: Visual cortex ; Contrast/response function ; Orientation and direction sensitivity ; Ocularity ; Binocular responses ; Feature specific responses ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The responses of neurons in area 17 were tested as a function of various stimulus parameters. The thresholds of individual cortical neurons were at contrasts between 0.01 and 0.1 (increment of 0.5×10−1 cd/m−2 on a background of 3 cd/m−2), the dynamic ranges were 1.0–2.0 log units of increment, and all cells showed a response decrease at increments above a certain maximum (supersaturation response). The averaged contrast/response curve for all neurons was S-shaped in the logarithmic plot, had a dynamic range of 2.5 log units, reached its maximum at a contrast of 0.75 and supersaturated above this level. The contrast/ sensitivity curves changed their slope under different stimulus conditions. They became flatter when the non-dominant eye was stimuated as compared to dominant eye stimulation or when the stimulation was done at a non-optimal orientation or direction, and they became steeper when both eyes were stimulated. But the maximum was reached at the same contrast and supersaturation was seen above maximum contrast no matter whether a cell was stronlgy (e.g. binocular stimulation at optimal orientation) or weakly excited (non-dominant or non-optimal orientation stimulation). After normalization, the averaged population contrast/response curves were virtually identical at all stimulus conditions. It was concluded, that range as well as maximum and supersaturation of cortical contrast/response curves are determined before the input reaches the cortex, and that the cortical cells summate, essentially, linearly. The findings furthermore demonstrate that the supersaturation of the cortical input must be due to subtractive inhibition, and that the same is true for the orientation sensitive inhibition in the cortex itself. Both, the peripheral contrast and the cortical orientation dependant inhibition cannot be explained by multiplicative inhibition. The fact, that the responses of neurons depend on many variables relativates their significance for feature representation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582601
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  • 2
    Electronic Resource
    Electronic Resource
    Peripheral nerve phospholipids in acrylamide neuropathy (1984)
    Springer
    Archives of toxicology 55 (1984), S. 178-181 
    Details
    ISSN: 1432-0738
    Keywords: Cat ; Phospholipids ; Acrylamide ; Neuropathy ; Lipids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Treatment of cats with acrylamide, either 7.5 or 15 mg/kg IM, once a day for 10 days, resulted in increases of 31 and 47% in the phospholipid content of sciatic nerve, respectively, from a control level of 41.1±2.7 mg/kg wet weight. Determination of the distribution of individual phospholipids indicated no significant differences between control cats and those receiving a cumulative dose of 150 mg/kg acrylamide. In a separate experiment, cats were treated with the 150 mg/kg dose of acrylamide and the sciatic nerve was divided into proximal and distal portions at the level of the triceps surae nerve. Significant increases in phospholipid content were observed in both the proximal and distal portions of peripheral nerve of the acrylamide-intoxicated cats. This effect was present even when the phospholipid content was expressed in terms of total protein, dry weight or total lipid. Total weight of nerve segments, however, was significantly decreased in the neuropathic animals. The data are consistent with a focal degeneration of axons with relative sparing of phospholipids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316124
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  • 3
    Electronic Resource
    Electronic Resource
    The termination of spinomesencephalic fibers in cat (1984)
    Springer
    Anatomy and embryology 170 (1984), S. 265-277 
    Details
    ISSN: 1432-0568
    Keywords: Midbrain ; Spinal cord ; Cat ; Degeneration-HRP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The projections to the midbrain from the spinal cord have been investigated in the cat with the degeneration technique and by using horseradish peroxidase (HRP) as an anterograde tracer. Two types of spinal cord lesions were performed: 1) Cordotomies at cervical or thoracic levels transecting the ventral and lateral funiculi. 2) Transections of the ventral, ventrolateral, dorsolateral or dorsal funiculus, respectively, at cervical levels. In the anterograde tracing experiments HRP was injected into the spinal cord at cervical, lumbar or sacral levels. The results show large projections to the lateral and ventrolateral parts of the periaqueductal gray (PAG1), the posterior pretectal nucleus (PP) and the nucleus of Darkschewitsch (D). More moderate projections go to the medial division of the periaqueductal gray (PAGm), the cuneiform nucleus (CF), the mesencephalic reticular formation (MRF), lateral part of the deep layer of the superio colliculus (SP) and magnocellular medial geniculate nucleus (GMmc), while scattered spinal fibers are present in the dorsal part of the periaqueductal gray (PAGd), the external inferior collicular nucleus (IX), the intermediate layer of the superior colliculus (SI), the lateral part of the red nucleus (NR) and in the Edinger-Westphal portion of the oculomotor nucleus (3). In addition a few fibers are present in the interstitial nucleus of Cajal (CA) and anterior pretectal nucleus (PAc). The results indicate that at midcervical levels most of the spinomesencephalic fibers ascend in the ventral funiculus, with only a moderate fraction ascending in the ventral half of the lateral funiculus. Almost no fibers ascend in the dorso-lateral funiculus and none appear to pass in the dorsal funiculus. No distinct somatotopic pattern was found in the spinomesencephalic projections, but more fibers from cervicobrachial segments terminate in the rostral than in the caudal parts of the terminal fields in PAG, CF, SP and IX, while the lumbar fibers were more numberous in the caudal parts. PP seems to receive spinal fibers mainly from the caudal half of the cord.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318730
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  • 4
    Electronic Resource
    Electronic Resource
    An anatomical study of the projections from the dorsal column nuclei to the midbrain in cat (1984)
    Springer
    Anatomy and embryology 170 (1984), S. 29-43 
    Details
    ISSN: 1432-0568
    Keywords: Anatomy ; Anterograde tracing ; Dorsal column nuclei ; Midbrain ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The termination of the fibers from the dorsal column nuclei (DCN) to the midbrain has been investigated in the cat with the degeneration method, the anterograde horseradish peroxidase (HRP) method and autoradiography after 3H-leucine injections. The results show that the DCN project to several midbrain regions. The external nucleus of the inferior colliculus (IX) receives the heaviest projection from both the gracile and cuneate nuclei. The DCN fibers form three joint terminal zones in IX. Each terminal zone contains clusters with dense aggregations of DCN fibers. Fairly dense terminal networks are found in the posterior pretectal nucleus (PP) and the compact part of the anterior pretectal nucleus (PAc) as well. More scattered DCN fibers are present in the cuneiform nucleus (CF), the lateral part of the periaqueductal gray (PAG1), the red nucleus (NR), the nucleus of the brachium of the inferior colliculus (B), the mesencephalic reticular formation (MRF) and the intermediate and deep layers of the superior colliculus (SI, SP). The projections to all regions are mainly contralateral. Most of the few ipsilateral fibers terminate in IX. A somatotopic organization was seen in IX and NR. The gracile fibers terminate preferentially in the caudal and lateral part of IX and the cuneate ones preferentially in its rostral and medial part. In the red nucleus the gracile fibers terminate ventral to the cuneate ones. In the pretectal region there was a predominance for gracile fibers. There also appeared to be quantitative differences in the projections from various levels of the gracile nucleus, with more midbrain projecting fibers originating in the rostral than in the middle and caudal parts of the nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319455
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  • 5
    Electronic Resource
    Electronic Resource
    Anatomy of the cecum of the cat (1984)
    Springer
    Anatomy and embryology 170 (1984), S. 177-186 
    Details
    ISSN: 1432-0568
    Keywords: Cecum ; Cat ; Macroscopic anatomy ; Light, scanning and transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a series of comparative anatomical studies on the ceca of various mammals the cat was chosen as representative of a “typical” carnivore. In the domestic cat, the cecum is conspicuously small and macroscopically relatively undifferentiated in comparison to most herbivores. Microscopically (light, scanning and transmission electron microscopy), however, it is characterized by an abundance of goblet cells and enterocytes rich in organelles, suggestive of functional activity. In addition to the morphological description, which also includes arterial supply and mesenteries of the cecum, the discussion is focussed on 1) the possible functional significance of the numerous goblet cells 2) a general categorization of the different types of ileal-caeco-colical junctions and 3) speculations concerning the justification for considering the carnivore cecum as being rudimentary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319003
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  • 6
    Electronic Resource
    Electronic Resource
    The blood vessels of the cat girdle placenta. Observations on corosion casts, scanning electron microscopical and histological studies (1984)
    Springer
    Anatomy and embryology 170 (1984), S. 209-216 
    Details
    ISSN: 1432-0568
    Keywords: Placenta ; Fetal microvasculature ; Corrosion casts ; Scanning electron microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fetal microvascular architecture of the feline near-term placenta was investigated using scanning electron micrographs of partially fractured corrosion casts from plastic-filled vessels. The findings were compared with those on corresponding semithin histological sections. The branches of both umbilical arteries and veins roughly follow a course parallel to the zonary girdle on the allantochorionic side of the feline placenta in an acute-angled pattern of ramifications. They join the double-layered capilary networks in the chorionic lamellae of the labyrinth, which generally exhibit a chorio-uterine orientation and are partially twirled. On the allantochorionic side of the labyrinth, these fetal capillary networks are “suspended” on the maternal stem-artery-system of the placenta; on the uterine side, they have peduncular or tuft-like endings of capillary loops and are flattened by the uterine septa, which at this level converge into the maternal veins. The chorionic capillary lamellae have a variable breadth and length and therefore need shorter or longer arterioles and venules from the allantochorionic side to become irrigated at any level of the labyrinth. As a result, the feline placenta is characterized by a generally one-way crosscurrent type of materno-fetal blood flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319006
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  • 7
    Electronic Resource
    Electronic Resource
    An autoradiographic study of topographical relationships between pallidal and cerebellar projections to the cat thalamus (1984)
    Springer
    Experimental brain research 54 (1984), S. 95-106 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellothalamic projections ; Pallidothalamic projections ; Ventral nuclei of thalamus ; Autoradiography ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Injections of 3H-leucine were made in the entopeduncular nucleus or dentate nucleus of the cerebellum in eight cats. The terminal projection zones of both pathways in the thalamus were studied using the sagittal plane and their relationships to one another as well as to cytoarchitectural boundaries of thalamic nuclei were compared. The data indicate that the territories controlled by the two projection systems are almost entirely segregated. The segregation is mainly along the antero-posterior axis as the main pallidal projection zone occupies the medio-ventral VA while the main dentate projection zone lies posterior to it in the VL. Furthermore, the dorsolateral part of the VA not occupied by pallidal projections receives dentate projections. In the VM, both afferent systems terminate in the lateral part of the nucleus with pallidal territory located anteriorly and dentate territory located posteriorly, again without overlap. As the delineations of nuclear subdivisions in the ventral thalamus of the cat have been a subject of some controversy, it is suggested that the boundaries of the VA, VL and VM in the cat thalamus be defined on the basis of basal ganglia and cerebellar projection zones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235822
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  • 8
    Electronic Resource
    Electronic Resource
    Distribution of corticospinal neurons with collaterals to lower brain stem reticular formation in cat (1984)
    Springer
    Experimental brain research 54 (1984), S. 107-120 
    Details
    ISSN: 1432-1106
    Keywords: Corticospinal collaterals ; Sensorimotor cortex ; Corticobulbar pathways ; Fluorescent tracers ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fluorescent retrograde double-labeling technique has been used to determine whether corticospinal neurons in the cat sensorimotor cortex distribute collaterals to the lower brain stem reticular formation. In this study the fluorescent tracers Nuclear Yellow and Diamidino Yellow 2HCl were used in combination with Fast Blue. One tracer was injected unilaterally in the spinal cord and the other was injected ipsilaterally in the bulbar medial reticular formation. The distribution of the retrogradely labeled neurons was studied in the contralateral hemisphere. In the sensorimotor cortex a large population of neurons was found which were labeled from the spinal cord and were double-labeled from the brain stem. These branching neurons were concentrated in the rostromedial part of area 4 and the adjoining lateral part of area 6. In this region the percentages of corticospinal neurons which were double-labeled from the brain stem ranged from 5% laterally to 30% medially. In two cats it was demonstrated by means of the anterograde transport of HRP that the corticobulbar fibers from this region which must include the corticospinal collaterals are distributed to the reticular formation of the lower brain stem. In view of the fact that the double-labeled neurons are concentrated in the anterior part of the motor cortex, those branching neurons are in all likelihood involved in the control of neck, back and shoulder movements. This control is probably exerted by way of two routes i.e. by way of the direct corticospinal connections to spinal interneurons, and by way of the indirect cortico-reticulospinal connections established by the cortical fibers to the bulbar reticular formation. The present findings suggest that this dual control may be exerted by one and the same cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235823
