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  • Articles  (12,361)
  • Articles: DFG German National Licenses  (12,361)
  • Inorganic Chemistry  (8,040)
  • Life and Medical Sciences  (2,965)
  • Cell & Developmental Biology  (2,592)
  • Engineering  (946)
  • Ultrastructure  (410)
  • 1975-1979  (6,978)
  • 1960-1964  (4,353)
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  • Articles  (12,361)
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  • Articles: DFG German National Licenses  (12,361)
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  • 1
    Electronic Resource
    Electronic Resource
    Studies on the biology of fish bone. III. Ultrastructure of osteogenesis and resorption in osteocytic (cellular) and anosteocytic (acellular) bones (1979)
    Springer
    Calcified tissue international 28 (1979), S. 43-56 
    Details
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteogenesis ; Fish bone ; Osteocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The comparative ultrastructure of fish bone osteogenesis and resorption induced by scale removal was described in the osteocytic (cellular-boned)Carassius auratus and the anosteocytic (acellular-boned)Tilapia macrocephala. Osteocytes, present in osteocytic bone, were lacking in anosteocytic bone. In osteocytic bone the osteoblast secreted a collagenous preosseous matrix in which it became enmeshed and then was termed a preosteocyte. When the preosseous matrix mineralized, the preosteocyte was termed an osteocyte and was completely surrounded by bone. In anosteocytic bone the osteoblasts receded from the mineralizing front and never became trapped as osteocytes. During resorption, types A and B resorptive cells, present in both bone types, invaded the matrix and demineralized the osseous zone. These cells were characterized by large amounts of granular endoplasmic reticulum and intracellular inclusions containing crystal-like material. Although functionally similar to mammalian osteoclasts, these cells lacked a characteristic ruffled border and were not multinucleated. The osteocytes of cellular bone did not appear to be involved during demineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441217
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure of collagen in sea urchin embryos (1979)
    Springer
    Development genes and evolution 186 (1979), S. 65-70 
    Details
    ISSN: 1432-041X
    Keywords: Sea urchin ; Embryo ; Collagen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Collagen fibrils with a main period banding of 610 Å and 220 Å in width were observed in the blastocoel of 72-h embryos of the sea urchin,Strongylocentrotus purpuratus. Non-striated fibrils of 50 Å diameter were also observed. The collagen is seen in highest concentration in the vicinity of mesenchyme cells which are richly endowed with endoplasmic reticulum and secretory vesicles. A role for collagen in cell attachment, orientation and spicule formation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848108
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the distal wing bud of the chick embryo after removal of the apical ectodermal ridge (1979)
    Springer
    Development genes and evolution 185 (1979), S. 333-346 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Limb bud ; Ultrastructure ; Cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural changes in the wing bud afterapical ectodermal ridge (A.E.R.) removal was studied to re-examine the issue of distal mesenchymal cell death. The A.E.R. of the right wing bud was removed microsurgically from chick embryos of stages 18 to 22 (HH 1951). The wing buds were examined at three hour intervals up to twelve hours after the operation with light, transmission and scanning electron microscopy. The main findings were: (1) Immediate and temporary shrinkage of the mesenchymal extracellular space 100 to 150 μm and chromatin condensation in the cells 50 to 75 μm from the wound. (2) Death of ectodermal and mesenchymal cells in the immediate vicinity of the wound. (3) Formation of a single squamous-like layer of mesenchymal cells to cover the wound. (4) Occasional evidence of cell death in the distal mesenchyme at later times after the operation. The pattern of cell death observed suggests only a traumatic etiology, and gives little evidence for the postulated developmental significance of cell death following A.E.R. removal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848520
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  • 4
    Electronic Resource
    Electronic Resource
    Methanogenium, a new genus of marine methanogenic bacteria, and characterization ofMethanogenium cariaci sp. nov. andMethanogenium marisnigri sp. nov. (1979)
    Springer
    Archives of microbiology 121 (1979), S. 147-153 
    Details
    ISSN: 1432-072X
    Keywords: Methanogenium cariaci ; Methanogenium marisnigri ; Marine methanogenic bacteria ; Ultrastructure ; TaxonomyMethanogenium gen. nov.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689979
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  • 5
    Electronic Resource
    Electronic Resource
    A comparative ultrastructural study of the ascospores of some Saccharomyces and Kluyveromyces species (1979)
    Springer
    Archives of microbiology 121 (1979), S. 53-59 
    Details
    ISSN: 1432-072X
    Keywords: Saccharomyces ; Kluyveromyces ; Ultrastructure ; Ascospore wall ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three types of structure of the ascospore wall were found among the haploid Saccharomyces species examined: a warty wall (S. rouxii), a smooth wall with a single electron-light inner layer (S. bailii) and a smooth wall with a double light inner layer (S. montanus, S. florentinus). The latter type also occurred in Kluyveromyces thermotolerans and K. waltii. In K. fragilis spores the wall had a single light inner layer. The taxonomic implications of these findings were discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409205
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  • 6
    Electronic Resource
    Electronic Resource
    Capnocytophaga: New genus of Gram-negative gliding bacteria. II. Morphology and ultrastructure (1979)
    Springer
    Archives of microbiology 122 (1979), S. 17-27 
    Details
    ISSN: 1432-072X
    Keywords: Gliding bacteria ; CO2-requiring ; Periodontal disease ; Gram-negative ; Ultrastructure ; Capnocytophaga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gram-negative, anaerobic gliding bacteria were isolated from normal supragingival plaque and from periodontal lesions. Isolates could be divided into two size classes: small 2.4–4.2 μm×0.38–0.5 μm and large 4.8–5.8 μm×0.42–0.6 μm cells. The outer membrane was either loose-fitting and wavy, or taut, and of variable thickness. An electron-dense fuzz was discernible on several of the isolates. The periplasmic region was of variable electron-density. The genus Capnocytophaga has been proposed for these organisms based on morphological and cultural characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408041
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  • 7
    Electronic Resource
    Electronic Resource
    Biosynthesis of the basal lamina as a result of interaction between thyroid and mesenchymal cells in culture (1979)
    Springer
    Cell & tissue research 200 (1979), S. 69-81 
    Details
    ISSN: 1432-0878
    Keywords: Thyroid follicular cells ; Basal lamina, biosynthesis ; Cellular interaction ; Cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Porcine thyroid cells were cultured alone or in mixed cultures with mesenchymal cells. The formation of a basal lamina in vitro was investigated ultrastructurally. Follicular reassociation of thyroid cells occurred in both types of culture; however, it was followed by formation of the basal lamina only when mesenchymal cells were present. The present findings suggest an epithelial origin of the basal lamina resulting from an interaction with mesenchymal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236888
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural identification of non-adrenergic, non-cholinergic nerves in the rat anococcygeus muscle (1979)
    Springer
    Cell & tissue research 200 (1979), S. 257-271 
    Details
    ISSN: 1432-0878
    Keywords: Anococcygeus muscle ; Innervation ; P-type nerves ; Purinergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the rat anococcygeus muscle has been investigated ultrastructurally following fixation with a modified chromaffin reaction for the demonstration of biogenic amines (Tranzer and Richards, 1976). Three types of nerve profiles were revealed: (1) 60–70 % of the profiles are adrenergic; (2) less than 5% of the profiles appear to be cholinergic; (3) up to 40% of the profiles are distinguished by the presence of a characteristically high proportion of electron-opaque, chromaffin-negative vesicles, 85–110nm in diameter. This third type of profile was not affected by 6-OHDA, and is considered to represent the non-adrenergic, non-cholinergic inhibitory innervation of this tissue. Because of the morphological similarity of this nerve type, apart from the smaller vesicle size, to classical peptidergic nerve endings, they have been termed “small p-type” (sp-type). These results are discussed in relation to a previous report describing only two types of nerve profiles in this tissue (Gillespie and Lüllmann-Rauch, 1974).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236418
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  • 9
    Electronic Resource
    Electronic Resource
    A stereological ultrastructural study of stimulated peritoneal macrophages in the germ-free mouse (1979)
    Springer
    Cell & tissue research 200 (1979), S. 299-309 
    Details
    ISSN: 1432-0878
    Keywords: Germ-free mice ; Inflammation ; Macrophages ; Peritoneum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peritoneal macrophage ultrastructure was analysed stereologically in germ-free mice given a single intraperitoneal injection of sterile, pyrogen-free saline. Thus the stimulant was non-particulate, non-antigenic and inorganic, and effects of immune reactions were minimal. Macrophages were recovered 1, 6, 24 and 72 h after stimulation. A sequence of structural alterations is reported which may be fundamental to macrophage activation. The plasma membrane and nuclear envelope increased in area within only 1 h of saline injection. During the next 5 h loss of plasma membrane, probably by pinocytosis, caused cellular “rounding” and clear-cut alteration in surface configuration. At the same time lysosome-like granules enlarged but decreased in number. By 24 h most cellular structures and compartments (including the plasma membrane) were enlarged. Morphological evidence of nuclear activation accompanied a rather modest enlargement of the nucleus at this stage. The RER hypertrophied last and must, therefore, be judged sufficient in resident macrophages to support the initial growth response which results after stimulation. Thus hypertrophy was observed eventually in every structure examined. Even the minimally activated macrophages resident in the peritoneum of germ-free mice respond readily to stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236422
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructure of an excitatory synapse (1979)
    Springer
    Cell & tissue research 200 (1979), S. 291-298 
    Details
    ISSN: 1432-0878
    Keywords: Excitatory synapse ; Lateral line-canal organ ; Synaptic body ; Ultrastructure ; Lota lota (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the afferent synapse in hair cells of the lateral line-canal organ was studied using different fixation and staining techniques. Glutaraldehyde-fixed tissue without post-osmication, contrasted by section staining with uranyl acetate and lead citrate, was compared with (a) osmium tetroxide-fixed tissue followed by the same staining procedure, and with (b) glutaraldehyde-fixed tissue, block-impregnated with phosphotungstic acid (PTA). The results reveal a pronounced heterogeneity in the composition of the synaptic body, reflecting regional differences in chemical affinity to the fixatives and staining agents. It is proposed that the “intracleft substance”, the synaptic structure defined by the PTA staining technique, is actually due to the glutaraldehyde fixation procedure and is apparently the outer leaflet of the postsynaptic membrane. A special technique that allows alternate sections of a series to be differentially stained for electron microscopy is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236421
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  • 11
    Electronic Resource
    Electronic Resource
    Functional morphology of the midgut of Aedes aegypti L. (Insecta, Diptera) during blood digestion (1979)
    Springer
    Cell & tissue research 200 (1979), S. 193-203 
    Details
    ISSN: 1432-0878
    Keywords: Mosquitoes ; Midgut ; Ultrastructure ; Stereology ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Morphometrische Untersuchungen des Magenepithels von A. aegypti weisen darauf hin, daß die Verdauung des ersten Blutmahls in eine Reihe von Phasen gegliedert werden kann, die sich mit physiologischen Daten aus der Literatur korrelieren lassen. In einer Phase Ia (0–10 h nach Blutmahl [BM]) entfalten sich die “whorls” des rauhen endoplasmatischen Retikulums, die Golgi-Zonen werden größer, und das basale Labyrinth wird erweitert. Dies stimmt mit Synthese- und Sekretionsprozessen (z.B. peritrophische Membran, Esterasen, Lipasen) und mit Transportvorgängen durch das Magenepithel überein. In Phase Ib (10–20 h nach BM) nehmen die gemessenen zellulären Parameter weiter zu und weisen damit auf hohe Synthese- und Sekretionsaktivitäten (z.B. Verdauungsenzyme) hin. In Phase Ic (20–30 h nach BM) zeigen die an Synthese und Sekretion beteiligten Zellstrukturen, in Übereinstimmung mit der maximalen Proteasenaktivität im Darm, immer noch hohe Werte. Vergrößerte Mikrovillioberfläche, auffallende Lipideinschlüsse und Auftreten von Glykogendepots im Magenepithel deuten auf erhöhte Resorptions-, Speicher- und Transportfunktionen der Zellen hin. In Phase II (30–36 h nach BM) läßt sich anhand der strukturellen Veränderungen der Wechsel von Synthese- und Sekretionvorgängen zu Resorption, teilweiser Speicherung und Transport von Verdauungsprodukten erkennen. In Phase III (36–72 h nach BM) wird der Zellapparat in Übereinstimmung mit dem Ende der Verdauung reduziert. Lipid- und Glykogendepots werden mobilisiert und verschwinden fast vollständig aus den Magenepithelzellen.
    Notes: Summary Morphometric analysis of the epithelial lining of the stomach of A. aegypti suggests that digestion of the first blood meal in the stomach of this species can be viewed as a series of phases that can be correlated with physiological data from the literature. In phase Ia (0–10 h after blood meal [abm]) the whorls of the rough endoplasmic reticulum unfold, the Golgi zones increase, and the basal labyrinth is enlarged. This coincides with processes of synthesis and secretion (e.g., peritrophic membrane, esterases and lipases) and transport by the stomach epithelium. In phase Ib (10–20 habm) the cellular parameters measured further increase, indicating high synthetic and secretory activities (e.g., digestive enzymes). In phase Ic (20–30 habm) cell structures involved in synthesis and secretion still exhibit high values coinciding with maximal activity of proteases in the gut. Enhanced surface area of microvilli, prominent lipid inclusions, and appearance of glycogen deposits in the gut epithelium suggest increased absorption, storage, and transport functions of the stomach cells. In phase II (30–36 habm) structural alteration points to a gradual shift from synthesis and secretion to absorption, partial storage, and transport of nutrients. In phase III (36–72 habm) the cellular apparatus is reduced concomitant with the ending of the digestive cycle. Lipid inclusions and glycogen deposits disappear from the stomach epithelum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236412
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  • 12
    Electronic Resource
    Electronic Resource
    A new type of synapse in the ventral cochlear nucleus (1979)
    Springer
    Cell & tissue research 198 (1979), S. 373-380 
    Details
    ISSN: 1432-0878
    Keywords: Ventral cochlear nucleus ; Calyceal processes ; Flattened synaptic vesicles ; Ultrastructure ; Morphometric study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this paper we report the appearance of flat vesicle-containing endings in aldehyde-fixed ventral cochlear nucleus of rats with qualitative and quantitative properties suggesting they should be identified as calyceal processes. Their synaptic vesicles are elongate and significantly smaller than the vesicles in the calyces of Lenn and Reese (1966). Therefore these endings are flat vesicular calyceal processes, possibly of inhibitory function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232018
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  • 13
    Electronic Resource
    Electronic Resource
    Control of the pars intermedia of the lizard, Anolis carolinensis (1979)
    Springer
    Cell & tissue research 198 (1979), S. 411-426 
    Details
    ISSN: 1432-0878
    Keywords: Intermediate lobe ; Hypophysis ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the intermediate lobe of the hypophysis was studied in Anolis carolinensis with the use of a threefold aldehyde fixative. Lizards with a brown skin were selected. The possibility of two types of secretory cells is discussed; neither cell type is innervated. Type I cells are rarely found and contain dense granules approximately 0.3 μm in diameter; Type II cells vary widely in secretory activity. Most of the Type II cells contain a large number of dense secretory granules (up to about 1.3 μm in diameter) almost filling the cytoplasm. Rough endoplasmic reticulum (RER), Golgi apparatus and mitochondria are poorly developed. Only some of these cells show signs suggesting a high secretory activity, namely a well developed RER, Golgi apparatus and numerous mitochondria. In these cells the RER sometimes forms large intracisternal droplets (up to 7 μm in diameter). Two of the animals exhibited a more uniform, high secretory activity. Large (about 2 μm in diameter), pale vacuoles, probably of extracellular character, were found mostly in the vicinity of the perivascular septum. Their role in the release of MSH is discussed. The present data, which are discussed with reference to earlier findings (Forbes, 1972), form the morphological basis for an experimental study on regulation of MSH release (Larsson et al., 1979).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234186
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  • 14
    Electronic Resource
    Electronic Resource
    Quantitative comparison of low- and high-output neuromuscular synapses from a motoneuron of the lobster (Homarus americanus) (1979)
    Springer
    Cell & tissue research 198 (1979), S. 455-463 
    Details
    ISSN: 1432-0878
    Keywords: Neuromuscular synapses ; Presynaptic density ; Ultrastructure ; Serial sections ; Crustaceans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Representative examples of lowand high-output neuromuscular synapses between motoneuron and distal accessory flexor muscle of the lobster were selected on the basis of their mean quantal content, and subsequently analysed by serial section electron microscopy. The high-output terminal has twice as many synapses as the low-output terminal. However, since the mean surface area of synapses is significantly smaller in the high-output terminal than in the low-output one, the total synaptic surface area between the two types of terminals is similar. Also, though the high-output terminal possesses a greater number of presynaptic dense bodies than its low-output counterpart, the mean number per synapse is similar for the two terminals. The terminals, however, differ significantly in the size of their dense bodies. Thus both the mean and total surface area of these bodies is greater in the high-output terminal than in the low-output one. Moreover, the mean ratio of dense body area to synaptic area is significantly greater for the high-output terminal than for its low-output counterpart. This difference in dense body area parallels the difference in quantal content of synaptic transmission between the lowand high-output terminals and supports the hypothesis that presynaptic densities represent the ultrastructural correlates of transmitter mobilization and/or release.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234190
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  • 15
    Electronic Resource
    Electronic Resource
    Effects of pimozide on the ultrastructure of the pars distalis in the rat (1979)
    Springer
    Cell & tissue research 199 (1979), S. 483-492 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; Luteotroph cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars distalis of the rat. The animals received 100μg/100 g pimozide daily for 5, 10, 15, and 20 days. Pimozide induces striking ultrastructural changes after 5 days of treatment. The number of luteotroph (LTH) cells is significantly increased; they display characteristics of stimulation. The extrusion of granules into the intercellular space via exocytosis is frequently observed. The intercellular spaces are highly dilated, forming a lacunar system filled with an amorphous material, erythrocytes and involuted LTH cells. Transitional stages in the process of involution are observed in LTH cells. Luteotroph cells also form a syncytium. Twenty days after treatment the abovedescribed changes decrease in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in the luteotroph cells, an effect that is less evident with longer treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236084
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  • 16
    Electronic Resource
    Electronic Resource
    The filum terminale of the frog spinal cord (1979)
    Springer
    Cell & tissue research 199 (1979), S. 519-528 
    Details
    ISSN: 1432-0878
    Keywords: Filum terminale ; Spinal cord ; Glial cells ; Ultrastructure ; Frog (Rana pipiens)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The filum terminale, or terminal portion of the spinal cord, was studied in normal adult frogs (Rana pipiens) by means of light and electron microscopy. Astroglial cells are the predominant elements in this region. The rostral portion of the filum terminale consists mainly of (1) a peripheral dense ring of myelinated and some unmyelinated nerve fibers, and processes of astrocytes terminating at the subpial space; (2) an intermediate zone, in which astrocytes are the main cellular elements in addition to a few degenerated neurons; and (3) a central region where the central canal is lined by dark and light ependymal cells. In the caudal portion of the filum terminale, the amount of neuropil is greatly reduced. This region is formed mainly by astrocytic glial cells and very few neuronal elements. The central canal in the caudal portion is located ventrally and contains a lining consisting almost exclusively of dark ependymal cells.
