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  • 1995-1999
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  • 1955-1959
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  • Inorganic Chemistry  (816)
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  • Electronic Resource  (1,750)
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  • 1995-1999
  • 1975-1979  (1,750)
  • 1955-1959
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Langenbeck's archives of surgery 343 (1977), S. 133-151 
    ISSN: 1435-2451
    Keywords: Peptic ulcer ; Anastomosis ; Duodenogastric reflux ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die vorliegende Studie gilt dem Anastomosengeschwür am operierten Magen. Diese schwerwiegende Komplikation entsteht nahezu ausschließlich nach Resektionsverfahren mit duodenaler Exklusion (Billroth II; Verlegung des Duodenum in den Nebenschluß). - An 54 männlichen Wistarratten wurden verschiedene Formen der duodenalen Exklusion mit und ohne duodenogastrischen Reflux durchgeführt. Die Ergebnisse unserer Untersuchungen zeigen, daß nach duodenaler Exklusionmit Reflux gesetzmäßig peptische Anastomosengeschwüre entstehen. Der kontinuierliche Reflux von Galle und Pankreassekret ist der ausschlaggebende ätiologische Faktor für die Ulcusentstehung im Grenzgebiet der Anastomose von Magen und Dünndarm. Stase im ausgeschalteten Zwölffingerdarm (Syndrom der zuführenden Schlinge) fördert die lcerogene Refluxwirkung. Fehlt der Pylorus, so potenzieren sich Reflux und Stase zur größten Ulcusfrequenz (〉 90%). Bei erhaltenem Pylorus ist die Geschwürsincidenz wesentlich geringer. Der duodenogastrische Reflux hemmt die meßbare Salzsäuresekretion signifikant (P 〈 0,01); Salzsäure spielt demnach für die Entstehung des experimentellen Anastomosengeschwürs der Ratte keine wesentliche Rolle. - Im Hinblick auf die Prophylaxe des Anastomosengeschwürs führen diese Erkenntnisse zu der Forderung, auf Operationsverfahren mit duodenaler Exklusion und Reflux (Billroth II) zu verzichten und das Operationsziel bei der Magenresektion auf die Wiederherstellung der orthograden MagenDarm-Passage zu richten.
    Notes: Summary Different types of duodenal by-pass operations with and without duodenogastric reflux were performed on 54 male Wistar rats. The results of our investigation show that following duodenal by-pass with reflux peptic anastomotic ulcer regularly occurs. The constant reflux of bile and pancreas juice is the most important aetiologic factor in the development of ulcer in the vicinity of the anastomosis between the stomach and small intestine. Stasis in the by-passed duodenum (afferent loop syndrome) promotes ulcerogenic action of reflux. In the absence of the pylorus the effects of ref lux and stasis potentiate, resulting in a high frequency of ulcer (〉 90 %). With intact pylorus the incidence is low. Duodenogastric reflux prevents hydrochloric acid secretion significantly (P 〈 0.01); hydrochloric acid thus plays a minor role in the development of experimental anastomotic ulcer of the rat. - In considering the prophylaxis against anastomotic ulcer, these findings support the claim of avoiding surgical techniques involving duodenal by-pass and reflux (Billroth II with short loop GE). Gastric resection should, therefore, aim at the reconstruction of the orthograde peristalsis.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 215 (1977), S. 1-9 
    ISSN: 1434-4726
    Keywords: Respiratory epithelium ; Larynx ; Microridge cells ; Rat ; Scanning electron microscopy ; Respiratorisches Epithel ; Kehlkopf ; Mikroleistenzelle ; Ratte ; Rasterelektronenmikroskopie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Kehlkopfepithel ausgewachsener männlicher Albinoratten wird rasterelektronenmikroskopisch untersucht. Zusätzlich zu den zilientragenden und zu den Mikrovillizellen, zu den Bürsten- und Becherzellen, welche insgesamt für das respiratorische Epithel charakteristisch sind, werden in bestimmten Abschnitten des Larynx die Mikroleisten- oder Labyrinthzellen beschrieben. Die freie Oberfläche typischer Labyrinthzellen ist durch ein System von sich verzweigenden Mikroleisten gekennzeichnet, die miteinander durch Querbrücken verbunden sind und in der Zellperipherie eine bevorzugte Parallelausrichtung zur Zellgrenze zeigen können. Der Durchmesser der Mikroleisten beträgt ca. 0,05–0,15 μm. Die Querverbindungen zwischen den Mikroleisten haben einen Durchmesser von ca. 0,01 μm. Der Raum zwischen zwei benachbarten Querbrücken variiert. Labyrinthzellen können außer Mikroleisten auch Mikrovilli zeigen und es gibt Übergänge zwischen den Mikroridge- und den Mikrovillizellen. Die bevorzugte Lokalisation der Mikroleistenzellen im Bereich der Glottis und des Aditus laryngis wird belegt. Die mögliche Funktion dieser Zellen und ihre Bedeutung für die Diagnostik pathologischer Schleimhautveränderungen wird diskutiert.
    Notes: Summary The laryngeal epithelium of male white rats is studied by reflection scanning electron microscopy (SEM). In addition to ciliated cells, microvilli cells, brush cells and goblet cells that are characteristic for normal respiratory epithelium the microridge or labyrinth cell can be seen in particular regions of the larynx. The apical surface of a typical labyrinth cell is characterized by a system of narrow standing microridges of about 0.05–0.15 μm in diameter and interconnecting microridges with a diameter of about 0.01 μm. The microridge system of a labyrinth cell originates from the fusion of densely standing microvilli. Between microridge cells and microvilli cells all transition forms can be observed. The preferable localiziation of the microridge cell in the larynx and its possible function is discussed.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 217 (1977), S. 41-51 
    ISSN: 1434-4726
    Keywords: Respiratory epithelium ; Epiglottis ; Rat ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epithelial surface of the epiglottis in adult male and female albino rats is studied by scanning electron microscopy. Prominent differences exist between the surface morphology as observed in the males and that observed in the females sacrificed in the estrus phase of the ovarial cycle. The differences are most pronounced in respect to the amount of secretory vesicles, microvilli- and microridge-cells and in respect to the observable number of desquamating cells. The existence and the importance of the microridge-cells are discussed. Special attention is also paid to the results indicating that at least some parts of the extrapulmonary airway epithelia act as possible target organs for sex hormones. Finally the importance of the observed differences is discussed for the correct interpretation of pathomorphological alterations in the extrapulmonary airway epithelia that have been observed under experimental conditions and during infections.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 296 (1977), S. 187-190 
    ISSN: 1432-1912
    Keywords: Cyclic nucleotide phosphodiesterase ; Gastric mucosa ; Human ; Rat ; Inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cyclic adenosine-3′,5′-monophosphate (cAMP) phosphodiesterases (PDE) were partially purified from human and rat gastric mucosa. Drugs known to affect the cyclic nucleotide system and/or gastric secretion were tested for effects on the PDE-activities from both species. In rat gastric mucosa PDE-activity can be detected in the 100 000×g sediment (K m =8.3 μM; V max=3.2 nmoles cAMP hydrolyzed/mg protein x min) and the cytoplasma (K m =5.6 μM; V max=2.6 nmoles cAMP hydrolyzed/mg protein x min). The most effective inhibitors of the particle-bound activity are papaverine (K i =4 μM, non-competitive) and 3-isobutyl-1-methylxanthine (K i=14 μM, competitive). There was only a modest competitive inhibition by theophylline (K i =495 μM). PDE-activity in the cytoplasma was inhibited competitively by these three drugs (papaverine: K i =6.5 μM; 3-isobutyl-1-methylxanthine: K i =37 μM; theophylline: K i =152 μM. In human gastric mucosa PDE-activity can be detected in the particular fraction (K m =23.9 μM; V max=1.2 nmoles cAMP hydrolyzed/mg protein x min), and the soluble fraction (K m =12.1 μM; V max=2.4 nmoles cAMP hydrolyzed/mg protein x min). PDE-activity in the 100 000×g sediment was inhibited by papaverine (K i =5.6 μM, non-competitive), 3-isobutyl-1-methylxanthine (K i =16 μM, non-competitive), theophylline (K i =165 μM, non-competitive), and N6-2′-O-dibutyryl-cAMP (K i =746 μM, competitive). Inhibition in the 100 000×g supernatant was noncompetitive with 3-isobutyl-1-methylxanthine (K i =7.1 μM and papaverine (K i =8.5 μM), but competitive with N6-2′-O-dibutyryl-cAMP (K i =170 μM), and theophylline (K i =225 μM). This study indicates that PDE-activities of the two species are qualitatively similar, but quantitative differences exist.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 23 (1977), S. 161-170 
    ISSN: 1432-0827
    Keywords: Bone ; Growth ; Rat ; Remodeling ; Tetracyclines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Cortical bone remodeling along the femur diaphysis was determined in normal female rats (Sprague-Dawley) with the tetracycline technique. Three segments on the cortical bone circumference (the anterolateral, the medial, and the posterior) were found to be most suitable for the study of the remodeling process. Oxytetracycline was administered at age 60 and 75 days, and groups of animals were killed at age 75, 85, 95, and 105 days. The accumulated endosteal growth during age 60 to 75 days in the anterolateral segment was found to increase uniformly in the distal direction along the femur diaphysis. A method is described where this accumulated endosteal growth is used. This method eliminates the use of calipers to determine the section level and makes it possible to study comparable sections even after varying periods of time. The proximal part of the diaphysis showed periosteal apposition in all three segments. The periosteal apposition turned into resorption in the distal part of the diaphysis in the anterolateral and medial segments, whereas the periosteal appsition increased in the posterior segment. The endosteal growth increased in the distal direction in the anterolateral and medial segments. Irregular OTC bands made measurements of endosteal remodeling in the posterior segment impossible. The cortical width decreased in the distal direction along the femoral shaft. Comparison between the different age groups is described and also the relation between the accumulated endosteal growth and the diameter of the medullary cavity.
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  • 6
    ISSN: 1432-1106
    Keywords: Spinal cord ; Dorsal horn interneurones ; Pain mechanisms ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrophysiological properties of neurones in the spinal cord dorsal horn were studied in decerebrated, immobilized spinal rats. Extracellular recordings were performed at the thoraco-lumbar junction level. Each track was systematically located by extracellular injection of pontamine sky blue. According to their responses to mechanical peripheral stimuli, cells were classified in four classes: Class 1 cells: Cells activated only by nonnoxious stimuli. They were divided into — 1A: hair movement and/or touch and 1B: hair movement and/or touch and pressure or pressure only. Class 2 cells: Cells driven by both nonnoxious and noxious stimuli, divided into — 2A: hair movement and/or touch, pressure, pinch and/or pin-prick, and 2B: pressure, pinch and/or pin-prick. Class 3 cells: Cells only activated by noxious stimuli (pinch and/or pin-prick). Class 4 cells: Cells responding to joint movement or pressure on deep tissues. Peripheral transcutaneous or sural nerve stimulation clearly showed that class 1 cells were activated only by A fiber input while 68% of classes 2 and 3 cells received A and C input. Histological examination indicated that cells driven only by noxious input were located either in the deepest part or in the marginal zone (lamina I) of the dorsal horn. Nevertheless, some lamina I cells were also driven by both nonnoxious and noxious stimuli. In addition, there is a great deal of overlap between class 1 and class 2 cells. This fact was confirmed by considering the wide distribution in the dorsal horn of cells receiving A and C input. However, spinal organization of the different classes of cells consists of a preferential distribution rather than a strict lamination. This study indicates that properties of dorsal horn interneurones in the rat have a high degree of similarity with those previously described in other species (cat and monkey).