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  • 9
    Electronic Resource
    Electronic Resource
    Ascending projections from the nucleus of the brachium of the inferior colliculus in the cat (1984)
    Springer
    Experimental brain research 54 (1984), S. 203-211 
    Details
    ISSN: 1432-1106
    Keywords: Ascending auditory pathway ; Inferior colliculus ; Medial geniculate body ; Cat ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ascending projections from the nucleus of the brachium of the inferior colliculus (NBIC) in the cat were studied by the autoradiographic tracing method. Many fibers from the NBIC ascend ipsilaterally in the lateral tegmentum along the medial border of the brachium of the inferior colliculus. At midbrain levels, fibers from the NBIC end in the superior colliculus, the pretectum, the central gray and the peripeduncular tegmental region bilaterally with ipsilateral predominance. NBIC fibers to the superior colliculus are distributed densely to laminae VI an III throughout the whole rostrocaudal extent of the colliculus. In the pretectum, NBIC fibers terminate in the anterior and medial nuclei and the nucleus of the posterior commissure. NBIC fibers to the dorsal thalamus are distributed largely ipsilaterally. Many NBIC fibers end in the dorsal and medial divisions of the medial geniculate body, but few in the ventral division. The NBIC also sends fibers to the suprageniculate, limitans and lateralis posterior nuclei and the lateral portion of the posterior nuclear complex; these regions of termination of NBIC fibers constitute, as a whole, a single NBIC recipient sector. Additionally, the NBIC sends fibers to the centralis lateralis, medialis dorsalis, paraventricular and subparafascicular nuclei of the thalamus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236219
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  • 10
    Electronic Resource
    Electronic Resource
    Locomotion in adult cats with early vestibular deprivation: Visual cue substitution (1984)
    Springer
    Experimental brain research 54 (1984), S. 395-405 
    Details
    ISSN: 1432-1106
    Keywords: Neonatal ; Bilabyrinthectomy ; Recovery ; Locomotion ; Vision ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four cats labyrinthectomized shortly after birth (DELAB) exhibited the classical vestibular syndrome and recovery, while their motor development was otherwise unimpaired. As adults, they were tested for visual vestibular substitution in a locomotor task with either orientation requirements (tilted platforms) or balance requirements (narrow platforms). Visual motion cues or static visual cues were controlled using normal or stroboscopic lighting, or darkness. Measurements of the average speed of locomotion showed that: Although all cats increase their speed when more visual cues become available, a marked deficit occurs in darkness only in the DELAB cats. With either vestibular cues alone or static visual cues alone, cats are able to reach the same level of performance in the tilted platform test, which suggests a total visual-vestibular interchangeability in orientation. DELAB cats perform very poorly in the narrow rail test. When continuous vision is allowed in the narrow rail test the DELABs' performance rises but does not match that of the control group. A specific deficit in balance for the DELAB group is thus reduced by normal continuous vision as compared to stroboscopic vision, suggesting a significant, though imperfect, substitution of motion visual cues for the missing dynamic vestibular cues. Dynamic visual cues play only a minor role in most situations, when locomotory speed is high. This results support the view that both the vestibular and the visual system can subserve two distinct functions: dynamic information may stabilize the stance in narrow unstable situations, during slow locomotion. and static orientation cues may mainly control the direction for displacement. Possible interactions between head positioning and body orientation in the DELAB cats are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235464
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  • 11
    Electronic Resource
    Electronic Resource
    Afferents to the cortical pupillo-constrictor areas of the cat, traced with HRP (1984)
    Springer
    Experimental brain research 54 (1984), S. 377-381 
    Details
    ISSN: 1432-1106
    Keywords: Pupillo-constrictor areas ; Afferents ; HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Afferents of the cortical pupillo-constrictor areas (PCAs) of the cat were studied using the horseradish peroxidase method. PCAs receive heavy cortical inputs from areas 7, 19, 21, the lateral suprasylvian area, the splenial visual area, and subcortically from the claustrum, the intralaminar nuclei, the pulvinar-lateral posterior nuclear complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236240
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  • 12
    Electronic Resource
    Electronic Resource
    Brainstem afferents to the lateral geniculate nucleus of the cat (1984)
    Springer
    Experimental brain research 54 (1984), S. 253-258 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Pretectal nuclei ; Superior colliculus ; Parabigeminal nucleus ; Reticular formation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ascending connections from the brainstem to the dorsal division of the lateral geniculate nucleus were examined using retrograde transport of horseradish peroxidase. Labelled cells were identified in a variety of structures, including the nucleus of the optic tract (NOT), the posterior pretectal nucleus (NPP), the superior colliculus (SC), the parabigeminal nucleus (PBN), the midbrain reticular formation (MRF), locus coeruleus and nucleus sub-coeruleus, the substantia nigra (SN), and parts of the raphe complex. The projections from NOT, NPP, MRF, LC and PBN were all bilateral in origin. The most intense labelling was observed in the nucleus of the optic tract and the superior colliculus. Colliculo-geniculate cells were located primarily in the superficial gray lamina II1 and II2 of Kaneseki and Sprague (1974), but sparse labelling was also observed in lamina II3 and in statum opticum (lamina III). Consistent with the report of Harrell et al. (1982), these cells represent a morphologically diverse population, which includes stellate cells, granule cells, and both vertical and horizontal fusiform cells. A similarly diverse population of cell types contributes to the geniculate projection arising from NOT. These results confirm and extend earlier descriptions of the brainstem projections to the cat LGNd, and serve to emphasize the diversity of brainstem influences over the geniculate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236224
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  • 13
    Electronic Resource
    Electronic Resource
    The control of rapid limb movement in the cat (1984)
    Springer
    Experimental brain research 55 (1984), S. 134-144 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Tracking ; Isometric ; Updating ; Delayed feedback
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. In cats trained to track a moving display by making rapid, isometric force adjustments, responses are characterized by extremely short reaction times (60–70 ms) and a stereotyped temporal configuration. The animal uses early derivatives of display movement to scale force responses to target stimuli of different sizes according to a learned relationship between initial display motion and required force (Ghez and Vicario 1978a, 1978b). In the present study we altered that relationship by using double stimulation and delayed feedback to assess the animals' ability to update their responses. 2. In experiments where a second target stimulus followed the first after a controlled interval (15–120 ms) on random trials, the animal modified its response in the appropriate direction with little or no increase in reaction time. When the second stimulus called for a return to baseline, the animal aborted the ongoing response. When the second stimulus called for a doubling of force, the animal increased its phasic force output; however, this increase was not sufficient to reach the new target level and late responses were emitted. 3. The control response which followed each experimental double stimulation trial showed consistent differences from other controls in the amplitude of both peak force and peak dF/dt. Control responses following trials calling for a return were reduced in size; those following stimuli requiring response doubling were increased. We concluded that the experimental trials not only elicited modification of ongoing responses but also caused the animal to alter its internalized gain function relating initial display derivatives to required force. 4. In experiments where feedback was delayed after giving a first target stimulus such that the compensatory display failed to reflect the animal's initial response, the animal emitted a new updated response 70–80 ms after the first. The display trajectory which caused the cat to update its response on delayed feedback trial was identical to that of control trials with long reaction times. In this case, however, the information eliciting response updating had to be derived as a difference between the actual display trajectory and that expected by the animal, based on its experience with the tracking task. This suggests that the animal develops an internal model of display properties which is used to determine when a new response is required.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240507
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  • 14
    Electronic Resource
    Electronic Resource
    The transformation of cross-reinnervated slow-twitch muscle after deafferentation in the cat (1984)
    Springer
    Experimental brain research 55 (1984), S. 152-157 
    Details
    ISSN: 1432-1106
    Keywords: Deafferentation ; Cross reinnervation ; Contractile properties ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cross-reinnervations were effected between the extensor digitorum longus and soleus muscles in the cat hind limb. At the same time dorsal root section or ganglionectomy was performed over segments L6-S1. Completeness of the deafferentation was subsequently confirmed either by dissection or by dorsal root recording. The isometric and forcevelocity properties of the muscles were measured. In animals with a unilateral cross plus deafferentation the conversion of the contractile properties of the normally slow-twitch soleus to those resembling a fast-twitch muscle was typical of that seen with an intact afferent supply. In cats with a bilateral cross-reinnervation and unilateral deafferentation there was no significant difference in the degree of transformation between the two sides. It is concluded that at least for the conversion of a slow-twitch to a fast-twitch muscle afferent feedback does not play a major role.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240509
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  • 15
    Electronic Resource
    Electronic Resource
    Electroretinographic responses and retrograde changes of retinal morphology after intracranial optic nerve section. A quantitative analysis in the cat (1984)
    Springer
    Experimental brain research 55 (1984), S. 483-493 
    Details
    ISSN: 1432-1106
    Keywords: Optic nerve section ; Cat ; Pattern ERG ; Retinal morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous experiments have shown that the ERG response to alternating gratings vanishes gradually within 4 months after transection of the optic nerve, changes begin after 2–3 weeks. The response to gratings of low spatial frequencies deteriorates earlier than the response to gratings of high spatial frequencies (Maffei and Fiorentini 1981). Quantitative analysis of ganglion cell sizes in retinal wholemounts shows that ganglion cell shrinkage and ganglion cell loss begin at three weeks in the periphery of the retina, particularly in the temporal retina. The same morphological alteration subsequently becomes apparent also in the area centralis and the nasal retina, respectively. The main and early cell loss occurs among medium sized ganglion cells, supposedly the beta-cells. Among the alpha-cells only shrinkage is observed up to two months postoperatively. Light- and electron microscopic examination of cross sections through the retina show that pathological changes are restricted to the innermost layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235279
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  • 16
    Electronic Resource
    Electronic Resource
    Evidence for glutamate as a neurotransmitter in the cat vestibular nerve: radioautographic and biochemical studies (1984)
    Springer
    Experimental brain research 56 (1984), S. 523-531 
    Details
    ISSN: 1432-1106
    Keywords: Glutamatergic synapses ; Vestibular nerve lesion ; Vestibular nuclei ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Evidence that glutamate acts as a neuro-transmitter in vestibular nerve fibers was sought (1) by electron microscope radioautographic identification of the uptake sites of [3H]-glutamic acid after incubation of slices of cat vestibular nuclei, and (2) by measuring changes in sodium-dependent high affinity glutamate uptake in nerve endings containing homogenates from normal and deafferented vestibular nuclei 8 to 11 days after unilateral vestibular nerve lesion. Electron microscopic radioautography revealed that glutamate had been taken up by numerous nerve endings projecting over the whole vestibular nuclear complex. The biochemical approach indicated that after section of the vestibular nerve, a significant decrease in high affinity glutamate uptake occurred in the vestibular nuclei, which lost their exclusively ipsilateral projection. This decrease varied from one area of the deafferented vestibular nuclei to another, reaching −58% in the lateral area of the central part corresponding to the ventral lateral vestibular nucleus and the rostral part of the descending vestibular nucleus. It is concluded that glutamate (or aspartate) is used by the vestibular nerve fibers as a neurotransmitter in the vestibular nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237993