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    URL: http://dx.doi.org/10.1007/BF00236087
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  • 17
    Electronic Resource
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    Cytological changes in the pars distalis of the female rat hypophysis grafted under the kidney capsule (1979)
    Springer
    Cell & tissue research 199 (1979), S. 539-543 
    Details
    ISSN: 1432-0878
    Keywords: Pars distalis ; Graft ; Ultrastructure ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intact female rats received transplants of two hypophysial partes distales under the kidney capsule. The plasma levels of prolactin were determined, and the ultrastructure of the grafted gland was studied 15, 45 and 90 days after the operation. Although prolactin levels in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in the 45-day samples. Parallel ultrastructural changes suggest that between the 45th and 90th postoperative day a process is initiated leading to hyperplasia and hypertrophy of prolactotrophs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236089
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  • 18
    Electronic Resource
    Electronic Resource
    Maturation of secretory granules in the endosalpinx one to four days post coitum in sheep (1979)
    Springer
    Cell & tissue research 201 (1979), S. 145-158 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Secretory granules ; Endosalpinx ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of granules in the secretory cells of the endosalpinx of 20 Merino ewes was examined on days 1, 2, 3, and 4 post coitum. Based on the different frequency of granules of different size and structure on days one to four post coitum, one can assume that the ovoid, membrane bounded secretory granules mature in five successive stages. In stage I small, electron-lucent vesicles with a finely granulated and filamentous content become apparent, initially in the neighbourhood of the Golgi complex. In stage II the granules become larger and progressively more eletron-dense by an increase of the granulated material. In stage III, the primarily granulated content forms membranes, that lie in characteristic stacks at different angles to one another, separated by electron-dense areas. This structure fragments when the granule comes to lie beneath the surface of the cell (stage IV) and opens into the lumen of the oviduct, where its content is discharged in membrane fragments or vesicles (stage V). This discharge is mainly observed shortly before the egg is transported into the uterus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238054
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  • 19
    Electronic Resource
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    Fine structure of the rhombencephalic tela of the bullfrog, Rana catesbeiana (1979)
    Springer
    Cell & tissue research 202 (1979), S. 479-491 
    Details
    ISSN: 1432-0878
    Keywords: Ependyma ; Ultrastructure ; Posterior tela choroidea ; Rhombencephalon ; Rana catesbeiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The posterior rhombencephalic tela choroidea of the bullfrog was examined by electron microscopy. This membrane, the pia-ependymal roof of the caudal hindbrain, contains a large central region characterized by cuboidal ependymal cells which surround sizable microscopic apertures — the interependymal pores. Ultrastructurally ependymal cells of this area are characterized by infrequent apical microvilli and cilia. They contain irregularly shaped nuclei and few cytoplasmic organelles that are largely apical in position. The most striking feature is an abundance of cytoplasmic filaments forming an extensive cytoskeleton. Laterally these cells are joined by numerous elaborate desmosomes. The majority of the ependymal cells have a basal lamina consisting of single, double, or triple laminae lying parallel to the basal plasma membrane. Several unusual specializations are seen at the margins of the interependymal pores. The ependymal cells have lateral cytoplasmic processes that form the actual border of each pore. These processes originate from the apical surface of the cell and partially enclose an elaborate network of basal lamina associated with the interependymal pores. These findings demonstrate microscopic apertures in the roof of the fourth ventricle in the bullfrog that are associated with an unusual form of supportive ependyma.
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1979)
    Springer
    Cell & tissue research 199 (1979), S. 1-23 
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    ISSN: 1432-0878
    Keywords: Neuro-intermediate lobe ; Hypophysis ; Disconnection ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological changes in the disconnected neuro-intermediate lobe were studied in the lizard, Anolis carolinensis from the 2nd to the 14th post-operative day using a threefold aldehyde fixative (Rodríguez, 1969). Two phases of colour change capacity were exhibited: Phase I started immediately after the transection, lasted for 6 days (mean) and was characterised by an excessive MSH release (brown skin). This phase proceeded gradually into Phase II, designated by an interruption of the MSH release (green skin). The degenerative processes and final elimination of neurons in the disconnected neural lobe propagate in a rostro-caudal direction from the transected area. The aminergic fibres (Type II) disappear within 2 days postoperatively, whereas the degeneration continues for more than 10 days in the peptidergic fibres (Type III, IV and V). The glia cells (ependyma and pituicytes) serve as very active macrophages, engulfing fragments of axons already affected by autolysis and transferring them into glial lysosomes. No apparent morphological changes occur in the shift from Phase I to II. The great majority of the secretory cells of the intermediate lobe are not affected by degenerative processes and appear to be markedly activated by the stalk transection. They exhibit numerous mitochondria, well-developed Golgi complexes forming numerous Golgi vesicles and extensive parallel cisternae of the rough endoplasmic reticulum, sometimes forming large intracisternal droplets (7 μm in diameter). Numerous pale vacuoles are seen, especially toward the intact capillaries, suggesting their coupling to the MSH release by extension of the active membrane area toward the perivascular septum. The number of these vacuoles is very markedly reduced in Phase II (no release), whereas the formation of new granules seems to proceed in early stages. The interruption of the MSH release implies a successive refilling of gradually growing secretory granules and a concomitant reduction in the development of the synthetic apparatus. Mechanisms probably involved in the control of the synthesis and release of MSH are discussed.
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    URL: http://dx.doi.org/10.1007/BF00237724
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    Ultrastructural studies on erythropoiesis in the avian thymus (1979)
    Springer
    Cell & tissue research 199 (1979), S. 37-61 
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    ISSN: 1432-0878
    Keywords: Avian thymus ; Ultrastructure ; Erythropoiesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thymus lobes from three species of birds, Quelea quelea, Passer domesticus and Sturnus vulgaris, have been examined ultrastructurally. The component cell types are compared with their counterparts in mammalian thymus glands, and found to be similar. Greater differences exist between small, intermediate and enlarged lobes of one species than exist between species. Developing erythroid cells are present in most enlarging and some enlarged glands. They appear to be developing at the expense of lymphoid cells in some birds. The origin of these cells is discussed. Cells that are possible candidates for the production of some thymic hormones are also described.
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    An ultrastructural and cytochemical study of the interaction between latex particles and the haemocytes of the wax moth Galleria mellonella in vitro (1979)
    Springer
    Cell & tissue research 199 (1979), S. 127-137 
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    ISSN: 1432-0878
    Keywords: Haemocytes ; Phagocytosis ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The plasmatocytes are the major phagocytic blood-cell type in the haemolymph of the wax-moth, Galleria mellonella. In the present study, these cells were allowed to attach to tissue culture dishes for 1 h, rinsed and then incubated with latex beads for up to 72 h. These cells were then fixed for routine transmission electron microscopy and acid phosphatase cytochemistry. Intracellular latex particles were found in tight, ill-defined phagosomes, which were often clearly associated with the Golgi complexes of the plasmatocytes. Fusion of both primary lysosomes and multivesicular bodies with the phagosomes occasionally occurred and this resulted in the accumulation of an acid phosphatase positive reaction product around the test particles. Subsequent experiments showed that this acid phosphatase activity was mainly associated with the primary lysosomes. The results of the lysosome/latex interactions are compared with those obtained from similar studies on the digestive mechanisms in other phagocytes.
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    Reformation of gap and tight junctions in regenerating liver after cholestasis (1979)
    Springer
    Cell & tissue research 199 (1979), S. 257-270 
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    ISSN: 1432-0878
    Keywords: Liver ; Bile duct ligation ; Tight junctions ; Gap junctions ; Ultrastructure ; Freeze-fracturing ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphometric analysis of the alterations in interhepatocyte junctions induced by bile duct ligation revealed that after 48 h, during which time the serum bilirubin increased 6 to 8 fold, the membrane area occupied by gap junctions on the apico-lateral and medio-lateral sides decreased from 3.6% in controls to 0.02% in the ligated group. The strands of the zonulae occludentes were reduced in number and showed increased discontinuities. Within 45 min of recanalization of the common bile duct, clusters of particles appeared within and adjacent to the tight junctional areas or in the lateral hepatocyte membrane. Subsequently, the particle aggregations localized in the apico-lateral membrane areas increased in number and size becoming finally indistinguishable from those of controls within 96 h after the onset of recanalization. The zonulae occludentes also rearranged and reestablished their original structure during this period. The serum bilirubin fell to normal within 24 h of recanalization. It is concluded that metabolic and ultrastructural restitution associated with the recanalization of the ligated bile duct have no strict temporal correlation to one another. These studies provide further evidence that alterations in gap and tight junctions induced by pathological processes, e.g. during bile duct ligation, are completely reversible when regeneration occurs.
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    URL: http://dx.doi.org/10.1007/BF00236137
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    Vacuolated neurons in the hypogastric ganglion of the rat (1979)
    Springer
    Cell & tissue research 199 (1979), S. 373-386 
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    ISSN: 1432-0878
    Keywords: Hypogastric ganglion (rat) ; Vacuolated neurons ; Catecholamine fluorophore ; Ultrastructure ; Testosterone ; Castration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vacuolated neurons (VN) of the main hypogastric ganglion of the male rat were studied using the formaldehyde-induced fluorescence (FIF) method for the histochemical demonstration of catecholamines. Microspectrofluorimetry was performed to identify the fluorophores and to quantify the FIF. The thiocholine method (Koelle-Gomori) was used to demonstrate acetylcholinesterase activity. The fine structure of the VN was studied using glutaraldehyde/OsO4 fixation. (1) In the untreated adult male rat VN represent only a small population of the total number of hypogastric neurons (0.8–1.2%). The vacuoles are similar to those of the VN from the corresponding female ganglion. (2) The VN are considered to be adrenergic due to the nature of their fluorophore, indicating a primary catecholamine. (3) The first VN appear in the hypogastric ganglia at the age of 7 weeks. After testosterone administration to young rats, VN are found at the age of 4 weeks. (4) The basic fine structure of the VN is similar to that of other ordinary neurons of the hypogastric ganglia. (5) The content of the vacuoles could not be identified. (6) Indications of degeneration were not observed in the VN. (7) The VN are interpreted as being a functional stage of the “short” adrenergic neurons, which are under the control of steroid hormones. (8) Fifteen months after castration, no VN could be found in the hypogastric ganglia, while their number was normal in the corresponding control animals.
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    Ultrastructural heterogeneity of the mesocoxal muscles of Periplaneta americana (1979)
    Springer
    Cell & tissue research 201 (1979), S. 305-314 
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    ISSN: 1432-0878
    Keywords: Cockroach ; Muscle heterogeneity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies have been performed upon the posterior coxal depressor muscle (136) and a coxal branch of the main depressor group (135d′) from the mesocoxa of the cockroach, Periplaneta americana. The quantitative stereometric analyses performed have shown the latter muscle to consist of a dorsal band of fibers having 25.5% mitochondria and 13.6% sarcoplasmic reticulum (SR) and T-tubules (TTS), and a ventral group of fibers with only 4.4% mitochondria and 26.6% SR/TTS. The volume fractions characteristic of the ventral fibers of muscle 135 d′ are also typical of muscle 136.
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    A dense-cored filamentous body in Leydig cells of the golden hamster (1979)
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    Cell & tissue research 201 (1979), S. 369-376 
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    ISSN: 1432-0878
    Keywords: Leydig cells ; Filaments ; Golden hamster ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A unique cytoplasmic structure has been observed in Leydig cells of the golden hamster. It consists of a laminar core made up of electron dense material surrounded by a filamentous matrix of lower density, and is tentatively called a dense-cored filamentous body (DCFB). DCFBs vary in overall size and in configuration of the centrally disposed dense lamina. They are typically located in the vicinity of the centrosome and the Golgi complex. The body has no limiting membrane, and may be in contact with virtually every type of organelle. The DCFB is well developed in active Leydig cells, whereas it is small in the quiescent stage of the secretory cell. It is likely that the DCFB is a constant organelle in the hamster Leydig cell and may be involved in the physiological function of the Leydig cell, which remains to be specified.
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    The mineralization processes in Teleost fish scales (1979)
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    Cell & tissue research 202 (1979), S. 203-212 
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    ISSN: 1432-0878
    Keywords: Mineralization processes ; Scales ; Teleost fish ; Matrix vesicles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In Teleost fish scales, growth and mineralization are continuous. Different mineralization processes can be distinguished. The external layer of the scale is the first to be mineralized and may be classified as the initial calcifying structure of the scale. The initial calcification loci are matrix vesicles of cellular origin always observed during the formation of this layer. This mineralization process takes place progressively, closely following the elaboration of the organic matrix in the scale periphery. The outer limiting and internal layers of the scale are developed after the external layer has been formed. A mineral substance is deposited without the mediation of matrix vesicles, but in contact with the previously mineralized external layer. This type of mineralization is called subsequential. However, the mineralization of the outer limiting layer closely follows the secretion of a collagen-free organic matrix and is thus different from the mineralization of the internal layer in which the calcification front remains remote from the collagen matrix surface and corresponds to a delayed mineralization process. The isolated calcifications (Mandl's corpuscles) which develop in the unmineralized laminae of the internal layer are mineralized in the absence of matrix vesicles and without making contact with a pre-existing calcified tissue, probably by a heterogeneous nucleation of the collagen fibrils.
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    Pancreatic endocrine cells of Barbus conchonius (Teleostei, Cyprinidae), and their relation to the enteroendocrine cells (1979)
    Springer
    Cell & tissue research 203 (1979), S. 9-23 
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    ISSN: 1432-0878
    Keywords: Pancreatic endocrine cells ; Enteroendocrine cells ; Ultrastructure ; Cyprinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic endocrine cells of Barbus conchonius are concentrated in a large (principal) islet, located near the gall bladder, and in a number of smaller islets. Five types of endocrine cells can be distinguished in these pancreatic islets: B cells, A1 (or D cells), 2 types of A2 cells (A2r cells with round granules; and A2fl cells with flocculent granules) and a scarce 5th cell type. The hormones produced by B and A2fl cells are probably insulin and glucagon respectively. The A2r cell contains granules with the same diameter as the granules of the enteroendocrine type III cell of the gut. Both cell types may resemble the enteroglucagon-producing EG cell of mammals. The function of the A1 cells, which are frequently found without secretory granules, and of the 5th cell type, will be discussed. The pancreatic islets of B. conchonius are strongly innervated, which suggests the presence of a direct nervous control system. Some intermediate or mixed cells containing exocrine and endocrine A2r granules are found contiguous with the principal islet. The origin of pancreatic endocrine cells is also the subject of discussion.