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 29 (1977), S. 249-263 
    ISSN: 1432-1106
    Keywords: Preoptic area ; Basal septum ; Amygdala ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular microelectrode recordings were made from single neurones in the medial preoptic area and basal septum of normal female rats anaesthetised with urethane and the effects of stimulation of the ipsilateral amygdala (AMY) was tested. 1. Quiescent cells were excited with latencies between 4 and 〉 40 msec with the majority being between 10 and 27 msec. Variable latency, changing latency and recruitment were observed and suggest that many pathways are oligo- or polysynaptic. 2. A minority of spontaneously active units (20.6%) were excited with latencies between 5 and 36 msec. The predominant initial response was inhibition (67.1%). The remaining 12.3% of neurones did not respond. 3. A predominantly positive complex field potential was associated with excitation, particularly of quiescent neurones. 4. Inhibitory responses were classified according to duration (short: 20–60 msec; long: 100–400 msec). All responses contained an inhibitory component. Responses were further described on the basis of presence and rhythmicity of post-inhibitory excitation. 5. The majority of action potentials evoked from quiescent neurones were of small amplitude (80–150 μV) and occurred in small groups. These characteristics and their occurrence at the onset of inhibition are consistent with the view that all or a proportion of them may be generated by inhibitory interneurones. 6. Only minor differences were observed between response characteristics evoked by stimulation of the corticomedial or basolateral AMY indicating that differential effects of these regions on adenohypophysial hormone secretion are determined at the septopreoptic level.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 30 (1977), S. 149-154 
    ISSN: 1432-1106
    Keywords: Dentate and interpositus nuclei ; Pontine gray ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following removal of a significant part of the dentate nucleus and most of the interpositus nucleus in the rat cerebellum degenerated cerebellopontine fibres are shown to end in three fairly restricted regions in the contralateral pontine gray: in the paramedian position, in the middle and in the lateral third. The three regions are arranged in rostro-caudal longitudinal columns in the caudal three-quarters of the pons and these columns are continuous with one another by regions of scattered degeneration. The fibres appear to end in relation to distal dendrites of the pontine cells.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 30 (1977), S. 313-321 
    ISSN: 1432-1106
    Keywords: Rat ; Hypoglossal nucleus ; Botulinum toxin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural effects of local injection of botulinum toxin into the left half of the tongue of the rat, were studied quantitatively 35 days postoperatively in the left hypoglossal nucleus. The results showed (1) a decrease in somatic and neuropil bouton numbers because of loss of boutons with symmetrical synapses and clear spherical synaptic vesicles, (2) a decrease in the numbers of dendrite profiles in the neuropil, (3) an increase in the proportion of dendrites and boutons with unusual inclusions, suggestive of profile retraction, (4) an increase in the proportion of profiles which were unusually electron-dense, (5) an increase in the amount of astrocyte, and a growth of astrocyte sheaths around bouton-free neurone surfaces, (6) the presence of occasional microglia, and (7) subastrocytic subsurface cisterns. Control rats injected with boiled toxin had no responses except (3) and (4) above, and then only to a modest extent, possibly due to mechanical damage of a few axons or terminals at the time of injection, or to insufficient inactivation of the toxin by boiling. The results were compared with those at 35 days after axotomy, and it was concluded that botulinum toxin, which interrupts neuromuscular transmission, elicits the same responses in the hypoglossal neurones, as does transection of the hypoglossal nerve, even though earlier studies had discovered no glial replication after botulinum toxin, in contrast to axotomy.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 27 (1977), S. 211-219 
    ISSN: 1432-1106
    Keywords: Visual system ; Degeneration ; AChE ; Choline acetyltransferase ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of unilateral enucleation, ablation of the visual cortex or coagulation of the lateral geniculate nucleus (LGN) upon the activity of choline acetyltransferase (ChAc) and acetylcholinesterase (AChE) in different structures of the visual system of albino rats was studied. The localization and extent of the degeneration pattern were followed up by histological silver degeneration methods. Afferents from the retina project mainly contralaterally to the dorsal and ventral LGN, the pretectal region and the superior colliculus. Afferent fibres from the dorsal LGN enter the visual cortex in area 17 only. Neurons of this area project back ipsilaterally to the LGN and the superior colliculus (SC). No significant decrease in the activity of the cholinergic marker enzyme choline acetyltransferase could be observed under any of the experimental conditions; there was rather a tendency to increased activity in the subcortical centres. AChE as a less specific marker also exhibited no gross changes in activity in the lesioned animals. The results add more direct proof to pharmacological and physiological evidence that ACh is not involved in the synaptic transmission of the direct optic projections in rats, either at the subcortical or at the cortical level.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 29 (1977), S. 219-231 
    ISSN: 1432-1106
    Keywords: Rat ; Hypoglossal nucleus ; Delayed regeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron micrographs of the left hypoglossal nucleus of adult male albino rats were quantitatively analyzed from 9–70 days after allowing the transected left hypoglossal nerve to regenerate after an 84 day delay. Delay was achieved by implanting the proximal stump into already innervated sternomastoid muscle, where no regeneration occurred. Regeneration was then allowed by denervating the sternomastoid. During the regenerative period the initially high number of abnormally electron dense perikarya and dendrites decreased to almost normal values, but no cell removal was seen. This suggested that the degenerate appearance of many profiles after prolonged prevention of regeneration, was reversible. The neuropil bouton and dendrite counts, and the numbers of synapsing boutons per dendrite, increased steadily to normal values from the low values of suppressed regeneration. Somatic bouton frequencies, even though already low, decreased further at 32 days, and later increased but not to normal values. The decrease at 32 days coincided with the loss of many subsurface cisterns, and dispersion of Nissl substance, all suggestive of chromatolysis. Later the subsurface cisterns and Nissl substance returned. It was suggested that the delay of complete recovery of somatic bouton frequencies might be because of lack of sensory information from the denervated muscle into which the hypoglossal nerve was regenerating, or because of abnormally low starting values for the recovery phase. Astrocyte (or, occasionally microglial) sheaths persisted along boutonfree perikaryal surfaces.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 151 (1977), S. 29-34 
    ISSN: 1432-0568
    Keywords: Optic tectum ; Rat ; Cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The death of cells was studied by light microscopy in the optic tectum of normal, developing rats. Normal cell death in the tectum during development has previously been described in chickens but not in a mammal. The total period of cell death was from the 20th embryonic day through the 11th postnatal day. During this period the number of dying cells was comparatively small for the first 2 days, reached a peak at birth and then decreased over the next 11 days. In comparison to the number of surviving cells the number of dead cells in each section was small. The dead cells appeared to be randomly distributed in all layers of the optic tectum.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 151 (1977), S. 335-339 
    ISSN: 1432-0568
    Keywords: Autoradiography ; Hippocampus ; Neurogenesis ; Rat ; Thyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postnatal development of the dentate gyrus and the effect of 5 μg/day triiodothyronine treatment was examined by means of tritiated thymidine autoradiography. The polymorph layer of the dentate gyrus is a secondary germinal layer and forms cells for the granular layer. The cell formation in the dentate gyrus was found to be nearly completed on the 21st day, but development ended only in adulthood. Thyroid-hormone treatment did not affect significantly the postnatal cell formation of the dentate gyrus, but resulted in the appearance of a great number of pycnotic cells in the granular layer.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 152 (1977), S. 43-64 
    ISSN: 1432-0568
    Keywords: Habenula ; Ependyma ; Supraependymal cells ; Supraependymal axons ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The surface features of the ependymal lining of the habenular complex in rats, aged between three weeks and nine months, were studied by means of scanning and transmission electron microscopy. The ependyma of the medial habenular nucleus is heavily ciliated, the cilia obscuring underlying substructure in SEM — preparations. On the habenular commissure most cilia are arranged in tufts. Cilia are provided with segmental indentations and occasional apical thickenings. Vesicular protrusions of the ependymal cytoplasm into the ventricular lumen and the frequent occurrence of homogeneous supraependymal globules were interpreted as signs of ependymosecretory activity of nucl. hab. med. Supraependymal cells are most numerous on the anterior and superior surface of the habenular commissure. Cells presenting features identical to Kolmer (epiplexus) cells were identified on the ventricular surface of nucl. hab. med. in one specimen showing degenerative changes of undetermined aetiology in the habenular nuclei. It is therefore suggested that such cells need not necessarily be restricted to the choroid plexus. Supraependymal unmyelinated axons are particularly numerous on both nucl. hab. med. and commiss. hab. They make desmosome contacts (maculae adherentes) with the ependymal plasmalemma. Contacts presenting all features of typical synapses were not encountered. The vesicle population of the axonal profiles mainly comprises 35–50 nm translucent round vesicles besides small numbers of 60–100 nm dense-cored vesicles and large pleiomorphic vesicles. Most probably the axons belong to the well-established dense population of serotonergic axons in the dorsal part of the third ventricle.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 151 (1977), S. 53-62 
    ISSN: 1432-0568
    Keywords: Large intestine ; Intestinal absorption ; Postnatal development ; Rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The absorption of horseradish peroxidase in the rat large intestine during the postnatal developing period was investigated by cytochemical and ultrastructural methods. In the ceca and ascending colons from 4-, and 5-day-old rats, intraluminaly injected peroxidase became localised on microvilli, in the intracytoplasmic network of the apical tubules and small vacuoles (tubulo-vacuolar system), in the large supranuclear vacuole, in the Golgi apparatus, on the lateral and basal cell membranes of the surface principal cells, and also in the lumen of blood capillaries in the subjacent propria. On the other hand, the protein tracer was not seen in the large intestinal epithelial cells that lack tubulo-vacuolar systems and large supranuclear vacuoles within their cytoplasm. In the descending colons of rats of any postnatal age, the epithelial principal cells are devoid of these membrane systems, and exogenous peroxidase was not detected in the cytoplasm of the principal cells. It is assumed that at least the proximal portion of the large intestine in neonatal animals has the capacity to absorb macromolecular protein through those surface principal cells that have specialized intracellular membrane systems.
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  • 16
    ISSN: 1432-0568
    Keywords: Neurosecretion ; Adrenalectomy ; Diabetes insipidus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of adrenalectomy on the amount of “Gomori-positive” neurosecretory material in the outer layer of the median eminence and in the supraoptico-hypophysial system was studied in normal Long-Evans rats and in Long-Evans rats heterozygous and homozygous for hypothalamic diabetes insipidus. In all non-adrenalectomized rats very few “Gomori-positive” granules were found in the outer median eminence layer. After adrenalectomy the amount of the granules increased markedly in normal Long-Evans rats and only slightly in Long-Evans rats heterozygous for diabetes insipidus. However, no augmentation of the granules occurred in homozygous diabetes insipidus rats. The amount of “Gomori-positive” substances demonstrable in the supraoptic and paraventricular nuclei, in the inner layer of the median eminence, and in the neural lobe of the hypophysis was less in rats heterozygous for diabetes insipidus than in normal Long-Evans rats and the smallest in homozygous diabetes insipidus rats. No differences in the amounts of the substances were observed between adrenalectomized and non-adrenalectomized animals. The findings suggest that the “Gomori-positive” granules occurring in the outer layer of the median eminence of adrenalectomized rats are of similar origin as those of the supraoptico-hypophysial system and represent a vasopressin-neurophysin-complex. The results support the concept that vasopressin is involved in the regulation of ACTH release.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 151 (1977), S. 241-265 
    ISSN: 1432-0568
    Keywords: Scanning E.M. ; Third ventricle ; Neurohypophysis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The surface of the recessus infundibularis of the third ventricle has been studied with the scanning and transmission technique in normal and experimental material. Surface specializations such as microvilli, craters and areas of discontinuous lining are described. Supraependymal cells and fibres have been found; some of these cells form wide-meshed networks. The supraependymal fibres may be regular or varicose; the former seem to perforate the ependyma. With the transmission electron microscope the supraependymal cells are divided into three categories: nerve cells, lymphocytes and “dense cells”. Two fibre populations are distinguished: thin profiles (nerve fibres) and thick profiles (nerve terminals). Axosomatic and axoaxonic synapses are described. Synapses between supraependymal fibres and ependyma cells have also been found.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 151 (1977), S. 63-69 
    ISSN: 1432-0568
    Keywords: Rat ; Phrenic nerve ; Accessory phrenic nerve ; Diaphragmatic myotomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Reinnervation studies of the diaphragm led us to reinvestigate the normal anatomy of the phrenic nerve of the rat. The phrenic nerve originates from the cervical nerve roots C4 and C5. In 16 out of 19 normal rats an accessory phrenic nerve was observed receiving its segmental fibres from C6. The number of myelinated axons of the accessory phrenic nerve varied from 41 to 101 (mean: 64.3, i.e. about 15% of the average number of axons in the common phrenic nerve). The accessory phrenic nerve innervates the dorsal part of the costal and the lateral part of the crural region, whereas the remaining parts of the hemidiaphragm are supplied by the segments C4 and C5. There is no evidence for any additional contribution to the motor innervation of the diaphragm from intercostal nerves.
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  • 19
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    Electronic Resource
    Springer
    Acta neuropathologica 40 (1977), S. 253-257 
    ISSN: 1432-0533
    Keywords: Protein-calorie malnutrition ; Rat ; Spinal root ; Paranodal region ; OTAN method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During the early postnatal development of spinal roots in rats paranodal regions were often found, containing OTAN-positive inclusions in the Schwann cell cytoplasm. The presence of OTAN-positive paranodal regions showed variations in time, which were synchronous for ventral and dorsal roots. Dorsal roots, however, showed a more marked presence during development than ventral roots. Spinal roots of animals submitted to a 50% food restriction, were shown to contain more OTAN-positive paranodal regions than controls. This was true for ventral as well as dorsal roots. It is suggested that crowding of internodal segments could be one factor, determining the presence of paranodal, OTAN-positive material.
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  • 20
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    Acta neuropathologica 40 (1977), S. 249-252 
    ISSN: 1432-0533
    Keywords: Low-protein diet ; Rat ; Peripheral nerve ; Paranodal area ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Young rats, submitted to severe protein restriction were studied concerning the width of intermyelin gaps at the nodes of Ranvier in peripheral nerve fibres. The results gave no proof of increased paranodal myelin retraction in lumbar spinal roots or the sciatic nerves of low-protein rats. Malnourished rats as well as controls showed great interindividual differences as to the presence of nodes with wide inter-myelin gaps.
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  • 21
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    Calcified tissue international 22 (1977), S. 77-84 
    ISSN: 1432-0827
    Keywords: Fluoride ; Blood plasma ; Enamel mineralization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract It is postulated that tissue fluid F concentrations are the primary determinants of fluoride effects on bones and developing teeth and that these concentrations are dependent on, or mirrored by, blood plasma F. It has earlier been shown that the plasma F levels are dependent on the dietary F supply as well as on skeletal F concentration. Fasting and post-ingestion or postinjection plasma F levels have been determined in rats on F doses that cause different degrees of enamel fluorosis. The results indicate that temporary peak values rather than elevated fasting values are responsible for the occurrence of enamel fluorosis and that the peak values must approach about 10 μM in order to block enamel formation by the ameloblasts. The diagnostic and prognostic importance of plasma F determinations is discussed.
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  • 22
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    Experimental brain research 28 (1977), S. 335-344 
    ISSN: 1432-1106
    Keywords: Hippocampus ; Rat ; Lamellae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A series of experiments was conducted in the urethane anaesthetised rat to determine the organisation of some hippocampal pathways in this species, using stimulating and recording microelectrodes to elicit and record population spikes. It was found that the mossy fibres, alvear fibres and perforant path were clearly arranged in a lamellar fashion. Lamellar organisation could not be demonstrated for the afferents in the stratum radiatum which include the Schaffer collaterals. It was concluded that hippocampal organisation in this species essentially resembles that in the rabbit and cat.
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  • 23
    ISSN: 1432-2072
    Keywords: Rat ; Exploratory behaviour ; Stereotyped behaviour ; Hole-board ; dl-Amphetamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A technique is described for studying exploratory as well as stereotyped behaviour in rats using an automated hole-board. Both visual and automated recordings can be employed using the technique. Hole dipping is monitored automatically using an infra-red detector system. Repetitive patterns of hole-dipping are used as parameters of stereotyped behaviour while the more random patterns of hole-dipping are used as parameters of exploration. There was a high significant correlation between the records of hole-dipping behaviour as recorded visually and automatically. There was also a high significant correlation between the measures of repetitiveness/randomness of hole-dipping behaviour from automatic and visual recordings. The pattern and levels of hole-dipping conformed with expectations both as regards changes with time and with increasing doses of dl-amphetamine.
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  • 24
    ISSN: 1432-2072
    Keywords: Abstinence syndrome ; Tolerance ; Physical dependence ; Rat ; THC ; Morphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ten rats were injected s.c. with THC twice daily for 5 weeks in increasing doses. In the last 3 weeks they received 40 mg/kg THC in each administration. Ten control rats received the same amount of vehicle by the same route for the same period. The comparison of rectal temperatures of the first and fifteenth days showed that a very pronounced tolerance developed to the hypothermic effect of THC. The administration of naloxone on the 22nd and 31st days precipitated an opiatelike abstinence syndrome. The termination of the drug administration on the 35th day also produced a similar withdrawal syndrome. The most common signs of abstinence syndrome in THC-treated animals were teeth chattering, defecation, urination, dyspnea, and complete palpebral closure. Although the frequency of the incidence of the following signs were not high, they have been observed only in THC-treated animals: chewing, tremors on the face, escape behavior, jumping, eating of objects, biting of fingers, and sniffing. During abstinence, an increased locomotor activity was recorded by an activity-meter. Similarly, the total amount of excreted feces and urine was higher in the THC group than in the controls. Both abstinence scores and increased motility exhibited the peak in the 48th h of withdrawal. Some similarities between the effects of THC and morphine have been reviewed.
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  • 25
    ISSN: 1432-2013
    Keywords: Dibutyryl cyclic AMP ; Pancreas ; Rat ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary DbcAMP≥0.1 mM induces the discharge of exportable enzymes from rat pancreas fragments incubated in vitro. This effect is qualitatively similar to the action of physiological secretagogues acting via hormone receptors: 1) it is accompanied by the appearance of exocytotic images at the acinar cell apex; 2) it is energy dependent but energy supply is low while that required for the carbamylcholine or caerulein response is high and can only be afforded by oxidative phosphorylation; 3) it is calcium dependent, but no alteration of inward or outward calcium movement can be observed; 4) it is altered by agents known to disrupt the microfilamentous microtubular system [41]. However, the secretory response to DbcAMP is quantitatively less than that obtained with hormonal stimuli. A damaging effect of DbcAMP on pancreatic acinar cells is ruled out on histological and biochemical grounds: there is no significant leakage of LDH; protein synthesis, 2-deoxy-d-glucose andl-leucine uptake are unaltered. The secretagogue effect of DbcAMP is reversible, dose-related and specific. It is not mediated by neuro-transmitter release or by interaction with their receptors. The evidence presented points to a direct interaction of DbcAMP on the pancreatic acinar cell and suggests the last step of the secretory cycle as the most probable site of action of the nucleotide derivative.
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  • 26
    ISSN: 1432-2013
    Keywords: Altitude ; Myocardium ; Regional blood flow ; Blood volume ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Circulating blood volume, cardiac output and relative organ perfusion changes were studied, using the Sapirstein method of86Rb tissue uptake, in male 75-day-old rats exposed to intermittent high altitude hypoxia (gradually up to 7000 m, 4 h daily, 5 days a week; the total number of exposures was 24). Intermittent hypobaric exposure caused a significant rise of the erythrocyte volume, whereas the plasma volume remained unchanged. The relative perfusion of the left and particularly of the right ventricular myocardium, as well as of the spleen, liver, lung, small intestine and skeletal muscle, was significantly higher. The cardiac output determined in other experimental animals similarly treated was significantly higher after 24 exposures to the intermittent high altitude hypoxia. We suggest that these changes are triggered by tissue hypoxia and a greater blood flow demand.
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  • 27
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    Pflügers Archiv 368 (1977), S. 125-128 
    ISSN: 1432-2013
    Keywords: Endotoxin ; Rat ; Fever ; Anti-endotoxin system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In conscious unrestrained rats, at an ambient temperature of 22°C, oesophageal temperature was measured and temperature effect of single and repeated intravenous injection ofE. coli endotoxin was examined. The first injection of endotoxin in a dose of 10.0 μg/rat did not change the rat body temperature. The second injection of this dose in the same animals repeated after 48 h produced fever. With following injections the fevers observed were less pronounced. The absence of fever after a single injection of endotoxin was accompanied by the rapid loss of pyretic activity of the rat plasma samples (bioassayed in rabbits). When fever was observed (48 h interval between endotoxin injections) the pyretic activity of the rat plasma remained unchanged for 90 min following endotoxin injection. It was concluded that after a single injection endotoxin is rapidly detoxified in the rat circulation while this process does not take place after the second endotoxin injection (48 h interval). The process of endotoxin detoxification can be depressed by the pretreatment with nitrogen mustard. Analysis of changes of skin temperature following endotoxin injections and the influence of aspirin on endotoxin-induced fever suggest that the fever observed was of central origin.