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  • 17
    Electronic Resource
    Electronic Resource
    Corticocortical connections to the motor cortex from the posterior parietal lobe (areas 5a, 5b, 7) in the cat demonstrated by the retrograde axonal transport of horseradish peroxidase (1984)
    Springer
    Experimental brain research 54 (1984), S. 476-484 
    Details
    ISSN: 1432-1106
    Keywords: Corticocortical connections ; Motor cortex ; Areas 4, 5a, 5b, 7 ; Posterior parietal lobe ; Retrograde transport of HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neurons in the parietal region of the cerebral cortex, projecting to the ipsilateral distal forelimb area of the motor cortex (area 4γ) were identified in the cat brain using the horseradish peroxidase (HRP) retrograde tracing method. After making microinjections of HRP into the distal forelimb area of the motor cortex, clusters of HRP-labeled cell bodies were observed in different regions of the ipsilateral parietal cortex. In particular these clusters of labeled cells were found in areas 5a, 5b and 7. The area 5a cluster is formed from closely packed irregularly-shaped cells, the area 5b cluster is made up of dispersed medium-sized pyramidal cells, while area 7 contains a cluster of widely dispersed small pyramidal cells. Typically, labeled cell bodies were found in lamina III of cortex. Labeled cell bodies were neither observed in the contralateral cortex nor in the visual cortex (areas 17, 18 and 19). Since parietal cortex receives projections from primary somatosensory and visual cortex, the projections from parietal to motor cortex may well form the neural substrate for the processing of convergent sensory information used in voluntary movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235473
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  • 18
    Electronic Resource
    Electronic Resource
    Differences between cats in response properties of horizontal semicircular canal primary afferents (1984)
    Springer
    Experimental brain research 56 (1984), S. 162-166 
    Details
    ISSN: 1432-1106
    Keywords: Vestibular nerve afferents ; Semicircular canal biophysics ; Semicircular canal time constants ; Vestibular neurophysiology ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response properties of cat horizontal canal afferents (N = 81) were characterized by three parameters: their long time constants (τ), low frequency gain constants (G1), and middle frequency gain constants (Gm). An average value of each of these parameters was calculated for each of eight animals and comparisons were made across animals. There were significant differences between individual animals in their average values of τ and Gm. There was also a significant negative correlation between τ's and Gm's. An animal with a larger average τ tended to have a smaller average Gm. We also used anatomic data on membranous canal duct diameter from the literature to independently estimate the potential effect of interanimal anatomic variability on the predicted range of τ and Gm values in a population. We then compared the data from our 81 afferents with the predictions from the anatomic data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237453
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  • 19
    Electronic Resource
    Electronic Resource
    Specialized subregions in the cat motor cortex: Anatomical demonstration of differential projections to rostral and caudal sectors (1984)
    Springer
    Experimental brain research 53 (1984), S. 259-276 
    Details
    ISSN: 1432-1106
    Keywords: Motor cortex ; Thalamocortical ; Corticocortical ; HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary (1) Ipsilateral cortico-cortical and thalamo-cortical projections to the cat motor cortex were determined from the locations of retrogradely labeled neurons following single small intracortical injections of HRP in area 4γ. These projections were also examined by studying the distribution of anterogradely transported axonal label following multiple injections of HRP or of tritiated amino acids in areas 1–2 of SI and in area 2pri (SII). (2) The number of retrogradely labeled cells in areas 1–2 and in area 2pri differed markedly between HRP injection sites located in the precruciate (anterior sigmoid gyrus) and postcruciate (posterior sigmoid gyrus) subregions of area 4γ. These associational projections from primary and secondary somatosensory cortices were dense to postcruciate subrogions but weak to the precruciate subregions. (3) The associational projections from areas 1–2 and from area 2pri to the postcruciate subregion of area 4γ were topographically organized, but no clear topographic organization could be demonstrated for the precruciate projection. (4) Anterograde terminal labeling following injection of either HRP or tritiated amino acids into areas 1–2 and area 2pri confirmed the preferential projection of somatosensory cortex to the postcruciate subregion of motor cortex. The projection from somatosensory areas 1–2 was uniform over its terminal field, but that from area 2pri was more patchy and complex. (5) HRP injections in area 4γ gave rise to lamellae of labeled neurons in the ventrolateral nucleus of thalamus (VL). A topographic relationship was found between the site of injection and the location of the lamella of labeled neurons. (6) The percentage of retrogradely labeled neurons in the shell zone surrounding the border of the ventrolateral nucleus and the ventrobasal complex (VB) was greater following postcruciate than precruciate injections, whereas fewer retrogradely labeled neurons were found in central lateral nucleus (CL) after postcruciate injections than after precruciate injections. (7) These observations support the hypothesis that differential cortical and thalamic projections to different subregions of area 4γ may give rise to the different physiological properties of neurons observed in these subregions (Vicario et al. 1983; Martin et al. 1981).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238155
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  • 20
    Electronic Resource
    Electronic Resource
    Pyramidal control of skin potential responses in the cat (1984)
    Springer
    Experimental brain research 54 (1984), S. 283-288 
    Details
    ISSN: 1432-1106
    Keywords: Skin potential response ; Cat ; Pyramidal tract ; Reticulospinal tracts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pyramidal command of Skin Potential Response (SPR) was investigated in 20 cats paralyzed by gallamine and under a halothane anaesthetic. For each animal, a transection of the medulla sparing only the pyramidal tract was carried out. The pyramidal tract and Mesencephalic Reticular Formation (MRF) were stimulated before and after the transection. Results taken before transection show that the SPR can be elicited from stimulation of the pyramidal tract and the MRF. After transection, stereotaxic stimulations of the pyramidal tract still evoked the SPR even after aspiration of the medullary tissue posterior to the section and overlying the pyramids. Control reticular stimulations with higher stimulus intensities failed to evoke the SPR. These results show that stimulation of the pyramidal tract can elicit the SPR independently of reticulospinal neurons. It is hypothesized that a group of corticospinal fibers could transmit volleys having autonomic activity on preganglionic autonomic neurons of the intermediate zone of the grey matter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236228
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  • 21
    Electronic Resource
    Electronic Resource
    Neck muscle afferent input to spinocerebellar tract cells of the central cervical nucleus in the cat (1984)
    Springer
    Experimental brain research 55 (1984), S. 286-300 
    Details
    ISSN: 1432-1106
    Keywords: Central cervical nucleus ; Spinocerebellar tract ; Neck muscle afferents ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular and intracellular recordings were made from spinocerebellar tract neurones of the central cervical nucleus (CCN) in C1–C3 segments of the anaesthetized cat. These neurones were identified by antidromic activation from the cerebellar peduncle. Stimulation of the ipsilateral dorsal root elicited extracellular spikes or EPSPs with a monosynaptic latency in almost all CCN neurones in the same segment (segmental input). Late excitatory effects were also observed in about one third of CCN neurones. The monosynaptic EPSP was occasionally followed by an IPSP. The excitatory input from the dorsal root to CCN neurones was extended over several segments for some CCN neurons (extrasegmental input). Monosynaptic excitation was evoked in CCN neurones after stimulation of dorsal neck muscle nerves as well; i.e. splenius (SPL), biventer cervicis and complexus (BCC), rectus capitus dorsalis, and obliquus capitus caudalis. Thresholds for this excitation were near the threshold of the nerve, suggesting that it originated from group I fibres. The component of excitation added after strong stimulation of neck muscle nerves would be attributed to group II fibres. When a CCN neurone received excitatory input from the nerve of one muscle, it was generally not affected by stimulation of other nerves in the same segment. Such muscle specificity of segmental input was the principal pattern of connexion of neck muscle afferents with CCN neurones. In some cases, however, excitatory convergence from SPL and BCC nerves onto single CCN neurones or excitation from the SPL nerve and inhibition from the BCC nerve were also observed. Nearly half of the CCN neurones received input from one muscle nerve of the same segment and not from the afferent of the same muscle of different segments, indicating a segment specificity of input. In the remaining CCN neurones, weaker excitatory effects were induced from afferents of different segments as well. In such extrasegmental effects, inputs to CCN neurones from caudal segments predominated in frequency over those from rostral segments. The origin of extrasegmental input was generally confined to the same muscle. Low threshold muscle afferents from the SPL and BCC were intraaxonally stained with HRP. The collaterals of the stained fibre distributed branchlets and terminals to the CCN, laminae VII, VIII, and motor nuclei. Two fibres responding to local muscle prodding or stretch showed a similar morphology. The findings indicated that muscle spindle afferents from primary endings projected to the CCN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237279
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  • 22
    Electronic Resource
    Electronic Resource
    A physiological study of identification, axonal course and cerebellar projection of spinocerebellar tract cells in the central cervical nucleus of the cat (1984)
    Springer
    Experimental brain research 55 (1984), S. 272-285 
    Details
    ISSN: 1432-1106
    Keywords: Central cervical nucleus ; Spinocerebellar tract ; Cerebellum ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spinocerebellar tract (SCT) neurones in and around the central cervical nucleus (CCN) were physiologically identified by antidromic activation of these cells on stimulation of the cerebellum. Among the Spinocerebellar tract cells thus identified, those ascending the contralateral spinal funiculi were found in the CCN and ventralwards, whereas those ascending the ipsilateral funiculi existed mostly dorsal to the CCN partly overlapping with crossed cells in the nucleus. Mapping sites from which CCN cells were antidromically activated showed that axons of the CCN-SCT cross at the same segment, ascend the ventral funiculus initially, the lateral funiculus at rostral C1 and the lateral border of the medulla to reach the cerebellar peduncle, enter the cerebellum mainly via the restiform body but possibly also via the superior peduncle. Systematic mapping of stimulation within the cerebellum indicated that the CCNSCT projects to the medial part of the anterior lobe and the posterior lobe bilaterally. Projection to lobules I–II was found in almost all CCN-SCT cells examined. Three fourths of CCN-SCT cells projected to the posterior lobe, as revealed by less extensive mapping. Mapping of axonal regions of the same single CCN-SCT cells showed that they project multifocally in the cerebellum, where projection to lobules I–II was common and that to other areas varied with individual cells. Conduction velocites decreased within the cerebellum probably as the result of repeated branching. Mossy fibre responses evoked on stimulation of the C2 dorsal root in cats with the transected dorsal funiculi were shown to be mediated mostly via the CCN-SCT. Mapping the field potential showed that the response was by far the largest in lobules I–II. This suggested that the terminals provided by the CCN-SCT are the densest in these lobules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237278
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  • 23
    Electronic Resource
    Electronic Resource
    Endogenous peroxidase-like activity in the feline dorsal column nuclei and spinal cord (1984)
    Springer
    Experimental brain research 55 (1984), S. 325-332 
    Details
    ISSN: 1432-1106
    Keywords: Endogenous peroxidase ; Light and electron microscopy ; Spinal cord ; Dorsal column nuclei ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Endogenous peroxidase-like activity was investigated with a combined light and electron microscopical technique in 15 cats. The lateral cervical nucleus, the dorsal column nuclei, and segments C6 and L5 of the spinal cord were incubated with diaminobenzidine-tetrahydrochloride (DAB) or tetramethylbenzidine (TMB). After histochemical reaction with DAB a considerable amount of activity was found in nerve cells, astrocytes and pericytes. The neuronal labelling was mainly located in mitochondria of axon terminals and in dendrites whereas the astrocytic and pericytic activity was found in cytoplasmic dense bodies. The quantity of stained structures differed considerably between the animals. In TMB reacted tissue endogenous peroxidase-like activity was only sparsely seen. It was found mainly in frozen sections, in which the neuropil and perivascular structures sometimes contained granules and irregular filaments. The significance of the findings is discussed in relation to observations in tracer studies using horseradish peroxidase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237283
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  • 24
    Electronic Resource
    Electronic Resource
    Shortage of binocular cells in area 17 of visual cortex in cats with congenital strabismus (1984)
    Springer
    Experimental brain research 55 (1984), S. 470-482 