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    Estrogen-induced ultrastructural changes in cultured chick embryo hepatocytes (1979)
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    Cell & tissue research 199 (1979), S. 249-256 
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    ISSN: 1432-0878
    Keywords: Hepatocytes ; Birds ; Ultrastructure ; Estrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Administration of estradiol-17-β induces the synthesis of vitellogenin in primary cultures of chick embryo liver. The ultrastructural changes accompanying steroid induced vitellogenin synthesis were investigated in hepatocytes cultures incubated for 0, 12 and 24 h following hormonal treatment. Both electron microscopy and immuno-chemical techniques were used. The immuno-fluorescence data indicate that the cultures contain a cell population of 90–95% hepatocytes, both in control and estradiol-treated groups. Ultrastructurally, cultured hepatocytes are similar to in vivo ones, except for a reduced accumulation of storage materials, glycogen and lipids. In the estradiol-treated cultures hepatocytes show an accumulation of free ribosomes, enlargement of rough endoplasmic reticulum, and development of the Golgi apparatus. The data are discussed in relation to previous biochemical findings.
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    The ultrastructure of the striated muscle of the tail of Cercaria chackai Nadakal et al., 1969 (1979)
    Springer
    Cell & tissue research 201 (1979), S. 479-486 
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    ISSN: 1432-0878
    Keywords: Ultrastructure ; Cercaria ; Striated tail muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The electron microscopic study of the tail of Cercaria chackai reveals that it contains four sets of striated muscle bundles located central to the nonstriated circular and longitudinal muscles. The striated muscle consists of longitudinally oriented lamellar myofibres. Each myofibre contains a single “U” shaped myofibril. The banding pattern is analogous to that of vertebrate striated muscle. The sarcolemma is a simple surface membrane. There are no transverse tubular extensions of sarcolemma. The sarcoplasmic reticulum (SR) is very well developed with cisternae, tubules, and vesicles. SR cisternae form dyadic couplings with the sarcolemma. There is a set of flattened tubules of SR origin traversing the myofibril exactly at the Z region. These tubules are unique to the striated muscle of the cercarian tail and may have functional significance. A diagrammatic reconstruction of the myofibre is presented.
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    Oogenesis in Campodea sp. (Diplura) (1979)
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    Cell & tissue research 202 (1979), S. 133-143 
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    ISSN: 1432-0878
    Keywords: Oogenesis ; Yolk formation ; Nurse cells ; Ultrastructure ; Diplura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The egg chamber of Campodea consists of a group of nurse cells and an oocyte, and is surrounded by a simple, markedly flattened follicular epithelium. Three types of yolk occur in the oocytes: type I appears within elements of the rough endoplasmic reticulum; type II is produced by specific complexes of endoplasmic reticulum and dictyosomes; type III is incorporated by micropinocytosis. Histochemical tests show that mature yolk spheres contain proteins and polysaccharides. The main function of the nurse cells is to synthesize RNA, but they also produce small amounts of type I yolk. Phylogenetic conclusions are drawn from this and other studies of oogenesis in apterygote insects.
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    Ultrastructural studies on oogenesis in Symphyla (1979)
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    Cell & tissue research 202 (1979), S. 145-153 
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    ISSN: 1432-0878
    Keywords: Oogenesis ; Yolk formation ; Ultrastructure ; Symphyla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paired ovaries of Symphyla are sac-shaped. Their interior is filled with synchronously developing oocytes surrounded by a simple follicular epithelium. Previtellogenic oocytes have spherical or oval nuclei, the latter containing a large number of small nucleoli. Part of the nuclear surface is covered by a thick “coat” made up of a granular substance of medium electron density. The “coat” is penetrated by cisternae of the smooth endoplasmic reticulum. Micropinocytosis is the principal source of yolk in Symphyla; a small amount of yolk material arises within the mitochondrial cristae. Vitellogenic oocytes are characterized by a highly active rough endoplasmic reticulum synthesizing a material, probably lipoprotein in nature, which is incorporated into lipid droplets.
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    Ultrastructure of the heart of the sturgeon Acipenser stellatus (Chondrostei) (1979)
    Springer
    Cell & tissue research 202 (1979), S. 431-438 
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    ISSN: 1432-0878
    Keywords: Sturgeon ; Heart ; Ultrastructure ; Sarcoplasmic reticulum ; Granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of atrial and ventricular myocardial cells from Acipenser stellatus is described. The cells of the atrium are more loosely connected than those of the ventricle. Cell contact is by simple intercalated discs and by desmosomes. The cells are flattened, with peripheral myofibrils and a central region of mitochondria and the nucleus. The sarcoplasmic reticulum consists of subsarcolemmal tubules, that frequently extend towards the central mitochondria. Dyads are small and positioned at any sarcomeric level. No T-tubules are present. Specific granules are restricted to the atrial cell, and are sometimes present within the SR tubules.
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    The collagen of the vertebrate peripheral nervous system (1979)
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    Cell & tissue research 202 (1979), S. 453-460 
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    ISSN: 1432-0878
    Keywords: Collagen ; Nerves ; Ganglia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerves and ganglia from a variety of fish, amphibian, reptilian and mammalian species were studied by optical and electron microscopy. Observations using the Picrosirius-polarization method strongly suggest that two different types of collagen fibers are present in the connective tissues of nerves and ganglia. Electron microscopy of nerves and ganglia showed the presence of two different collagen fibril populations, distinguishable on the basis of diameter, located in different compartments of these structures. Thicker fibrils are present in nerve and ganglionic epineurium. Thinner fibrils are present in the endoneurium, surrounding nerve fibers and ganglionic cells, and between the concentric layers of perineurial cells. These results were consistently observed in all species studied and very probably represent a general phenomenon in vertebrates.
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    Ultrastructural changes in rat adrenal cortical cells after chronic stimulation with β1–24-corticotropin (1979)
    Springer
    Cell & tissue research 204 (1979), S. 267-277 
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    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Zona fasciculata ; Ultrastructure ; Stereology ; β 1–24-corticotropin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult rats were given 15 daily subcutaneous injections either of synthetic β 1–24-corticotropin or of the corresponding placebo (controls) and were sacrificed 1 h after the final injection. In stimulated animals, the adrenal glands were increased in weight as compared to those of controls. Stereological analysis at light microscopic level of the outer zona fasciculata cells showed moderate volumetric increases of nuclei, cytoplasm and capillaries and a marked volumetric increase of lipid droplets in stimulated animals. Stereologic analysis of electron micrographs confirmed the marked increase in relative volume and surface density of lipid droplets, while volume fractions alone were increased for the Golgi apparatus and decreased for the endoplasmic reticulum and mitochondria. Biochemical analysis of the whole adrenal gland showed that the corticotropin injections produced a moderate increase in protein concentration, a marked increase in triglycerides and no appreciable changes in either phospholipid or cholesterol concentrations. The synthetic polypeptide therefore appears to have stimulating trophic effects on adrenal cortical cells, as shown by the increase in protein and cell size. However, it depresses the activity of the two types of organelle, endoplasmic reticulum and mitochondria, which have a major functional role in steroid synthesis. The increase of lipid droplets was interpreted as being primarily due to neutral fat accumulation, and secondarily to a diminished utilization of cholesterol for steroid synthesis. These findings suggest that, using this regime of administration, synthetic β 1–24 corticotropin, unlike native ACTH, inhibits steroid synthesis.
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    An ultrastructural study of the neurosecretory canopy cell of the pond snail Lymnaea stagnalis (L.), with the use of the horseradish peroxidase tracer technique (1979)
    Springer
    Cell & tissue research 204 (1979), S. 453-462 
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    ISSN: 1432-0878
    Keywords: HRP injection ; Lymnaea Stagnalis ; Neurohaemal areas ; Neurosecretory cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paired, electrotonically coupled neurosecretory Canopy Cells (CC) of the pond snail Lymnaea stagnalis were microiontophoretically injected with horseradish peroxidase (HRP). Whole mount preparations and ultrathin sections of injected CC were studied to describe in detail the morphology of the CC, their axon tracts and neurohaemal areas. The CC release their secretory product at three different sites, viz. from the soma and from axon terminals in the intercerebral commissure and in the median lip nerve. Neural control over the CC occurs by few synapses found exclusively on the CC axon, not on the cell body. One type of “en passant” synapse was identified. Two morphologically distinct types of synapselike structures (SLS) are numerous. The site of electrotonic coupling between the two CC is most probably located in the cerebral commissure. Serial sectioning showed that the axons contact each other over more than 130 μm. The contact is very intimate and the axon membranes interdigitate in a complex manner. Gap junctions, which are often described as the sites of electrotonic coupling, were not found.
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    Bacteria-like structures in the endoplasm of Gregarina garnhami (Eugregarinida, Protozoa) (1979)
    Springer
    Cell & tissue research 202 (1979), S. 33-39 
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    ISSN: 1432-0878
    Keywords: Gregarina ; Ultrastructure ; Gram negative bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An investigation of bacteria-like structures, which are found in large numbers in the endoplasm of the eugregarine, Gregarina garnhami, was carried out using light and electron microscopy. Gram staining indicates that these structures are gram negative; they show orange fluorescence when stained with acridine orange. Ultrastructural observations show that they resemble the endosymbiotic bacteria found in other protozoan species. Some of these structures appear to be dividing, and the possibility that these structures are in fact bacteria is discussed.
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    Ultrastructural studies on early events in fertilization of the bivalveLaternula limicola (1979)
    Springer
    Protoplasma 100 (1979), S. 73-83 
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    ISSN: 1615-6102
    Keywords: Bivalve ; Fertilization ; Laternula limicola ; Sperm-egg interaction ; Temporary-acrosome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural studies on sperm-egg interaction at the time of fertilization inLaternula limicola were performed. The “temporary-acrosome” did not change morphologically while the sperm passed through the egg investments. At the onset of sperm entrance into the egg, however, the temporary-acrosome and mitochondria were eliminated from the sperm. Afterwards the sperm was engulfed by the egg surface without membrane fusion of the gametes. After entry the sperm nucleus was surrounded by four membranes: the plasma membranes of the egg and of the sperm, and the membranes of the sperm nuclear envelope. As the sperm nucleus differentiated into the male pronucleus, the plasma membranes of both the sperm and egg were initially vesiculated, then dispersed into the egg cytoplasm. Finally, the sperm nuclear envelope changed into the male pronuclear membrane accompanying sperm chromatin dispersion.
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    Feinstrukturelle und mikroanalytische Untersuchungen an den Kristallen und Lithosomen des CiliatenEuplotes vannus (1979)
    Springer
    Protoplasma 99 (1979), S. 67-77 
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    ISSN: 1615-6102
    Keywords: Ciliata ; Crystals ; Euplotes ; Lithosomes ; Microanalysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the cytoplasm of the marine ciliateEuplotes vannus, there exist two conspicuous types of membrane bound inclusions: 1. irregularly shaped crystals which are highly anisotropic; 2. globular lithosomes characterized by concentrically arranged layers of deposits which exhibit only faint birefringence. Normally, both structures form distinct accumulations. Energy dispersive X-ray microanalysis of these accumulations reveals a high content of calcium and phosphorus, besides magnesium, sulphur and chlorine. Analysis of cell areas devoid of the inclusions show significantly lower calcium- and phosphorus-peaks.
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    Ultrastructure of primary sporidia of a wheat-bunt fungus,Tilletia caries, during ontogeny and mating (1979)
    Springer
    Protoplasma 99 (1979), S. 189-202 
    Details
    ISSN: 1615-6102
    Keywords: Mating ; Sporidia ; Tilletia ; Ultrastructure ; Wheat bunt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Primary sporidia ofTilletia caries (DC.) Tul. are borne on denticles at the tips of promycelia. The promycelia contain many small vacuoles and mitochondria and numerous lipid bodies. As the primary sporidia develop, the promycelial cytoplasm passes into the nascent cells. Septa develop between the bases of mature sporidia and the tips of the denticles. Sporidia that abscise from the denticles commonly have prominent birth scars at their bases. The sporidia have very thin walls, few vacuoles, attenuated mitochondria, and numerous lipid bodies. Conjugation pegs are generally produced by both members of a conjugating pair of sporidia and there are bud scars where they emerge from the sporidia. The sporidial walls are apparently hydrolyzed during emergence of the pegs. Vesicles are sometimes present at the tips of the conjugation pegs and, before fusion, electron-dense accumulations are sometimes observed between the tips of adjacent pegs. The approaching conjugation pegs are precisely aligned prior to fusion, suggesting polar communication. The walls of the conjugation pegs fuse and then are hydrolyzed. Fused sporidia are relatively homogeneous in content. The nucleus in a sporidum is often close to the conjugation tube and occasionally is partly within the fusion tube.
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    The effects of anaerobiosis and metabolic inhibitors on mitochondrial ultrastructure inAmoeba proteus (1979)
    Springer
    Protoplasma 99 (1979), S. 275-288 
    Details
    ISSN: 1615-6102
    Keywords: Amoeba proteus ; Anaerobiosis ; Metabolic inhibitors ; Mitochondria ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Anaerobiosis or exposure to the metabolic inhibitors potassium cyanide and Antimycin A produced changes in the form of living amoebae. These were accompanied by mitochondrial changes in fixed cells. Increasing the anaerobic period increased the percentage of mitochondria affected and resulted in a gradual reduction and eventual loss of the condensed Type I mitochondria ofAmoeba proteus. The rounder Type II mitochondria were not lost but underwent varying degrees of disruption, vesiculation of the cristae being evident after 5 hours exposures and matrical inclusions after 18 hours exposures. Similar cristal vesiculation was seen after 30 minutes treatments with potassium cyanide. Providing treatments were terminated before cell viability was lost, all mitochondrial abnormalities were reversible on return to normal culturing conditions. The longer the period of anaerobiosis the longer was the recovery time required for the return of normal mitochondrial structure and the re-equilibration of control Type I to Type II mitochondrial frequencies. The relationship between mitochondrial conformation and functional integrity is discussed in the light of these findings.
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    Bicyclo[2.1.1]hexane aus Tricyclo[3.1.0.02,6]hexanen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2012-2021 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bicyclo[2.1.1]hexanes from Tricyclo[3.1.0.02,6]hexanesThe novel tricyclo[3.1.0.02,6]hexane derivatives 3 and 4, being fused with a fife- and a sixmembered ring respectively, are prepared from benzvalene in several steps. They and their lower homologues 1 and 2, having a three- and fourmembered ring respectively, add thiophenol under conditions of a radical reaction to form smoothly one cyclobutylphenyl thioether (16-19) in each case. Therefrom the parent hydrocarbons (5-8) which contain the bicyclo[2.1.1]hexane skeleton, are obtained by means of reduction with lithium in ethylamine.
    Notes: Ausgehend von Benzvalen werden in mehreren Stufen die neuen Tricyclo[3.1.0.02,6]hexan-Derivate 3 und 4 mit anelliertem Fünf- bzw. Sechsring dargestellt. Sie und ihre niedrigeren Homologen 1 und 2 mit Drei- bzw. Vierring nehmen unter Bedingungen einer Radikalreaktion Thiophenol auf, wobei glatt jeweils ein Cyclobutylphenylthioether (16-19) gebildet wird. Mit Lithium in Ethylamin sind aus 16-19 die tricyclischen Stammkohlenwasserstoffe mit dem Bicyclo[2.1.1 ]hexan-Gerüst (5-8) erhältlich.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120611
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    Der Einfluß anellierter Ringe auf die 13C-NMR-chemischen Verschiebungen von Tricyclo[3.1.0.02,6]hexan- und Bicyclo[2.1.1]hexan-Derivaten (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2022-2027 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Influence of Fused Rings on the 13C Shieldings of Tricyclo[3.1.0.02,6]hexane and Bicyclo[2.1.1]hexane DerivativesThe 13C shieldings of the tricyclo[3.1.0.02,6]hexane derivatives 2-5 and of the bicyclo[2.1.1]-hexane derivatives 7-10 and 12-15 show a strong dependence on the size of the fused rings. Especially the γ-anti-effects, which cause downfield shifts, and the γ-syn-effects of these rings, which result in upfield shifts, are subject to unexpected variations.
    Notes: Die 13C-chemischen Verschiebungen der Tricyclo[3.1.0.02,6]hexan-Derivate 2-5 und der Bicyclo[2.1.1]hexan-Derivate 7-10 und 12-15 zeigen eine starke Abhängigkeit von der Größe der anellierten Ringe. Insbesondere die nach tieferem Feld gerichteten γ-anti-Effekte und die nach höherem Feld gerichteten γ-syn-Effekte dieser Ringe unterliegen unerwarteten Variationen.
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    URL: http://dx.doi.org/10.1002/cber.19791120612
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    Reaktionen an Indolderivaten, XXXIX. Stereoselektive Totalsynthese von Eburnamonin, Eburnamin und Eburnamenin (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1902-1912 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Indole Derivatives, XXXIX. A Stereoselective Synthesis of Eburnamonine, Eburnamine, and EburnamenineStudies on the five-membered lactams 1 and 2 disclose a stereoselective access to eburnamonin-19-one (22). This substance is easily transformed into eburnamonine (25), eburnamine (30), and eburnamenine.
    Notes: Das Studium der 5-Ring-Lactame 1 und 2 eröffnet einen stereoselektiven Zugang zum Eburnamonin-19-on (22). Diese Substanz läßt sich auf einfache Weise in die drei Alkaloide Eburnamonin (25), Eburnamin (30) und Ehurnamenin überführen.