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  • 28
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    Archives of toxicology 37 (1977), S. 159-164 
    ISSN: 1432-0738
    Keywords: Nickel ; Rat ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zu verschiedenen Zeiten nach täglicher Zufuhr von Nickelsulfat an Ratten wurden Leber, Niere, Hoden und Herzmuskel auf biochemische und histologische Änderungen untersucht. Während sich in der Initialphase noch keine signifikanten Veränderungen nachweisen ließen, traten nach längerer Exposition deutliche enzymatische und histopathologische Veränderungen in allen vier untersuchten Organen auf. Das Ausmaß der Organläsionen zeigte einen direkten Zusammenhang mit der Behandlungsdauer.
    Notes: Abstract Biochemical and histological alterations in liver, kidney, testis and myocardium of albino rats were investigated at various intervals after daily administration of nickel sulphate. No significant changes were observed during the initial periods of the treatment, but longer exposures produced marked enzymatic and histopathological alterations in all the four organs examined. The severity of the histological lesions was found to be directly related to the duration of the treatment.
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  • 29
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    Archives of toxicology 37 (1977), S. 319-325 
    ISSN: 1432-0738
    Keywords: Sulfhydryls ; Enzymes ; Brain ; Liver ; Testis ; Manganese ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Wirkung von Mangan auf Sulfhydrylgruppen und SH-enthaltende Enzyme in Gehirn, Leber und Hoden von Ratten wurde untersucht. Mangan verminderte den Gehalt an Nicht-Eiweiß-SH und hemmte die Glucose-6-phosphatdehydrogenase sowie die Glutathionreduktase in diesen Geweben. In Gehirn, Leber und Hoden der Mn-behandelten Tiere war der Mn-Gehalt signifikant erhöht.
    Notes: Abstract The effect of manganese on sulfhydryls and sulfhydryl-containing enzymes in brain, liver and testis of rats was investigated. Manganese produced lowering in the contents of non-protein sulfhydryl groups and inhibited the activity of glucose-6-phosphate dehydrogenase and glutathione reductase in these tissues. The contents of the metal increased significantly in brain, liver and testis of manganese administered rats. The significance of these findings is discussed.
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  • 30
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    Archives of toxicology 37 (1977), S. 275-288 
    ISSN: 1432-0738
    Keywords: Carbromal ; Bromoethylbutyramide ; Ethylbutyrylurea ; Rat ; Pharmacokinetics ; Smooth muscle ; Carbromal ; Carbromid ; Äthylbutyrylharnstoff ; Ratte ; Pharmakokinetik ; glatter Muskel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Oral verabreichtes Carbromal und Carbromid wurden bei Ratten in Dosen unter 20 mg/kg rasch aus dem Magen-Darmtrakt aufgenommen, aus dem Dünndarm 5–8mal rascher als aus dem Magen. Die enterale Resorption von Carbromaldosen größer als 20 mg/kg verlief wesentlich langsamer. Dies ist hauptsächlich auf eine verzögerte Magenentleerung zurückzuführen. Sowohl Carbromal als auch Carbromid hemmten in vitro den Tonus und die durch Acetylcholin induzierte Kontraktion glatter Muskeln des Magenfundus. Carbromal und Carbromid fanden sich im Organismus in gleicher Konzentration in Serum, Gehirn und Skelettmuskulatur. Im Fettgewebe wurden dreimal höhere Werte gemessen. Die Konzentrationen beider Stoffe fallen in den untersuchten vier Organen mit der gleichen Geschwindigkeit wieder ab. Es lassen sich daher mit Hilfe der leicht zu messenden Serumkonzentrationen rasch die im Organismus verteilten Mengen beider Substanzen ermitteln. Intraperitoneal injizieŕtes Carbromal und Carbromid verlassen Serum und Gehirn mit einer Halbwertzeit von 3–4 h, Äthylbutyrylharnstoff mit einer Halbwertzeit von 5–7 h. Carbromal, Carbromid und Äthylbutyrylharnstoff werden von der Ratte rasch und nahezu vollständig metabolisiert. In Urin und Kot erschienen nur Spuren dieser Substanzen. Für eine Sekretion von Carbromal und seinen beiden Metaboliten in den Magen ergab sich kein Anhalt. Die Ergebnisse werden im Hinblick auf die akute Carbromalvergiftung beim Menschen diskutiert.
    Notes: Abstract Oral doses up to 20 mg/kg of carbromal and of bromoethylbutyramide were rapidly absorbed in the rat. Absorption from the stomach ligated at the pyloric end was 5–8-fold less than absorption of carbromal injected directly into the small intestine. Oral doses greater than 20 mg/kg of carbromal disappeared more slowly from the gastro-intestinal tract because gastric emptying was delayed. Both carbromal and bromoethylbutyramide were able to reduce the basal tone and the acetylcholine-induced contraction of isolated rat fundus strips. Carbromal and bromoethylbutyramide distributed evenly between serum, brain and skeletal muscle. Concentrations in adipose tissue were three times those in the other three tissues. Concentrations of both carbromal and of bromoethylbutyramide in all four tissues declined at the same rate. Thus, serum concentration of either compound may be used to estimate the total body content. Intraperitoneally injected carbromal, bromoethylbutyramide and ethylbutyrylurea disappeared from the brain and from the serum with a half-life of 3–4 h and 5–7 h, respectively. Traces only of unchanged carbromal, bromoethylbutyramide, or ethylbutyrylurea were excreted with urine or feces indicating rapid and extensive biotransformation of the three compounds in this species. No evidence was obtained of secretion of either carbromal or its two metabolites into the lumen of the stomach. The findings are discussed as to their relevance for acute carbromal poisoning in humans.
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  • 31
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    Archives of toxicology 37 (1977), S. 219-225 
    ISSN: 1432-0738
    Keywords: Inorganic mercury ; Renal enzyme excretion ; Chelating agents ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Wirkung von intravenös verabreichtem HgCl2 auf die renale Ausscheidung von alkalischer Phosphatase (AP) und Leucinaminopeptidase (LAP) wurde an Ratten untersucht. Am ersten Tag nach Hg-Injektion erfolgte ein Anstieg der Enzymausscheidung, der von einem Schwellenwert von 0.44 mg Hg/kg ausgehend eine lineare Abhängigkeit von der Hg-Dosis aufwies. Am zweiten Tag wurde ein statistisch signifikanter Effekt bereits nach 0.25 mg Hg/kg beobachtet. Nach Dosen von 0.75 mg Hg/kg oder mehr fand ein Abfall der Enzymaktivität unter die Kontrollwerte statt, der mehr als 4 Tage anhielt. Behandlung mit 2,3-Dimercaptopropansulfonat (DMPS) bewirkte eine Normalisierung der AP-Ausscheidung. Eine Wirkung auf die LAP-Exkretion wurde nur bei baldiger Verabreichung von DMPS beobachtet. Das gleiche gilt für den Effekt von DMPS auf die Hg-induzierte Letalität. Die Nützlichkeit einer LAP-Bestimmung im Urin zur Abschätzung einer Hg-Inkorporation wird diskutiert.
    Notes: Abstract The effect of intravenous injections of HgCl2 on the renal excretion of alkaline phosphatase (AP) and leucine aminopeptidase (LAP) was investigated in rats. On the first day after Hg enzyme excretion showed a linear rise with the Hg dose from a threshold value of 0.44 mg Hg/kg. On the second day a statistically significant effect was seen already after 0.25 mg Hg/kg. After doses of 0.75 mg/kg or more a decrease of enzyme activity below control values occurred which persisted for more than 4 days. Treatment with 2,3-dimercaptopropansulfonate (DMPS) brought about a normalization of AP excretion. An effect on LAP excretion was observed only with early treatment. The same holds for the effect of DMPS on Hg-induced lethality. The usefulness of a measurement of LAP excretion for estimating the exposure to inorganic mercury is discussed.
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  • 32
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    Archives of toxicology 37 (1977), S. 247-263 
    ISSN: 1432-0738
    Keywords: Lead in blood ; Longterm exposure ; Learning deficit ; Overreaction ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zur Erfassung neuropsychologischer Störungen nach ontogenetisch früher Bleiexposition wurde bei männlichen Wistar-Ratten pränatal über deren Mütter, neonatal über die Muttermilch und postnatal über Bleiazetathaltiges Futter (745 mg Pb/kg Futter) chronisch ein erhöhter Blutbleispiegel (PbB) eingestellt. In der Trächtigkeits-und Säugezeit stieg der PbB-Spiegel der Mütter von 24.2 auf 31.2 μg-% an, während derjenige der Nachkommen im Alter von ca. 16 Tagen 26.6 μg-% und im Alter von ca. 190 Tagen 28.5 μg-% betrug. PbB altersgleicher Kontrollen war stets 〈 6 μg-%. Im Alter zwischen 100 und 200 Tagen wurden 20 Bleitiere und 20 Kontrollen blind verschiedenen Verhaltensprüfungen unterzogen, und zwar einem Open Field-Test und einer visuellen Unterscheidungs-Lernaufgabe. Zwei Lernprobleme unterschiedlicher Schwierigkeit, Richtungs- und Größenunterscheidung, wurden benutzt. Im Open Field-Test waren die Bleitiere im Vergleich mit den Kontrollen signifikant unruhiger: Lokomotorische Aktivität, Aufrichten und Putzverhalten waren gesteigert. Die schwierige Größenunterscheidung erlernten nur die Kontrollen, während das leichte Problem, nämlich die Richtungsunterscheidung, von Kontroll- und Bleitieren gleich schnell erlernt wurde. Die beobachteten Bleiwirkungen, gesteigerte motorische Unruhe und Lernleistungshemmung, lassen sich als Indikatoren einer funktionellen Hirnschädigung deuten. Sie legen den Schluß nahe, daß die „Wirkschwelle” für neuropsychologische Störungen nach ontogenetisch frühzeitiger Bleieinwirkung bei der Ratte als unterhalb 35 μg/100 ml liegend angenommen werden muß.
    Notes: Abstract In order to assess neurobehavioral deficit subsequent to early low-level lead-exposure, Wistar-rats were prenatally Pb-exposed via their mothers, neonatally via their dams' milk, and later on via their diet containing lead acetate (745 mg Pb/kg diet). Blood-lead levels (PbB) of dams increased from 24.2–31.2 μg-% during pregnancy and suckling-periods, those of offsprings were 26.6 μg-% at about 16 days of age and 28.5 μg-% at about 190 days of age. Between 100 and 200 days of age 40 male offsprings were subjected to behavioral testing, namely an open field-test and a visual discrimination-learning task. Two learning-tasks of different complexity, i.e. orientation-and size-discrimination, were used. Data of 20 lead-treated animals were compared with those of 20 age-matched controls. In the open-field test lead-fed animals were significantly more restless than controls; an increase of ambulation, rearing and grooming was observed. In the difficult learning-task, i.e. size discrimination, only the controls did learn the problem, whereas only one of the lead-group did; there was, however, no difference between lead-and control-animals for the easy task, i.e. orientation-discrimination. The observed effects, namely overreaction in the open field and a deficit of visual discrimination learning, may be interpreted in terms of lead-induced CNS-dysfunction. They clearly suggest that the “no-response level” for neurobehavioral damage in the rat, subsequent to early lead-exposure, must be assumed to be lower than 35 μg/100ml.
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  • 33
    ISSN: 1432-1440
    Keywords: Histidin ; Gehirn ; Skelettmuskel ; Leber ; Urämie ; Ratte ; Histidine ; Brain ; Striated muscle ; Liver ; Uremia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Intracellular histidine levels were determined in brain, striated muscle and liver of rats with chronic renal insufficiency (5/6-nephrectomy) and compared both with normal rats and food-restricted (pair-fed) animals. There was no difference in plasma histidine concentration of the three groups whereas in the brain of the uremic rats histidine was significantly increased. Since there existed no alteration of the cerebral histidine in the corresponding pair-fed group, the finding of a raised histidine level in the renal insufficient rats seems to be due to a specific uremic disorder caused by a cerebral disturbance in histidine metabolism.
    Notes: Zusammenfassung Bei chronisch niereninsuffizienten Ratten (5/6-Nephrektomie) wurden die intrazellulären Histidin-Konzentrationen verschiedener Organe (Gehirn, Skelettmuskel und Leber) bestimmt. Als Vergleichsgruppen dienten gesunde Kontroll-Ratten sowie sog. „pair-fed“ Ratten, die entsprechend den niereninsuffizienten Tieren eine verminderte Nahrungsmenge zu sich nahmen. Während sich in den untersuchten Gruppen die Plasma-Histidin-Konzentration nicht unterschied, war Histidin im Gehirn der chronisch niereninsuffizienten Tiere signifikant erhöht. Dieser Konzentrations-Anstieg dürfte als urämie-spezifisch anzusehen sein, da die entsprechend minderernährten Kontrolltiere keine Alteration zeigten. Als Ursache ist in erster Linie eine cerebrale Störung des Histidin-Metabolismus zu diskutieren.
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  • 34
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    Psychopharmacology 51 (1977), S. 279-283 
    ISSN: 1432-2072
    Keywords: Morphine ; Naloxone ; Abstinence signs ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Morphine pellets (75 mg) were implanted subcutaneously in albino rats. Three days later, following 24 h without water, these rats (Group MSN) were given access to a saccharin solution for 30 min, then injected with naloxone hydrochloride. The classical abstinence signs, including “wet dog shakes” and weight loss, were noted in these subjects, but not in controls given placebo pellets and/or saline injections. In addition, when given an opportunity to drink either saccharine solution or water 24 h later, Group MSN rats drank significantly less saccharin than any of the control groups. Similar drinking patterns were found even when naloxone injection was delayed as long as 3 weeks after pellet implantation, when none of the classical abstinence signs were seen and serum levels of morphine and its metabolites were 100 times lower according to radioimmunoassay. This simple and objective technique is thus more sensitive as a measure of prior morphine exposure than any of the commonly used indices. The continued utility of a dependent-nondependent dichotomy is also examined in light of these and other findings.
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  • 35
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    Psychopharmacology 54 (1977), S. 139-143 
    ISSN: 1432-2072
    Keywords: Atropine ; Cholinergic mechanisms ; Learning ; Ontogeny ; Passive avoidance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The maturation of cholinergic inhibitory mechanisms that may be involved in passive-avoidance learning was studied in rats 14, 17, 21, 25, 28, and 34 days of age. Acquisition and extinction of the conditioned response were examined under saline and atropine sulfate (5 mg/kg). Learning was also tested following scopolamine hydrobromide injections (1, 4, 8 mg/kg) in rats 17 days of age and following α-methylatropine (5 mg/kg) in 17-and 34-day-old groups. In normal animals the rate of acquisition increased during ontogenesis, with a significant improvement between postnatal days 17 and 21, whereas the rate of extinction did not vary with age. Acquisition was impaired by atropine sulfate at all ages and even totally prevented in younger groups (14 and 17 days of age). It was also completely disrupted by scopolamine in 17-day-old rats. Extinction following acquisition under atropine was more rapid than after normal acquisition. Methyl-atropine was without effect. These results support the hypothesis of central cholinergic mechanisms involved in response suppression, already functioning in the rat 14 days of age and maturing mainly between the 17th and the 21st postnatal days.
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  • 36
    ISSN: 1432-2072
    Keywords: Rat ; Exploratory behaviour ; Stereotyped behaviour ; Hole-board ; dl-Amphetamine ; Haloperidol ; Apomorphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Exploratory and stereotyped behaviour of Male Wistar rats was studied on a hole-board. The two forms of behaviour were differentiated according to the pattern of hole-dipping activity. Increasing doses of dl-amphetamine stimulated both forms of behaviour with stereotyped behaviour becoming predominant particularly at the higher dose levels. At the highest dose of amphetamine used (16 mg/kg) a gradual transition from exploratory to stereotyped behaviour was observed with time. As the drug wore off this transition was reversed. Haloperidol at a dosage of 0.1 and 0.05 mg/kg blocked the response to a high dose of amphetamine whereas a lower dose (0.02 mg/kg) blocked the stereotyped response to amphetamine while some exploratory behaviour still took place. Apomorphine inhibited hole-dipping but at lower doses another form of exploratory behaviour was induced, this behaviour becoming stereotyped as the dose was increased. It is concluded that there is a close relationship between exploratory and stereotyped behaviours. Monoamine systems appear to play a significant role in the regulation of both forms of behaviour.