    Details
    ISSN: 1432-1106
    Keywords: Congenital microstrabismus ; Cat ; Visual cortex ; Binocularity ; Visual axis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twenty-nine pigmented offspring of an innately esotropic female cat exhibited varying deficits in the number of binocular cells recorded in area 17 of the visual cortex as compared to 12 normal cats. Misalignment of the two eyes in these cats was found in the awake as well as in the paralysed state. Pupillography combined with measurements of visual disparity yielded abnormal esotropia of up to 8.4° under paralysis, which corresponds to an abnormal convergence of the freely moving eyes of up to 14° (average 7.4°). In the majority of animals cortical binocularity was found reduced by the two eyes controlling independent sets of separate units (U-shaped ocular dominance distribution) whereas in 7 cats the reduction was due to a partial loss of one eye's influence. The proportion of monocular units correlated with the degree of crossover of the visual axes (r = 0.73). Anatomical investigation of the retinofugal projections revealed normal appearance in three previously recorded cats in which more than 50% of cortical units had been monocularly driven. The small angles of esotropia and the “normal” appearance of eye position judged by the pupillary positions in the orbit of these cats, might suggest that we found an animal model for microstrabismus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235278
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  • 25
    Electronic Resource
    Electronic Resource
    Inspiratory on-switch evoked by stimulation of the mesencephalon: Activity of phrenic and laryngeal motoneurones (1984)
    Springer
    Experimental brain research 55 (1984), S. 197-204 
    Details
    ISSN: 1432-1106
    Keywords: Phrenic and laryngeal motoneurones ; Inspiratory on-switch ; Stimulation ; Mesencephalic structures ; Patterned response ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In anaesthetized cats (chloralose-urethan) the effects of brief tetanic electrical stimulation (50 to 100 ms) of the mesencephalic central gray matter and reticular formation on the inspiratory on-switch were studied during the expiratory (E) phase on the gross and unitary activities of phrenic, laryngeal inspiratory and laryngeal expiratory nerves. On the inspiratory laryngeal and phrenic nerves, stimulation elicited a short latency gross response concomitant with the train: the inspiratory Primary Response (Prim.R.) which is followed by an inspiratory Patterned Response (Patt.R.) of longer duration which corresponded to the inspiratory on-switch. The Patt.R. generally appeared from the Prim.R. within a latent period (Silent Phase: Sil.P.) as long as 100 ms. On the expiratory laryngeal nerve, stimulation elicited a brief activation (expiratory Prim.R.) concomitant with the beginning of the inspiratory laryngeal Prim.R. and which rapidly stopped as the latter continued during the stimulus train. The inspiratory Prim.R. corresponded to a simultaneous activation of both early and late (so defined during their spontaneous discharge) inspiratory motoneurones. The laryngeal motoneurones were more strongly activated than the phrenic ones. During the inspiratory Patt.R. all the phrenic motoneurones presented a recruitment delay earlier, compared with the spontaneous one, whereas the recruitment drastically changed from an inspiratory laryngeal motoneurone to another. Thus, the two pools of motoneurones presented different properties of activation. During the inspiratory Sil.P. no concomitant expiratory laryngeal activation was observed when most of the inspiratory motoneurones were inactive. As some inspiratory laryngeal motoneurones did not stop firing, the existence of some central respiratory neurones exhibiting a similar persistent activity and subserving the inspiratory on-switch mechanisms may be hypothesized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237270
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  • 26
    Electronic Resource
    Electronic Resource
    An HRP study of the cat's spinal respiratory motoneurones during postnatal development (1984)
    Springer
    Experimental brain research 56 (1984), S. 458-467 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Postnatal development ; Phrenic motoneurones ; Intercostal motoneurones ; Horseradish peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The localization and morphology of spinal respiratory motoneurones (phrenic and intercostal) were studied in the cat by retrograde labelling using Horseradish Peroxidase (HRP), at different stages of postnatal development. At birth, the distribution of the phrenic and intercostal motoneurones in the cervical and thoracic ventral horn, respectively, is similar to that observed in adult animals. At birth, the phrenic and intercartilaginous motoneurone somata have respectively 60% and 40% of their adult volume, appearing much more developed than the motoneurones involved in the motor control of limbs. During postnatal development, the phrenic and intercartilaginous motoneurones undergo a characteristic sagittal elongation without evident modification along their transverse axes. From birth, the ratio of the somatic volume to that of its corresponding motor column markedly decreases inside of the phrenic column compared to the data obtained in the limb's muscle motor columns by other authors. Similar determinations in intercostal motor columns give intermediate values between those obtained from the phrenic column and from the motor system. These results indicate that the motoneurones innervating the respiratory muscles have some specific features of development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237986
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  • 27
    Electronic Resource
    Electronic Resource
    Contralateral corticofugal projections to cat visual thalamus (1984)
    Springer
    Experimental brain research 53 (1984), S. 462-466 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Contralateral connections ; Thalamus ; Cat ; Sub-cortical commissures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Contralateral corticofugal projections from visual cortical areas to thalamic nuclei were demonstrated in the cat using anterograde transport of tritiated proline. Thalamic nuclei receiving projections from contralateral visual cortex include both subdivisions of the lateral-posterior nucleus, the posterior nucleus of Rioch, and the posterior nuclear complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238176
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  • 28
    Electronic Resource
    Electronic Resource
    Origin of signals conveyed by the ventral spino-cerebellar tract and spino-reticulo-cerebellar pathway (1984)
    Springer
    Experimental brain research 54 (1984), S. 426-431 
    Details
    ISSN: 1432-1106
    Keywords: Spinal cord ; Scratch reflex ; Ventral spino-cerebellar tract ; Spino-reticulo-cerebellar pathway ; Cerebellum ; Cooling the nervous tissue ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary (1) The “fictitious” scratch reflex was evoked in decerebrate curarized cats by pinna stimulation. Activity of neurons of the ventral spinocerebellar tract (VSCT) from the L4 and L5 segments of the spinal cord as well as of neurons of the spinoreticulo-cerebellar pathway (SRCP) from the lateral reticular nucleus of the medulla oblongata was recorded. Cooling and destruction of different parts of the lumbo-sacral enlargement of the spinal cord were performed. (2) Cooling of the L5 or L6 segment abolished the rhythmic activity in the greater part of the spinal hindlimb centre but did not affect the generation of rhythmic oscillations in the remaining (rostral) segments of the lumbo-sacral enlargement. Under these conditions, neither the rhythmic activity of VSCT neurons located rostral to the thermode nor that of SRCP neurons changed. (3) A normal rhythmic activity of SRCP neurons also persisted after destruction of grey matter in the L3 and L4 segments. It can be concluded that activity of these neurons is independent of whichever part of the enlargement generates rhythmic oscillations. (4) From these observations a hypothesis is advanced that the main content of signals conveyed by the VSCT and SRCP to the cerebellum is the information regarding activity of the generator of rhythmic oscillations that is located in the L3-L5 spinal segments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235467
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  • 29
    Electronic Resource
    Electronic Resource
    The use of retrograde transport of horseradish peroxidase for studying the dendritic trees and axonal courses of particular groups of tract cells in the spinal cord (1984)
    Springer
    Experimental brain research 54 (1984), S. 529-537 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Rat ; Spinal tract neurons ; Retrograde HRP transport ; Procedure and evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Modifications have been made in Mesulam's method for labelling neurons by retrograde transport of horseradish peroxidase, with tetramethylbenzidine as chromogen, with the object of increasing the extent of labelling of dendrites and axons. A procedure was devised specifically for studying spinomedullary and medullospinal tract systems, involving implanting easily-made HRP-agar pellets into areas of controlled damage in particular spinal fascicles, and sealing the site of implant with cyanoacrylate glue. Lesions of other fascicles were often made to limit transport to the implanted fascicle. Fourth-order dendrites were regularly labelled over long (30 cm or more) transport distances: axons were also labelled over this whole distance, often allowing exact study of the initial course of particular axons. Controls in both cat and rat showed that the uptake of HRP under these circumstances occurred almost wholly from the region of axonal damage at the site of implant which can be characterized histologically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235478
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  • 30
    Electronic Resource
    Electronic Resource
    Effects of accessory optic system lesions on vestibulo-ocular and optokinetic reflexes in the cat (1984)
    Springer
    Experimental brain research 55 (1984), S. 49-59 
    Details
    ISSN: 1432-1106
    Keywords: Accessory optic system ; Vestibulo ocular reflex ; Optokinetic nystagmus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Horizontal vestibulo-ocular reflex (VOR) and optokinetic nystagmus (OKN) were studied before and after lesions within the accessory optic system (AOS) in the cat. Post-lesion retinal input to the AOS was evaluated using the autoradiographic technique. Unilateral lesion of the lateral terminal nucleus of the AOS (LTN) and the resulting retinal deafferentation of the medial terminal nucleus of the AOS (MTN) induced a spontaneous nystagmus in the dark whose slow phase was directed ipsilaterally to the lesion. VOR gain was reduced for both directions with a maximal decrease for stimulation directed ipsilaterally to the lesion. OKN gain obtained for both directions of binocular stimulation was decreased, mainly when the stimulus was directed contralaterally to the lesion. After two postoperative weeks, spontaneous nystagmus disappeared and the VOR symmetry recovered simultaneously. A symmetrical OKN was only observed after one month. In spite of the known visual selectivity for vertical direction in LTN-MTN cells, the results of this study support a functional involvement of these nuclei in horizontal VOR and OKN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240497
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  • 31
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    Visual cortical cell classification criteria: Reliability and equivalence of the quantitative dynamic — and static — field plotting procedures (1984)
    Springer
    Neurological sciences 5 (1984), S. 359-367 
    Details
    ISSN: 1590-3478
    Keywords: Cat ; area 18 ; classification criteria ; receptive field types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario È noto che non tutti i campi recettivi dei neuroni corticali visivi rientrano nelle due grandi categorie delle cellule semplici e delle cellule complesse. Pertanto, quei campi recettivi che non presentano proprietà ben definite o solo intermedie a quelle delle cellule semplici e complesse da alcuni autori vengono considerati semplici e da altri complessi. Queste incertezze classificatorie dipendono dal fatto che non esiste un unico schema di classificazione dei neuroni corticali visivi, poiché i due schemi attualmente più seguiti, quello di Hubel e Wiesel e quello di Bishop, vengono considerati non comparabili essendo il primo uno schema qualitativo basato sull'uso di stimoli luminosi stazionari ed il seconda uno schema quantitativo basato sull'uso di stimoli luminosi in movimento. Campi recettivi che non posseggono le proprietà tipiche delle cellule semplici e complesse sono stati osservati nel gatto oltre che nell'area 17 anche nell'area 18. I vari campi recettivi registrati in quest'ultima area sono stati analizzati sia qualitativamente che quantitativamente usando i criteri di classificazione dei due schemi attualmente esistenti. È stato osservato che, almeno per quanto riguarda le cellule semplici, tali schemi di classificazione dei neuroni corticali visivi non sono antitetici ma equivalenti.
    Notes: Abstract There is in vision research a general unwillingness to classify or define visual cortical cell types, particularly new cell types, outside the classical simple/ complex dichotomy. Cells lacking clear-cut characteristics are, therefore, considered simple by some authors and complex by others. The present unsatisfactory state has largely arisen because of the absence of any rigorous, generally accepted, classification scheme of visual cortical neurons. Actually the present two classification schemes of visual cortical neurons, that is the Hubel and Wiesel and the Bishop schemes, are generally considered to be not comparable since the former is based on the cell qualitative static-field properties as revealed by hand-held stationary flashing stimuli, whereas the latter is based on the cell quantitative dynamic-field plotting properties as revealed by moving light stimuli. Since receptive fields lacking clear-cut characteristics of simple and complex cells have been observed in area 18 of the cat as well, all the receptive field types of this area have been classified either qualitatively or quantitatively using both the Hubel and Wiesel and the Bishop classifying procedures. It has been observed, at least as far as simple cells are concerned, that the two schemes are not antithetic but, on the contrary, equivalent if averaging procedures are taken into consideration.