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    URL: http://dx.doi.org/10.1002/cber.19791120541
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    En-Reaktionen mit Cyanthioformaniliden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1916-1918 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ene Reactions with CyanothioformanilidesCyanothioformanilides 3 react with methylenecyclohexane (1) and β-pinene (2) in boiling toluene to yield the adducts 4 and 5, resp., according to the mechanistic scheme of an ene reaction.
    Additional Material: 3 Tab.
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    Masthead (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120601
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    Synthesis of new chiral hydrocarbons (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1919-1922 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthese von neuen chiralen KohlenwasserstoffenUnsymmetrisches Anheften einer aliphatischen (CH2)n-Brücke an ein an sich achirales aromatisches System führt zu starren chiralen Kohlenwasserstoffen des Typs 2; die Enantiomeren 2 a konnten mit Hilfe von TAPA angereichert werden. Die Racemisierungskinetik wurde polarimetrisch bestimmt: ΔG≠20 = 93.6 kJ · mol-1.
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    Pheromone, XXIV. Notiz zur Synthese der Sexuallockstoffe (Z)-7-Dodecenylacetat und (Z)-7-Tetradecenylacetat (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1923-1925 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pheromones, XXIV. Synthesis of the Sex Attractants (Z)-7-Dodecenyl Acetate and (Z)-7-Tetradecenyl Acetate(Z)-7-Dodecenyl acetate, the female sex pheromone of the Noctuid moth Trichoplusia ni, and (Z)-7-tetradecenyl acetate, the sex attractant of Amathes c-nigrum (Lepidoptera), are prepared by stereoselective Wittig olefination using the „silazide“ -technique.
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    URL: http://dx.doi.org/10.1002/cber.19791120545
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    Dynamische NMR- Untersuchungen an (Di-tert-butylamino)arsanen und -stibanen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1927-1933 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dynamic NMR Studies of (Di-tert-butylamino)arsanes and -stibanesThe reaction of LiN[C(CH3)3]2 with AsX3 (X = F → Br). (CH3)3CAsCl2 and SbCl3 yields the di-tert-butylamino)arsanes 1a-c, 2 and dichloro(di-tert-butylamino)stibane (1d). LiN(CR3)-(SiR3), R=CH3and 1a-c form 3. The El — N torsional barriers of these compounds (measured by temperature dependent 1H-NMR spectroscopy) are compared with those of the (diisopropylamino)arsanes 4. and other related compounds. The influence of the N and El ligands with respect to the El — N torsional barrier is discussed. Thermolysis of 3c affords the di-tert-butylaminyl radical.
    Notes: Durch Umsetzung von LiN[C(CH3)3]2 mit AsX3 (X = F → Br), (CH3)3CAsCl2 und SbCl3 erhält man die (Di-tert-butylamino)arsane 1a-c und 2 sowie Dichlor(di-tert-butylamino)stiban reagieren mit LiN(CR3)(SiR3), R=CH3 zu 3 weiter. Die durch temperaturabhängige 1 H-NMR-Messungen ermittelten El- N-Rotationsbarrieren dieser Verbindungen werden hinsichtlich des Ligandeneinflusses am N- El - Atom mit den (Diisopropylamino)arsanen 4. und verwandten Molekülen verglichen. 3c. ergibt bei der Thermolyse das Di-tert-butylaminyl-Radikal.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120602
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    Isocyanidkomplexe, I. Isocyanphosphane und -arsane als Komplexliganden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1934-1940 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isocyanide Complexes, I. Isocyanophosphanes and -arsanes as Ligands of ComplexesThe reaction of K[CpMn(CO)2CN] (Cp = η-C5H5) with PR2Cl (R=C2H5, OC2H5, C6H5) and As(C6H5)2Cl yields the complexes CpMn(CO)2CNPR2 (3a - c) and CpMn(CO)2CNAsPh2 (3d) with C-coordinated isocyanophosphanes and -arsanes. In the reaction of CpMn(CO)2CNPPh2 with CpMn(CO)2 THF or of K[CpMn(CO)2CN] with CpMn(CO)2PPh2Cl a complex with an isocyanophosphane bridge, {CpMn(CO)2}2(CNPPh2) (4), is obtained. The IR, NMR, and mass spectra of the compounds 3a-d and 4 are discussed.
    Notes: Bei der Umsetzung von K[CpMn(CO)2CN] (Cp = η-C5H5) mit PR2Cl (R=C2H5, OC2H5, C6H5) und As(C6H5)2Cl entstehen die Komplexe CpMn(CO)2CNPR2 (3 a - c) und CpMn(CO)2CNAsPh2 (3d) mit C-gebundenen Isocyanphosphanen und -arsanen. Durch Reaktion von CpMn(CO)2CNPPh2 (3c) mit CpMn(CO)2 THF bzw. von K[CpMn(CO)2]CN mit CpMn(CO)2PPh2Cl erhält man den Komplex {CpMn(CO)2}2(CNPPh2) (4) mit einer Isocyanphosphan-Brücke. Die IR-, NMR- und Massenspektren der Verbindungen 3a-d und 4 werden diskutiert.
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    Barrieren der behinderten Rotation um die N-glycosidische Bindung, IV. 1-(β-D-Ribofuranosyl)isocyanursäuren (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1941-1947 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Barriers to Hindered Rotation Around the N-Glycosidic Bond, IV. 1-(βD-Ribofuranosyl) isocyanuric AcidsThe β-ribofuranosyl nucleosides 5a-c and 6b, c are synthesized. The temperature dependency of the 1H- and 13C-NMR spectra can only be interpreted as hindered rotation around the N-glycosidic bond2). The Gibbs activation energies (43-46 kJmol-1) are independent of acetylation of the OH groups of the furanose ring or restriction of its flexibility through formation of a 2′,3′-isopropylidene derivative, and are considerably lower than the corresponding data (about 69 kJmol-1) of the glucopyranosyl nucleosides 7b, c. The activation entropies are small. The results are interpreted.
    Notes: Es werden Synthesen der β-Ribofuranosylnucleoside 5a-c und 6b, c beschrieben. Die Temperaturabhängigkeiten der 1H-und 13C-NMR-Spektren lassen sich nur als Folge behinderter Rotation um die N-glycosidische Bindung deuten2) Die Gibbsschen Aktivierungsenergien (43-46 kJmol-1) sind unabhängig von einer Acetylierung der OH-Gruppen des Furanoseringes oder einer Einschränkung von dessen Flexibilität durch Bildung eines 2′,3′-Isopropylidenderivates und liegen erheblich tiefer als die entsprechenden Werte (um 69 kJmol-1) der Glucopyranosylnucleoside 7b, c. Die Aktivierungsentropien sind gering. Die Befunde werden gedeutet.
    Additional Material: 3 Tab.
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    Synthesen von α-Bromisothiocyanaten (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1948-1955 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of α-BromoisothiocyanatesSecondary isothiocyanates (1j-q) and primary isothiocyanates R—CH2 - NCS with an activating group R (1f, g) react with N-bromosuccinimide (NBS) to form α-bromoisothiocyanates 2 in high yields. The not activated primary isothiocyanate 1c slowly forms the stable α,α-dibromoisothiocyanate 10. In the presence of β-hydrogens some of the α-bromoisothiocyanates 2 eliminate HBr spontaneously, and secondary products may be formed. The α-bromination of isothiocyanates is a radical reaction following a Goldfinger mechanism.
    Notes: Sekundäre Isothiocyanate (1j-q) und primäre Isothiocyanate R-CH2 - NCS mit einer aktivierenden Gruppe R (1f, g) lassen sich mit N-Bromsuccinimid (NBS) in hohen Ausbeuten zu den α-Bromisothiocyanaten 2 bromieren. Das nicht aktivierte Isothiocyanat 1c reagiert langsam zum stabilen α,α-Dibromisothiocyanat 10. Bei Anwesenheit von β-Wasserstoffatomen spalten die α-Bromisothiocyanate 2 zum Teil spontan HBr ab, und es entstehen Folgeprodukte. Die α-Bromierung der Isothiocyanate erfolgt radikalisch nach einem Goldfinger-Mechanismus.
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    Reaktionen von α-Bromisothiocyanaten (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1956-1972 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of α-Bromoisothiocyanatesα-Bromoisothiocyanates 11.2) with a hydrogen in β-position eliminate HBr to form vinyl isothiocyanates (products 2, 3, 5). Water hydrolyzes 1 to carbonyl compounds (7a). Hard nucleophiles attack 1 at the α-C-atom with substitution of bromine (products 8-12), but soft nucleophiles add to the C-atom of the isothiocyanato group (products 14, 19). Compounds 1 react with bifunctional nucleophiles to heterocycles (e. g. products 16, 21). The chemical properties of the classes of compounds, part of which are new, e. g. the geminal diisothiocyanates 12, are examined. The alkylidene thiourea 14f shows hindered rotation around the amide-CS—N bond (ΔG≠394 = 82.8 kJmol-1) and around the C=N double bond (ΔG≠244 = 52.9 kJmol-1).
    Notes: α-Bromisothiocyanate 1 mit einem β-Wasserstoff spalten HBr zu Vinylisothiocyanaten ab (Produkte 2, 3, 5). Wasser hydrolysiert 1 zu Carbonylverbindungen (7a). Harte Nucleophile greifen 1 am α-C-Atom unter Substitution des Broms an (Produkte 8-12), weiche Nucleophile lagern sich dagegen an das C-Atom der Isothiocyanatgruppe an (Produkte 14, 19). Verbindungen 1 reagieren mit bifunktionellen Nucleophilen zu Heterocyclen (z. B. Produkte 16, 21). Die chemischen Eigenschaften der z. T. neuen Verbindungsklassen, z. B. der geminalen Diisothiocyanate 12, werden untersucht. Der Alkylidenthioharnstoff 14f zeigt behinderte Rotation um die Amid Cs—N-Bindung (ΔG≠394 = 82.8 kJmol-1) und um die C=N-Doppelbindung (ΔG≠244 = 52.9 kJmol-1).
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    Die Kristallstruktur von (η3-Allyl)dicarbonyl(triphenyl-phosphan)cobalt und sein dynamisches Verhalten in Lösung (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1973-1980 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structure and the Fluxional Behaviour in Solution of (η3-Allyl)dicarbonyl(triphenyl-phosphane)cobalt[Co(η3-C3H5)(CO)2PPh3] (1) crystallizes in the triclinic space group P1 with two molecules per unit cell. The crystal structure was solved and refined with X-ray diffraction data (R = 0.031, 2046 observed reflections). The cobalt atom has a distorted square pyramidal coordination with the formally bidentate η3-allyl ligand, the phosphane, and one carbonyl in the basal positions. According to the NMR spectra at temperatures down to 135 K, in solution there exists a fluxional equilibrium with the η3-allyl ligand oscillating between two enantiomeric positions.
    Notes: [Co(η3-C3H5)(CO)2PPh3] (1) kristallisiert triklin in der Raumgruppe P1 mit zwei Molekülen pro Elementarzelle. Die Kristallstruktur wurde mit Röntgenbeugungsdaten ermittelt und verfeinert (R = 0.031, 2046 beobachtete Reflexe). Das Cobaltatom ist verzerrt quadratisch-pyramidal koordiniert, mit dem formal zweizähnigen η3-Allylliganden, dem Phosphan und einem Carbonylliganden in der Pyramidenbasis. Nach den NMR-Spektren bei Temperaturen hinab bis 135 K liegt in Lösung ein dynamisches Gleichgewicht vor, bei dem die η3-Allylgruppe zwischen zwei enantiomeren Positionen fluktuiert.
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    Hydrazidine, III. Synthese von 1,2,4,5-Tetrazino [3,2-a]isoindolen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1981-1990 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrazidines, III. Synthesis of 1,2,4,5-Tetrazino[3,2-a]isoindolesReaction of acetohydrazide hydrazone hydrochloride (1) with phthalaldehydic acid (5) yields 3-methyl-1,10b-dihydro-1,2,4,5-tetrazino[3,2-a]isoindol-6(4H)-one (8), which affords 1,2,4,5-tetrazino[3,2-a]isoindol-6(4H)-one (9a) by mild oxidation. 9a is also obtained by the reaction of 1 with the phthalic acid derivatives 6a, 7a, and 7b. Starting with 9a, the 1,2,4,5-tetrazino[3,2-a]isoindoles 12-15 are synthesized. Interaction of 1 and 3-nitrophthalic anhydride (6b) yields two isomeric nitro-1,2,4,5-tetrazino[3,2-a]isoindol-6(4H)-ones (9b,c). Oxidation of 9a or b with KMnO4 in methanol affords the 1,2,4,5-tetrazino 17a, b. Mild Oxidation of 9a with KMnO4 in water/trichloromethane yields a dimer (20), which dissociates in nitromethane into the radical 19.
    Notes: Durch Reaktion von Acetohydrazid-hydrazon-hydrochlorid (1) mit Phthaladehydsäure (5) wird 3-Methyl-1, 10b-dihydro-1,2,4,5-tetrazino[3,2-a]isoindol-6(4H)-on (8) erhalten das durch milde Oxidation in 3-Methyl-1,2,4,5-tetrazino[3,2-a]isoindol-6(4H)-on (9a) übergeführt wird. 9a entsteht auch aus 1 und den Phthalsäurederivaten 6a, 7a und 7b. Ausgehend von 9a werden die 1,2,4,5-Tetrazino[3,2-a]isoindole 12-15 synthetisiert. Aus 1 und 3-Nitrophthalsäureanhydrid (6b) werden zwei isomere Nitro-1,2,4,5-tetrazino[3,2-a]isoindol-6(4H)-one (9b, c) erhalten. Oxidation von 9a oder b mit KMnO 4 in Methanol ergibt die 1,2,4,5-Tetrazine 17a, b. Vorsichtige Oxidation von 9a mit KmnO4 in Wasser/Chloroform ergibt ein Dimeres (20), das in Nitromethan in das Radikal 19 dissoziiert.
    Additional Material: 2 Ill.
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    Stereochemie der Metall-Metall-Bindung. Strukturvergleich der Komplexe Cr2(CO)8(AsMe2)2, CrFe(CO)7(AsMe2)2 und Fe2(CO)6(AsMe2)2 (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1991-1998 
    Details
    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 Metal-Metal Bond. Structural Comparison of the Complexes Cr2(CO)8(AsMe2)2, CrFe(CO)7(AsMe2)2, and Fe2(CO)6(AsMe2)2The molecular structures of the new complexes CFer2(CO)8(AsMe2)2 (1) and CrFe(CO)7(AsMe2)2 (2) were determined crystallographically, that of Fe2(CO)6(AsMe2)2 (3) was redetermined. In all three compounds the metal-metal bond lengths are determined by the goemetrical requirements of the ligands. The fact that the M2As2 framework is planar in 1 and strongly folded in 2 and 3 can also be explained by the steric demands of the ligands. Aspects of the fluxionality of these complexes are discussed.
    Notes: Die Molekülstrukturen der neuen Komplexe Cr2(CO)8(AsMe2)2 (1) und CrFe(CO)7(AsMe2)2 (2) wurden kristallographisch ermittelt, die von Fe2(CO)6(AsMe2)2 (3) wurde neu bestimmt. In allen drei Verbindungen sind die Metall-Metall-Bindungslängen durch die geometrischen Ansprüche der Liganden festgelegt. Auch die Tatsache, daß das M2As2-Gerüst in 1 eben und in 2 und 3 jeweils stark gefaltet ist, läßt sich auf den Raumbedarf der Liganden zurückführen. Aspekte der Fluktuation dieser Komplexe werden diskutiert.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120609
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    Untersuchungen an Stoffwechselprodukten von Mikroorganismen, XX. Die Konstitutionen der Pigmente vom Flexirubin-Typ aus Cytophaga johnsonae Cyjl (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1999-2011 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Metabolites of Microorganisms, XX. The Structures of the Flexirubin-type Pigments from Cytophaga johnsonae CyjlCytophaga johnsonae Cy jl produces more than 25 different flexirubin-type pigments (2 a-h, 3 a-h, 4 a-h, 5) besides lower concentrations of carotenoids. These pigments could be separated using HPLC. Their structures have been elucidated. 5 is the first known member in this class of bacterial pigments containing two chlorine atoms.
    Notes: Das Gleitende Bakterium Cytophaga johnsonae Cy jl produziert neben wenig Carotinoiden mehr als 25 verschiedene Pigmente vom Flexirubin-Typ (2a-h, 3a-h, 4a-h, 5), deren Trennung u.a. durch Hochdruckflüssigchromatographie gelang. Über die Konstitutionen dieser Pigmente wird berichtet. Mit 5 wurde erstmals in dieser Verbindungsklasse ein dichlorhaltiges Pigment aufgefunden.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120610
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    Proton Magnetic Resonance Investigation of Inversion at Tervalent Nitrogen, 6. Preparative Separations of Enantiomeric Diaziridines by Liquid Chromatography on Triacetylcellulose. Racemizations Monitored by Polarimetry and by 1H NMR (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2028-2038 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Protonenresonanz-Untersuchugen zur Inversion am dreibindigen Stickstoffatom, 6. Präparative Trennungen enantiomerer Diaziridine durch Flüssigkeits-Chromatographie an Triacetylcellulose. Verfolgung der Racemisierungen mittels Polarimetrie und 1H-NMREnantiomere Diaziridine ließen sich durch Chromatographie an Triacetylcellulose anreichern. (-)-2, (+)-4 und (-)-4 wurden fast rein erhalten, wobei die enantiomeren Reinheiten (Tab. 1) mittels 1H-NMR in Gegenwart optisch aktiver Zusätze bestimmt wurden. Dasselbe Verfahren wurde im Hinblick auf die Verfolgung von Racemisierungen (Tab.2) erprobt, welche mit höherer Genauigkeit außerdem mittels Polarimetrie studiert wurden. Die Schwellen der Stickstoff-Inversion, welche die trans-Diaziridine 2 und 4 in cis-Zwischenstufen überführt, werden mit bekannten ΔG≠-Werten verglichen.