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  • 37
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    Naunyn-Schmiedeberg's archives of pharmacology 300 (1977), S. 205-216 
    ISSN: 1432-1912
    Keywords: Chronic ethanol treatment ; Rat ; Behaviour ; Central monoamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats weaned at 16 days of age were treated with various ethanol concentrations (8–24% w/v) for 270 days. The effect of the chronic ethanol treatment on the growth rate, the diurnal pattern of drinking, the open field activity, and the conditioned avoidance acquisition and retention of the rats were studied. Termination of the chronic ethanol administration caused two types of withdrawal syndromes. The first, an acute withdrawal syndrome was observed within 12 h after the discontinuation of the ethanol treatment and was characterized by extreme hyperexcitability. The second, a delayed withdrawal syndrome was characterized by a more coordinated behavioural stimulation and developed first after about 3 days after the discontinuation of the ethanol treatment. Biochemically, the latter withdrawal syndrome was accompanied by an increased rate of tyrosine hydroxylation (measured as the accumulation of dopa after inhibition of aromatic amino acid decarboxylase) in the striatum and dopamine-rich limbic structures. No differences in the accumulation of 5-hydroxytryptophan were observed. Furthermore, there was an increased level of dopamine concomitant with a decreased level of noradrenaline in the limbic areas during ongoing ethanol treatment. On the 4th day after withdrawal of ethanol the endogenous levels of dopamine and noradrenaline were statistically significantly reduced in the limbic structures. The data of the present study indicate that chronic ethanol administration induces various kinds of behavioural changes and that these changes at least partially are mediated via central catecholamine mechanisms.
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  • 38
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    Cell & tissue research 182 (1977), S. 505-511 
    ISSN: 1432-0878
    Keywords: Endothelium ; Cerebral artery ; Filaments ; Rod-shaped inclusion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Endothelia of the anterior cerebral arteries in rats aged 1 to 3 days were studied. Thin (about 50–90 Å) and thick (about 100–110 Å) filaments are present in the endothelia. Numerous spherical- or rod-shaped bodies, measuring approximately 0.07 to 0.3 μm in diameter and up to 0.6 μm in length occur in the endothelial cells. These bodies contain a tubular structure. The diameter of the individual tubules is about 200 Å. The present observations suggest that spherical- or rod-shaped inclusions are first synthesized in the rough endoplasmic reticulum and thereafter these materials are transported into the Golgi complex for maturation. A small number of the inclusions, however, may originate directly from the rough endoplasmic reticulum and not pass through the Golgi apparatus.
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  • 39
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    Cell & tissue research 176 (1977), S. 431-443 
    ISSN: 1432-0878
    Keywords: Cornea ; Rat ; NaK-ATPase ; K-NPPase ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sodium-potassium activated adenosine triphosphatase (NaKATPase) activity of the rat cornea was investigated histochemically using a Pb2+-precipitation technique in which adenosine triphosphate (ATP) is used as substrate and two methods for potassium-dependent para-nitrophenyl-phosphatase (K-NPPase) activity. With all the three techniques used it was demonstrated that the sodium-potassium-activated adenosine triphosphatase (NaK-ATPase) activity is localized in the cell membranes of the endothelium whereas a much weaker activity was observed in the epithelium. When the Pb2+-technique was used, the epithelial cell membranes showed a weaker reaction in the presence of ouabain. This activity was only Mg2+-dependent and was presumably due to an Mg2+-dependent ATPase. The validity of the histochemical techniques for NaK-ATPase activity is discussed. The results emphasize the importance of the endothelium as the main site of Na+ transport in the cornea. Small amounts of the enzyme are also present in the epithelium, which seems to be rich in Mg2+-ATPase. Provided that careful controls are performed, all the methods give consistent results in the cornea.
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  • 40
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    Cell & tissue research 176 (1977), S. 131-142 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Graft ; Ultrastructure ; Innervation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pineal glands were grafted under the kidney capsule of mature male rats for periods of 20, 40, 60 and 100 days. Each grafted gland was then excised and divided into two halves. One half was processed for conventional electron microscopy and the other was fixed in aldehydes and then incubated in a zinc iodide-osmium tetroxide mixture at pH 4.4 (A-ZIO-4.4). During the forty days following the operation pinealocytes showed the typical ultrastructural features associated with cells with a high protein and/or peptide secretory activity. On the other hand, during this period, the number of granular vesicles decreased progressively. From day 40 on, the grafted pinealocytes lacked granular vesicles. During the second half of the experimental period the ultrastructure of the pinealocytes indicated that their secretory activity was considerably decreased. During the acute phase of the experimental period numerous structures regarded as the tip of growing axons as well as typical nerve fibres appeared around blood vessels and within the parenchyma of the grafted gland. In the transplanted tissue obtained 60 and 100 days after the operation the growth cones were scarce, whereas typical nerve endings became numerous. These endings contained small clear vesicles which reacted positively when the tissue was treated with A-ZIO-4.4. The secretory activity of the grafted pineal gland and the nature of the nerve fibres which innervate the graft are discussed. The authors wish to thank Mrs. E.M. Rodríguez de Calderón for her valuable help
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  • 41
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    Cell & tissue research 177 (1977), S. 287-290 
    ISSN: 1432-0878
    Keywords: Liver ; Intralobular nerves ; Rat ; Cobalt and Procion Yellow staining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a recent study (Skaaring and Bierring, 1976) we found cholinesterase positive nerve-like structures in the lobules of rat liver, and scanning electron microscopy revealed cords having a distribution pattern similar to that of the cholinesterase-positive structures. To obtain further evidence for an intralobular nerve supply the methods of cobalt and Procion Yellow nerve staining (Stretton and Kravitz, 1968; Iles and Mulloney, 1971; Pitman, Tweedle and Cohen, 1972) were adapted, iontophoretic introduction of the dyes being attempted through cut axonal ends in the surface of small excised blocks of rat liver.
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  • 42
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    Cell & tissue research 177 (1977), S. 159-180 
    ISSN: 1432-0878
    Keywords: Muscle transplantation ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat soleus muscles were autografted from right to left legs, and regeneration following necrosis of all original myofibres was studied after 7 to 250 days. The best regenerates were from grafts replacing all calf muscles and sutured to the tendon stumps. After 30 days the size of such regenerates was equal to those from minced gastrocnemius muscles: the cross sectional area of muscle tissue was 30% (1.7 mm2) and the number of fibres was 180% (4500) of normal soleus muscles; the fibre diameters were 10 to 40 μm. To increase the number of myoblasts before grafting some muscles were injured by Ringer solution of 70° C and transplanted after 2 days. Nevertheless, this did not influence regeneration. After 7 days clusters of myotubes occurred in the periphery of the muscle. These myotubes originated from myoblasts growing like endothelial cells on the inner face of the persisting basal lamina tubes of necrotic fibres. After 30 days the muscles were vascularized. Fibres formed in a common basal lamina detached and so looked “split”. Satellite cells of new fibres came from undifferentiated cells associated with myotubes, i.e. from myoblasts. After 30 days and more regenerates contained three sorts of fibres. 1. Thin (5 to 20 μm) fibres resembling fetal muscle fibres. They were most prominent after 30 days, and probably not yet innervated. 2. Thin (10 μm) degenerating fibres as in long-time denervated muscles. 3. Thick (more than 30 μm) mature looking fibres which were innervated and revealed end-plates. Half of the grafts studied after 30 and 60 days contained unmyelinated and myelinated axons which had grown along strands of surviving Schwann cells. After 250 days, only two muscles were studied which both lacked innervation. Almost all regenerates contained muscle spindles, which, however, were not innervated. Within the persisting spindle capsules new muscle fibres had been formed from satellite cells of the former intrafusal fibres.
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  • 43
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    Cell & tissue research 178 (1977), S. 73-82 
    ISSN: 1432-0878
    Keywords: Atrioventricular node ; Rat ; Innervation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The problem of development of the innervation of the rat atrioventricular node has been investigated by electron microscopy. Nerve bundles appear in relation to the node as early as the second postnatal day and vesiculated axons are seen throughout the entire node by the fourth day. Intimate contacts between nodal cells, axons and terminal varicosities are frequently observed. Use of the 5-hydroxydopamine tracer technique has enabled the identification of both cholinergic and adrenergic axons. It is concluded that the node has a dual innervation although cholinergic endings far outnumber those classified as adrenergic on the sixth postnatal day. These results are quite different to earlier findings made at the light microscope level and the discrepancies are discussed with respect to the histochemical techniques used. The suggestion that nodal differentiation is induced by nerves is considered in relation to the differences in cholinesterase activity exhibited by nodal cells during normal development and following neonatal sympathectomy.
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  • 44
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    Cell & tissue research 178 (1977), S. 143-153 
    ISSN: 1432-0878
    Keywords: Median eminence ; Tanycytes ; Gonadal function ; Rat ; Japanese quail
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ependymal linings of the median eminence were destroyed by electric cautery or intraventricular injection of picric acid in the rat and Japanese quail. In these animals the ventricular lumen near the median eminence disappeared due to adhesion of lesioned walls on both sides of the third ventricle. Electric lesions of the ependymal layer containing tanycytes did not induce appreciable disturbance in the estrous cycles. Rats in which tanycytes were lesioned by picric acid displayed 4-day estrous cycles after prolonged diestrus (10–22 days). After destruction of tanycytes in the quail, a photostimulated gonadal growth was observed. It is concluded that the tanycyte transport of the ventricular fluid to capillaries of the portal vessels appears unnecessary for maintenance of adenohypophysial gonadotrophic activities.
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  • 45
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    Cell & tissue research 182 (1977), S. 193-204 
    ISSN: 1432-0878
    Keywords: Glucagon ; Exocrine pancreas ; Secretory process ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Glucagon was infused into conscious rats in doses of 10 to 80 μg/h for periods up to 24 h. The effect on the secretory process of the exocrine pancreas was studied in vitro using isolated pancreatic lobules. A pronounced inhibition of the rate of protein synthesis and discharge of stored and newly synthesized proteins combined with increased enzyme content in the pancreas were observed after 30 min infusion. This effect was absent after longer infusion periods of up to six hours. After 12 to 24 h infusions a marked degranulation and decrease in enzyme content was observed. While the rate of protein synthesis was not significantly enhanced, both the basal and stimulated discharge of enzymes from the pancreas were increased. The results suggest a biphasic response of the pancreas to prolonged glucagon infusion.
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  • 46
    ISSN: 1432-0878
    Keywords: Paraventricular nucleus ; Rat ; Types of neurons ; Secretory cycle ; Herring body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the neurosecretory cells in the paraventricular nucleus of the normal male rat was studied by electron microscopy during various functional states. Four morphologically distinct types of neurosecretory cells were observed. It appears that they do not represent different classes of cells but different phases of secretory activity of a single cell type. The perikarya of the neurosecretory cells show a definite cycle of formation and transportation of secretory granules. We have designated the phases of this cycle as: (1) phase of synthesis, (2) phase of granule production, (3) phase of granule storage and (4) phase of granule transport. The neurosecretory granules appear to be moved in bulk into the axons, forming a large axonal swelling filled with granules as a result of one cycle in the neurosecretory process. Thus it may be postulated that a secretory cycle in the perikaryon of the neurosecretory cell seems to result in the formation of a Herring body in its axon, and that its content is then conveyed to the posterior pituitary.
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  • 47
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    Langenbeck's archives of surgery 344 (1977), S. 207-217 
    ISSN: 1435-2451
    Keywords: Gastroenterostomy ; Duodenal reflux ; Epithelial lesions ; Nitrosoguanidine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Einfluß des chronischen duodenogastrischen Refluxes auf die Magenschleimhaut des nicht resezierten Magens wurde im Hinblick auf die Disposition der gastroenteralen Anastomose für die Krebsentstehung tierexperimentell an männlichen Wistarratten untersucht. Hierzu wurden Tiere mit einer Gastroenterostomie ohne Enteroanastomose und Tiere, bei denen ein Reflux durch eine Y-Gastroenterostomie nach Roux ausgeschlossen war, mit einer zeitlich unterschwelligen Cancerogendosis (Nitrosoguanidin) exponiert. Es wird gezeigt, daß auch unabhängig von der Cancerogenexposition ein chronischer duodenogastrischer Reflux zu adenomartigen Drüsenproliferationen mit z. T. atypischen Epithelregeneraten an der Anastomose führt, die durch eine Gastroenterostomie nach Roux verhindert werden können. Anastomosencarcinome, wie in früheren Untersuchungen am resezierten Magen bei sonst gleichen Versuchsbedingungen beschrieben, konnten nicht induziert werden. Somit spielen für die Krebsentstehung an der gastroenteralen Anastomose neben dem Reflux auch die durch die Magenresektion selbst hervorgerufenen Veränderungen eine nicht unwesentlilche Rolle.
    Notes: Summary The cancerogenic effect of continous duodenal reflux on the gastric mucosa has been investigated in male Wistar-rats after gastrointestinal anastomosis. Groups of animals with gastroenterostomy without enteroenteral anastomosis and with Roux-en-y-anastomosis preventing duodenal reflux were treated with lower dosages of the cancerogenic Nitrosoguanidine. Proliferative mucosal alterations near the gastroenteral anastomosis were observed. In addition the gastric mucosa was characterized by adenomatous lesions caused by duodenal reflux. The changes detected were not influenced by Nitrosoguanidine and did not appear in cases of Roux-en-y-anastomosis.
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  • 48
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    Langenbeck's archives of surgery 344 (1977), S. 71-82 
    ISSN: 1435-2451
    Keywords: Cancer risk ; Resected stomach ; Rat ; Duodenogastric reflux ; N-methyl-N′-nitro-N-nitrosoguanidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde die Frage geprüft, ob obligater duodenogastrischer Reflux unter Langzeitbedingungen das Wachstum von Carcinomen oder Sarkomen im resezierten Magen beeinflußt. 72 männliche Wistarratten wurden einer Magenresektion unterworfen. Die erforderliche Gastroenteroanastomose wurde bei 39 Tieren als short loop GE (Billroth II) mit obligatem Reflux von Galle und Duodenalsekret in den Restmagen angelegt. Die restlichen 33 Tiere erhielten eine Y-förmige GE (nach Roux) mit seitlicher Einmündung des Duodenum in den Dünndarm; Reflux von Galle in den resezierten Magen war dadurch unmöglich. Die Carcinominduktion erfolgte durch kontinuierliche Gabe von N-Methyl-N'-Nitro-N-Nitrosoguanidin im Trinkwasser. Bei der Sektion der Tiere mit Reflux 33 Wochen nach Carcinogengabe fand sich die Mehrzahl der malignen Tumore von Magenstumpf, Anastomose (GE) und angrenzendem Dünndarm in der Tiergruppe mit obligatem Reflux (13 von 22). Die Tiergruppe ohne Reflux (Y-Roux GE) wies demgegenüber signifikant weniger Carcinome auf (7 von 21); die Tumorincidenz dieser Gruppe entsprach derjenigen eines nicht operierten Kontrollkollektives (5 von 22). - Die Ergebnisse unserer Untersuchungen zeigen, daß die in der Technik des short loop durchgeführte Gastroenteroanastomose des Billroth 11-Magens das Krebswachstum im Anastomosengebiet in besonders ausgeprägtem Maße fördert. Ausschlaggebend für die gesteigerte Carcinominduktion ist der chronische Reflux von Galle und Duodenalsekret, der bei der short loop-GE obligat über den Magnrest fließt.
    Notes: Summary The purpose of this study was to find whether the reflux of bile and pancreatic juices following stomach resection (duodenogastric reflux) enhances the incidence of carcinomas near the gastroenteric anastomosis. 72 male Wistar rats were subjected to stomach resection. The gastroenteric anastomosis (GE) was performed either as short loop anastomosis (Billroth II;n = 39), thus providing a continuous duodenogastric reflux, or as Y-shaped GE (according to Roux;n = 33). By the latter technique, bile and pancreatic juices are derived quantitatively into the jejunum without coming into contact with the remaining part of the stomach. During a period of 33 weeks, operated rats as well as intact animals were given the carcinogen N-methyl-N′-nitro-N-nitrosoguanidine (NG; 120 mg/1) in the drinking water. At autopsy, 33 to 36 weeks after daily oral administration of NG, most of the tumours were found in operated rats undergoing continuous ref lux (Billroth II group). In contrast to these findings, the incidence of carcinomas was significantly lower in animals without reflux (Roux group or intact control rats).-The results of our experiments demonstrate that, in rats, the duodenogastric reflux contributes substantially to the development of carcinomas of the resected stomach.