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    URL: http://dx.doi.org/10.1007/BF02042617
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  • 32
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    Electronic Resource
    Angioarchitecture of the pancreas of the cat (1984)
    Springer
    Cell & tissue research 235 (1984), S. 675-682 
    Details
    ISSN: 1432-0878
    Keywords: Endocrine pancreas ; Angioarchitecture ; Cat ; Scanning and transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of scanningand transmission electron microscopy, the possible sources of errors in interpretation of the microcirculation of the pancreas can be reduced in comparison to the classical India-ink injection method. Sphincter-like structures in the capillary wall of the cat pancreas are established by pericytes. These sphincters encircle the junctional zones between the endocrine and exocrine capillaries. They are assumed to be regulatory structures of blood flow and to regulate indirectly hormone secretion according to demand.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226968
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  • 33
    Electronic Resource
    Electronic Resource
    Scanning electron-microscopic study of Reissner's fiber in the caudal spinal cord of the cat and rabbit (1984)
    Springer
    Cell & tissue research 237 (1984), S. 181-183 
    Details
    ISSN: 1432-0878
    Keywords: Reissner's fiber ; Scanning electron microscopy ; Spinal cord ; Cat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The caudal portion of Reissner's fiber was examined by scanning electron microscopy (SEM) in the spinal cord of the cat and rabbit. In some preparations of both species the fiber displayed in the sinus terminalis of the central canal either stump-like terminations or structural modifications such as knot-like swellings and convolutions. In the same area homogeneous material could also be found, which obviously originated from the disintegrating fiber.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229214
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  • 34
    Electronic Resource
    Electronic Resource
    Einfache Darstellung von 4-Oxo-tetrahydropyrimidinen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 279-286 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Convenient Synthesis of 4-Oxo-tetrahydropyrimidinesEnamino-nitriles as 6 or 11 yield 4-oxo-pyrimidines (2; 2a; 10; 12a-c) on treatment with cyclohexanone in basic media. Analogous compounds are obtained using acetone, butyraldehyde, benzaldehyde or substituted benzaldehydes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260213
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    Der „Nornialisierungsfaktor“ für die Toinatenmutante chloronerva. XV.XIV. Mitt.: J. FAUST, A. PREISS, K. SCHREIBER u. H. RIPPERGER, Tetrahedron, 39 (1983) 1593. Nomenklatur und Abkürzungen nach E. WÜNSCH in Methoden der Organischen Chemie (Houben-Weyl), Herausg. E. MÜLLER, Bd. XV/1, S. 1, Georg Thieme Verlag Stuttgart 1974; H.-D. JAKUBKE u. H. JESCHKEIT, Aminosäuren, Peptide, Proteine, 3. Aufl., S. 15, 97, Akademie-Verlag Berlin 1982. Ferner bedeutet: EEDQ = 2-Ethoxy-1-ethoxycarbonyl-1,2-dihydrochinolin; DCC = Dicyclohexylcarbodiimid. Peptidanaloga des Phytosiderophors Nicotianamin (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 266-272 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The “Normalizing Factor” for the Tomato Mutant chloronerva. XV. Peptide Analogues of the Phytosiderophore NicotianamineSome peptide analogues of the phytosiderophore nicotianamine, (2S, 3′S, 3″S)-N-[3-(3-amino-3-carboxypropylamino)-3-carboxypropyl]-azetidine-2-carboxylic acid, have been synthesized from protected amino acids by the EEDQ or the DCC method. They exhibited no biological effect with regard to the phenotypical normalization of the tomato mutant chloronerva.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260211
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    About nitrile-formamide-chloride-adducts. IX. Synthesis of 1,3- or 1,5-disubstituted 1,2,4-triazoles by the reaction of nitrile-formamide chloride-adducts and their products of hydrolysis with hydrazines (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 311-319 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Aza-3-chloro-2-propeniminium salts 5, which are easily available by the addition of formamide chlorides 1 to nitriles 2 react smoothly with hydrazines 9 giving rise to 1,3-disubstituted 1,2,4,-triazoles 11. When the 2-aza-3-chloro-2-propeniminium salts 5 are hydrolysed first the resulting N-acyl-formamidinium salts 6 react with hydrazines 9 to 1,5 disubstituted 1,2,4-triazoles 13 via isolable N-acyl-formamidrazones 12.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260216
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    Quantenchemische Untersuchungen zur Molekül- und Elektronenstruktur einfacher Azomethinimine und verwandter Verbindungen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 303-310 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantum Chemical Investigations of the Molecular and Electronic Structure of Simple Azomethine Imines and Related CompoundsThe molecular and electronic structure of simple azomethinimines are investigated by means of MINDO/3 and CNDO/2 calculations. The calculated molecular geometry is compared with X-ray results obtained for these compounds. Except for the NN-bond lengths MINDO/3 satisfactorily describes the molecular structure of azomethinimine and related π-electronic systems. The charges at the atoms along the conjugated chain are alternating as in polymethines. The terminal carbon atom carries a negative charge. This charge brings about an appreciable shielding of this carbon atom such as found in the 13C-n.m.r. spectrum. This result does not contradict a stabilization of azomethinimines in the crystal via = CH…O=C interactions.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260215
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    Synthese von Oligodeoxyribonucleotiden nach dem Triesterverfahren an einem Polystyren-Teflonträger (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 320-328 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Oligodeoxyribonucleotides on a Polystyrene Grafted Polytetrafluorethylene Support via Phosphotriester Intermediates
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260217
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    Chinazolincarbonsäuren. I. Chinazolin-4-on(2,4-dion)-3-yl-essigsäuren und deren Ester (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 342-348 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quinazolincarboxylic Acids. I. Quinazolin-4-on(2,4-dion)-3-acetic Acids and Esters
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260220
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    Selectivity in the Oxidation of Aliphatic Ketones by thallic sulphate in aqueous medium (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 374-380 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of temperature, structure and sulphuric acid concentration on the selectivity of the oxidation of aliphatic ketones (R1COR2) (1a-g) by thallic sulphate have been investigated. With increasing temperature the quantity of internal α-hydroxyketone (3a-d) decreases and the quantity of 1-hydroxyketone (2a-d) increases in the oxidation of methyl alkyl ketones (R2〉CH3) (1a-d). The same concerns to the oxidation products of hexan-3-one (1e): 2-hydroxy-hexan-3-one (2e) and 4-hydroxy-hexan-3-one (3e), respectively. “The inverse selectivity temperature” (IST) for oxidation of linear methyl alkyl ketones (1a-c) and hexan-3-one (1e) has been found. With the use of the linear free-energy relationship it has been found that the selectivity of the reaction decreases with increasing the polar and steric effects of substituents R1, R2. With increasing the sulphuric acid concentration the selectivity of the oxidation of methyl alkyl ketones (1a, 1d) increases.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260305
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    Elektrophile Reaktionen an der Maleinimiddoppelbindung (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 401-406 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrophilic Reactions on the Maleimide Double BondThe aminosubstituted maleimides 1 are deprotonated to the anions 2, which are reacted with various electrophiles. By this way with heterocumulenes, acid chlorides and vinylogous acid chlorides the new acylated maleimides 3-6, 9, 10 are isolated. This reaction presents a method of direct acylation on the maleimide double bond.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260308
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    Lichtinitiierte Polymer- und Polymerisationsreaktionen. 14.13. Mitteilung: siehe H.-J. TIMPE, C. GARCIA, S. P. PAPPAS, L. R. GATECHAIR, E. L. BRESKMAN, u. R. M. FISCHER: Polym. Photochem., im Druck. Radikalische Photopolymerisation mit Kaliumtrisoxalatocobaltat-Aryloniumsalz-Systemen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 415-425 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Light Induced Polymer and Polymerization Reactions. 14. Radical Photopolymerization by Potassium Trisoxalato Cobaltate Arylonium Salts Systems.The photopolymerization of acrylamide (AA) by trisoxalato cobaltate ([Co(ox)3]3⊖) is inefficient because the produced nucleophilic ·CO2⊖-radicals are oxidized or they terminate with polymer radicals. If onium compounds are added to this system the initiation efficiency is increased as follows : p-CH3OC6H4N2⊕〉Ph2I⊕〉PhCOCH2S(CH3)2⊕〉Ph3S⊕. By means of quantum yield measurements a mechanism was proposed including the electron transfer from ·CO2⊖ to onium compounds. The produced radicals also initiate the polymerization of AA. The exponent m of the polymerization rate (vp ≍ [AA]m) is decreased from 1.4 to 1.1 in the presence of Ph2I⊕, deciding the decrease of termination reaction between ·CO2⊖ and polymer radicals. In comparison with K3[Fx(ox)3] the corresponding cobalt complex possesses higher polymerization quantum yields for AA.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260310
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    Korrelationen vom Hammett-Typ zwischen 13C-NMR-chemischen Verschiebungen und Substitutentenkonstanten bei Anilen des p-Nitrozimtaldehyds (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 505-510 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hammett-like Correlations between 13C-NMR Chemical Shifts and Substituent Constants on Aniles of p-Nitrocinnamaldehyde
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260320
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    Zur Cyanethylierung von Hydrochinazolinonen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 849-852 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyanoethylation of HydroquinazolinonesBy the reaction of acrylonitrile with octahydroquinazolinone-spirocyclohexane (1), cyanoethyl-octahydroquinazolinone-spirocyclohexane (2) is formed. Compound 2 and hydrogen-peroxide yield 5a-cyanoethyl-5-oxo-perhydro-oxaziridino[3,2-j]-quinazolin-2-spirocyclohexane (5). 2-Phenyl-octahydroquinazolinone (7) and acrylonitrile form 3,5a-biscyanoethyl-2-phenyl-octahydroquinazolinone-(4) (8). Compound 8 and hydrogenperoxide yield 3-phenyl-4,5a-biscyanoethyl-4-oxoperhydro-oxaziridino[3,2-j]-quinazoline (9). Compound 9 rearranges with ferrous sulphate to 3,4a-bis-cyanoethyl-4-oxo-8a-hydroxy-2-phenyl-octahydro-quinazoline (10).
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    URL: http://dx.doi.org/10.1002/prac.19843260602
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    Untersuchungen zum Photochromie- und Thermochromie-Effekt an Benzilphenylhydrazonen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 876-892 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: About the Photochromic and Thermochromic Effect of Benzil PhenylhydrazonesBenzil phenylhydrazone 1 synthesized from benzil and phenylhydrazine possesses s-trans-E configuration detected by means of quantum chemical calculations and its spectral data. Upon irradiation a photochromic process proceeds with a λ-shift Δ λ ≈ 80 nm. The photoproduct has an s-cis-Z configuration. The quantum yields of the EZ-isomerization measured by spectroscopic methods depend on solvent (ΦEZ= 0,077 in CH3OH, ΦEZ= 0,22 in n-hexane), but are independent of the excitation wavelengths and O2. Benzil N-methylphenylhydrazone 2 is inactive under stationary irradiation. Both the Z/E-isomerization of 1 and 2 are be sensitized by benzil and m-methoxyacetophenone. On the basis of kinetic measurements the quantum yields of sensitized reactions of 1 are calculated (ΦEZsens = 0,43; ΦZEsens = 0,57). In protic solvents benzil phenylhydrazone 1 has thermochromic properties caused by E/Z-isomerizations. The measured activation parameters of these reactions are small. It is assumed that both the photoinduced and thermal isomerizations proceed via azo intermediates, as indicated by flash photolysis experiments.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260605
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    Photooxidation von Leukofarbstoffen. VIII. Kurzzeitspektroskopische Untersuchungen zum Mechanismus der Photooxidation von Leukokristallviolett (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 899-909 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photooxidation of Leuco Dyes. VIII. Time Resolved Investigations of the Mechanism of the Photooxidation of Leucocrystal VioletThe photooxidation of leucocrystal violet has been reexamined by means of conventional and laser flash photolysis as well as spin trap experiments. Three radical transients have been observed and assigned to the cation radical (λmax ≈ 490, 530 nm), the neutral radical with one—NCH3—CH2 moiety (λmax ≈ 480 nm) and the triphenyl methyl radical derivative (λmax ≈ 400 nm).
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260607
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    Praxis der Kapillar-Gas-Chromatographie. (Mit Beispielen aus Lebensmittel- und Umweltchemie), F. L. Boschke, W. Fresenius, J. F. K. Huber, E. Pungor u.a., 1. Aufl., 162 S., 29 Abb., 2 Tab., Format (cm) 16 × 24, Berlin, Heidelberg, New York: Springer-Verlag 1983. Anleitungen für die chemische Laboratoriumspraxis, Bd. 18, gebunden, 84,- DM (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 352-352 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260222
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    Darstellung von β-substituierten trans-Ethylen-diphenylphosphinen und -sulfiden durch P(O)- und P(S)-aktivierte Olefinierung (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 360-366 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of β-Substituted trans-Ethylene Diphenylphosphines and Sulphides by P(0) and P(S)-activated OlefinationMethylene bis-diphenylphosphine monoxide (3c) in tuluene reacts regiospecifically and stereoselectively with aldehydes in the presence of potassium tert-butoxide to ß-substituted transethylene diphenylphosphines 6, which can be oxidized to the sulphides 2 by sulphur in acetone. These sulphides 2 are to be obtained also directly from methylene bis-diphenylphosphine oxide sulphide 3b and methylene bis-diphenylphosphine disulphide 3d, respectively, under the same olefination conditions. But the yields are smaller and the purification of the raw products is much more difficult, if 3d is used.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260303
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    Synthesis of new nitrile imines with Pyridazin-3(2H)-one moiety and their addition to some dipoles. I (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 599-604 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present work deals with the synthesis of 6-aryl-2-ethoxycarbonyl pyridazin-3(2H)-ones (2) as useful synthetic intermediates because they allow formation of a new hydrazides (3), hydrazidoyl chlorides (4) and the highly reactive nitrile imine species (5). Dimerization and reaction of the latter species with benzonitrile, benzaldehyde and their p-methoxy and p-nitro derivatives provides a convenient method for the synthesis of substituted 1, 2, 4, 5-tetrazines (6), 1, 2, 4-triazoles (7) and 1, 3, 4-oxadiazoles (8), respectively, with pyridazin-3(2H)-one moiety.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260411
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    Cyansäureester. 35. Über Bildung und Folgereaktionen von N-Cyanatophthalimid. Neue spezifisch aktivierte und blockierte Isatosäurederivate (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 737-746 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyanic Acid Esters. 35. On Formation and Consecutive Reactions of N-Cyanato Phthalimide. New Specifically Activated and Blocked Isatoic Acid DerivativesDepending on the reaction conditions N-hydroxy-phthalimide affords on treatment with cyanogen bromide via N-cyanato phthalimide 2 the iminocarbonate 3 and isatoic acid derivatives 7 and 16. Both the latter react with nucleophiles as isatoic acid derivatives activated on the carboxylic group and protected on the carbamic group or vice versa, furnishing N,N-bis alkoxycarbonyl anthranilic acid amides 9, N-alkoxycarbonyl anthranilic acid amides 12, o-alkoxycarbonyl phenyl ureas 17 and the benzotriazepin-2,5-dione 14. The structures of the new compounds are proved by 1H-n.m.r. and 13C-n.m.r. measurements as well as independent synthesis.
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    Desaktivierungsverhalten von Arenen und Heteroarenen. XLI [1b]. Struktur- und Umgebungseinflüsse auf die intramolekulare [π4s + π4s]-photo-cycloaddition von α,ω-Bis-(9-acridiziniumyl)-alkanen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 757-764 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deactivation Behaviour of Arenes and Heteroarenes. XLI. Structural and Environmental Effects on the Intramolecular [π4s + π4s]- Photocycloaddition Reaction of α, ω-Bis-(9-acridiziniumyl) - alkanes.Fluorescence characteristics, including quantum yields and decay times, and quantum efficiencies for the reversible intramolecular [π4s + π4s]- photocycloaddition reaction for a series of α, ω-bis-(9-acridiziniumyl)-alkanes have been measured in several solvents and they have been compared with those of the model compounds acridizinium-ion. and 9-methyl-acridizinium-ion. These parameters of the bichromophores depend on the number of CH2-groups of chromophor linkage. The title compounds investigated were divided into groups of common behaviour, and differences are due to increasing bond angle strain and coulomb-repulsion in the photocyclomer state.