    Notes: Enantiomeric diaziridines have been partially separated by chromatography on triacetlycellulose. (-)-2, (+)-4, and (-)-4 were obtained almost pure, enantiomeric purities (Table 1) being measured by 1H NMR in the presence of optically active additives. The same procedure was tested for monitoring racemizations (Table 2) which were also studied, with higher accuracy, by polarimetry. The barriers to nitrogen inversion, converting the trans-diaziridines 2and4into cis-intermediates, are compared with known ΔG≠ values.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120613
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    Darstellung, Schwingungsspektrum und Kristallstruktur des dimeren (Isopropylidenamino) dimethylindiums (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2039-2044 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation, Vibrational Spectrum, and Crystal Structure of Dimeric (Isopropylideneamino) dimethylindiumThe title compound [Me2C=N—InMe2]2 was prepared from N-chloro-2-propanimine and trimethylindium. Its IR and Raman spectra were assigned; together with the 1H-NMR spectrum and the mass spectrum a centrosymmetric molecular structure with a four-membered (InN)2 ring was deduced. This was confirmed by an X-ray structure determination, according to which there exist two dimeric molecules per unit cell in the space group P21/c. The structure was refined with 958 reflexions up to a residual index of R = 0.024.
    Notes: Die Titelverbindung [Me2C=N-InMe2]2 wurde aus N-Chlor-2-propanimin und Trimethylindium synthetisiert. Das IR-und Raman-Spektrum wurde zugeordnet; zusammen mit dem 1H-NMR- und dem Massenspektrum ergibt sich eine zentrosymmetrische Molekülstruktur mit einem (InN)2-Vierring. Dies wird durch die Röntgenstrukturbestimmung bestätigt, nach der eine Struktur mit zwei dimeren Molekülen pro Elementarzelle in der Raumgruppe P21/c vorliegt. Die Struktur wurde bis zu einem Übereinstimmungsindex von R = 0.024 für 958 Reflexe verfeinert.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120614
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    Trimethylsilylcyanid als Umpolungsreagens, I. Nucleophile Acylierung von Alkylierungsmitteln mit aromatischen und heteroaromatischen Aldehyden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2045-2061 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Trimethylsilyl Cyanide  -  A Reagent for Umpolung, I. Nucleophilic Acylation of Alkylating Reagents with Aromatic and Heteroaromatic AldehydesThe readily accessible adducts 7 from (hetero)aromatic aldehydes and trimethylsilyl cyanide are deprotonated by lithium diisopropylamide. The so formed anions 8 react with alkyl halides, dialkyl sulfates and alkyl tosylates producing 19 with inversion and without interfering elimination. From 19 the protective group is removed under mild conditions and ketones 20 are produced mostly in 80-90% yield. The scope of the reaction sequence with respect to (hetero)aromatic aldehydes and alkylating agents is demonstrated. Lithium ions are shown to cooperate in the smooth substitution of tert-butyl iodide by 8. Within the given limits the described reaction sequence complements advantageously the known methods of nucleophilic acylation.
    Notes: Die aus (hetero)aromatischen Aldehyden und Trimethylsilylcyanid glatt zugänglichen Addukte 7 werden von Lithium-diisopropylamid zu den Anionen 8 deprotoniert, die ohne störende Eliminierung mit Alkylhalogeniden, Dialkylsulfaten und Alkyltosylaten unter Inversion zu 19 reagieren. Entfernung der Schutzgruppe aus 19 unter sehr milden Bedingungen liefert die Ketone 20 meist in Ausbeuten von 80-90%. Die Anwendungsbreite hinsichtlich der (hetero)aromatischen Aldehyde und der Alkylierungsmittel wird demonstriert. Für die glatte Substitution von tert-Butyliodid durch 8 wird Mitwirkung der Lithium-Ionen nachgewiesen. Im gesteckten Rahmen ergänzt diese nucleophile Acylierung die bekannten Methoden vorteilhaft.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120615
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    Trimethylsilylcyanid als Umpolungsreagens, II. Nucleophile Acylierung von Aldehyden und Ketonen unter anionischer 1,4-O,O-Silylgruppenwanderung (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2062-2067 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Trimethylsilyl Cyanide  -  A Reagent for Umpolung, II. Nucleophilic Acylation of Aldehydes and Ketones with Anionic 1,4-O,O-Silyl ShiftThe anion 9, derived from O-(trimethylsilyl) benzaldehyde-cyanohydrin (8), adds quantitatively to aldehydes and ketones. The primary adduct 11, which can be trapped as 12 after short reaction times, rearranges with 1,4-0,0-silyl shift. By subsequent cyanide elimination acyloin silyl ethers 14 are formed. Hydrolysis of 14 yields 80-90% of acyloins 15.
    Notes: Das Anion 9 des O-(Trimethylsilyl)benzaldehyd-cyanhydrins (8) addiert sich quantitativ an Aldehyde und Ketone. Das Primäraddukt 11, nach kurzer Reaktionszeit als 12 faßbar, lagert sich unter 1,4-0,0-Silylgruppenwanderung und Cyanidabspaltung zu den Acyloin - trimethylsilylethern 14 um, aus denen durch Hydrolyse die Acyloine 15 mit 80-90% Ausbeute entstehen.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120616
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    Zweifache Deprotonierung von 2-Aryl-1-nitroethanen Umpolung der Nitroolefin-Reaktivität (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 234-248 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Deprotonation of 2-Aryl-1-nitroethanes.  -  Umpolung of the Nitroolefin Reactivityβ-Arylnitroethanes 4 are doubly deprotonated to the dilithio derivatives 6 when treated with two equivalents of n-butyllithium in HMPTA-containing THF at -80 to -90°C. The reagents (6) may be considered as the products (see 3 and 16b) of reduction of ω-nitrostyrenes 2, They react with haloalkanes (→ 7), aldehydes and ketones (→ 8), α,β-unsaturated ketones (→ Michael adducts 13 and 14), and ω-nitrostyrenes (→ 15) in the benzylic position. With acyl chloride and chloro-trimethylsilane attack occurs probably on an oxygen of 6 (see intermediates 17-19). A representation of the novel reagents, best compatible with the chemical results, is that of super-enamines 16b; their charge affinity is compared with that of nitroethanes (the precursors) and that of nitroethylenes (the oxidized forms, see 2 → 3), and it is shown in table 1 that they are nitroolefins with reactivity umpolung or homonitronates. The comparison made in table 2 demonstrates that the dilithio derivatives 6 are synthetically equivalent with enamines and enolates of normal reactivity (“double umpolung”).
    Notes: β-Arylnitroethane 4 können bei -80 bis -90°C in HMPTA-haltigem THF mit zwei Equivalenten n-Butyllithium zu den Dilithiumderivaten 6 doppelt deprotoniert werden, die man als Reduktionsprodukte (s. 3 und 16b) von ω-Nitrostyrolen 2 auffassen kann. Sie reagieren mit Alkylhalogeniden (→ 7), Aldehyden und Ketonen (→ 8), α,β-ungesättigten Ketonen (→ Michael-Addukte 13 und 14) und ω-Nitrostyrolen (→ 15) am benzylischen C-Atom. Säurechlorid und Trimethylchlorsilan greifen wahrscheinlich am Sauerstoff an (s. Zwischenprodukte 17-19). Als mit den chemischen Befunden am besten vereinbare Schreibweise für die neuartigen Reagentien schlagen wir die von Super-enaminen 16b vor; in Tab. 1 ist ihre Ladungsaffinität mit der von Nitroethanen (den Vorläufern) und von Nitroethylenen (den oxidierten Formen, s. 2 → 3) verglichen und gezeigt, daß sie umgepolte Nitroolefine oder Homonitronate sind. Die Gegenüberstellung in Tab. 2 demonstriert. Daß die Dilithiumverbindungen 6 als Synthesebausteine für Amine und Carbonylverbindungen normale Reaktivität haben („Doppelumpolung“).
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791120121
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    Unerwartete Ringschlußreaktionen 2,2-disubstituierter N-Alkoxy-3-hydroxypropionamide mit Arylisocyanaten (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 600-606 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Unexpected Cyclisations of 2,2-Disubstituted N-Alkoxy-3-hydroxypropionamides with Aryl IsocyanatesTreatment of 2,2-disubstituted N-alkoxy-3-hydroxypropionamides (8) with aryl isocyanates (9) in a mole ratio of 1:2 in boiling benzene and in the presence of triethylamine yields 3-alkoxytetrahydro-2H-1,3-oxazine-2,4-diones (10) and 3-aryltetrahydro-2H-1,3-oxazine-2,4-diones (11). Formation of 10 and 11 depends largely on the nature of the substituents at C-2 of 8. In consequence of the cyclisation reactions ureas of type 13 and 14 and the 3-alkoxybiuret 15 are produced.
    Notes: 2,2-Disubstituierte N-Alkoxy-3-hydroxypropionamide (8) reagieren mit Arylisocyanat (9) im Molverhältnis 1:2 bei 80°C in Gegenwart von Triethylamin zu 3-Alkoxytetrahydro-2H-1,3-oxazin-2,4-dionen (10) und 3-Aryltetrahydro-2H-1,3-oxazin-2,4-dionen (11). Die Cyclisierungsrichtung zu 10 oder 11 wird maßgeblich von der Natur der Substituenten an C-2 von 8 bestimmt. Als Folge der Cyclisierungen lassen sich die Harnstoffe 13 und 14 sowie das 3-Alkoxybiuret 15 isolieren.
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    URL: http://dx.doi.org/10.1002/cber.19791120222
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    Nucleosidtransformationen, V. Umwandlung von Guanosin in 2′-Desoxy-, 3′-Desoxy-, 2′,3′-Anhydro- sowie xylo-Guanosin (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 625-639 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleoside Transformations, V. Transformation of Guanosine into 2′-Deoxy, 3′-Deoxy-, 2′,3′-Anhydro- and xylo-Guanosine3′-und 2′-deoxyguanosine (12 and 13, respectively) are obtained from guanosine (1) upon reaction with trimethyl orthoacetate, pivaloyl chloride/pyridine, tributyltin hydride and sodium methylate through the intermediates 2, 3a/4a. 2-N,5′-O-Dipivaloyl-2′,3′-anhydroguanosine (14) is formed on treatment of the 3′-iodoguanosine derivative 10 with potassium phthalimide. The 2′.3′-anhydroderivatives 14-16 form N-3 → C-3′-cyclonucleosides in aqueous solution. Stirring of 14 with a boron trifluoride etherate solution yields xylo-guanosine derivative 22.
    Notes: 3′-und 2′-Desoxyguanosin (12 bzw. 13) werden, ausgehend von Guanosin (1), durch Umsetzung mit Orthoessigsäure-trimethylester, Pivaloylchlorid/Pyridin, Tributylzinnhydrid und Natriummethylat über die Zwischenstufen 2, 3a/4a dargestellt. 2-N,5′-O-Dipivaloyl-2′,3′-anhydroguanosin (14) entsteht bei Behandlung des 3′-Iodguanosin-Derivats 10 mit Phthalimidkalium. In wäßriger Lösung zeigen die 2′,3′-Anhydroguanosin-Derivate 14-16 N-3 → C-3′-Cyclonucleosid-Bildung. Das xylo-Guanosin-Derivat 22 entsteht aus 14 beim Rühren mit einer Bortrifluoridetherat-Lösung.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791120224
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    Zum Mechanismus der Hydrierung bei Friedel-Crafts-Reaktionen α,β-ungesättigter Säuren mit Benzol (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 689-699 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Mechanism of Hydrogenation During Friedel-Crafts Reactions of α,β-Unsaturated Acids with BenzeneThe intermediate in the reaction of 3,3-diphenylpropenoic acid (1) with benzene/AlCl3 is the resonancestabilized carbenium ion 8. It reacts to give a mixture containing the products of hydrogenation 2 and of addition of benzene 3. Several artefacts of the working up (4 - 7) are found.  -  In the reactions of deuterated compounds hydrogen scrambling both in the phenyl groups and  -  to a smaller extent  -  in the α-position occurs.  -  Hydrogen (hydrid ions) derived from benzene, not from the side chain of a second molecule 1, is transferred to the β-position of 1.
    Notes: Die Umsetzung von 3,3-Diphenylpropensäure (1) mit Benzol/A1Cl3 führt über das mesomeriestabilisierte Carbenium-Ion 8 zu einem Substanzgemisch, in dem neben dem Hydrierungs- und dem Benzoladditionsprodukt (2 bzw. 3) Artefakte der Aufarbeitung,(4 - 7) enthalten sind.  -  Bei Einsatz deuterierter Ausgangsverbindungen tritt Äquilibrieren der Aryl- und (in geringem Umfang) der α-ständigen Wasserstoffe ein.  -  Bei der Hydrierung von 1 wird Wasserstoff des Benzols  -  nicht aber Wasserstoff aus der Seitenkette eines zweiten Moleküls 1  -  als Hydrid-Ion in die β-Stellung von 1 eingebaut.
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    URL: http://dx.doi.org/10.1002/cber.19791120230
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    Zur Autoxidation von cyclischen Iminen, I (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 734-742 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Autoxidation of Cyclic Imines, IIn a noncatalyzed reaction cyclic imines, e. g. 1a-d, bearing one or two α-tert. carbon atoms are oxidized by molecular oxygen. Usually, the products are relatively unstable α-iminohydroperoxides, which are subject to further rearrangement or reduction. These compounds are partially further oxidized. The isolation of the products as well as their structure elucidation by spectroscopic methods are established.
    Notes: Cyclische Imine mit einem oder zwei tert. α-C-Atomen, z.B. 1a-d, werden durch nichtsensibilisierten Sauerstoff oxidiert. Primär entstehen dabei meist instabile α-Iminohydroperoxide, die Folgereaktionen wie Umlagerung und Reduktion eingehen. Diese Verbindungen werden teilweise erneut oxidiert. Die Produkte der Autoxidation werden isoliert und ihre Konstitutionen ermittelt.
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    URL: http://dx.doi.org/10.1002/cber.19791120235
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    Schonende Veresterung von N-terminal geschützten Aminosäuren mittels der Vier-Komponenten-Kondensation (4 CC) (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 776-777 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mild Esterification of N-protected Amino Acids via Four-Component Condensation (4 CC)We describe the esterification of N-protected amino acid derivatives, e. g. glycine derivatives and Boc-Leu-OH, with methanol or ethanol, respectively, by the action of an enamine and an isocyanide.
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    URL: http://dx.doi.org/10.1002/cber.19791120239
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    Notizen. Dimerisierung von Diphenyl(trifluoracetyl)phosphanoxid (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 773-775 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dimerization of Diphenyl(trifluoroacetyl)phosphane OxideAt -25°C the phosphane oxide CF3C[(O)P(O)Ph2]2OC(O)CF3 (1) dimerizes to the trifluoroacetate CF3C[(O) PPh2]2OC(O)CF3 (2a), which is sensitive to hydrolysis and, at 40°C is transformed irreversibly into the phosphinate CF3C[(O)PPh2][OP(O)Ph2]C(O)CF3(3a). In contrast to 2a, the thermally more stable homologous octanate C7F15C[(O)PPh2]2OC(O)C7F15 (2b) is obtained from Ph2PCI and C7F15CO2H.
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    Masthead (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979) 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/cber.19791120301
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    In memoriam Walter Hieber 1895-1976 (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. XXI 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/cber.19791120241
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    Heterocyclische Siebenring-Verbindungen, XXII. Synthese und thermische Umlagerung von substituierten 4-Phenyl-1-benzothiepin-1-oxiden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 781-792 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic Seven-membered Ring Compounds, XXII. Synthesis and Thermolysis of Substituted 4-Phenyl-l -benzothiepin 1-Oxides4-Phenyl-l-benzothiepin l-oxides 3a and b have been prepared as well via the benzothiepinone 1-oxide 2 as by direct oxidation of the parent 1-benzothiepins 6a and b. The synthesis of 3c and d was only accomplished by the second way. Further oxidation of 3a-d yielded the thermally stable dioxides 4a-d. Thermolysis of 3a-d produced the corresponding naphthalenes 5a-d by elimination of SO. The rates of the reaction 3→5 have been estimated for one temperature each.