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  • 49
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    Langenbeck's archives of surgery 344 (1977), S. 109-114 
    ISSN: 1435-2451
    Keywords: Gastric carcinoma ; Gastroenterostomy ; Bacterial flora ; Nitrit ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Anlage einer Gastroenterostomie ohne Enteroanastomose führt zu einer Veränderung der bakteriellen Magenbesiedlung, wobei besonders der Anteil nitritspaltender Bakterien erhöht ist. Dies hat ein Ansteigen der Nitrit-Konzentration im Magensaft zur Folge. Die hierdurch mögliche vermehrte Bildung carcinogener Nitrosamine wird im Hinblick auf das Entstehen eines Carcinoms im operierten Magen diskutiert. Da die beschriebenen Veränderungen durch eine Gastroenterostomie nach Roux weitgehend verhindert werden, soll dies bei der Passagewiederherstellung nach Operation am Magen berücksichtigt werden.
    Notes: Summary A gastroenterostomy without enteroanastomosis leads to a change in the bacterial flora of the stomach, where-by in particular the proportion of nitrite-decomposing bacteria, is enhanced. This results in an increase of nitrite concentration in the gastric fluid, which may possibly be accompanied by an augmented production of carcinogenic nitrosoamine. This latter aspect is considered with respect to the origin of carcinoma in the operated stomach. Since the reported changes will be largely prevented by a Roux-Y-gastroenterostomy, this should be taken into consideration for reconstruction of the alimentary tract after gastric surgery.
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  • 50
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1-11 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation of Succinimide During the Synthesis of the Insulin A Chain(14-21) OctapeptideDuring the synthesis of insulin A chain (14-21) fragments it was observed that alkaline treatment of Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut and Msc-Tyr-(But)-Gln-Leu-Glu(OBut)Asn-Tyr(But)-Cys(Trt)-Asn-OBut caused quantitative formation of succinimide in position 21.
    Notes: Bei der Synthese von Teilsequenzen der Insulin-A-Kette (14-21) wurde während der alkalischen Abspaltung der Msc-Gruppe von Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys-(Trt)-Asn-OBut und Msc-Tyr-(But)-Gln-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut in allen Fällen Succinimidbildung in Position 21 beobachtet.
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  • 51
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 37-48 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, IX. On the Reaction of Amide Acetals with HeterocumulenesDeprotonation of the (dimethylamino)methoxycarbenium ion (10) by NaH liberated the carbene 2, which was trapped by aryl isocyanate to give the hydantoin 6 and by phenyl isothiocyanate to yield 8. Hence, the carbene 2 is assumed to be also an intermediate in the corresponding reactions of the amide acetal 1 which lead to the hydantoins 6 and 8. The reaction of 1 with phenyl isothiocyanate yielded the products 4, 7, 8, or 12 depending on the reaction conditions. An equilibrium between 1 and the carbene 2 is suggested by the reaction of 1 with sulfur to give 16, and is the basis for mechanistic discussions.
    Notes: Das durch Deprotonierung des (Dimethylamino)methoxy-carbenium-Ions (10) mit NaH freigesetzte Carben 2 addierte sich an-Arylisocyanat zum Hydantoin 6, an Phenylisothiocyanat zu 8. Dies legt nahe, daß auch bei der Umsetzung des Amidacetals 1 mit Heterocumulenen zu den Hydantoinen 6 bzw. 8 das Carben 2 beteiligt ist. Bei der Umsetzung von 1 mit Phenylisothiocyanat entstanden je nach Reaktionsführung die Produkte 4, 7, 8 oder 12. Für deren Bildung werden Mechanismen diskutiert, die von einer Gleichgewichtseinstellung von 1 mit dem Carben 2 ausgehen. Diese Annahme wird durch Umsetzung von 1 mit Schwefel zu 16 gestützt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 67-77 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Perhalomethylthio)heterocycles, VIII. (Perchlorofluoromethylthio)- and (Haloformylthio)-N-heteroaromaticsPyrrole reacts with Cl3-nFnC—SCl (n = 1-3) to give mixtures of 2- and 3-substituted pyrroles 1 a-c and 2a, b; CF3SCFCl—SCl and XC(O)SCl (X = F, Cl) merely yield 2-substituted derivatives 3. In the presence of excess CF3SCl also disubstituted products 4, 5 are available. Analogously pyrrole derivatives can be substituted directly, dependent on their reactivity (6-14). 1a is oxidized by 3-chloroperbenzoic acid to yield the sulfoxide 15 or the sulfone 16; the reaction with bromine and iodine results in the formation of the fully halogenated compounds 17, 18. Indole reacts with CF3SCl to give the 3-substituted 19, while carbazole yields the N-substituted product 20 in a Grignard reaction. 1H and 19F n. m. r. spectra are discussed.
    Notes: Pyrrol setzt sich mit Cl3-nFnC—SCl (n = 1-3) zu Isomerengemischen 2- und 3-substituierter Pyrrole 1a-c bzw. 2a, b, um; CF3SCFCl—SCl und XC(O)SCl (X = F, Cl) liefern lediglich 2-substituierte Derivate 3. In Gegenwart eines CF3SCl-Überschusses sind auch disubstituierte Produkte 4, 5 erhältlich. Analog sind Pyrrol-Derivate, je nach ihrer Reaktivität, einer direkten Substitution zugänglich (6-14). 1 a wird durch 3-Chlorperbenzoesäure zum Sulfoxid 15 bzw. Sulfon 16 oxidiert; die Umsetzung mit Brom bzw. Iod führt zu den vollständig halogenierten Verbindungen 17, 18. Indol reagiert mit CF3SCl zum 3-substituierten 19, während Carbazol in einer Grignard-Reaktion das N-Substitutionsprodukt 20 liefert. 1H- und 19F-NMR-Spektren werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 96-106 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Aldehydes and Ketones with the Makosza Dichlorocarbene ReagentPhase transfer-catalyzed reactions of aldehydes and ketones with trichloromethane and 50 per cent aqueous sodium hydroxide in the presence of benzyltriethylammonium chloride (BTEA) at low temperatures result in the formation of α-(trichloromethyl)carbinols 7; in the presence of dimethyl sulfate the corresponding methyl ethers 8 are obtained. At 56 ± 2°C the α-hydroxy-11, α-chloro- 12 and α,β-unsaturated carboxylic acids 13 are formed. In this reaction the α-(trichloromethyl)carbinols 7 can be excluded as intermediates. An alternative reaction mechanism for the formation of 11, 12, and 13 is discussed, which involves direct addition of dichlorocarbene to the C=O double bond to form the dichlorooxiranes 5 followed by rearrangement and saponification.
    Notes: Aldehyde und Ketone reagieren mit Trichlormethan im Zweiphasensystem mit 50proz. wäßrigem Natriumhydroxid unter Phasentransfer-Katalyse durch Benzyltriethylammonium-chlorid (BTEA) (1) bei tiefer Temperatur zu α-(Trichlormethyl)carbinolen 7, in Gegenwart von Dimethylsulfat zu den entsprechenden Methylethern 8. Bei 56 ± 2°C entstehen α-Hydroxy- 11, α-Chlor- 12 und α,β-ungesättigte Carbonsäuren 13, wobei die α-(Trichlormethyl)carbinole 7 als Zwischen-stufen auszuschließen sind. Als Alternativmechanismus wird die direkte Addition von Dichlor-carben an die C=O-Doppelbindung zu Dichloroxiranen 5 und deren Umlagerung und Verseifung diskutiert.
    Additional Material: 2 Tab.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 23-36 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, VIII. Selectivity of Nucleophilic Carbenes with Regard to HeterocumulenesThe selectivities of N-methylbenzothiazolinylidene (2) and 1,3-diphenylimidazolidinylidene (3) against aryl isocyanates and phenyl isothiocyanate have been determined. The selectivities increase from dimethoxycarbene (1) over 2 to 3. In contrast all three carbenes display equal selectivity with regard to different aryl isocyanates.
    Notes: Für N-Methylbenzothiazolinyliden (2) und 1,3-Diphenylimidazolidinyliden (3) wurden die Selektivitäten gegenüber verschiedenen Arylisocyanaten einerseits und Phenylisothiocyanat andererseits bestimmt. Diese nehmen vom Dimethoxycarben (1) über 2 zu 3 zu. Dagegen zeigen alle drei Carbene bei 140°C eine übereinstimmende Selektivität gegenüber Arylisocyanaten.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 12-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Metabolites of Microorganisms, XII. Michigazone, a New Phenoxazone Pigment from Streptomyces michiganensis  -  Structure Determination and SynthesisBy spectroscopic methods and chemical degradation michigazone has been shown to possess structure 7. 7 and some further related phenoxazones have been synthesized by the Kehrmann-method.
    Notes: Spektroskopische Untersuchungen und chemischer Abbau führten für Michigazon zur Konstitution 7. 7 und einige weitere bisher noch nicht beschriebene Phenoxazone wurden durch Kehrmann-Synthese dargestellt.
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 49-52 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, X. Ionic Intermediates in the Reaction of Trimethyl Orthoformate with Aryl IsocyanatesThe ion pair 2/3 is assumed to be the crucial intermediate in the reaction of trimethyl orthoformate with aryl isocyanates. The collapse of the ion pair to 4 is a fast subsequent reaction. The acid base reaction of the ion pair to the carbene 6 proceeds with a comparable rate. Methoxyl transfer of 2/3 to form 1 is considerably slower. Transalkylation of the ion pair to 8 has not been observed.
    Notes: Bei der Umsetzung von Orthoameisensäure-trimethylester mit Phenylisocyanat wird das Ionen-paar 2/3 als zentrale Zwischenstufe angenommen. Eine rasche Folgereaktion dieses Ionenpaares ist die Kombination zu 4. Vergleichbar schnell verläuft die Säure-Basen-Reaktion im Ionenpaar zum Carben 6. Eine Methoxyl-Übertragung aus 2/3 zu 1 ist erheblich langsamer. Die Umalkylierung zu 8 konnte nicht beobachtet werden.
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  • 58
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 86-95 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Activated Ethylenes, V. Reaction of Aromatic Compounds with Derivatives of Chloromethylenemalonic Acid. A new Synthesis of Aromatic AldehydesThe derivatives of chloromethylenemalonic acid 3 and 4 react with aromatic compounds in the presence of aluminium chloride to give the arylmethylenemalonic acid derivatives 5a-i and 6a-d. By hydrolysis of the C=C double bond the corresponding dinitriles 2a-g are converted into aldehydes.
    Notes: Chlormethylenmalonsäure-Derivate 3 und 4 lassen sich in Gegenwart von Aluminiumchlorid mit Aromaten umsetzen, wobei die Arylmethylenmalonsäure-Derivate 5a-i und 6a-d entstehen. Die entsprechenden Dinitrile 2a-g lassen sich durch Hydrolyse der C=C-Doppelbindung in Aldehyde überführen.
    Additional Material: 8 Tab.
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  • 59
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 107-123 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry of the Norcaradiene-Norcaradiene Rearrangement, I. The Synthesis of Optically Active [Norcaradiene ⇌ Cycloheptatriene] DerivativesAnion 14 derived from treatment of 1,3,5-cycloheptatriene-7-carbonitrile (13) with n-butyllithium or lithium diisopropyl reacts with methyl iodide, deuterium oxide, and carbon dioxide to give the corresponding 7,7-disubstituted derivatives 2, 13-D, and 16. By a sequence of reactions 2 was transformed into the optically pure [norcaradiene ⇌ cycloheptatriene] systems 4 and 10. The equilibrium concentrations of the [norcaradiene ⇌ cycloheptatriene] systems 2-12 were determined by 1H n.m.r. mesurements at low temperatures.
    Notes: Das aus 1,3,5-Cycloheptatrien-7-carbonitril (13) mit n-Butyllithium oder Lithium-diisopropylamid erzeugte Anion 14 reagiert mit Methyliodid, Deuteriumoxid und Kohlendioxid ausschließlich zu den entsprechenden 7,7-disubstituierten Derivaten 2, 13-D, und 16. Aus 2 lassen sich durch eine Folge von Reaktionen die optisch reinen [Norcaradien ⇌ Cycloheptatrien]-Systeme 4 und 10 synthetisieren. Mit Hilfe der Tieftemperatur-1H-NMR-Spektroskopie wurden die Gleichgewichtskonzentrationen der [Norcaradien ⇌ Cycloheptatrien]-Systeme 2-12 ermittelt.
    Additional Material: 3 Ill.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 146-153 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 4-Acetoxy-2-cyclopenten-1-oneBy using 4-acetoxy-2-cyclopenten-1-one (8) as a synthone for the non-existent cyclopentadienone (5), Michael additions are performed that give rise to trans-disubstituted cyclopentanone derivatives (11,12). In the case of tert-butyl acetoacetate as Michael donator the addition to 11 is followed by an aldol-cyclisation to the trans-perhydroazulene system 22.
    Notes: Unter Verwendung von 4-Acetoxy-2-cyclopenten-1-on (8) als Synthon für das nicht existenzfähige Cyclopentadienon (5) wurden Michael-Additionen durchgeführt, die zu trans-disubstituierten Cyclopentanon-Derivaten (11, 12) führen. Bei Verwendung von tert-Butyl-acetacetat als Michael-Donator schließt sich an die Addition zu 11 eine Aldolcyclisierung zum trans-Perhydroazulensystem 22 an.
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  • 61
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 605-610 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 3,3-Bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. Trapping Reactions of Nitrile Ylides with NitrosobenzeneTrapping reactions of bis(trifluoromethyl)-substituted nitrile ylides 2, generated by thermolysis of 3,3-bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. 1, with nitrosobenzene yield 5,5-bis-(trifluoromethyl)-Δ3-1,2,4-oxadiazolines 3, 3,3-bis(trifluoromethyl)-Δ4-1,2,4-oxadiazolines 4, and 4,4-bis(trifluoromethyl)-1,4-dihydro-1-quinazolinols 5. The compounds 5 are products of a thermal rearrangement of first formed [3 + 2]-cycloadducts. I. r., 1H n. m. r., 19F n. m. r., and mass spectra of the new compounds are described.
    Notes: Abfangreaktionen von bis(trifluormethyl)-substituierten Nitril-yliden 2, die durch Thermolyse aus 3,3-Bis(trifluormethyl)-Δ4-1,4,2λ5-oxazaphospholinen 1 erzeugt werden, mit Nitrosobenzol liefern 5,5-Bis(trifluormethyl)-Δ3-1,2,4-oxadiazoline 3, 3,3-Bis(trifluormethyl)-Δ4-1,2,4-oxadiazoline 4 und 4,4-Bis(trifluormethyl)-1,4-dihydro-1-chinazolinole 5. Die Verbindungen 5 sind das Resultat einer thermisch ausgelösten Umlagerung primär erhaltener [3 + 2]-Cycloaddukte. IR-, 1H-NMR-, 19F-NMR- und Massenspektren der neuen Verbindungen werden beschrieben.
    Additional Material: 4 Tab.
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  • 62
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 619-630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXIV. Benzo[12]annulenes: On the Annulene Character of Dibenzo- and Tribenzo[12]annulenesAs a contribution to the controversial discussion about the antiaromaticity of the [12]annulene system in the di- and tribenzo[12]annulenes 3 and 4 the compounds 5, 8, and 18 were prepared for comparison. The discussion of the 1H n. m. r. spectra with consideration of the anisotropy effect of the triple bonds led to the conclusion that in contrast to earlier assumptions the [12]annulene system in 3 and 4 in spite of the benzo-anellation is paratropic.
    Notes: Als Beitrag zu der kontroversen Diskussion über die Antiaromatizität des [12]Annulen-Systems in den Di- und Tribenzo[12]annulenen 3 und 4 wurden die Vergleichsverbindungen 5, 8 und 18 dargestellt. Die Diskussion der 1H-NMR-Spektren unter Berücksichtigung des Anisotropieeffektes der Dreifachbindungen ergab, daß entgegen früherer Auffassung das [12]Annulen-System in 3 und 4 trotz der Benzo-Anellierung paratrop ist.