    Additional Material: 2 Ill.
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    Zur Kenntnis der katalytischen Dimerisation von Acrylsäurederivaten mit Hilfe von Palladiumkomplexen. IV. Zur Dimerisation von Methyl-methacrylat (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 779-790 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Catalytic Dimerization of Acrylic Acid Derivatives by Palladium Complexes. IV. The Dimerization of Methyl Methacrylate.Methyl methacrylate has been dimerized to a mixture of 2.5-di(methoxycarbonyl)-hex-1-ene(1) and (E)-2.5-di(methoxycarbonyl)-hex-2-ene (2) by catalytic systems containing dichlorobis (nitrile)-palladium (II) complexes and silver tetrafluoroborate, Codimerization experiments with methyl acrylate show a lower reactivity of methyl methacrylate. Oxidative addition of ß-chloro methyl methacrylate to tetrakis (triphenylphosphine) palladium (O) gave ß-polladio methyl methacrylates (8, 9) suitable for model investigations of the catalytic reaction. A proposal is given for a mechanism via pd(IV) intermediates.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260509
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    Apocyanine Dyes from 4,5-Dioxo-3-methyl-1-phenyl-pyrazoline (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 811-816 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260513
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    Massenspektrometrische Fragmentierung von 4-substituierten 5-Hydroxynaphth[2,1-d]1,3-oxathiol-2-onenOxidative Kupplung CH-acider Vorbindungen mit p-Phenylendiaminen. IX (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 804-810 
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    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass Spectrometric Fragmentation of 4-Substituted 5-Hydroxynaphth[2,1-d]1,3-oxathiol-2-onesThe mass spectra of 5-hydroxynaphth[2,1-d]1,3-oxathiol-2-ones 1a-1x have been studied. They show characteristic fragmentations with participation of neighbouring groups. Investigations of isotopically labelled 4-alkyl and 4-acyl derivatives give evidence for the formation of cyclic ionic structures.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260512
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    Untersuchungen zur pH-Abhängigkeit der UV-Spektren substituierter Naphthalensulfonsäuren - ein Beitrag zur Strukturaufklärung von sauren Azofarbstoffen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 823-828 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Dependence of UV-Spectra of Substituted Naphthalenesulfonic Acids upon the pH-Value - A Contribution in Order to Elucidate the Structure of Acid Azo Dyes
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260515
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    Reversible photoisomerizations of sulfonephthalein indicator dyes. III. Kinetic Analysis of the Intermediate Sultone Formation (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 910-916 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A detailed kinetic analysis is presented of the transient sultone (A2) formation which proceeds thermally from a photogenerated intermediate species after flash excitation of bromo thymol blue and bromo xylenol blue in the presence of quinoline, pyridine and 4-methyl pyridine in toluene solution. The sultone ring cleavage is a bimolecular reaction with the base resulting in a hydrogen-bridged molecular complex (A1) which equilibrates consecutively with the most stable rotamer of the ion pair (A3). The rate constants for the latter reaction are controlled essentially by conformational changes rather than by the proper proton transfer.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260608
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  • 57
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    Diels-Alder-Reaktionen. IX. Über Bildung und Thermolyse der isomeren Tricyclopentadiene (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 924-934 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diels-Alder-Reactions. IX. On the Formation and the Thermolysis of Isomeric TricyclopentadienesThe formation of isomeric tricyclopentadienes by codimerisation of cyclopentadiene with endo- and exo-dicyclopentadiene between 100 and 140°C in the liquid phase, and the retrodiene reaction of the main isomeres of the tricyclopentadiene fraction by gas phase thermolysis were studied kinetically between 230 and 310°C. The rate constants and the parameters of activation were determined.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260610
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  • 58
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    10β-Chlor-östra-1,4-diene als Zwischenprodukte bei der Einführung einer 9(11)-Doppelbindung in Östra-1,3,5(10)-triene (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 941-946 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 10β;-Chloro-estra-1,4-dienes as Intermediates of the Introduction of a 9(11)-Double Bond in Estra-1,3,5(10)-trienesThe synthesis of 9(11)-didehydro-estra-1,3,5(10)-trienes 5 starting from estra-1,3,5(10)-trienes 1 is described. 1 can be transformed into the ketals 2 and 3 by means of isocyanuric acid chloride and an alcohol such as methanol or ethylene glycol in the absence of moisture.The ketals 2 and 3 are sensitive against hydrolysis and react in the presence of water and traces of acid under formation of chlorodienone 4. Dehydrochlorination of 2, 3 and 4 with potassium-tert.-butylate in dimethylsulfoxide gives the 9(11)-didehydro compounds 5. The reaction mechanism of the electrophilic addition of positive chlorine and alcohol to the aromatic A-ring of 1 is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260612
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  • 59
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    Pyryliumverbindungen, XXV. Quantenchemische Berechnungen zur Valenzisomerisierung von 2-Amino-2H-pyran und -thiopyran (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 955-961 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. XXV. Quantum Chemical Calculations Concerning the Valence Isomerization of 2-Amino-2H-pyran and -thiopyranThe equilibrium 2-amino-2H-pyran 6 ⇌ 5-amino-2,4-dien-1-one 7 was investigated using the semi-empirical MINDO/3 and MNDO methods. In accordance with experimental findings for the substituted derivatives 1/2a-d, the introduction of a methyl group into the position 3 of 6 or the exchange of oxygen by sulfur shifts the equilibrium towards the cyclic structures 8 and 10, respectively. Polar solvents, the influence of which was estimated applying the reaction field approach as well as the solvaton theory, and entropy effects are calculated to favour the ring-open valence isomer 7. These results also correspond to experimental results.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260614
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    Photokatalytische Systeme. LXIVLXIII. Mitt: H. Hennig, A. Rehorek, D. Rehorek u. Ph. Thomas, Inorg. Chim. Acta, 86 (1984) 41.. Theoretische Untersuchungen zum Ladungstransfer und zur Photoreaktivität von π-Akzeptorligandkomplexen mit d6-Übergangsmetallen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 962-970 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photocatalytical Systems. LXIV. Theoretical Investigations of the Charge Transfer and of the Photochemical Reactivity of d6 Transition Metal Complexes with π Acceptor LigandsQuantum chemical investigations concerning the charge transfer interactions between a d6 complex fragment and heterocyclic nitrogen ligands are reported. The influence of inductive, mesomeric and steric effects on the π acceptor ability of the isolated ligand and on the electronic structure of the pentacyano-ferrate(II) mixed ligand compounds has been investigated and possibilities to sensitize spectrally the Fe(CN)5L3- system (L= pyridine-type ligand) with regard to their photochemical reactivity are discussed.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260615
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  • 61
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    Untersuchungen zum photochemischen Ausbleichverhalten von tautomeriefähigen Azofarbstoffen. VIV. Mitt.: R. Haessner, H. Mustroph, J. Epperlein, J. prakt. Chem. 325 (1983) 943.. Zur photochemischen Oxydation von Phenylazo-acetylacetonen und Phenylazopyrazolonen durch SingulettsauerstoffHerrn Doz. Dr. K. Schiller zum 60. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 979-984 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations of the Photo-Fading of Tautomeric Azo Dyes. VI. The Photochemical Oxidation by Singlet Oxygen of Phenylazoacetylacetones and PhenylazopyrazolonesThe dye-sensitized photo-oxidation by singlet oxygen of phenylazoacetylacetones (1) and Phenylazopyrazolones (2) has been investigated. The photo-fading of dyes is accelerated in the presence of Methylene Blue, a sensitizer of singlet oxygen, in airsatured methanolAn excellent relationship exists between the fading-rate of a series of dyes (1) and Hammett-σ-constants. An unexpected trend was found for photo-fading of a series of dyes (2). The Hammett plot consists of two parts, with a negative slope derived from electron-releasing substituents and a positive slope derived from electron-withdrawing substituents. The anomalous photo-fading is due to an attack of singlet oxygen on the more reactive anion of the phenylazopyrazolones in the case of electron-withdrawing substituents. In methanol containing acetic acid the dyes (2) exist only as the hydrazone tautomers. Under these conditions the fading-rate show a linear relationship with σ-constants.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260617
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  • 62
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    Synthesis and some reactions of 7-methyl-5-phenyl-5H-pyrazolo[3,4-e]-1,2,4-triazine-3-thiol (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 994-998 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260619
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    Structural elucidation of isomeric Oxazolidinones and Isoxazolidinones by 13C N. M. R. (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 1008-1010 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260622
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  • 64
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    Prostaglandine und Prostaglandinvorstufen. XI.X. Mitteilung siehe. Synthese optisch aktiver bicyclischer Lactone als Zwischenprodukte für 8-Methyl-prostaglandine (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 1016-1020 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Prostaglandins and Prostaglandin Intermediates. XI. Synthesis of Optically Active Bicyclic Lactones - Convenient Intermediates for 8-Methyl Prostaglandins
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260624
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    Chinazolincarbonsäuren. III. Chinazolin-4-on-3-benzoesäuren und -ester (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 1027-1033 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quinazoline Carboxylic Acids. III. Quinazolin-4-on-3-benzoic Acids and Esters
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260627
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    Fluoreszenzverhalten von Polymethinfarbstoffen mit verbrückten Ketten (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 1034-1036 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorescence Properties of Polymethine Dyes with Bridged Chains
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260628
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    Marshall, J. L.: Carbon-carbon and carbon-proton NMR couplings: Applications to organic stereochemistry and conformational analysis. 241 S., 12 Abb., 39 tab., format 16 × 24 cm, Deerfield Beach (Florida): Verlag Chemie International 1983. (methods in stereochemical analysis, Vol. 2) Pappeinband, 175,-DM (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 1039-1039 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260631
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    Masthead (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984) 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260101
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  • 69
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    Komplexkatalyse. XV. Kationische η3-Allyl-bis(triorganylphosphit)nickel(II)-Komplexe als Katalysatoren für die stereoreguläre Butadienpolymerisation (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 1-11 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complex Catalysis. XV. Cationic η3-Allyl-bis(triorganylphosphite)nickel(II) Complexes as Catalysts for the Stereoregular Butadiene PolymerisationSynthesis and catalytic properties of [C3H5NiL2]PF6 complexes 1a-f with L = tri-ethyl-, -isopropyl-, -phenyl-, -o-tolyl-, -thymyl- and o-biphenylylphosphite are described. It is shown how electronic and steric effects of the phosphite ligands in these complexes control their catalytic activity and selectivity in 1,4-polymerization of butadiene.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260102
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    Mehrfunktionelle N-Tenside. VII. Substitution und Eliminierung bei der Reaktion von 1,2-Dihalogenalkanen mit Aminen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 12-22 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyfunctionalized N-Tensides. VII. Substitution and Elimination in the Reaction of 1,2-Dihalogenoalkanes with Amines1, 2-Dichloroalkanes, 1, 2-dibromoalkanes and mixtures of 1-bromo-2-chloroalkanes and 1-chloro-2-bromoalkanes react with primary or secondary amines and give both elimination and substitution products, often in a nearly 1:1 proportion.The elimination products are the cis and trans-1-halo-1-alkenes, the 2-halo-1-alkenes, the 1,3-and 2, 4-dienes and the 1-alkenes. The main substitution products are the 1, 2-bis-aminoalkanes. Physical dates, 1H-n.m.r.-spectra, surface tension values and CMC-dates are given.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260103
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    Kinetics of Dimerization of Amines by hydrogen peroxide in the presence of ferrous sulphate as catalyst (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 23-28 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetik der Dimerisierung von Aminen durch Wasserstoffperoxid in Gegenwart von Fe(II)SO4 als KatalysatorDie Kinetik der Dimerisierung von Diethyl, n-Butyl- und tert.-Butylamin durch Wasserstoffperoxid in Gegenwart von Fe(II)-Ionen wurde untersucht. Die Reaktion ist bezüglich Fe(II)-Ionen und der Amine 1. Ordnung und 0. Ordnung betreffs Wasserstoffperoxid. Produkte der Dimerisierungsreaktionen sowie einige ihrer kristallinen Derivate wurden erhalten und identifiziert. Die Aktivierungsenergien für Diethyl-, n-Butyl- und tert.-Butylamin betragen 153, 130 bzw. 105 KJ mol-1. Ein Reaktionsmechanismus wurde aufgrund der experimentellen Beobachtungen vorgeschlagen.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260104