    Notes: Die 4-Phenyl-l-benzothiepin-l-oxide 3a und b wurden sowohl über das Benzothiepinon-1-oxid 2 als auch durch direkte Oxidation der entsprechenden 4-Phenyl- 1-benzothiepine 6a und b dargestellt. Die Synthese von 3c und d erfolgte nur auf dem zweiten Weg. Weiteroxidation von 3a-d führte zu den thermisch stabilen Dioxiden 4a-d. Die Thermolyse von 3a-d lieferte unter Abspaltung von SO die entsprechenden Naphthaline 5a-d. Die Geschwindigkeitskonstanten der Reaktion 3→5 wurden für je eine Temperatur bestimmt.
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    Bevorzugte O-Glycosidbildung bei der Ribosidierung von 5-Methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-on (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 799-806 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Favoured Formation of an O-Glycoside during Ribosidation of 5-Methyl-2-methylthio-7H-pyrrolo-[2,3-d]pyrimidin-4(3H)-one6-Amino-5-(2,2-diethoxy-l-methylethyl)-2-mercaptopyrimidin-4-ol (3a) has been prepared via condensation of racem. ethyl 2-cyano-4,4-diethoxy-3-methylbutyrate (2) and thiourea. Alkylation of 3 a at 2-SH with dimethyl sulfate is accompanied by ring closure yielding 5-methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-one (4b). Silylation of 4b followed by reaction with 2,3,5-tri-O-acetyl-1-bromo-D-ribofuranose in the presence of mercury(II) salts (Wittenburg conditions) gives the O-glycoside 6a and not the N-7-glycoside formerly obtained during ribosidation of 2-methylthio-7H-pyrrolo[2,3-b]pyrimidin-4(3H)-one12). Hydrolysis of 6a under mild conditions leads to deacetylation giving 5-methyl-2-methylthio-4-(D-ribofuranosyloxy)-7H-pyrrolo[2,3-d]pyrimidine (6b). The latter compound shows UV spectra similar to 4-methoxy-5-methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine (4c) down to pH 2, but at lower pH values hydrolysis of the glycosidic bond occurs.
    Notes: 6-Amino-5-(2,2-diethoxy-1-methylethyl)-2-mercaptopyrimidin-4-of (3 a) wurde durch Kondensation von racem. 2-Cyan-4,4-diethoxy-3-methylbuttersäure-ethylester (2) und Thioharnstoff gewonnen. Die Alkylierung von 3a mit Dimethylsulfat führt zur Methylierung an 2-SH, wobei gleichzeitig Cyclisierung zu 5-Methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-on (4b) erfolgt. Verknüpft man silyliertes 4 b mit 2,3,5-Tri-O-acetyl-l-brom-D-ribofuranose in Gegenwart von Quecksilber(II)-Salzen (Wittenburg-Bedingungen), so entsteht das O-Glycosid 6a und nicht wie bei der Reaktion von 2-Methylthio-7H-pyrrolo[2,3-d]pyrimidin-4(3H)-on das N-7-Glycosid12). Durch milde Hydrolyse von 6a erhält man 5-Methyl-2-methylthio-4-(D-ribofuranosyloxy)-7H-pyrrolo[2,3-d]pyrimidin (6b), dessen UV-Spektren bis pH 2 denen von 4-Methoxy-5-methyl-2-methylthio-7H-pyrrolo[2,3-d]pyrimidin (4c) gleichen, im stärker Sauren jedoch Glycosid-Hydrolyse anzeigen.
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    Totalsynthese von Papaverrubin E (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 849-852 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Total Synthesis of Papaverrubine EThe phthalide isoquinoline alkaloid (-)-bicuculline (la), which has previously been prepared by total synthesis, is transformed into racemic papaverrubine E (±)-(6a), its natural (+)- and its unnatural (-)-enantiomer.
    Notes: Das totalsynthetisch zugängliche Phthalidisochinolinalkaloid (-)-Bicucullin (la) wird in das Racemat des Benzazepinalkaloids Papaverrubin E (±)-(6a) sowie in sein natürliches (+)-bzw. unnatürliches (-)-Enantiomeres übergeführt.
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    Basische Metalle, XI. Kationische (Cyclopentadienyl)rhodium-Komplexe mit Rh—H-, Rh—C-, Rh—Ge-, Rh—Sn- und Rh—Halogen-Bindungen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 834-843 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Basic Metals, XI. Cationic (Cyclopentadienyl)rhodium Complexes Containing Rh—H-, Rh—C-, Rh—Ge-, Rh—Sn-, and Rh—Halogen Bonds[C8H12RhCl]2 reacts with excess trimethylphosphane to give [(PMe3)4Rh]Cl (1). A very rapid exchange of the phosphane ligands occurs in solution of 1. The reaction of 1 with T1C5H5 leads to the complex C5H5Rh(PMe3)2 (9), in which the metal atom is a strong Lewis base. 9 reacts very readily with electrophiles Y+ to give the cations [C5H5(PMe3)2RhY]+ which possess stable Rh—H, Rh-alkyl, Rh—acyl, Rh—Ge, Rh—Sn, and Rh—halogen bonds. They were isolated as PF6 salts [Y = H (2), CH3 (3), C2H5 (4), COCH3 (10), COC6H5 (11), COC6H4OMe-(p) (12), GeMe3 (7). SnMe3 (8). Br (15), cl (13), I (14). The cation Me3SiC5H4(PMe3)2RhH ]+ is formed together with [C5H5(PMe3)2RhH]+ in the reaction of 9 with CF3SO3SiMe3, in ether. Reduction with NaH in THF gives Me3SiC5H4Rh(PMe3)2.
    Notes: [C8H12RhCl]2 reagiert mit einem Überschuß von Trimethylphosphan zu [(PMe3)4Rh]Cl (1). In Lösungen von 1 findet ein sehr rascher Austausch der Phosphanliganden statt. Die Reaktion von 1 mit TIC5H5 führt zu dem Komplex C5H5Rh(PMe3)2 (9), der ein stark Lewis-basisches Metallatom besitzt. 9 reagiert mit Elektrophilen Y+ sehr bereitwillig zu den Kationen [C5H5(PMe3)2RhY]+ die stabile Rh—H-, Rh—Alkyl-, Rh—Acyl-, Rh—Ge-, Rh—Sn- und Rh—Halogen-Bindungen besitzen und als PF6-Salze isoliert werden [Y = H (2), CH3 (3), C2H5 (4), COCH3 (10), COC6H5 (11), COC6H4OMe-(p) (12), GeMe3 (7), SnMe3 (8), Br (15), Cl (13). 1(14)]. Bei der Reaktion von 9 mit CF3SO3SiMe3 in Ether entsteht neben [C5H5(PMe3),2RhH] + das Kation [Me3SiC5H4(PMe3)2RhH]+. Die Reduktion mit NaH in Tetrahydrofuran ergibt Me3SiC5H4Rh(PMe3)2.
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    Photoelektronenspektren und Konformationen bi- und tricyclischer Hexahydro-1,2,4,5-tetrazine (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 853-861 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectra and Conformations of Bi- and Tricyclic Hexahydro-1,2,4,5-tetrazinesThe photoelectron spectra of three tricyclic (2-4) and three bicyclic (5-7) hexahydro-1,2,4,5-tetrazines have been interpreted with regard to gas phase conformations. The interactions of the n-orbitals have been studied by MINDO/2 calculations for different conformations of hexahydro-1.2.4,5-tetrazine (1). The observed n-electron ionization potentials permit the identification of tetraequatorial forms of 2-4 and diequatorial-diaxial forms of 5-7 as the dominant conformers. In addition, for 2 and 5 other less stable conformers could be detected.
    Notes: Die Photoelektronenspektren von drei tricyclischen (2-4) und von drei bicyclischen (5-7) Hexahydro-1,2,4,5-tetrazinen wurden hinsichtlich der in der Gasphase vorliegenden Konformeren ausgewertet. Für die infrage kommenden Konformationen wurden zum Studium der Wechselwirkung der n-Orbitale MINDO/2-Rechnungen an der Stammverbindung (1) ausgeführt. Anhand der beobachteten n-Ionisationsbanden lassen sich bei 2-4 tetraäquatoriale und bei 5-7 diäquatorial-diaxiale Formen als stabilste Konformere identifizieren. Bei 2 und 5 wurden daneben weniger stabile Konformere nachgewiesen.
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    Struktur und innere Beweglichkeit sterisch fixierter s-cis-Butadiene (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 890-898 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure and Internal Flexibility of Sterically Fixed s-cis-ButadienesForce Field Calculations yield a coplanar arrangement of the π systems of the vicinal exo-methylene derivatives 1 and 2 of cyclobutane and cyclopentane and of the corresponding derivatives 4-7 of norbornane, bicyclooctane, bicyclononane and bicyclooctene. The detailed geometry of the cis-butadiene unit is essentially determined by the ring system. For the cyclohexane derivative 3 on the other hand a chair conformation is obtained. 2,5 and 6 are rather flexible molecules for which torsions of the π system up to 20° require energies less than 5 kJ/mol, whereas for the more rigid systems 1, 4 and 7 approximately 10 kJ/mol are necessary for twisting the π system by 10°.
    Notes: Kraftfeldrechnungen ergeben für die vicinalen exo-Methylenderivate 1 und 2 des Cyclobutans und des Cyclopentans sowie für die entsprechenden Derivate 4-7 des Norbornans, Bicyclooctans, Bicyclononans und des Bicyclooctens eine planare Anordnung des π-Systems. Dessen genaue Geometrie im wesentlichen durch das cyclische Gerüst bestimmt wird. Das Cyclohexanderivat 3 dagegen liegt in einer Sesselform vor. Die Moleküle 2, 5 und 6 zeichnen sich durch große Flexibilität aus, Torsionen des π-Systems bis etwa 20° erfordern Energien von weniger als 5 kJ/mol, während für die starreren Systeme 1,4 und 7 bereits bei Verdrillungen um 10° etwa 10 kJ/mol erforderlich sind.
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    Ligandstruktur und Komplexierung, XLIV. Synthese und Selektivität neuartiger vierarmiger nichtcyclischer Neutralliganden (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 899-907 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ligand Structure and Complexation, XLIV. Synthesis and Selectivity of New Four-Armed Noncyclic Neutral LigandsNew, noncyclic neutral ligand systems 4-6 and 8-11 of the tetrapode type 3, equipped with various end groups, were synthesized. The cation selectivity depends on the structure of the end groups. The potentiometrically determined values of the complex stability constants as a rule lie between those of the analogous tripode (2) and dipode ligands (1). Numerous complexes between the four-armed complexing agents and several dipodands (14-16) and alkali and alkaline earth metal salts are reported.
    Notes: Neue nichtcyclische Neutralligandsysteme 4-6 und 8-11 vom Tetrapodentyp 3 mit verschiedenen Endgruppen wurden synthetisiert. Die Kation-Selektivität hängt von der Endgruppenstruktur ab. Die potentiometrisch bestimmten Komplexstabilitätskonstanten liegen i. a. zwischen denjenigen der Tripoden- (2) und Dipoden-Liganden (1). Zahlreiche kristalline Komplexe der vierarmigen Komplexbildner sowie einiger zum Vergleich synthetisierter neuer Dipodanden (14-16) mit Alkali- und Erdalkalimetallsalzen wurden erhalten.
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    Über N-Silyl- und N-Germylpyridinyl-Radikale sowie ihre Stabilisierungsreaktionen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 936-949 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Silyl and N-Germylpyridinyl Radicals, and Their Stabilization ReactionsPyridines, functionally substituted in 2-, 3-, or 4-position, give N-silylpyridinyls (3, 7, 11, 16, 19, 23) upon reaction with (Me3Si)2Hg, and further on mostly N,ω-bis(silyl) derivatives (5), tetrahydro-4,4′-or -2,2′-bipyridines (9, 17, 20, 21, 24, 25), depending on mesomeric and steric conditions. 2- and 3-acylpyridines yield O-silylated hydropyridoins (27, 30), 2-cyanopyridine forms a persistent pyridinyl (29). N-Germylpyridinyls (32-34) are generated for the first time. With (Me3Ge)2Hg, they are formed, however, only in the case of substituted pyridines of low electron density or strong mesomeric stabilization of the radicals. Several N ω-bis(germyl)-dihydropyridines (36, 37) rearrange, in part even at -30°C, with a surprising N, C-migration of a germyl residue, restoring the aromatic system, giving 35, 39. ESR data are given for most of the generated radicals.
    Notes: In 2-, 3- oder 4-Stellung funktionell substituierte Pyridine geben mit (Me3Si)2Hg N-Silylpyridinyle (3, 7, 11, 16, 19, 23), die je nach Mesomeriestabilisierung und sterischer Hinderung meistens zu N,ω-Bis(silyl)-Derivaten (5) oder zu Tetrahydro-4,4′- bzw. -2,2′-bipyridinen (9, 17, 20, 21, 24, 25) weiterreagieren. 2- und 3-Acylpyridine ergeben O-silylierte Hydropyridoine (27, 30), 2-Cyanpyridin ein kinetisch stabiles Pyridinyl (29). N-Germylpyridinyle (32-34) werden erstmals erhalten. Sie entstehen mit (Me3Ge)2Hg nur im Falle elektronenarmer substituierter Pyridine bzw. starker Mesomeriestabilisierung der Radikale. Bei N,ω-Bis(germyl)dihydropyridinen (36, 37) wurde, z. T. schon bei -30°C, eine überraschende N,C-Wanderung eines Germylrestes unter Rückbildung des aromatischen Systems zu 35, 39 gefunden. Für die meisten der erhaltenen Radikale werden die ESR-Daten angegeben.
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    Stoffwechselprodukte von Mikroorganismen, 172. Isolierung des Antibioticums semi-Vioxanthin aus Penicillium citreo-viride und Synthese des Xanthomegnins (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 957-978 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metabolic Products of Microorganism, 172. Isolation of the Antibiotic semi-Vioxanthin from Penicillium citreo-viride and Synthesis of XanthomegninBesides xanthomegnin (16 b), 3,4-dehydroxanthomegnin (29a), viomellein (23) and vioxanthin (3) from Penicillium citreo-viride under different culture conditions semi-vioxanthin (7) was isolated. Structure 7 has been established by its spectra and the fact that oxidation with Fremy's salt gives 3,4,6,9-tetrahydro-10-hydroxy-7-methoxy-3-methyl-1,6,9-trioxo-1H-naphtho[2,3-c]pyran (9a = semi-xanthomegnin). -9c, prepared by demethylation of 9a, was dimerized by potassium peroxydisulfate/sodium hydroxide and methylated, giving 16b. Synthetic 16b and authentic xanthomegnin were identical, which verifies the structure revised by Höfle and Röser9) and shows, that the dyes of the xanthomegnin series are biogenetically homogenous. - The metabolic products of the strain inhibit the growth of bacteria. 16b and 26 furthermore have an effect against insects.
    Notes: Neben Xanthomegnin (16b), 3,4-Dehydroxanthomegnin (29 a), Viomellein (23) und Vioxanthin (3) wurde aus Penicillium citreo-viride unter veränderten Kulturbedingungen semi-Vioxanthin (7) isoliert. Konstitution 7 folgt aus den Spektren und dem Befund, daß mit Fremy-Salz 3,4,6,9-Tetrahydro-10-hydroxy-7-methoxy-3-methyl-1,6,9-trioxo-1H-naphtho[2.3-c]pyran (9a = semi-Xanthomegnin) entsteht. - Das durch Entmethylierung von 9a zugängliche 9c ließ sich mit Kaliumpersulfat/Natriumhydroxid zu 16a dimerisieren, das zu 16b methyliert wurde. Synthetisches 16b war mit nativem Xanthomegnin identisch, was die von Höfle und Röser9) revidierte Konstitution bestätigt und beweist, daß die Farbstoffe der Xanthomegnin-Reihe biogenetisch einheitlich sind. - Die Stoffwechselprodukte des Stammes hemmen das Wachstum von Bakterien, 16b und 23 wirken ferner gegen Insekten.
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    Mikrobiologische Umwandlung von Steroiden, XVI. Synthese von 11β, 21-Dihydroxy-6, 16α-dimethyl-1,4,6,-pregnatrien-3,20-dion und dessen 11-Ketoverbindung (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 979-989 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbial Transformations of Steroids XVI. Synthesis of 11β,21-Dihydroxy-6, 16α-dimethyl-1,4,6-pregnatriene-3,20-dione and of its 11-Keto Compound21-Acetoxy-5α,6α-epoxy-3β-hydroxy-6β16α-dimethyl-20-pregnanone (3a), prepared from 3β-hydroxy-6, 16α-dimethyl-5-pregnen-20-one (1) by epoxidation and chemical introduction of the 21-acetoxy group, was oxidized to 6α,21-dihydroxy-6β,16α-dimethyl-4-pregnene-3,20-dione (4) by Flavobacterium dehydrogenans and dehydrated to the 3-keto-4,6-diene 5. The 11β-hydroxy group was introduced by Curvularia lunata to give 6, and the 11α-hydroxy group by Aspergillus ochraceus to yield 8. Both compounds were dehydrogenated with Bacillus lentus to from 7 and 9. The 11α-hydroxy compound 9 was selectively acetylated to 10, which was oxidize to 11. This on saponification yielded 12.