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  • 63
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 631-637 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXV. Benzo[12]annulenes: Synthesis and Properties of a Benzo-naphtho[12]annuleneThe benzo-naphtho[12]annulene 4, where in contrast to 1, 2, and 3 a planar twelve-membered ring is present, has been synthesized via 6-9. 1H n. m. r. absorption of the internal hydrogen is observed at δ = 13.13 ppm. The allotment of this considerable down-field shift to the paratropic effect of the annulene system and the anisotropy of the triple bonds is discussed. For this purpose, the twelve-ring system 5 in which the macrocyclic conjugation is interrupted has been synthesized from 9 via 10 and 11.
    Notes: Das Benzo-naphtho[12]annulen 4, bei dem im Gegensatz zu den Verbindungen 1, 2 und 3 eine ebene Zwölfring-Struktur fixiert ist, wurde über 6-9 synthetisiert. Die 1H-NMR-Absorption des inneren Wasserstoffatoms wird bei δ = 13.13 ppm beobachtet. Die Aufteilung dieser beträchtlichen Tieffeld-Verschiebung in den Paratropie-Effekt des Annulen-Systems und den Anisotropie-Effekt der Dreifachbindungen wird diskutiert. Hierzu wurde das Zwölfring-System 5, bei dem die makrocyclische Konjugation unterbrochen ist, von 9 über 10 und 11 synthetisiert.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 651-655 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XV. Reactions of trans,trans-1,3-Diphenyl-2-azaallyllithium with Heterocumulenestrans,trans-1,3-Diphenyl-2-azaallyllithium (1) reacts with phenylisocyanate, phenylisothiocyanate, and methylisothiocyanate to give an imidazolidine-4-one (2a) or imidazolidine-4-thione (2b, c), respectively. When reacting with carbon disulfide or dicyclohexylcarbodiimide (symmetrical heterocumulenes) the cycloaddition is followed by a fast secondary reaction (→ 4, 7).
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich regiospezifisch an die CN-Doppel-bindung des Phenylisocyanats sowie Phenyl- und Methylisothiocyanats unter Bildung eines Imidazolidin-4-ons (2a) bzw. -4-thions (2b, c). Bei entsprechenden Umsetzungen mit den symmetrischen Heterokumulenen Schwefelkohlenstoff und Dicyclohexylcarbodiimid folgt der Cycloaddition jeweils eine schnelle Sekundärreaktion (→4, 7).
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 667-676 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of trans-[Pt(CO2R)(CO)(PPh3)2]+BF4- with Alkynes: Formation of Alkynyl- and Alkenylplatinum(II) ComplexesThe alkoxycarbonyl complexes [Pt(CO2R)(CO)(PPh3)2]+ BF4- 1 react with alkynes HC≡CR to give the acetylides 2a-c. On the other hand, cationic β-methoxyvinyl 3 or β-hydroxyvinyl complexes 4, respectively, are obtained from the reactions of 1 with disubstituted acetylenes R1C≡CR2 under participation of the nucleophiles methanol and water. Compounds 3 and 4 are converted into neutral derivatives (5, 6, 8) by methoxide or azide ions. The synthesis of Ir(CO2CH3)(CO)(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 is described. Bonding is discussed for the new complexes by means of n. m. r. and i. r. data.
    Notes: Die Alkoxycarbonyl-Komplexe [Pt(CO2R)(CO)(PPh3)2]+BF4- 1 setzen sich mit Alkinen HC ≡ CR zu den Acetyliden 2a-c um. Dagegen entstehen aus 1 und disubstituierten Acetylenen R1C≡CR2 unter Beteiligung der Nucleophile Methanol und Wasser kationische β-Methoxyvinyl- 3, bzw. β-Hydroxyvinyl-Komplexe 4. Die Verbindungen 3 und 4 werden mit Methylat- oder Azid-Ionen in neutrale Derivate (5, 6, 8) umgewandelt. Ferner wird die Synthese von Ir(CO2CH3)(CO)-(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 beschrieben. Die Bindungsverhältnisse werden mit Hilfe von NMR- und IR-Daten diskutiert.
    Additional Material: 3 Tab.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 703-716 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Bridged 5,6-Diamino-4,7-dialkyl-1,3-benzodioxoles as Intermediates for the Synthesis of Molecules with Knot StructureIn a reaction sequence involving metalation with butyllithium followed by alkylation. cyclohexanone pyrocatechol acetal 4 is converted to the 3,6-dialkylpyrocatechol 11. By subsequent acetalisation with 1,25-dichloro-13-pentacosanone (14), followed by nitration (19), reduction (20), acylation (26), renewed reduction (27), and cyclization, the double bridged benzodioxole 28 is obtained. The compound represents an intermediate in the projected synthesis of a molecule with knot structure.
    Notes: Ausgehend vom Cyclohexanon-brenzcatechinacetal 4 wird durch Metallierung mit Butyllithium und nachfolgende Alkylierung in einer mehrstufigen Reaktionsfolge das 3,6-Dialkylbrenzcatechin 11 synthetisiert. Durch nachfolgende Acetalisierung mit 1,25-Dichlor-13-pentacosanon (14), gefolgt von Nitrierung (19), Reduktion (20), Acylierung (26), erneuter Reduktion (27) und Cyclisierung wird das zweifach überbrückte Benzodioxol 28 erhalten. Es stellt ein Zwischenprodukt in der geplanten Synthese eines Moleküls mit Knotenstruktur dar.
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  • 67
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 463-467 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XIV Sulfinato-O,S Complexes of Palladium(II) and Rhodium(III)The directed preparation of the sulfinato-O,S complexes {R(O)OS}nM (2a, b; 5a, b) was successful for the first time by elimination of coordinated water from the sulfinato-S complexes {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] by 2,2-dimethoxypropane. The O,S-linkage is unequivocally shown from their chemical behaviour and the i. r. spectra. The criteria necessary for the formation of sulfinato-O,S complexes are discussed.
    Notes: Durch Abspaltung von koordiniertem Wasser aus den Sulfinato-S-Komplexen {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] mit 2,2-Dimethoxypropan gelang erstmals die gezielte Darstellung der Sulfinato-O,S-Komplexe {R(O)OS}nM (2a, b; 5a, b). Die O,S-Verknüpfung ergibt sich eindeutig aus dem chemischen Verhalten und den IR-Spektren. Die für die Bildung von Sulfinato-O,S-Komplexen notwendigen Kriterien werden diskutiert.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 474-486 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 78 Further Constituents of South African Senecio SpeciesFrom representatives of the section Rigidi besides already known compounds four new benzofurans (3, 5, 6, and 10) as well as six new furanoeremophilanes (13, 15, 19-21, and 23) are isolated. From Senecio pterophorus a new type of a pyrrolizidine derivative (25) is isolated. Senecio cissampelinus contains similar compounds (34-37). The structures are elucidated by spectroscopic methods as well as by some chemical reactions. The chemotaxonomical aspects are discussed.
    Notes: Aus Vertretern der Sektion Rigidi werden neben bereits bekannten Verbindungen vier neue Benzofurane (3, 5, 6 und 10) sowie sechs neue Furanoeremophilane (13, 15, 19-21 und 23) isoliert. Aus Senecio pterophorus wird ein neuer Typ eines Pyrrolizidin-Derivats (25) isoliert. Ähnliche Verbindungen (34-37) enthält Senecio cissampelinus. Die Konstitutionen werden durch spektroskopische Methoden sowie durch einige chemische Reaktionen geklärt. Die chemotaxonomischen Aspekte werden diskutiert.
    Additional Material: 6 Tab.
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  • 69
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 491-499 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Monohydrazones of Dicarbonyl Compounds, IV. New Syntheses of Pyrroles and PyrrolinesKetones and aldehydes with an active methylene group condense easily with monohydrazones of glyoxal (1 + 2 → 3). The hydrazonoethylidene derivatives thus obtained can be reduced to give pyrroles, pyrrolines, pyrrolidines, or N-aminopyrroles.
    Notes: Methylenaktive Ketone und Aldehyde lassen sich mit Monohydrazonen des Glyoxals zu Hydrazonoethyliden-Derivaten umsetzen (1 + 2 → 3). Durch Reduktion dieser Produkte sind Pyrrole, Pyrroline, Pyrrolidine sowie N-Aminopyrrole darstellbar.
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  • 70
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 522-539 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 78. Additions of C-(2,2′-Biphenylylene)-Nα-(4-chlorophenyl)-Nβ-cyano-azomethine Imine to Styrene, Alkenes, Enol Ethers and EnaminesThe cycloaddition of the title compound 1 to styrene at 70°C produces 95% of a pyrazolidine; the hydrogenolytic degradation to 9-phenethylfluorene as well as the n. m. r. spectrum reveal the addition direction. The 1-cyanopyrazolidine derivative shows reactions typical for cyanamides. - The azomethine imine 1 likewise accepts many nonconjugated alkenes, cycloalkenes and derivatives of styrene in high yield. The cycloadducts of butyl vinyl ether, cis- and trans-propenyl propyl ether, β-methoxystyrene and vinyl acetate suffer with dilute acids elimination of alkoxide or acetate, respectively, and of the N-cyano group to yield 2-pyrazolines. The electrophilicity of the azomethine imine carbon center determines the addition direction; substituents on the ethylenic dipolarophile which stabilize positive charge in the transition state of cycloaddition show up in position 5 of the pyrazolidine.
    Notes: Die Cycloaddition der Titelverbindung 1 an Styrol bei 70°C ergibt 95% eines Pyrazolidins; die Additionsrichtung geht aus der Hydrogenolyse zu 9-Phenethylfluoren ebenso wie aus dem NMR-Spektrum hervor. Das 1-Cyanpyrazolidin zeigt für Cyanamide typische Reaktionen. - Das Azomethin-imin 1 addiert viele nichtkonjugierte Alkene, Cycloalkene und Derivate des Styrols in hoher Ausbeute, wobei spektroskopische Daten die Addukt-Strukturen sichern. Die Cycloaddukte des Butylvinylethers, cis- und trans-Propenylpropylethers, β-Methoxystyrols und Vinylacetats erleiden schon mit verdünnter Säure eine Eliminierung des Alkoxyls bzw. Acetats und des N-Cyans unter Bildung von 2-Pyrazolinen. Die Additionsrichtung des 1,3-Dipols wird von der Elektrophilie des Azomethin-imin-Kohlenstoffs bestimmt; Substituenten am ethylenischen Dipolarophil, die positive Ladung im Übergangszustand der Cycloaddition zu stabilisieren vermögen, erscheinen in 5-Stellung des Pyrazolidins.
    Additional Material: 3 Ill.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 611-618 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 2,2,2-Trifluor-4,4,5,5-tetrakis(trifluormethyl)-1,3,2λ5-dioxaphospholanePF5 and PhPF4 react with 2-[bis(trimethylsilyl)amino]-2,2-difluoro-4,4,5,5-tetrakis (trifluoromethyl)-1,3,2λ5-dioxaphospholane (1b) to yield the trifluorophosphorane 2 or 3, respectively. 3 is the first known example of a stable fluorophosphazophosphorane. 2 reacts with methoxytrimethylsilane to give the thermally stable difluoromethoxyphosphorane4; with hexamethyldisiloxane 5 is obtained. PF5 easily converts 5 into 2. Diphenyl(trimethylsilyl)phosphine reduces 2 to the cyclic fluorophosphite 6, which displaces the coordinated cycloolefin in (C7H8)Mo(CO)4 (C7H8 = norbornadiene) with formation of the cis-complex 7. The spectroscopic data are discussed.
    Notes: Die Reaktion von PF5 bzw. PhPF4 mit 2-[Bis(trimethylsilyl)amino]-2,2-difluor-4,4,5,5-tetrakis-(trifluormethyl)-1,3,2λ5-dioxaphospholan (1b) ergibt das Trifluorphosphoran 2 bzw. 3, das erste stabile Fluorphosphazophosphoran. 2 setzt sich mit Methoxytrimethylsilan zu dem thermisch beständigen Difluormethoxyphosphoran 4 um, mit Hexamethyldisiloxan entsteht 5, das mit PF5 leicht in 2 umgewandelt werden kann. Diphenyl(trimethylsilyl)phosphin reduziert 2 zu dem cyclischen Fluorphosphit 6, das in (C7H8)Mo(CO)4 (C7H8 = Norbornadien) das Cycloolefin unter Bildung des cis-Komplexes 7 substituiert. Die spektroskopischen Daten werden diskutiert.
    Additional Material: 2 Tab.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 638-644 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XIII. endo-exo-Isomeric Cycloadducts of trans,trans-1,3-Diphenyl-2-azaallyllithium and Acenaphthylenetrans,trans-1,3-Diphenyl-2-azaallyllithium adds at O or -70°C to acenaphthylene with retention of configuration to give a mixture of N-lithio-syn- and N-lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrole (3a, 4a, R = Li) (ca. 1:1). The syn-isomer (endo-cycloadduct) rearranges to the anti-isomer (exo-cycloadduct) at +35°C.
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich bei O oder -70°C unter Retention an Acenaphthylen zu einem Gemisch von N-Lithio-syn- und N-Lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrol (3a, 4a, R = Li) (ca. 1:1). Das syn-Isomere (endo-Cycloaddukt) lagert sich bei +35°C in das anti-Isomere (exo-Cycloaddukt) um.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 677-682 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Simple Phosphorus and Arsenic Ylides with Methylgermanium, -tin, and -lead SubstituentsThe syntheses of the ylides (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2, and (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 are reported. The relative substituent effect of all IVb elements on the carbanionic function of ylides is discussed in the light of the 13C and 31P n. m. r. spectra of these compounds and their Si and Sn analogues.
    Notes: Die Darstellung der Ylide (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2 und (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 wird beschrieben. Der relative Substituenteneffekt aller IVb-Elemente auf die Carbanion-Funktion von Yliden wird an Hand der 13C- und 31P-NMR-Spektren dieser Verbindungen und ihrer Si- und Sn-Analoga diskutiert.
    Additional Material: 1 Ill.
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  • 74
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 717-720 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Alkyl and Aryl Compounds, XIX. Preparation and Crystal Structure of Methylrubidium and MethylcaesiumCH3Rb and CH3Cs are prepared from CH3Li and rubidium tert-butoxide or caesium 2-methyl-2-pentanolate, respectively. As shown by X-ray diffraction of the crystal powders the compounds possess a hexagonal structure of the NiAs type with isolated methyl anions and alkali cations like CH3K investigated earlier.
    Notes: CH3Rb und CH3Cs werden durch doppelte Umsetzung von CH3Li mit Rubidium-tert-butylat bzw. Caesium-2-methyl-2-pentanolat dargestellt. Nach röntgenographischen Untersuchungen der Kristallpulver besitzen die Verbindungen wie das bereits früher untersuchte CH3K eine hexagonale Struktur vom NiAs-Typ mit isolierten Methyl-Anionen und Alkali-Kationen.
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  • 75
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 730-736 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometrical Investigations of Dicarbonyl(cyclopentadienyl)(thioamidato) Complexes of Molybdenum and TungstenThe mass spectra of several dicarbonyl(cyclopentadienyl)(thioamidato) complexes of Mo and W and of the corresponding free thioamides are reported and the fragmentation processes are discussed. The fragmentation modes of the ionized complexes reveal structural rearrangements of the organic ligands, which cannot be observed in the spectra of the free thioamides.
    Notes: Die Massenspektren einiger Dicarbonyl(cyclopentadienyl)(thioamidato)-Komplexe von Mo und W und die der zugehörigen freien Thioamide werden angegeben und die Fragmentierungsprozesse diskutiert. Der organische Ligand unterliegt im ionisierten Komplex tiefgreifenden strukturellen Umlagerungen, für die sich in den Spektren der freien Thioamide keine Parallele finden läßt.
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  • 76
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 744-748 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Interactions of Triple Bonds, XVI. The Crystal and Molecular Structure of 5,6,12,13-Tetradehydro-8,9,10,11-tetrahydro-7H-dibenzo-[a,c]cyclotrideceneThe crystal structure of the title compound was solved by direct methods and has been refined to R = 0.056. The triple bonds are crossed by an angle of 64.0°. Their centres have a distance of 3.174 Å. Because of transannular repulsion within the thirteen-membered ring system the acetylene group deviates by 4.1° and 4.6° respectively in a cisoid manner from a linear arrangement. The other angles are enlarged. In the present conformation the length of the [CH2]5-bridge corresponds the length of the CH2—S—S—CH2-group. The chiral molecule lies on a crystallographic twofold axis.