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    Konfigurationsbestimmung von Steroiden mit Primärer und sekundärer Aminogruppe durch Messung des Circulardichroismus der Kupfer-Succinimidat-Komplexe (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 29-34 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Configurational Assignment of Steroids with Primary and Secondary Amino Groups by CD Measurements of the Copper Succinimidate complexesThe CD spectra of the copper succinimidate complexes of 9 different steroids with a primary and 3 steroids with a secondary amino group were investigated. A good correlation between the sign of the Cotton effects in visible range and the chirality of the immediate neighbourhood of the nitrogen atom was observed. The results obey the earlier established octant rule for this chromophor.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260105
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    Thermitase - eine thermostabile Serinprotease. I. Synthese von Alaninpeptidestern als Substrate des Enzyms (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 35-40 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermitase - A Thermostable Serine Protease. I. Synthesis of Alanine Peptide Esters as Substrates of the EnzymeThe synthesis of N-acetylated and N-succinylated peptide esters of alanine is described. The peptides are built up from the Z-Abkürzung: Z = Benzyloxycarbonyl, Ac = Acetyl, Suc = Succinyl, OMe = Methylester, MA = Mischanhydridmethode, E = Ether, PE = Petrolether, Etac = Ethylacetat, AcOH = Essigsäure, Dibu = n-Dibutylether, DMSO = Dimethylsulfoxid, DMF = Dimethylformamid, TEA = Triethylamin, Ac2O = Essigsäureanhydrid protected peptides by liquid phase fragment condensation and by acylation of the deprotected peptide esters. The kinetic parameters K m and K cat of some compounds are presented.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260106
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    Thermitase - eine thermostabile Serinprotease. II. Synthese von substratanalogen Peptidchlormethylketonen als potentielle irreversible Enzyminhibitoren (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 41-47 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermitase - A Thermostable Serine Protease. II. Synthesis of Substrate Analogous Peptide Chloromethyl Ketones as Irreversibly Acting InhibitorsThe preparation of dipeptide to pentapeptide chloromethyl ketones of alanine wth variation of the amino acid in the P1 and P2 positionNomenklatur für die individuellen Aminosäurereste der Peptide nach I. Schechter u. A. C. Berger, Biochem. Biophys. Res. Commun. 27, 157 (1967). of the peptides is described. The synthesis is performed by fragment condensation of N-acylated amino acids or peptides with the unprotected chloromethyl ketone derivatives of amino acids and peptides, respectively. Some examples of enzyme inactivation by peptide chloromethyl ketones are discussed.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260107
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    13C-NMR-Untersuchung der interannularen Konjugation in substituierten Pyrazolen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 54-62 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C-N.M.R. Investigation of Interannular Conjugation in Substituted PyrazolesThe correlation of the 13C-chemical shifts with the Hammet values for substituted 3-anilino-1, 5-diphenylpyrazoles (1a-k) and substituted 3-methyl-1, 5-diphenylpyrazoles (2a-g) provides evidence for extensive interannular conjugation only between the N-benzene-and the pyrazole rings, whereas in the capto-dative disubstituted system 1 extensive conjugation through the whole molecule is possible. The chemical shifts correlate well with the HMO-calculated π-electron densities. From a comparison of the chemical shifts of unsubstituted 1 and diphenylamine it can be concluded that the 1,5 -diphenylpyrazol-3-yl group has the same electronic effect as the phenyl group.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260109
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    Thermitase - eine thermostabile Serinprotease. III. Synthese von N-Acyl-peptidmethylketonen als reversible Enzyminhibitoren (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 48-53 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermitase - A Thermostable Serine Protease. III. Synthesis of N-Acylated Peptide Methyl Ketones as Inhibitors Reversibly Bound to the EnzymeMethyl ketone derivatives of dipeptides to pentapeptides are used as suitable tools in the investigation of the non-covalent binding for subsite mapping of the active site of the enzyme. The synthesis is mainly performed by fragment condensation of N-acylated peptides or amino acids with methyl ketone derivatives of amino acids. These are prepared from the Z-protectedAbkürzungen: Ac = Acetyl, Z = Benzyloxycarbonyl, Boc = t-Butyloxycarbonyl, Suc = Succinyl, Glp = Pyroglutamyl, OBz = Benzylester, pNA = p-Nitranilid, CH3 = Methylketon, CH2Cl = Chlormethylketon, MA = Mischanhydridmethode, TEA = Triethylamin, NEM = N-Ethylmorpholin, CKEE = Chlorkohlensäureethylester, CKBE = Chlorkohlensäurebutylester, MeOH = Methanol, EtOH = Ethanol, AcOH = Essigsäure, Ac2O = Acetanhydrid, Etac = Ethylacetat, THF = Tetrahydrofuran, E = Ether, PE = Petrolether, DMF = Dimethylformamid, DMSO = Dimethylsulfoxid, DMAP = 4-(Dimethylamino)-pyridin cloromethyl ketones by catalytic hydrogenation. For the coupling steps the Z-protection is preferred. The peptide methyl ketones used in kinetic studies were N-protected by the Z, acetyl, Boc or pyroglutamyl residue.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260108
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    The Autoxidation of 1-Phenylalk-1-ynes. Proof of oxirenes as intermediates in the oxidation of acetylenes (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 73-80 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the autoxidations of 1-phenylprop-1-yne, 1-phenylbut-1-yne, and 1-phenyl-3-methylbut-1-yne a considerable attack at the C≡C triple bond takes place. Both products of the oxidative cleavage of the C≡C bond and products formed through the corresponding oxirenes were detected. The oxirenes rearrange via the isomeric ketocarbenes to ketenes, which yield the corresponding carboxylic acids or their esters. A part of the intermediate ketenes is oxidized with decarboxylation to lower ketones. All products were identified and quantitatively determined after LiAlH4 reduction to the corresponding alcohols.
    Additional Material: 8 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260111
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    Zum Einfluß von Lösungsmitteln auf das VIS-Spektralverhalten von 4′-Dialkylamino-α-cyano-stilben-4-diazoniumsalzen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 63-72 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solvatochromism of 4′-Dialkylamino-α-Cyano-Stilbene-4-Diazonium-Salts4′-Dialkylamino-stilbene-4-diazonium-salts are deep coloured compounds and give strong solvatochromism. 4′-Diethylamino-α-cyano-stilbene-4-diazonium-tetrafluoroborate was investigated in 52 different solvents and 3 binary solvent mixtures. With increasing solvent basicity the longest wave lenght absorption maximum (\documentclass{article}\pagestyle{empty}\begin{document}$ \nu^{\hspace{-5pt}\sim}_{\rm max} $\end{document}) decrease. Complex formation by crown ethers causes a decrease of \documentclass{article}\pagestyle{empty}\begin{document}$ \nu^{\hspace{-5pt}\sim}_{\rm max}$\end{document}, too. In solvents with dielectricity constants higher than about 15 dissociation effects superpose solvatochromism. The summary of experimental dates support the approach of specific nucleophilic solvatation of diazonium ions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260110
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  • 79
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    Ionisation und Dissoziation von Triphenylmethylhalogeniden in Methylenchlorid (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 81-86 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionization and Dissociation of Triphenylmethyl Halides in MethylendichlorideThe Winstein scheme is valid for triphenylmethyl halides in methylendichloride. The equilibrium of ionization and dissociaton has been determined by investigation of the ratio between the sum of concentrations of ionic species and the covalent form. Tritylbromide in methylendichloride shows an exothermic ionization but endothermic dissociation. In the case of tritylchloride ionization and dissociation are nearly independent on the temperature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260112
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  • 80
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    Zur Beeinflussung des Ionisations-Dissoziationsgleichgewichtes von Tritylhalogenidlösungen in Methylenchlorid bei Zugabe von Styren (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 87-91 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Influence of Styren Addition on the Ionization-Dissociation Equilibrium of Trityl Halides in Methylene DichlorideThe ionization-dissociation equilibrium in solutions of trityl halides in methylene dichloride is effected by the addition of π-donors as a function of the temperature. The intensity of the trityl absorption of trityl fluoride and trityl chloride is decreased as it can be shown by u.v.-spectroscopy. The trityl absorption of trityl bromide solutions in methylene dichloride is very sensitive towards temperature changes. Measurements of the equilibrium constants for the ionization - dissociation-equilibrium, when styrene is added to the solution, indicate a specific solvation effect by the styrene molecules, however, a stabilization of ion pairs by specific solvation due to styrene molecules does not occur.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260113
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  • 81
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    Eine neue Synthese für 6H-1,3-Thiazine (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 101-110 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Synthesis of 6H-1,3-ThiazinesA new method for the synthesis of 1,3-thiazines is described. The addition of nucleophiles to γ-isothiocyanatoallylchlorides (1a-j) leads to functionalisation and subsequent cyclisation (nucleophilic cyclofunctionalisation). Reaction of secondary amines or alcohols under catalysis by tert. amines gives numerous 2-dialkylamino- (3a-w) or 2-alkoxy-6H-1,3-thiazines (4a-p).
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260115
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  • 82
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    Photoinduzierte Elektronentransfer-Reaktionen von Komplexen der Arendiazoniumsalze mit KronenethernVortrag auf der Hauptjahrestagung der Chemischen Gesellschaft der DDR 1980 in Karl-Marx-Stadt. (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 92-100 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoinduced Electron Transfer-Reactions of Arenediazonium Ions Complexed with Crown EthersThe photolysis (full light of a medium pressure Hg-lamp) of p-methylbenzenediazonium-tetrafluoroborate in the presence of the crown ether 18-crown-6 (1) yields mainly the products of a heterolytic dediazoniation via arene cations as intermediates. The quantum yield ϕges of the photolysis from p-methoxybenzenediazonium-tetrafluoroborat in CH2Cl2 decreases in the presence of 18- crowns-6 (1) from 0.66 to 0.08. In contrast to 1, the photolysis of arenediazonium salts in the presence of dibenzo-18-crown-6 (3) yields mainly the products of a homolytic dediazoniation as a consequence of an electron transfer from 3 to the diazonium ion. ϕges of this reaction increases with decreasing wavelength of the exciting light from 0.09 (436 nm) to 0.32 (366 nm). this wavelength dependence is explained by formation of a correlated radical pair after excitation. In agreement with this situation a photo-CIDNP-effect is observed in the 15N-n.m.r.-spectra of isotopically labeled arenediazonium salts complexed by 3 and benzo-18-crown-6(2). No photo-CIDNP-effect is observed in the presence of 1. This different behaviour of the EDA-complexes formed by arenediazonium salts with the two different groups of crown ethers 1 and 2, 3 is discussed as a control of the electron transfer-reaction by the structure of the frontier orbitals.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260114
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  • 83
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    Dicyclopentadienoxidation. IV. Oxidation von 4,5- und 8,9-Dihydro-dicyclopentadien (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 121-128 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dicyclopentadiene Oxidation. IV. Oxidation of 4,5- and 8,9-Dihydro-dicyclopentadieneA mixture of exo- and endo-4,5-dihydro-dicyclopentadiene 5 and also pure endo-8,9-dihydro-dicyclopentadiene 7 and pure exo-dicyclopentadiene 10 was oxidized in the absence and in the presence of catalysts. The compounds containing the norbornene structure mainly gave the corresponding exo-epoxides. No catalytic effects were observed in the formation of these nor-bornene epoxides. Compound 7 containing only the cyclopentene structure mainly yielded the corresponding hydroperoxide 9. In this case a catalytic effect of epoxidation catalysts was observed: in the presence of such catalysts the epoxide was increased.The results obtained prove the mechanism of dicyclopentadiene oxidation proposed by us.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260117
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  • 84
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    Acylierung von Heterocyclen mit Kohlensäurederivaten. IV. Umsetzung von Benzoxazolin 2-thion mit Arylcyanaten. Kinetik und Mechanismus (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 129-138 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acylation of Heterocycles with Carbonic Acid Derivatives. IV. Reaction of Benzoxazolin-2-thione with Aryl Cyanates. Kinetics and MechanismThe arylcyanate benzoxazoline-2-thione (1) reaction in the presence and absence of the tertiary amines yields 1-aryloxyiminocarbonylbenzoxazoline-2-thione (2) and 2-thiocyanatobenzoxazole (4). A mechanism is proposed based on the influences of the reactants concentration, the concentration and basicity of tertiary amines, the solvent-water concentration, the arylcyanate substituents electronic effects on the reaction rate and the apparent activation parameters. This mechanism consists in the nucleophilic attack of the benzoxazoline-2-thione S-atom on the cyanate, followed by rearrangement through a four-center transition state.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260118
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  • 85
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    INDO-Berechnung der 15N-13C-Kopplungskonstanten von einfachen Cyaninen und Merocyaninen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 145-147 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: INDO Calculation of 15N-13C Coupling Constants in Simple Cyanines and Merocyanines
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260120
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  • 86