    Notes: 21-Acetoxy-5α,6α-epoxy-3β-hydroxy-6β,16α-dimethyl-20-pregnanon (3a), dargestellt aus 3β-Hydroxy-6, 16α-dimethyl-5-pregnen-20-on (1) durch Epoxidierung und 21-Acetoxylierung, wurde mit Flavobacterium dehydrogenans zu 6α,21-Dihydroxy-6β, 16α, -dimethyl-4-pregnen-3,20-dion (4) oxidiert und zu 21-Hydroxy-6, 16α-dimethyl-4,6-pregnadien-3,20-dion (5) dehydratisiert. Mit Curvularia lunata wurde die 11β-Hydroxygruppe eingeführt zu 6, während Aspergillus ochraceus die entsprechende 11α-Hydroxyverbindung 8 ergab. Beide Verbindungen wurden mit Bacillus lentus zu 7 bzw. 9 dehydriert. Die 11α-Hydroxyverbindung 9 wurde nach selektiver Acetylierung der 21-Hydroxygruppe zu 10 zum 11-Keton 11 oxidiert, dessen Verseifung 12 ergab.
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    Neue Synthesen mit Diazodiketonen, IV. Cyclische S-Oxide (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1012-1022 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Syntheses with diazodiketones, VI. Cyclic S-OxidesThe S-oxides 4 of 3,4-dihydro-1,2,3-oxathiazines and 5 of 1,2-oxazetidines are prepared a) by thermolyzing diazodiketones 1 with N-Sulfinylamines 3; b) by condensing the 2-acylacetamides 6 which are readily accessible from 1, with thionyl chloride in the presence of a basic catalyst. From 6, the aminoacrylamides 7 are obtained. These react with thionyl chloride according to the base employed, to afford either the monocyclic 3,6-dihydro-1,2,6-thiadiazine-S-osides 10 or the 4-amino-quinolines 8, presumably via the intermediacy of an imine 9. - The introduction of the SO group into (hetero)cyclic iminocarboxamides, diamines or aminophenols give rise to the S-oxides 13 of condensed thiadieazines, 15a-c of benzothiadiazole, or 15d of benzoxathiazole, respectively.
    Notes: Die 3,4-Dihydro-1,2,3-oxathiazin- 4 und 1,2-Oxazetidin-S-oxide 5 werden a) durch Thermolyse der Diazodiketone 1 mit N-Sulfinylaminen 3 b) durch basenkatalysierte Kondensation der aus 1 leicht zugänglichen 2-Acylacetamide 6 mit Thionylchlorid hergestellt. Aus 6 weden die Aminoacrylamide 7 erhalten. Diese reagieren mit Thionylchlorid je nach der verwendeten Base entweder zu monocyclischen 3,6-Dihydro-1,2,6-thiadiazin-S-oxiden 10 oder über eine Imidoylketenimin Zwischenstufe 9 zu den 4-Aminochinolinen 8. - Der SO-Einbau mittels Thionylchlorid in (hetero)-cyclische Iminocarboxamide, Diamine und Aminophenole führt zu den S-oxiden 13 kondensierter Thiadiazine, 15a-c des Benzothiadiazols bzw. 15d des Benzoxathiazols.
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    Untersuchungen zur Modifizierung der Mannobiose und Synthese von Methyl-4-O-β-D-rhamnosyl-α-D-olivosid (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1035-1045 
    Details
    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 Modification of Mannobiose and Synthesis of Methyl 4-O-β-D-Rhamnosyl-α-D-OlivosideBy acid-catalyzed reaction of α-mannobiose octaacetate (2) with trichloroethanol or phenol the glycosides 6 or 9a, and with hydrogen bromide/acetic acid the glycosyl bromide 3 are obtained. Koenigs-Knorr reaction of 3 with methanol of benzyl alcohol yields the orthester derivatives 7a or 7b, respectively. Mannobial hexaacetate 8 is obtained from 3 an d transformed into 12a by iodomethoxylation. The selective tosylations of 9b or 12b in the 6- and 6′ -positions yields the ditosylates 10 or 13a, which in turn give the corresponding diiodo compounds 11a or 5a, respectively. By subsequent reduction using nickel chloride/sodium borohydride the syntheses of the glycosides 14 and 17b of 4-O-(β-D-rhamnopyranosyl)-α-D-rhamnopyranose or 4-O-(β-D-rhamnopyranosyl)-α-D-olivopyranose, respectively, are achieved. All new compounds are characterized by peracetates, and their structural assignment is confirmed from their NMR spectra.
    Notes: α-Mannobiose-octaacetat (2) läßt sich sauer katalysiert mit Trichlorethanol oder Phenol zu den Glycosiden 6 bzw. 9a oder mit Bromwasserstoff in Eisessig zum Glycosylbromid 3 umsetzen. Koenigs- Knorr-Reaktion von 3 mit Methanol oder Benzylalkohol ergibt die Orthoester 7a bzw. 7b. Aus 3 wird Mannobial-hexaacetat 8 gewonnen und zu 12a iodmethoxyliert. 9b bzw. 12b lassen sich selektiv in 6- und 6′- Position zu 10 bzw. 13a tosylieren und anschließend in die entsprechenden Iodide 11a bzw. 15a überführen. Deren Reduktion mit Nickelchlorid/Natriumboranat in Ethanol erlaubt die Darstellung der Glycoside 14 and 17b von 4-O-(β-D- Rhamnopyranosyl)-α-D-rhamno-pyranose bzw. 4-O-0(β-D-Rhamnopysanosyl)-α-D-olivopyranose. Alle Syntheseprodukte werden durch Peracetate charakterisiert und strukturell an Hand der NMR-Spektren zugeordnet.
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    URL: http://dx.doi.org/10.1002/cber.19791120325
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    Synthese, Strukturaufklärung und Konformationsuntersuchungen 1→4-verknüpfter Disaccharidglycoside vom 2,3-Anhydro-4-O-(hex-2-enopyranosyl)-α-D-allopyranosid-Typ (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1023-1034 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Structure Elucidation, and Conformational Studies of 1→4-Linked Disaccharide Glycosides of the 2,3-Anhydro-4-O-(hex-2-enopyranosyl)-α-D-allopyranoside TypeTriacetyl-D-glucal (1) or tetraacetyl-2-hydroxy-D-glucal (6) and 2,3-anhydro-α-D-allopyranosides 2 or 7, respectively, undergo smooth acid-catalyzed allylic rearrangement reactions to yield the crystalline α-linked disaccharide derivatives 4, 5, and 9 with hex-2-enopyranosyl structure in the non-reducing rings in good yields. By hydrogenation of 4 and 5, 8 is obtained, in which the α-linkage can be demonstrated. X-ray analysis confirms the interglycoside α-linkage in the considerably stretched disaccharide derivative 5. Both the saccharide ring adopt SO5 sofa conformations, in which only C-5 and C-5′ ae observed significantly below the plane of the remaining ring atoms. The NMR data of 5 and 9 suggest also SO5 sofa conformation in solution. On the contrary the β-isomer 10 adopts 5SO sofa conformation which is consistent with the allylic effect.
    Notes: Durch sauer katalysierte Addition der 2,3-Anhydro-α-D-allopyranoside 2 bzw. 7 an Triacetyl-D-glucal (1) bzw. Tetraacetyl-2-hydroxy-D-glucal (6) lassen sich unter Allylumlagerung die α1→4-verknüpften Disaccharide 4, 5 und 9 mit Hex-2-enopyranosyl-Struktur im nicht-reduzierenden Saccharidring milde und in guten Ausbeuten kristallin gewinnen. Durch Hydrierung von 4 und 5 wird 8 erhalten, bei dem die interglycosidische α-Verknüpfung nachgewiesen wird. Die Röntgenstrukturanalyse von 5 bestätigt die α-Verknüpfung in dem erheblich gestreckten Disaccharidderivat. Beide Saccharidringe weisen eine SO5-Sofakonformation auf, bei der nur die Atome C-5 und C-5′ wesentlich aus der Ebene der übrigen Ringatome nach unten herausstehen. Konformationsbetrachtungen legen auch in Lösung für 5 und 9 das Vorliegen einer SO5-Sofakonformation nahe. Das interglycosidische β-Isomere 10 weist dagegen eine 5SO-Sofakonformation auf, was auf den Allyleffekt zurückgeführt werden kann.
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    Untersuchungen zur Modifizierung der Laminaribiose und Synthese von Methyl-3-O-β-D-chinovosyl-α-D-olivosid (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1046-1056 
    Details
    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 Modification of Laminaribiose and Synthesis of Methyl 3-O-β-D-Quinovosyl-α-D-olivosideLaminaribiose (2) and the peracetates 3a and b are obtained by acetolysis of laminaran or pachyman, respectively. Via formation of the bromide 5, the β-methyl (6) and β-benzyl glycosides (7a and b) as well as the glycals 9a and b are obtained in crystalline form. Iodoalkoxylations with benzyl alcohol yield the epimeric benzyl glycosides 10a and b, whereas with methanol 11a is obtained exclusively. 11b is transformed into the dibenzylidene compounds 12a-c. the reaction of which with N-bromosuccinimide leads to the formation of the 2,6,6′- trihalo derivatives 13a and b. By subsequent reduction the title compound 14b is obtained and characterized as its peracetate.
    Notes: Ausgehend von Laminaribiose (2) und ihren Peracetaten 3a und b, die durch Acetolyse von Laminaran bzw. Pachyman zugänglich sind, lassen sich über das Bromid 5 die β-Methyl- (6) und β-Benzylglycoside (7a und b) sowie die Glycale 9a und b kristallin gewinnen. Iodalkoxylierung mit Benzylalkohol gibt die epimeren Benzylglycoside 10a und b, während mit Methanol einheitlich 11a isoliert wird. Aus 11b werden die Dibenzylidenverbindungen 12a-c dargestellt, deren Öffnung mit N-Bromsuccinimid zu den 2,6,6′-Trihalogenderivaten 13a und b führt. Durch Reduktion wird daraus die Titelverbindung 14b gewonnen und als Peracetat charakterisiert.
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    Tertiäres Phosphan/Hexachlorethan als Kondensationsreagenz für die Peptidsynthese (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1057-1063 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tertiary Phosphane/Hexachloroethane as Condensing Agent in Peptide SynthesisThe action of tertiary phosphane/hexachloroethane on N-protected amino acids and amino acid esters is found applicable for peptide synthesis. No difficulties are found when the side chains of serine, threonine, tyrosine, asparagine and glutamine are present. By addition of 1-hydroxybenzotriazole racemisation is prohibited as indicated by the test of Anderson.
    Notes: Mit dem Dehydratisierungsreagenz tertiäres Phosphan/Hexachlorethan lassen sich N-geschützte Aminosäuren und Aminosäureester in hohen Ausbeuten zu Peptiden kondensieren. Funktionelle Gruppen in den Seitenketten von Serin, Threonin, Tyrosin, Asparagin und Glutamin werden nicht angegriffen Unter Zusatz von 1-Hydroxybenzotriazol verläuft der Anderson-Test racemisierungsfrei.
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  • 86
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    Synthetische Arbeiten in der Reihe der aromatischen Erythrina-Alkaloide, XXIII. 1,7-Cyclo-cis-erythrinane (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1110-1125 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Aromatic Erythrina Alkaloids, XXIII. 1,7-Cyclo-cis-erythrinanesThe 1,7-cyclo-cis-erythrinane derivative 17 is formed by heating the bromo compound 13 with potassium hydroxide in diethylene glycol to 180°C. Hydrolysis of 17 yields the ketone 18 which, by reactions of the carbonyl group, is transformed into the cyclic compounds 19 - 21 and 27 - 33. The cyclopropane ring is easily cleaved by reduction to give the unsaturated lactam 10 or the saturated lactam 1. The 1,7-cyclo-cis-erythrinane structures 37 and 38 can be synthesized by way of the cyclic olefin 35.
    Notes: Durch Erhitzen der Bromverbindung 13 mit Kaliumhydroxid in Diethylenglycol auf 180°C entsteht das 1,7-Cyclo-cis-erythrinan-Derivat 17. Nach Hydrolyse zum Keton 18 erhält man durch Umwandlung der Ketogruppe die Cycloverbindungen 19 - 21 und 27 - 33. Reduzierende Bedingungen spalten den Cyclopropanring sehr leicht auf unter Bildung des Olefinlactams 10 oder des gesättigten Lactams 1. Über das Cycloolefin 35 gelingt die Darstellung von 37 und der zugehörigen Base 38 mit dem Grundgerüst der 1,7-Cyclo-cis-erythrinane.
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    URL: http://dx.doi.org/10.1002/cber.19791120407
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    Synthetische Arbeiten in der Reihe der aromatischen Erythrina Alkaloide, XXIV. Über die Bromierungsprodukte von 15,16-Dimethoxy-cis-erythrinan-2,8-dion (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1126-1139 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Aromatic Erythrina Alkaloids, XXIV. On the Products of Bromination of 15,16-Dimethoxy-cis-erythrinane-2,8-dioneBromination of 1 as well as hydrolysis of 5 (with inversion at C-l) yields the bromoketolactam 2. This can be converted back to 5, again with inversion. On reduction of 2 with sodium tetrahydridoborate, the bromohydrines 11-13 and the epoxide 17 are obtained. The epimeric bromoketolactam 6 cannot be isolated, but is an intermediate in the formation of 12 and 13. 2 reacts with potassium hydroxide in methanol or ethylene glycol to give the hydroxyacetals 18 and 19, respectively. From 1 the dibromoketones 24 and 25 were prepared which exhibit unusual spectral properties.
    Notes: Das Bromketolactam 2 wird aus 1 durch Bromierung oder aus 5 durch Hydrolyse unter Umkehrung der Konfiguration an C-l erhalten. Auch die entgegengesetzte Reaktion von 2 nach 5 verläuft unter Umkehr. Mit Natriumboranat liefert 2 die Bromhydrine 11, 12, 13 und das Epoxid 17. Bei der Bildung von 12 und 13 ist wieder das selbst nicht faßbare epimere Bromketolactam 6 Zwischenprodukt. Die Umsetzung von 2 mit Kaliumhydroxid in Methanol oder Ethylenglycol führt zu den Hydroxyacetalen 18 oder 19. Die aus 1 dargestellten Dibromketone 24 und 25 haben auffallende spektroskopische Eigenschaften.
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    Methylschwefelpentafluorid und einige seiner Derivate (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1140-1146 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Methylsulfurpentafluoride and Some of its DerivativesMethylsulfurpentafluoride (5) was systematically synthesized, starting with SF5Cl and ketene. It is stable at room temperature against HF elimination. The reaction of SF5Cl and diketene gives compounds of the type SF5—CH2—X, but the title compound is not produced in this way.
    Notes: Methylschwefelpentafluorid (5) wurde systematisch synthetisiert, ausgehend von SF5Cl und Keten. Es ist bei Raumtemperatur stabil gegen HF-Eliminierung. Die Reaktion von SF5Cl und Diketen führt zu einer Vielzahl anderer Verbindungen des Typs SF5—CH2—X, in einfacher Weise jedoch nicht zur Titelverbindung.
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    Synthesen biologisch wichtiger Kohlenhydrate, 20. N-Acetyl-1,4-di-O-acetyl-β-DL-vancosamin (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3273-3281 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Biologically Important Carbohydrates, 20. N-Acetyl-1,4-di-O-acetyl-β-DL-vancosamineClaisen rearrangement of 1-methyl-2-butenyl vinyl ether (3) yields trans-3-methyl-4-hexenal (4), the ethylene acetal 5 of which is aminated with selenium and chloramine T forming a mixture of the 3-methyl-3-tosylamino- (6) and 3-methyl-6-tosylamino derivatives 7. After detosylation of 6 and N-acetylation trans-3-acetylamino-3-methyl-4-hexenal ethylene acetal (9) is cis-hydroxylated to give 10/11. Cleavage of the protecting group at C-1 and peracetylation gives n-acetyl-1,4-di-O-acetyl-β-DL -vancosamine (13). The constitution of 13 is proved by mass spectrometry and the lyxo-configuration is assigned with high probability on the basis of 1 H NMR investigation *).
    Notes: Die Claisen-Umlagerung von (1-methyl-2-butenyl)-vinyl-ether (3)liefert trans-3-Methyl-4-hexenal(4), dessen Ethylenacetal 5 mit Selen und Chloramin-T zu den 3-Methyl-3-tosylamino-(6) und 3-Methl-6-tosylamino-Derivaten 7 aminiert wird. Nach Detosylierung von 6 und N-Acetylierung wird trans-3-Acetylamino-3-methyl-4-hexenal-ethylenacetal (9) zu 10/11 cis-hydroxyliert. Abspaltung der Schutzgruppe an C-1 und Peracetylierung liefert n-Acetyl-1,4-di-O-acetyl-β-DL-vancosamin (13), dessen Konstitution durch MS bewiesen und dessen lyxo-Konfiguration durch 1 H-NMR-Untersuchungen weitgehend gesichert wird *).