    Notes: Die Kristallstruktur der Titelverbindung wurde mit direkten Methoden gelöst und bis zu einem R-Wert von 0.056 verfeinert. Die Dreifachbindungen sind unter einem Winkel von 64.0° gekreuzt angeordnet und zeigen einen Mittelpunktsabstand von 3.174 Å. Auf Grund der transannularen Abstoßung innerhalb des dreizehngliedrigen Ringsystems ist die Acetylengruppe um 4.1° bzw. 4.6° aus der linearen Anordnung cisoid deformiert. Die übrigen Winkel sind aufgeweitet. Die Länge der [CH2]5-Brücke entspricht in der vorliegenden Konformation der einer CH2—S—S—CH2-Gruppe. Das chirale Molekül liegt auf einer zweizähligen kristallographischen Achse.
    Additional Material: 1 Ill.
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 693-702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Question of Inner Hexacoordination with Pentaarylphosphoranes; Phosphorane Rearrangements at the Level of Coordination Number 5The spirocyclic pentaarylphosphoranes 13 and 18b containing hydroxy groups in the direct neighbourhood of the molecule centre, isomerize more or less readily to the oxyphosphoranes 14 and 22, resp., with retention of coordination number 5. Inner onium-ate complexations could not be detected with the starting materials.
    Notes: Die spirocyclischen Pentaarylphosphorane 13 und 18b, die in unmittelbarer Nachbarschaft zum Molekülzentrum Hydroxylgruppen aufweisen, isomerisieren mehr oder weniger leicht unter Beibehaltung des Koordinationsniveaus 5 zu den Oxyphosphoranen 14 bzw. 22. Innere Onium-At-Komplexierungen konnten bei den Ausgangsverbindungen nicht nachgewiesen werden.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 683-692 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 1,3,5-Trifluoro-1,3,5-trioxo-1λ6,3λ6,5λ6,2,4,6-trithiatriazine (Sulfanuric Fluoride) with AminesWhereas the reaction of the trithiatriazine 1 with diethylamine yields only mono- and disubstituted derivatives (2b, 3), the reaction with dimethylamine results in the replacement of one, two, or three fluorine atoms (→ 2a, 3a, 4). On the other hand, only mono- or trisubstituted compounds (5a, b or 9a, b, resp.), are formed by the reactions of 1 with primary amines such as methylamine and ethylamine. Ammonia reacts with 1 to give 10·NH3. The free compound 10 is formed by treatment with HCl gas. 10 reacts with P(C6H5)4Cl to yield the ionic compound 11 and with benzaldehyde to form the Schiff base 12. With secondary diamines 1 preferentially undergoes intermolecular linkage with formation of 13, but a bicyclic compound 14 could also be prepared in low yield. 1 reacts with silylamines such as RN(SiMe3)2 (R = CH3, C2H5) only after addition of RNH(SiMe3) (→ 15a, b). Sn—N cleavage reactions with 1 occur more readily. Only monosubstituted products (e. g. 16) are formed. Reaction of 1 with phenylhydrazine results in reduction of a sulfur atom and formation of the anion 17. A substituted anion (18) was also prepared from 2a by this method. The reaction behavior of 1 is discussed in detail.
    Notes: Während das Trithiatriazin 1 mit Diethylamin nur zu Mono- und Disubstitutionsderivaten (2b, 3b) reagiert, kann Dimethylamin ein, zwei oder auch drei Fluoratome austauschen (→2a, 3a, 4). Die Reaktion von 1 mit primären Aminen wie Methylamin und Ethylamin liefert hingegen nur Mono- und Trisubstitutionsprodukte (5a, b bzw. 9a, b). Ammoniak reagiert mit 1 zu 10·NH3, die freie Verbindung 10 entsteht nach Behandeln mit HCl-Gas. Mit P(C6H5)4Cl gibt 10 die ionische Verbindung 11, mit Benzaldehyd die Schiffsche Base 12. Mit sekundären Diaminen setzt sich 1 bevorzugt unter intermolekularer Verknüpfung (13) um, aber auch eine bicyclische Verbindung 14 ist in geringer Ausbeute darzustellen. Mit Silylaminen wie RN(SiMe3)2 (R = CH3, C2H5) reagiert 1 erst nach Zusatz von RNHSiMe3 (→ 15a, b). Sn-N-Spaltungsreaktionen mit 1 verlaufen erheblich leichter, wobei ausschließlich Monosubstitutionsprodukte (z. B. 16) gebildet werden. 1 gibt mit Phenylhydrazin unter Reduktion eines Schwefelatoms das Anion 17. Auch ein substituiertes Anion (18) konnte auf diesem Wege aus 2a dargestellt werden. Das Reaktionsverhalten von 1 wird ausführlich diskutiert.
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  • 79
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the 8-, 4′-, and 7-Monomethyl Ethers of Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavone) and Structure of Ranupenin from Ranunculus repens L.By synthesis of 8-, 4′- and 7-O-monomethylgossypetin via a modified Allan-Robinson condensation as well as directly from gossypetin (3,3′,4′,5,7,8-hexahydroxyflavone), it is shown that ranupenin from Ranunculus repens L., which occurs in the plant as an O-monogalactoside, has the structure not of 8-O-monomethyl- but of 7-O-monomethylgossypetin.
    Notes: Durch die Synthese von 8-, 4′- und 7-O-Monomethylgossypetin über eine modifizierte Allan-Robinson-Kondensation bzw. direkt aus Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavon) konnte geklärt werden, daß dem als O-Monogalactosid natürlich vorliegenden Ranupenin aus Ranunculus repens L. nicht die Konstitution eines Gossypetin-8-, sondern -7-methylethers zukommt.
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  • 80
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 773-777 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molecular Mechanics Calculations on the Stability of Bridgehead OlefinsEmpirical force field calculations were used to determine the limits of application of the rules proposed by Fawcett Wiseman and Köbrich for the stability of bridgehead olefins (Bredt compounds). The stability is ruled by the size of the trans-cycloolefin unit, whereas the sum of the number of atoms in the three bridges is of minor importance. With a given skeleton the double bond was found less favourable in the largest bridge than in the second largest in most cases studied.
    Notes: Mittels empirischer Kraftfeldrechnungen wird der Gültigkeitsbereich der Regeln von Fawcett, Wiseman und Köbrich zur Vorhersage der Stabilität von Brückenkopfolefinen (Bredt-Verbindungen) untersucht. Die Größe der trans-Cycloolefineinheit ist für die Stabilität ausschlaggebend, die Summe der Ringgliederzahl in den drei Brücken ist von untergeordneter Bedeutung. Bei gegebenem Gerüst ist in der Mehrzahl der untersuchten Moleküle die Doppelbindung in der größten Brücke weniger günstig als in der zweitgrößten.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 816-819 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Borabenzene Derivatives, IX. Paramagnetic Chromium Complexes of 1-Methylborinate and 1-Phenylborinate IonsPotassium borinates, K[C5H5B-R] (R = CH3, C6H5), react with CrCl3 or CrCl2·THF to give paramagnetic bis(borinato)chromium complexes, Cr(C5H5B-R)2 (R = CH3, C6H5). For these a sandwich structure with a 16-electron valence shell is proposed.
    Notes: Durch Umsetzung von Kaliumborinaten, K[C5H5B-R] (R = CH3, C6H5), mit CrCl3 oder CrCl2·THF werden paramagnetische Bis(borinato)chrom-Komplexe, Cr(C5H5B-R)2 (R = CH3, C6H5), erhalten. Für diese wird eine Sandwich-Struktur mit einer 16-Elektronen-Valenzschale vorgeschlagen.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 994-999 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Reactions of Hydroxy-N,N-dimethylcarboxamides3-Hydroxy-N,N-dimethyl-1-carboxamides (2, 7) are converted into the corresponding γ-butyrolactones (3, 8) by treatment with an acidic ion-exchange resin in acetone or by thermolysis. 2-Hydroxy-N,N-dimethyl-1-carboxamides (10, 12, 14, 16b, 18) on the contrary form the corresponding carbonyl compounds (9, 11, 13, 15b, 17).
    Notes: 4-Hydroxycarbonsäure-dimethylamide (2, 7) lassen sich durch Behandlung mit saurem Ionenaustauscher in Aceton oder durch Thermolyse in die entsprechenden γ-Butyrolactone(3,8) überführen. 3-Hydroxycarbonsäure-dimethylamide (10, 12, 14, 16b, 18) bilden hingegen beim Erwärmen die entsprechenden Carbonylverbindungen (9, 11, 13, 15b, 17) zurück.
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  • 83
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, XIV. The Reactions of Aliphatic Diazo Compounds with the Tricarbonyl(cyclopentadienyl) Hydrides of Molybdenum and TungstenDepending on their constitution, aliphatic diazo compounds 3 behave differently in their reactions with tricarbonyl(cyclopentadienyl)hydridomolybdenum (1) and -tungsten (2). Diazomethane (3a), diazoethane (3b), and 2-diazopropane (3c) are stabilized as alkane diazo ligands in complexes of the type C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7). Phenyl-, (4-nitrophenyl)-, (4-methoxyphenyl)diazomethane (3d, e, f), and 9-diazofluorene (3g) form in clean reactions the carbene insertion products C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), whereas ω-diazoacetophenone (3h) and diazodimedone (3i) yield the binuclear diazo complexes C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10). Diethyl diazomalonate (3h) is coordinated as an imino-amido ligand in the coordination compound 14 which arises from a 1,1-insertion of 3k into the polar tungsten-hydrogen bond of 2.
    Notes: In ihrer Reaktivität gegenüber Tricarbonyl(cyclopentadienyl)hydridomolybdän (1) und -wolfram (2) weisen Diazoalkane 3 starke konstitutionsbedingte Unterschiede auf: Diazomethan (3a), Diazoethan (3b) und 2-Diazopropan (3c) werden als Alkandiazo-Liganden in Komplexen vom Typ C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7) stabilisiert; Phenyl-, (4-Nitrophenyl)-, (4-Methoxyphenyl)diazomethan (3d, e, f) sowie 9-Diazofluoren (3g) bilden in glatten Reaktionen die Carben-Insertionsprodukte C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), während ω-Diazoacetophenon (3h) wie auch Diazodimedon (3i) die zweikernigen Diazoketon-Komplexe C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10) ergeben. Diazomalonsäure-diethylester (3k) wird im Zuge einer zur Koordinationsverbindung 14 führenden 1,1-Insertion in die polare Wolfram-Wasserstoff-Bindung von 2 als Imino-amido-Ligand komplexiert.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 948-953 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XXI. On Dehydro Amino Acids, VIII. N-Acyl-α,β-dehydro Amino Acids by Rearrangement of N-Acyl-α-imino AcidsAcetylation of 2-iminoisovaleric acid ester 1 gives the acetyl imino derivative 2. By addition of nucleophilic reagents the α-substituted valine esters 5 and 6 are obtained; base catalyzed rearrangement affords acetyl-α,β-dehydrovaline ester 7. The latter reaction opens a general approach to Boc-α,β-dehydroamino acids 11a-d and esters 9a-d.
    Notes: Durch Acetylierung von 2-Iminoisovaleriansäureester 1 wird die Acetyliminoverbindung 2 erhalten. Addition von nucleophilen Reagentien führt zu den α-substituierten Valinestern 5 und 6, basenkatalysierte Umlagerung zu Acetyl-α,β-dehydrovalinester 7. Letztere Reaktion eröffnet einen allgemeinen Weg zu Boc-α,β-Dehydroaminosäuren 11a-d und ihren Estern 9a-d.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 979-984 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Natural Dibenzo-α-pyrones, II. Synthesis of Alternariol and Alternariol 9-Methyl EtherThe synthesis of 3,7,9-trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-one (alternariol, 1) and the first synthesis of its 9-methyl ether (2) as well as an extension of the Hurtley condensation to o-bromobenzamides are reported.
    Notes: Die Synthese von 3,7,9-Trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-on (Alternariol, 1), die erste Synthese von Alternariol-9-methylether (2) und eine Erweiterung der Hurtley-Kondensation auf o-Brombenzamide wird beschrieben.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1020-1026 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylchlorobis(tri-tert-butylphosphine)rhodium(I)Tri-tert-butylphosphine reacts with tetracarbonyl-μ-dichlorodirhodium (1) to form carbonylchlorobis(tri-tert-butylphosphine)rhodium(I) (2), existing in an equilibrium with dicarbonyl-μ-dichlorobis(tri-tert-butylphosphine)dirhodium (3) in pentane solution, which can be seen in the i. r. and 31P-n. m. r. spectra. The crystal structure of 2 has been determined from single crystal X-ray data. The compound crystallizes with 4 molecules in a unit cell of symmetry P21/n in the monoclinic system.
    Notes: Tri-tert-butylphosphin reagiert mit Tetracarbonyl-μ-dichlorodirhodium (1) unter Bildung von Carbonylchlorobis(tri-tert-butylphosphin)rhodium(I) (2), das in Pentanlösung mit Dicarbonyl-μ-dichlorobis(tri-tert-butylphosphin)dirhodium (3) im Gleichgewicht steht, was sich im IR- und 31P-NMR-Spektrum verfolgen läßt. Die Kristallstruktur von 2 wurde röntgenographisch aus Diffraktometer-Einkristalldaten bestimmt. Die Verbindung kristallisiert mit 4 Molekülen in der Elementarzelle der Symmetrie P21/n im monoklinen System.
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  • 87
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1042-1046 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stable Mercury(I)-Sulfur Compounds, 3. Investigations on the Donor Capacity of Sulfur at the Mercury(I) IonNew mercury(I)-sulfur compounds have been prepared by reactions between mercury(I) nitrate, perchlorate or hexafluorosilicate solutions with methanol, water/benzene or water/methylene chloride solutions of the following sulfur donor ligands: 1,3-dithiolane, 2-phenyl-1,3-dithiolane, 2,2′-trimethylenebis(1,3-dithiolane), bis(benzylthio)methane, dibenzylsulfide. With mercury(I)-dinitrate, the products are the 1:1 adducts (1a), (4a), (6a), and (11a). With mercury(I)-perchlorate the 1:2 adducts (1b),(4b),(6b) or the 1:1 adducts (5b) and (11b) have been obtained. Dibenzylsulfide forms a 1:1 adduct (11c) with dimercury(I)-hexafluorosilicate.
    Notes: Neue Quecksilber(I)-Schwefel-Verbindungen wurden durch Umsetzung von Quecksilber(I)-nitrat, -perchlorat bzw. -hexafluorosilicat-Lösungen mit folgenden Schwefel-Donor-Liganden in methanolischen Lösungen bzw. im Zweiphasensystem wäßrige Lösung/Benzol oder Methylenchlorid hergestellt: 1,3-Dithiolan, 2-Phenyl-1,3-dithiolan, 2,2′-Trimethylenbis(1,3-dithiolan), Bis-(benzylthio)methan, Dibenzylsulfid. Mit Quecksilber(I)-nitrat werden 1:1-Addukte (1a), (4a), (6a) und (11a), mit Quecksilber(I)-perchlorat 1:2-Addukte (1b), (4b) und (6b) bzw. 1:1-Addukte (5b) und (11b) erhalten. Mit Diquecksilber(I)-hexafluorosilicat bildet das Dibenzylsulfid ein 1:1-Addukt (11c).
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  • 88
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1069-1085 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of Thiacyclanone-1,1-dioxides with DiazoalkanesThiacyclanone-1,1-dioxides 1a-e, 9, 13, 15a react with diazomethane and diazoethane to give the enol ethers 2a-j, epoxides 4c, h, 10a, 14a, 17a, α-alkyl-β-ketosulfones 3d, e, j, and ring-enlarged ketosulfones 5h, i, 7h, 11b, 12b, 15b, 16b and 18a, depending on the size of the ring and the position of the carbonyl and sulfonyl group to each other. The enol ethers are easily hydrolysed with mineral acids forming the β-ketosulfones 1a-e. In the presence of lewis acids ethyl diazoacetate yields ethoxycarbonylmethoxy compounds 2k, I, and ring-enlarged β-ketoesters 5k-o, 7m, n, 15c, 16c, and 18c. Only the γ-ketosulfone 9 with ethyl diazoacetate gives, in addition to the ring-enlarged product 11c, the glycidic ester 10c. The β-ketoesters undergo hydrolysis and decarboxylation to the ketosulfones in very good yield. In the ring-expansion of ketosulfones with diazoethane and ethyl diazoacetate the preferred insertion of the diazo compound occurs between the C-3 and C-4 atoms.