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    Quantenchemische Berechnungen an Radikalen vom Allyltyp: Cycloalkenyl- und Cycloalk-1-enylmethylradikale (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 139-144 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantum-Chemical Calculations on Allyl-Type Radicals: Cycloalkenyl- and Cycloalk-1-enylmethyl RadicalsThe ability of the MINDO/3-HE-method for predicting various molecular properties was tested for cycloalkenyl- (1 to 4), cycloalk-1-enylmethyl-(5 to 8), and for the resonance-stabilized cyclic radicals (9 to 12). Close by it was established that the calculated heats of formation are largely correct. The electronic distribution in the allylic part of 1 to 12 is evidently too levelled.Based on the defination of allyl resonance energy (ARE - SZWARC (1948)) a mean value for the ARE of 1 to 8 is derived to 55 ± 12 kJ · mol-1.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260119
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  • 87
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    13C-kernmagnetische Resonanzspektren der PhenylfulgideXI. Mitt. zur Photochemie der Fulgide; X. Mitt. s. [1]. (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 222-232 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon-13 Nuclear Magnetic Resonance Spectra of PhenylfulgidesThe carbon-13 chemical shifts are determined in a series of phenylfulgides in order to investigate steric and electronic influences of substituents. By means of the shift differences between suitably substituted compounds results can be obtained as to the relative variation of the rotation angles of the phenyl rings as well as to te angle alterations between the exocyclic double bonds and the anhydride ring. Introducing 4-CH3O- and 4-NO2-groups at the phenyl rings the substituent induced alterations of the carbon-13 chemical shifts and the π-polarization effects related with it are discussed.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260206
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  • 88
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    Elektronische und sterische Substituenteneinflüsse auf die UV/VIS-Absorptionsspektren der PhenylfulgidisomerenXII. Mitt. zur Photochemie der Fulgide, XI. Mitt. s. [1] (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 233-247 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electronic and Steric Substituent Influences on the U.V./VIS-Absorption Spectra of Phenylfulgide IsomersThe u.v./vis spectral data of a large number of phenylfulgides (E-, Z-, E-E-, E-Z-, Z-E-, Z-Z-isomers, 1.8a-dihydronaphthalenes) are presented. An increase of the number of phenyl rings as well as substitution of the phenyl rings cause correlatable bathochromic spectral shifts. Steric influences became obvious by introducing methyl groups, by coplanarization of phenyl groups and in the series of isomers. By means of PPP calculations shifts in position and/or intensity of absorption bands are ascribed to the substituent effects.The calculated band polarization of E(E-E)-isomers are in agreement with the results of polarization spectra in oriented liquid crystal mesophases. The polarization spectra allow the assignment of the longwave absorption band to the S2 ← S0 and S1 ← S0 electronic transitions for E-E-Isomers with a C2v-symmetry.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260207
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  • 89
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    Activated nitriles in heterocyclic synthesis: Novel Synthesis of Pyrimidine and of Pyridine Derivatives (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 248-252 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Cyanochalcone reacted with thiourea and guanidine to yield the corresponding pyrimidine derivatives 2 and 4. On the other hand, urea reacted with the same reagent under the same experimental conditions to yield the known urea derivatives 3. A new synthesis of polyfunction pyridine via reaction of 1a with malononitrile in presence of aniline could be developed. Similar to the behaviour of 1a, Compounds 1b, c reacted with malononitrile in presence of aniline to yield compounds 8 and 9. In contrast to the behaviour of compounds 1a-c, 1d reacted with malononitrile to yield the malononitrile derivatives 10 or 11 based on the reaction conditions. Mechanisms to account for formation of the reaction products were suggested.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260208
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  • 90
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    Gibberelline. CIII. Synthese von 8-Amino-gibbanen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 253-258 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Gibberellins. CIII. Synthesis of 8-Amino-gibbanesFor investigations of the structure-activity relationships of gibberellin phytohormones the synthesis of 8-amino-gibbanes is described. The reaction pathway involves condensation of gibberellin C (1a) and its methylester 1b with primary amines to the corresponding azomethins 1c-11 followed by stereoselective NaBH4-reduction to 8α-amino gibbanes 2a-2r.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260209
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  • 91
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    Untersuchungen zum UV/Vis-Spektralverhalten von Azofarbstoffen. XI.X. Mitt. s. H. MUSTROPH u. J. EPPERLEIN, Z. Chem. 23 (1983) 298. Allgemeine Zusammenhänge zwischen Struktur und Farbe protonierter Azofarbstoffe (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 259-265 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on U.V./Vis Absorption Spectra of Azo Dyes. XI. General Relationships between Structure and Colour of Protonated Azo DyesThe U.V.-VIS spectra of a wide range of azo dyes having structural variations in both diazo and coupling components in acidic solution are discussed.The azonium cation can be regarded as a donor-acceptor chromophore. Thus, structural variations which give a bathochromic shift in λmax, are explained. The negative halochromism is also discussed with reference to this model.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260210
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  • 92
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    Pyryliumverbindungen. XXI. Struktur und Tautomerie von Pseudobasen unsymmetrisch substituierter 2,4,6-Triarylpyryliumsalze (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 287-302 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. XXI. Structure and Tautomerism of Pseudobases of Unsymmetrically Substituted 2,4,6-Triarylpyrylium SaltsHydrolytic ring opening of unsymmetrically substituted 2,4,6-triarylpyrylium salts 11 results in a mixture of two tautomeric pseudobases, the penten-1,5-diones 13 and 14. In crystalline state as a rule one of these tautomers markedly predominates, whereas in solution a rapid equilibrium establishment occurs which can be followed by 1H-n.m.r. and u.v. spectroscopy (equilibrium ratio nearly 1:1). The 1H-n.m.r. spectroscopic structural assignment of the two isomeric forms was supported by u.v. spectroscopic studies using 1:1 mixtures of the chromophoric partial systems ArCOCH=CHPh and ArCOMe or the pseudobases 10 of symmetrically substituted 2,4,6-triarylpyrylium salts 9 as reference systems. From the mass spectra of the pseudobases 10 and 13/14 follows that - if hydrolysis of 11 is performed in media containing H218O - mass spectrometric isotopic analysis of the resulting 18O-labelled pseudobases allows no information to be made about the regioselectivity of the ring opening. - Novel starting pyrylium salts of type 9 and 11 are characterized by u.v./vis data and by transformation into the corresponding pyridine derivatives.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260214
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    2, 2-Disubstituierte Cyclopentan-1, 3-dione. IV3. Mitteilung siehe [1]. Gleichzeitig 12. Mitteilung der Reihe „Prostaglandine und Prostaglandinvorstufen“. 11. Mitteilung siehe [2]. Der Inhalt dieser Arbeit ist z.T. Gegenstand des DDR-Wirtschaftspatentes 134 761 vom 30. 01. 1978 [3].. Synthese prochiraler Zwischenprodukte für 8-Methyl-prostaglandin C2 durch C-Alkylierung von 2-Methylcyclopentan-1,3-dion mit 1-Brom-alk-2-inen (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 426-432 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2, 2-Disubstituted Cyclopentane-1, 3-diones. IV. Synthesis of Prochiral Intermediates for the Synthesis of 8-Methyl-prostaglandin C2 by Alkylation of 2-Methyl-cyclopentane-1, 3-dione with 1-Bromo-alk-2-ynes.2-Methyl-cyclopentane-1, 3-dione (1) is preferentially C-alkylated by 1-bromo-alk-2-ynes in aqueous sodium hydroxide solution. By this method it is possible to prepare 2,2-disubstituted-1, 3-diones (3-8), which can be converted into prochiral intermediates for 8-methyl-PGC2, containing the complete carboxylic side chain.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/prac.19843260311
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    Synthese und Eigenschaften kristallin-flüssiger Derivate des Rhodanins (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 457-466 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Properties of Liquid Crystalline Derivatives of RhodanineSubstituted benzylidene-rhodanines 3-8 were prepared both by condensation of 1 a-f with suitable aldehydes and by acylation of 2a-g with substituted benzoyl chlorides or cinnamoyl chlorid. The mesomorphic properties of the compounds are discussed in respect to molecular structure with the aid of i.r.-, Raman- and u.v./vis-spectra of 3d, 3k, 4, 5, 6g, 8a. We have investigated the dielectric and electrooptic behaviour of 31.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260314
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    13C-Spin-Echo J-Modulation experiments and long-range coupling (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 515-518 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260322
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  • 96
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    Zwei modifizierte Pulssequenzen zur 13C-NMR-spektroskopischen Charakterisierung von CHn-Baugruppen Ein rationelles Verfahren zur Bestimmung von n und zur Abschätzung von 1J(13C—1H) (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 524-528 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two Modified Pulse Sequences for the 13C NMR Spectroscopic Characterization of CHn Building Groups. An Effective Method for the Determination of n and for the Estimation of 1J(13C—1H)
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/prac.19843260324
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    Kationische Photopolymerisation von Isobutylglycidether mit Benzoinderivat/Aryloniumsalz- bzw. Benzildimethylketal/Aryloniumsalz-InitiatorsystemenLichtinitiierte Polymer- und Polymerisationsreaktionen 17. Mitt.; 16. Mitt.: siehe [26]Herrn Prof. Dr. J. Ulbricht zum 60. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 529-536 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic Photopolymerization of Isobutylglycidyl Ether with Benzoine Derivatives/Arylonium Salts- or Benzildimethyl Ketal/Arylonium Salts-Initiator SystemsRadicals produced by photolysis of benzoine derivatives and benzile dimethylketale decompose arene diazonium salts (ArN2⊕), diphenyliodonium salts (Ph2I⊕) and triphenylsulfonium salts (Ph3S⊕), respectively. The carbenium ions or protons formed in this way can be used for the cationic polymerization of isobutylglycidyl ether (IBGE). The efficiency of this polymerization depends on the quantum yields of the onium salts decomposition. A reactivity ArN2⊕ 〉 Ph2I⊕ 〉 Ph3S⊕ was found. In the case of ArN2⊕ the salt decomposition is caused by electron transfer between the photolytically produced substituted benzylic radicals and the diazonium ions. It is assumed that by the decomposition of Ph2I⊕ and Ph3S⊕ intermediates occur, which give rise to some reversible reactions. Therefore, the quantum yields of onium salt decomposition are less than those of initiator photolysis. The rate of cationic polymerization of IBGE is also influenced by the anion of onium compounds. A sequence PF6⊖ 〉SbF6⊖ 〉BF4⊖ was found.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260402
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    Komplikationen bei der Initiierung kationischer Polymerisationen mit Lewis-Säuren - Modellrechnungen an Antimon-(V)-halogenidenHerrn Prof. Dr. J. Ulbricht zum 60. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 537-544 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complications in the Initiation of Cationic Polymerizations by Lewis Acids - Model Calculations for Antimony(V)halogenidsQuantum-chemical CNDO/2-calculations including geometry-optimization show that complex anions (X5Sb-Z-SbY5)⊖ are formed as a result of interaction between Lewis acids SbX5 and anions SbY5Z⊖ (X, Y, Z = F, Cl, Br). This interaction is very strong in the case of X, Z = F and Y = Br. When the complex anions decompose the simple anions with the greatest number of fluorine ligands are formed.The interaction between the two different Lewis acids SbX5 and SbY5 yields a random distribution of the ligands of both acids.During formation of the ions SbX4⊕ and SbXY5⊖ the anion with the greatest number of fluorine ligands is formed.The probability of the conversion Sb(V)-Sb(III) is higher for SbCl5 than for SbCl6⊖.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260403
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  • 99
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    Studies on the autoxidation of nonbranched aliphatic monocarboxylic acids and their methyl estersHerrn Prof. Dr. J. Ulbricht zum 60. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 572-578 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Valeric, caproic, and heptanoic acid and their methyl esters were oxidized at 140°C by molecular oxygen. The oxidation mixtures were reduced by LiAlH4 and the mono- and dihydroxy compounds formed were analyzed gaschromatographically. From the results obtained one can conclude that nonbranched aliphatic acids and their methyl esters are attacked by the chain-carrying peroxy radicals at the different C—H bonds with almost the same regioselectivity as normal paraffins Only the ß- and to a smaller extent the α-positions are desactivated by the neighbouring carboxylic group.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260407
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  • 100
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    Radikalabfang. I. ESR-spektroskopische Untersuchungen von Radikalreaktionen einiger 3-Nitrono-6-oxo-cyclohexadieneHerrn Prof. Dr. J. Ulbricht zum 60. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 588-593 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spin Trapping. I. Investigation of Radical Reactions of Some 3-Nitrono-6-oxocyclohexadienes by ESR-SpectroscopyThe title compounds (3, 4 and 5) add O- and C-centered radicals to the nitrono group to yield spin adducts containing a 4-oxo-cyclohexadienyl group in the α-position (6, 7 and 8). These new nitroxylradicals undergo α- and ß-scission. The nitroxyl radicals and the paramagnetic decomposition products were detected by esr-spectroscopy.Further, a more general way of radical-induced decomposition was discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19843260409
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