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    URL: http://dx.doi.org/10.1002/cber.19791120922
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    Monomere Bis[dialkylphosphonium-bis(methylid)]-Komplexe des Nickels, Palladiums und Platins (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3311-3317 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monomeric Bis[dialkylphosphonium bis(methylide)] Complexes of Nickel, Palladium, and PlatinumThe reaction of bis(trimethylphosphane) complexes of NiCl2 and PdCl2 with the bulky ylide CH3[(CH3)3C]2P = CH2 in a molar ratio 1:4 leads to transylidation and formation of corresponding phosphonium salt and the new ylide chelates [(CH3)3C]2P(CH2)2M(CH2)2P[(CH3)3]2; M = Ni (1); M = Pd (2). In similar experiments with PtCl2, only the salt-like half-complex [(CH3)3C]2P(CH2)2Pt[P(CH3)3]2+Cl¯ (3) is obtained. However, the reaction of the lithiated ylide with (l,5-cyclooctadiene)PtCl2 yields the missing Pt analogue of the above type (4). Contrary to the results with Pd11, Ni11 reacts with 1 -methyl- l-methylene-λ.5-phospholane and -phosphorinane to give monomeric bis-chelates of the formula CH2]nP(CH2):Ni(CH2)2:P[CH2]n; n = 4 (5): n = 5 (6). The monomeric Structure was confirmed by 1H, 13C, 31P NMR, and mass spectra, and attributed to steric effects in the case of the tert-butyl compounds. The opening of the CPC chelate angle induced by the strained ring system of the cyclic ylides appears to favour pseudo-allyl type interactions with the nickel centre.
    Notes: Die Bis(trimethylphosphan)-Komplexe von NiCl2 und PdCl2 reagieren mit dem sterisch anspruchsvollen Ylid CH3[(CH3)3C]2P≡CH2 im Molverhältnis 1:4 unter Umylidierung zum zugehörigen Phosphoniumsalz und den neuen Ylid-Chelaten [(CH3)3C]2P(CH2)2M(CH2) P[2CH3)3 M] ≡Ni (1), M = Pd (2). Mit PtCl2 entsteht dagegen bei deràrtigen Ansätzen nur der salzartige Halbkomplex [(CH3)3C]2P(CH2)2Pt[P(CH3)3]2-;Cl+ (3). Die Reaktion des lithiierten Ylids mit (l,5-Cyclooctadien)PtCI2 liefert dagegen das fehlende Pt-Analoge des obigen Typs (4). - lm Gegensatz zu den Verhältnissen bei Pd11 ergibt NiII auch mit l-Methyl-l-methylen-λ5-phospholan und -phosphorinan monomere Doppelchelate der Formel [CH2]nP(CH2)2Ni(CH2)2P[CH2]n: n = 4(5), n = 5 (6). Die Monomerstruktur wurde durch 1H. 13C, 31P-NMR- und Massenspektren gesichert und bei den tert-Butyl-Verbindungen durch sterische Effekte gedeutet. Bei den cyclischen Yliden begünstigt die starke Winkelöffnung der Chelateinheit eine Pseudo-Allylwechselwirkung mit dem Nickelzentralatom.
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    Reaktivität von Metall-Metall-Bindungen. Wiederholte Schließung und Öffnung einer Fe - Co-Bindung durch Eliminierung und Addition (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3390-3412 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of Metal-Metal Bonds. Repeated Formation and Cleavage of a Fe - Co Bond by Elimination and AdditionIn arsenic-bridged dinuclear metal carbonyl complexes the sequence of formation and cleavage of the metal-metal bond by elimination of CO and addition of a phosphine ligand is repeatable. Starting from (CO)4Fe -AsMe2 - Co(CO)4 it can be performed four times in a row. The ligand which in each case is introduced at the cobalt atom can be transferred to the iron atom by isomerisation in complexes with and without metal-metal bonds. With Pme3 and P(OMe)3 as phosphines and up to the introduction of three ligands thus 44 different complexes are possible of which 35 were isolated (scheme 1). By side reactions or for the purpose of comparisons further complexes with chain-like arrangements of metal and P or As atoms were obtained. When four ligands are introduced the elimination/addition scheme reaches a natural limit since then phosphine elimination is preferred to CO elimination. The described sequences can be understood as basic patterns of catalytic activity by opening of metal-metal bonds.
    Notes: In arsenverbrückten Metallcarbonyl-Zweikernkomplexen ist die Sequenz von Bildung und Lösung der Metall-Metall-Bindung durch Eliminierung von CO und Addition eines Phosphanliganden wiederholbar. Ausgehend von (CO)4Fe-AsMe2-Co(CO)4 läßt sie sich viermal hintereinander durchführen. Der jeweils am Cobaltatom eingeführte Ligand kann in Komplexen mit und ohne Metall-Metall-Bindung durch Isomerisierung auch auf das Eisenatom übertragen werden. Mit PME3 und P(OMe)3 als Phosphanen sind so bis zur Einführung von drei Liganden 44 verschiedene Komplexe denkbar, von denen 35 isoliert wurden (Schema 1). Durch Nebenreaktionen bzw. zu Vergleichszwecken wurden weitere Komplexe mit kettenförmiger Anordnung von Metall- und P- bzw. As-Atomen erhalten. Nach der Einführung von vier Liganden findet das Eliminierungs/ Additions-Schema eine natürliche Grenze, da dann Phosphan-Eliminierung gegenüber der CO-Eliminierung bevorzugt wird. Die beschriebenen Sequenzen lassen sich als Grundmuster katalytischer Aktivität durch Öffnung von Metall-Metall-Bindungen verstehen.
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    Darstellung und Eigenschaften von Carbamoyleisen-Komplexen; Kristallstruktur von Nickelbis[tetracarbonyl-μ-(dimethyl-carbamoyl-O)-eisen] (2 Ni-Fe) (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3413-3423 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of Carbamoyliron Complexes;. Crystal Structure of Nickelbis[tetracarbonyi-μ-(dimethylcarbamoyl-O)-iron](2M-Fe)The carbamoyl complex 1 can be transaminated with piperidine and pyrrolidine to give 2 and 3. 1-3 react with anhydrous nickel bromide to yield the nickelbis[tetracarbonyl-μ-(carbamoyl-O)-iron] (2 Ni-Fe) complexes 4-6, which are studied by spectroscopic methods. The X-ray analysis proves a linear iron nickel iron spine in 4. The crystals are triclinic, space group PT, with one molecule in the unit cell.
    Notes: Der Carbamoylkomplex 1 läßt sich mit Pyrrolidin und Piperidin zu 2 und 3 umaminieren. 1-3 reagieren mit wasserfreiem Nickelbromid zu den Nickelbis[tetracarbonyl-μ-(carbamoyl-0)-eisen](2N - Fei)-Komplexen 4-6, die spektroskopisch untersucht werden. Die Röntgenstrukturanalyse von 4 beweist das Vorliegen einer linearen Eisen-Nickel-Eisen-Anordnung. Die Kristalle sind triklin, Raumgruppe PT, mit einem Molekül in der Elementarzelle.
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    URL: http://dx.doi.org/10.1002/cber.19791121009
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  • 93
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    Zum Mechanismus der Reaktion von 2-Brom-N,N-dimethyl-2, 2-diphenylacetamid mit Natriummethoxid in 2,2-Dimethoxypropan. Eine Methode zum Nachweis des Radikalanion-Radikal-Kettenmechanismus (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3520-3522 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Mechanism of the Reaction of 2-Bromo-N,N-dimethyl-2,2-diphenylacetamide and Sodium Methoxide in 2,2-Dimethoxypropane. A Method for Establishing the Radical-Anion Radical Chain MechanismThermolysis of N,N-dimethyl-2,2-diphenyl-2-(phenylazo)acetamide (1, X = C6H5N≡N-) in the presence of sodium methoxide in 2,2-dimethoxypropane furnishes N,N-dimethyl-2,2-diphenylacetamide (1, X = H), the dimeric product 3, and 2-hydroxymethyl-2,2-diphenylacetamide (1, X = -CH2OH). An analysis of this result leads to the conclusion that the title reaction, which yields compounds 1 (X = H) and 3, is a radical-anion radical chain process.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791121019
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  • 94
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    Zinnorganische Verbindungen des 1,2-Diethinylbenzols (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3552-3558 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organo Tin Compounds of 1,2-DiethynylbenzeneThe preparation and the properties of the compounds o-C6H4(C≡C — SnR3)2 (R equals; CH3, C6H5),[o-C6H4(C ≡ C)2SnR2]2 (R = CH3, C6H5, 1-Naphthyl; R2 = Pentamethylene), [o-C6H4(C≡C)2)3-(SnC6H5)2]n (n = 2, 8, 〉8) and [(o-C6H4(C≡C)2)2Sn]n (n = 12-15,〉15) are described. The structures of these compounds are supported by their spectra.
    Notes: Darstellung und Eigenschaften der Verbindungen o-C6H4(C≡C — SnR3)2 (R = CH3 C6H5), [o-C6H4(C≡C)2SnR,sb2]2 (R = CH3, C6H5, 1-Naphthyl; R2 = Pentamethylen), [(o-C6H4(C≡C)2)3-(SnC6H5)2]n (n = 2, 8, 〉8) und [(o-C6H4(C≡C)2)2Sn]n (n = 12-15, 〉15) werden beschrieben. Die Konstitutionen der Verbindungen werden spektroskopisch gestützt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791121104
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  • 95
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    Beiträge zur Chemie der Cycl[4.3.2]azine (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3577-3588 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Chemistry of Cycl[4.3.2]azines1)6-tert-Butyl-4H-3a-aza-4-azulenone (3c) and the cycl[4.3.2]azine derivatives 1d and e are synthesized. Attempts to eliminate the ester groups of 1d and e by thermolysis failed. Using Fe2(CO)9, 1d and e are transformed into the complexes 9a and b. The thermolysis of 9b yields the anhydride 10. 5-Azacycl[4.3.2]azine-4-carbonic esters 11 are obtained of two independent routes. 12 is prepared from 11 and Fe2(CO)9 -From the NMR spectra it is concluded that a paratropic effect exists of the cycl[4.3.2]azine π-system of about 4-5 ppm being largest in the 7-membered ring. The shifts of all protons are affected by the nitrogen atom in perimeter-position 5 of 11, the maximum effect being observed again in the 7-membered ring.
    Notes: 6-tert-Butyl-4H-3a-aza-4-azulenon (3c) und die Cycl[4.3.2]azin-Derivate 1d und e werden dargestellt. Versuche zur thermolytischen Entfernung der tert-Butoxycarbonylgruppen aus 1d und e scheiterten. Mit Fe2(CO)9 konnten aus 1d e die Tricarbonyleisen-Komplexe 9a und b erhalten werden. Die Thermolyse von 9b führte zum Anhydrid 10. 5-Azacycl[4.3.2]azin-4-carbonsäureester 11 werden auf zwei Wegen dargestellt. Aus 11b wurde der Tricarbonyleisen-Komplex 12 erhalten.  - Die1H-NMR-Spektren weisen auf eine durch das Cycl[4.3.2]azin-π-System verursachte Paratropie von etwa 4-5 ppm, welche im Siebenring am größten ist. Der Einfluß des perimeterständigen Stickstoffatoms auf die chemischen Verschiebungen von 11 erstreckt sich über das gesamte Ringsystem und ist ebenfalls im Siebenring am stärksten ausgeprägt.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791121107
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  • 96
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    Polare Cycloadditionen von elektronenreichen Mehrfachbindungssystemen an 1,3,4-Oxadiazolium-Salze: Synthese von 3aH-[1,3,4]Oxadiazolo[3,2-α]chinolinen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3623-3636 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polar Cycloadditions of Electron-rich Multiple Bond Systems to 1,3,4-Oxadiazolium Salts: Synthesis of 3aH-1,3,4 Oxadiazolol 3,2-α quinolinesThe 1,3,4-Oxadiazolium-salts 6c,g,h,i,j react withN,N-Diethyl-1-propin-1-amin(7) in a [4⊕ + 2]-Cycloaddition to afford the 3aH[1,3,4]Oxadiazolo[3,2-a]quinolines 8 c,g,h,i,j.. A [2⊕ + 2] cycloaddition of diethyl acetylenedicarboxylate with 8i yields the tetracycle 9. Alkaline hydrolysis of 8 leads to the quinolone 10. A [3⊕ + 2]-cycloaddition cycloreversion is observed with 6e, I and 18 yielding (→ 12, 15, 20 + 21) respectively. Ketene diethyl acetal (22) reacts with 6k in the same manner (→ 23)
    Notes: Die 1,3,4-Oxadiazolium-Salze 6c,g,h,i,j reagieren mitN,N-Diethyl-1-amin(7) in einer [4⊕ + 2]-Cycloaddition zu den 3aH[1,3,4]Oxadiazolo[3,2-a]chinolinen 8. Eine [2⊕ + 2] Cycloaddition von Acetlylendicarbonsäure-diethylester an 8i führt zum Tetracyclus 9. Die alkalische Hydrolyse von 8 ergibt die Chinolone 10. Eine [3⊕ + 2]-Cycloaddition-Cycloaddition-Cycloreversion wird bei 6e, I und 18 beobachtet (→ 12, 15, 20 + 21). Auch Keten-diethylacetal (22) reagiert mit 6k in dieser Weise (→ 23).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791121112
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  • 97
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    Alicyclische Verbindungen, II. Darstellung und Photoelektronenspektren der Cyclopropanierungsprodukte von 3,4-Dimethylen-1-cyclobuten (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3691-3702 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alicyclic Compounds, II. Preparation and Photelectron Spectra of the Cyclopropanation Products of 3, 4-Dimethylene-1-cyclobuteneCyclopropanation of 3, 4-Dimethylene-1-cyclobutene (1) with diazomethane/cuprous chloride in pentane provides the novel spiro compounds 6-methylenespiro[2.3]hex-4-ene (2) and dispiro[cyclopropane-1, 2′-bicyclo[2.1.0]pentane-3′, 1″-cyclopropane] 94) as well as the already known dispiro[2.0.2.2]oct-7-ene (3). The photoelectron spectra of these hydrocarbons have been analyzed.
    Notes: Die Cyclopropanierung von 3,4-Dimethylen-1-cyclobuten (1) mit Diazomethan/Kupfer (I) chlorid in Pentan liefert die neuen Spiroverbindungen 6-Methylenspiro [2.3]hex-4-en (2) und Dispiro[cyclopropan-1,2′-bicyclo[2.1.0]pentan-3′,1″-cyclopropan] (4) sowie das bekannte Dispiro [2.0.2.2]oct-7-en (3). Die Photoelektronenspektren dieser Kohlenwasserstoffe werden diskutiert.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791121117
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  • 98
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    Photolyse von Cycloalkeno-1,2,3-thiadiazolen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3728-3736 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photolysis of Cycloalkeno-1,2,3-thiadiazolesPhotolysis of the title compounds leads to several types of heterocycles: 1,4-dithiins 5, 1,3-dithioles 9, thiophenes 11, and 1,2,4,5-tetrathianes 12. The yields of the reaction routes 1 - VI depend on the ring size of the cycloalkeno-l,2,3-thiadiazoles (table 1).
    Notes: Bei der Photolyse der Titelverbindungen 1a-d werden Heterocyclen der Typen 1,4-Dithiin 5, 1,3-Dithiol 9, Thiophen 11 und 1,2,4,5-Tetrathian 12 isoliert. Die Ausbeute auf den Reaktionswegen I-VI in Abhängigkeit von der Cycloalkeno-l,2,3-thiadiazol-Ringgröße ist von Interesse (Tab. 1).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791121121
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  • 99
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    NMR-Spektroskopische Untersuchungen zur Kinetik und Thermodynamik reversibler Dissoziationsreaktionen, VII. Direkte Beobachtung der Ionisation und Ionenrekombination von Tritylchlorid in SO2 (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3715-3722 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Studies on Kinetics and Thermodynamics of Reversible Dissoziation Reactions VII. Direct Observation of Ionisation and Ion Recombination of Trityl Chloride in SO2The equilibriaWere analyzed in SO2 by 1H NMR spectroscopy at variable temperature in the partially deuterated compound. The ionisation of trityl chloride into the ion pair was kinetically studied by total line shape analysis of the 1H NMR spectra of the deuterated and the nondeuterated compound. The origin of the relatively high barrier (ΔG1≢ ≈ 42 kJ/mol, ΔS1≢ ≈ -90 J/grad mol) is discussed.
    Notes: Die GleichgewichteIn SO2 wurden in der partiell deuterierten Verbindung durch NMR-Spektroskopie bei variabler Temperatur analysiert. Die Ionisierung des Tritylchlorids in das Ionenpaar wurde durch Linienformanalyse der 1H-NMR-Spektren der deuterierten und nichtdeuterierten Verbindung kinetisch untersucht. Die Ursache der relativ hohen Barrieren (ΔG1≢ = 42 kJ/mol, ΔS1≢ = 25 kJ/mol, ΔS1≢ = - 90 J/grad · mol) wird diskutiert.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19791121119
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  • 100
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    Diskussion der UV-Spektren von 3-Keto-Δ4,8(14)-Steroiden als Beispiel einer, through space'-Konjugation (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3748-3752 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Discussion of the UV Spectra of 3-keto-Δ4,8(14)-steroids as an Example of a “Through Space” Conjugation
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19791121125
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