    Notes: In Abhängigkeit von der Ringgliederzahl und der Lage von Carbonyl- und Sulfonylgruppe zueinander reagieren Thiacyclanon-1,1-dioxide 1a-e, 9, 13 und 15a mit Diazomethan bzw. -ethan zu Enolethern 2a-j, Epoxiden 4c, h, 10a, 14a, 17a, α-Alkyl-β-ketosulfonen 3d, e,j oder zu ringerweiterten Ketosulfonen 5h,i, 7h, 11b, 12b, 15b, 16b und 18a. Die Enolether spalten leicht mit Mineralsäure zurück zu den β-Ketosulfonen 1a-e. Mit Diazoessigester in Gegenwart von Lewis-Säuren entstehen die Ethoxycarbonylmethoxy-Verbindungen 2k, I bzw. die ringerweiterten β-Ketoester 5k-o, 7 m, n, 15c, 16c und 18c; lediglich das γ-Ketosulfon 9 gibt mit Diazoessigester neben dem Ringerweiterungsprodukt 11c den Glycidester 10c. Die β-Ketoester lassen sich in guten Ausbeuten zu den Ketosulfonen verseifend decarboxylieren. Bei den Ringerweiterungen der Ketosulfone mit Diazoethan und Diazoessigester ist eine bevorzugte Insertion des Diazoalkanrestes zwischen C-3 und C-4 festzustellen.
    Additional Material: 2 Tab.
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  • 89
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1124-1129 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Four- and Five-membered Phosphorus Heterocycles, 15. The Products of Carbohydrazide/Phosphonic Chloride Reaction: 2,2′-Spirobi(1,3,4,2λ5-oxadiaza-phospholines)The products of the 2:1-condensation of carbohydrazides 1 with phosphonic dichlorides 2 are not cyclic anhydrides 4 of the phosphonic bis(acylhydrazides), as has been assumed until now. Instead they possess the structure of the spirocyclic phosphoranes 9 named in the title. Their formation is due to the unusual reaction of a P = O-bond involving elimination of water. With dimethylphosphinic chloride (14) the hydrazides 1 react in quite the same sense to give the dimers 17 of oxadiazaphospholes in which the pentacoordinate phosphorus (as a bridgehead) is again part of two small rings. The phosphoranes 9 are also obtained from the reaction of 1 with tetrachloro-phosphoranes 5 or thiophosphonic dichlorides 18 or even bis(dimethylamino)phosphines 19.
    Notes: Die 2:1-Kondensationsprodukte aus Carbonsäurehydraziden 1 und Phosphonyldichloriden 2 stellen nicht - wie bisher angenommen - durch Anhydridbildung cyclisierte Phosphonsäure-bis(acylhydrazide) 4 dar, sondern die im Titel genannten spirocyclischen Phosphorane 9. Ihr Entstehen beinhaltet das „Aufrichten“ einer P = O-Bindung unter Wasserabspaltung. Mit Di-methylphosphinylchlorid (14) reagieren die Hydrazide 1 im gleichen Sinn zu Oxadiazaphosphol-Dimeren 17 mit ebenfalls bicyclisch (als Brückenkopf) eingebautem Phosphoranphosphor. Die Phosphorane 9 entstehen auch aus 1 und Tetrachlorphosphoranen 5 oder Thiophosphonyl-dichloriden 18 oder auch Bis(dimethylamino)phosphinen 19.
    Additional Material: 1 Tab.
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  • 90
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1684-1690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Hydronium Tetrachloroaurate(III)-2,2-dimethyl-2H-benzimidazole 1,3-Dioxide, (C9H10N2O2)H3O+ [AuCl4]-1,2-Benzoquinone dioxime (1) reacts with tetrachlorogold(III) acid-trihydrate in dialkyl ketones as solvents to yield solids 5-7 which contain H3O+ and [AuCl4]- ions and neutral 2,2-dialkyl-2H-benzimidazole 1,3-dioxides (2-4). The organic, neutral molecule can easily be isolated from this solid by means of an ion-exchanger. The structure of hydronium tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazole 1,3-dioxide (5), which can be obtained from acetone solutions, is obtained by X-ray analysis.
    Notes: Die Reaktion von 1,2-Benzochinondioxim (1) mit Tetrachlorogold(III)-säure-trihydrat in Dialkyl-ketonen als Lösungsmittel führt zu Festkörpern 5-7, die aus H3O+- und [AuCl4]--Ionen sowie aus neutralen 2,2-Dialkyl-2H-benzimidazol-1,3-dioxiden (2-4) aufgebaut sind. Daraus läßt sich das organische neutrale Molekül mittels eines Ionenaustauschers abtrennen und in Substanz isolieren. Die Struktur des aus Aceton erhältlichen Hydronium-tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazol-1,3-dioxids (5) wird durch Röntgenstrukturanalyse ermittelt.
    Additional Material: 1 Ill.
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  • 91
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1744-1747 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Photochemistry of Two Tribenzo-(CH)12-Valence IsomersA new synthesis of the tribenzo[12]annulene 1 and the photochemical transformations of 1 and of its valence isomer 2 are described. A reaction mechanism is proposed.
    Notes: Eine neue Synthese des Tribenzo[12]annulens 1 und die photochemischen Umwandlungen von 1 und seines Valenzisomeren 2 werden beschrieben. Ein Reaktionsmechanismus wird vorgeschlagen.
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  • 92
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1759-1762 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 94. New Furanoeremophilanes from Ligularia vorobierii Worosh.L. vorobierii contains besides already known five new furanoeremophilane derivatives (5 and 7-10). Their structures have been elucidated by spectroscopic methods. The constituents show again a close relationship to the neighbouring genus Senecio.
    Notes: L. vorobierii enthält neben bereits bekannten fünf neue Furanoeremophilan-Derivate (5 und 7-10), deren Konstitutionen durch spektroskopische Methoden geklärt werden. Die Inhaltsstoffe zeigen erneut eine enge Verwandtschaft zu der Nachbargattung Senecio.
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  • 93
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Reactivity of Metal π-Complexes, XXII. Sandwich-like Dinuclear (Pd-Pd)-Complexes with Bridging Cyclopentadienyl and Allyl LigandsThe reaction of C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-allyl) with tertiary phosphines or phosphites in the molar ratio of 1:1 produces in practically quantitative yields the dinuclear complexes (C5H5)(2-RC3H4)Pd2L2 (4-20) in which palladium has the oxidation state +1. The crystal structure analysis of 5 (R = CH3, L = P(C6H5)3) and 12 (R = CH3, L = P(OC6H4-o-CH3)3) shows that the cyclopentadienyl as well as the allyl ligand is bonded in a sandwich manner to the Pd-Pd unit. The Pd-Pd distance of 267.9 (in 5) or 268.9 pm (in 12) is suggestive of a metal-metal bond. It is not possible to determine whether the cyclopentadienyl ring in 4-20 exists as a pentahapto- or trihapto-bonded ligand on the basis of the 1H- and 13C n. m. r. data. The reactivity of the dinuclear complexes is in agreement with square planar coordination of the metal atoms.
    Notes: Bei den Reaktionen von C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-Allyl) mit tertiären Phosphinen oder Phosphiten im Molverhältnis 1:1 entstehen in praktisch quantitativer Ausbeute die Zweikernkomplexe (C5H5)(2-RC3H4)Pd2L2 (4-20), in denen Palladium in der Oxidationszahl +1 vorliegt. Wie die Kristallstrukturanalysen von 5 (R = CH3, L = P(C6H5)3) und 12 (R = CH3, L = P(OC6H4-o-CH3)3) zeigen, sind sowohl der Cyclopentadienyl- als auch der Allyl-Ligand sandwichartig an die Pd2-Einheit gebunden. Der Pd-Pd-Abstand von 267.9 (in 5) bzw. 268.9 pm (in 12) weist auf das Vorliegen einer Metall-Metall-Bindung hin. Aufgrund der 1H- und 13C-NMR-Daten ist nicht zu entscheiden, ob in 4-20 der Cyclopentadienylring als pentahapto-oder trihapto-gebundener Ligand vorliegt. Die Reaktivität der Zweikernkomplexe steht mit einer quadratisch-planaren Koordination der Metallatome in Einklang.
    Additional Material: 3 Ill.
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  • 94
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1833-1851 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Metallation of Benzyl- and Allylmercaptanes; the Thiobenzaldehyde and Thioacrolein DianionsDouble deprotonation of benzyl, allyl and 2-methylallyl mercaptane furnishes thiocarbonyl dianiones 2, 12, and 15, respectively. The novel nucleophiles react with alkyl halides, epoxides, and carbonyl derivatives to give good yields of products of type 3, 13/14, and 16/17, respectively. The doubly lithiated allyl mercaptanes are preferentially attacked by all of the employed electro-philes in the γ-position (60/40-90/10 γ/α-ratio) to lead to cis-vinyl sulfides 13 and 16. These can be converted into sulfur-free propanal derivatives 22-26 in high yields. 12 resembles synthetically the otherwise not available 3-lithiopropionaldehyde (18′, homoenolate).
    Notes: Thiocarbonyl-Dianionen lassen sich quantitativ durch doppelte Deprotonierung aus Benzyl-(→2), Allyl- (→12) und 2-Methylallylmercaptan (→15) erzeugen. Die neuen Nucleophile setzen sich mit Alkylhalogeniden, Epoxiden und Carbonylverbindungen in guten Ausbeuten zu Produkten vom Typ 3, 13/14 bzw. 16/17 um. Die doppelt metallierten Allylmercaptane reagieren mit allen bisher getesteten Elektrophilen bevorzugt in γ-Stellung (60/40—90/10 für γ/α) zu cis-Vinyl-sulfiden 13 und 16, die in guten Ausbeuten in schwefelfreie Propionaldehydderivate 22-26 übergefuhrt werden konnten. 12 entspricht damit synthetisch dem nicht direkt zugänglichen 3-Lithio-propionaldehyd (18′, Homoenolat).
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  • 95
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1896-1907 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched-chain Sugars, XV. Glycoside Syntheses with L-StreptoseThe halogeno derivatives of the cyclic carbonates 11 a and 11 b are most suitably used in the synthesis of L-streptose β-glycosides. α-Glycosides are obtained from the benzylidene compound 20. The benzylidene group can be subsequently removed by catalytic hydrogenation. Using the glycosyl halide 16 a also α-glycosides are formed in high yields. However, it is difficult to cleave the isopropylidene group under acidic conditions. Acetylated halides of type 4 are very labile and therefore not useful in glycoside synthesis.
    Notes: Zur Herstellung β-L-glycosidischer Verknüpfungen der L-Streptose sind die Halogenide des cyclischen Carbonats 11 a und 11 b am besten geeignet. α-L-Glycosidische Verknüpfungen der L-Streptose werden am günstigsten mit der Benzylidenverbindung 20 erhalten. Die Benzylidengruppe ist anschließend hydrogenolytisch abspaltbar. Auch das Halogenid 16 a liefert hohe Anteile an α-Glycosid. Die Isopropylidengruppe ist aber schwierig sauer abspaltbar. Acetylierte Halogenide wie 4 sind wegen ihrer Empfindlichkeit zur Glycosidsynthese weniger geeignet.
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  • 96
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1925-1930 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, VI. Synthesis of StreptobiosamineA synthesis of 5-deoxy-2-O-(2-deoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-streptobiosamine) is described. The same synthesis was repeated with the corresponding L-sugars. It leads to 5-deoxy-2-O-(2-deoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-streptobiosamine), the disaccharide portion of streptomycin.
    Notes: Eine Synthese der 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-Streptobiosamin) wird beschrieben. Die gleiche Synthese wurde auch mit den entsprechenden L-Zuckern durchgeführt. Sie lieferte 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-Streptobiosamin), das den Disaccharidbaustein des Streptomycins darstellt.
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  • 97
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1971-1977 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XIV. The Catalysed Reaction of Aldehydes with Mannich BasesAlkali cyanide- and thiazolium salt-catalysed addition of aldehydes to Mannich bases of saturated and unsaturated ketones leads to the formation of 1,4-diketones (1-6, 9-22).
    Notes: Alkalicyanid- und thiazoliumsalz-katalysierte Additionen von Aldehyden an Mannich-Basen von gesättigten und ungesättigten Ketonen führen zu 1,4-Diketonen (1-6, 9-22).
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  • 98
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mechanism of the Aluminium Chloride-catalysed Rearrangement of 7 H-Dibenzo[c,g]carbazole to 7 H-Dibenzo[a,g]carbazole and of Related Aromatic Skeleton RearrangementsOn an experimental basis a mechanism for the aluminium chloride-catalysed rearrangement of 7 H-dibenzo[c,g]carbazole (1) to 7 H-dibenzo[a,g]carbazole (2) is derived, that involves in the first step formation of the 5,6-dihydro derivatives 3 and 9 which rearrange via a spiro cation 14. This mechanism should also be valid for topologically analogous systems.
    Notes: Für die aluminiumchlorid-katalysierte Skelettumlagerung von 7 H-Dibenzo[c,g]carbazol (1) in 7 H-Dibenzo[a,g]carbazol (2) wird aus Experimenten ein Mechanismus abgeleitet, nach dem zunächst Bildung der 5,6-Dihydro-Derivate 3 und 9 erfolgt, die über ein Spirokation 14 umlagern. Dieser Mechanismus sollte auch für topologisch analoge Systeme zutreffen.
    Additional Material: 1 Tab.
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  • 99
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2019-2027 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclophosphates, III. Synthesis and Properties of Uridine 3′,5′-Cyclophosphate EstersThe uridine 3L′,5′-cyclophosphate esters 4-11 were synthesized by reaction of the free acid of uridine 3′,5′-cyclophosphate (1-3) with the appropriate diazoalkane. The configuration of the isomeric 1,3,2λ5-dioxaphosphorinanes is assigned on the basis of an X-ray analysis with the aid of 31P n. m. r. The stereoselectivity was influenced in part by the degree of reactivity of the diazo compound, by steric hindrance in the 2′-position of the ribose, and by variation in the reaction temperature. The newly synthesized compounds were characterized by u. v. and 31P n. m. r. spectra.
    Notes: Die Uridin-3′,5′-cyclophosphat-ester 4-11 wurden durch Reaktion der freien Säure des Uridin-3′,5′-cyclophosphates (1-3) mit den entsprechenden Diazoalkanen erhalten. Die Zuordnung der stereoisomeren 1,3,2λ5-Dioxaphosphorinane läßt sich mit Hilfe der 31P-NMR-Spektren aufgrund einer Röntgenstrukturanalyse zeigen. Eine stereoselektive Beeinflussung durch Variation der Reaktivität der Diazokomponente oder durch sterische Hinderung an der 2′-Position der Ribose, sowie in Abhängigkeit von der Temperatur, konnte partiell erzielt werden. Sämtliche synthetisierten Verbindungen wurden durch UV- und 31P-NMR-Spektren charakterisiert.
    Additional Material: 4 Tab.
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1462-1469 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mannich Reaction at 2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one, the Chromophore of the Ribonucleoside “Q”2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (6a) reacts with dimethylamine and cyclopentylamine in the presence of formaldehyde to form the Mannich bases 6c and d. From 6c the amine moiety was split off on hydrogenation under pressure. The degradation product was identical with 2-amino-6-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (6b), which was obtained by unambiguous synthesis. This shows that in contrast to 3,7-dihydropyrrolo[2,3-d]-pyrimidin-4-one, Mannich reaction involving 6a leads to substitution at C-6.
    Notes: 2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-on (6a) reagiert mit Dimethylamin und Cyclo-pentylamin in Gegenwart von Formaldehyd zu den Mannich-Basen 6c und d. Aus 6c ließ sich durch Druckhydrierung das Amin abspalten. Das Abbauprodukt war identisch mit 2-Amino-6-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-on (6b), das auf eindeutigem Syntheseweg erhalten worden war. Damit wird gezeigt, daß die Mannich-Reaktion bei 6a im Gegensatz zu 3,7-Dihydropyrrolo[2,3-d]pyrimidin-4-on zur Substitution an C-6 führt.
    Additional Material: 1 Ill.
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