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  • Articles  (1,123)
  • Inorganic Chemistry  (816)
  • Engineering  (234)
  • Electron microscopy  (73)
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  • 1975-1979  (1,123)
  • 1950-1954
  • 1977  (1,123)
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  • 1975-1979  (1,123)
  • 1950-1954
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mycopathologia 60 (1977), S. 175-177 
    ISSN: 1573-0832
    Keywords: Aspergillus fumigatus ; Spore formation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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  • 2
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    Mycopathologia 61 (1977), S. 117-119 
    ISSN: 1573-0832
    Keywords: Prototheca ; Colorless alga ; Plastids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract An ultrastructural investigation of six different species of Prototheca showed that all of them contained starch grains enclosed in double-membrane-bounded structures recognized as plastids. It is concluded that these unicellular species of Prototheca must be considered as non-photosynthetic algae.
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  • 3
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    Calcified tissue international 23 (1977), S. 215-223 
    ISSN: 1432-0827
    Keywords: Amorphous mineral ; Bone ; Electron microscopy ; Ultracryotomy ; Ultramicro-incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The fine structure of the extracellular phase of avian medullary bone and embryonic chick femur was examined in thin sections prepared by ultracryotomy and ultramicroincineration. Since contact with solutions was completely avoided, little or no loss or dislocation of mineral constituents could occur. Amorphous bone mineral (ABM) was present in two forms: as 15–30 nm spheres and as a structure-free haze. Removal of all organic material by low temperature ashing left the ABM intact. Crystals were usually associated with the ABM. In newly ossifying regions clusters or nodules of randomly oriented crystals and ABM appeared to coalesce when they reached approximately 1 μm in diameter. In highly calcified regions crystals appeared to be oriented along collagen fibers. ABM did not appear to be associated with collagen. Unmineralized collagen was visible in osteoid after staining with dry OsO4 vapor and it appeared to be diverted around nodules. Structures which resembled matrix vesicles were present. Selected area electron diffraction patterns indicated the presence of hydroxyapatite.
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  • 4
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    Calcified tissue international 24 (1977), S. 191-197 
    ISSN: 1432-0827
    Keywords: Amelogenesis imperfecta ; Hypocalcification ; Hypoplasia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An ultrastructural study of teeth with amelogenesis imperfecta revelaed various aspects of microcavities in the enamel surface, which ranged from isolated imprints of ameloblasts corresponding to the mildest lesions at the end of amelogenesis, to pits caused by the death of 20 to 30 ameloblasts at the beginning of amelogenesis. Abnormalities in the shape of the prisms can be observed. Further, crystals are distributed randomly within a prism or at the junction of 2 contiguous prisms while intercrystalline spaces are widened, indicating in various places the lack of a preferred orientation of the crystals. In amelogenesis imperfecta, two different crystalline periods are found: 1 of about 250 Å, the other of about 500 Å and over. The fact that amorphous areas are found among the crystals of enamel may be related to different stages of crystallization. However, it was not possible to find any lattice defect.
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  • 5
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    Calcified tissue international 24 (1977), S. 239-242 
    ISSN: 1432-0827
    Keywords: Cementum ; Lysis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Examination of microradiographs from the deciduous teeth of pigs revealed large lacunae or radiolucent zones close to the cemento-dentinal junction. Electron microscopic studies of the ground sections showed areas or irregularly shaped zones devoid of mineral and filled with collagen fibers. In the wide unmineralized zones, spherical clusters of crystallites were noted. Several cementum lacunae bordered by a broad rim of unmineralized collagen fibers were noted and some lacunae also contained zones of a moderately electron dense material. This material did not yield a diffraction pattern, while the mineralized part of the cementum gave the diffraction pattern typical of hydroxyapatite.
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  • 6
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    Archives of microbiology 113 (1977), S. 197-204 
    ISSN: 1432-072X
    Keywords: Gliding bacterium ; Simonsiella ; Oral cavity ; Electron microscopy ; Morphology ; Dorsal-ventral differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the aerobic, Gram-negative multicellular-filamentous bacteria of the genus Simonsiella were investigated by scanning and transmission electron microscopy. The flat, ribbon-shaped, multicellular filaments show dorsal-ventral differentiation with respect to their orientations to solid substrata. The dorsal surface, orientated away from the substrate, is convex and possesses an unstructured capsule. The ventral surface, on which the organisms adhere and glide, is concave and has an extracellular layer with fibrils extending at right angles from the cell wall. The cytoplasm in the ventral region contains a proliferation of intracytoplasmic membranes and few ribosomes in comparison to the cytoplasm in other parts of the cell. Centripetal cell wall formation is asymmetrical and commences preferentially in the ventral region. Quantitative differences in morphology and cytology exist among selected Simonsiella strains. Functional aspects of this dorsalventral differentiation are discussed with respect to the colonization and adherence of Simonsiella to mucosal squamous epithelial cells in its ecological habitat, the oral cavities of warm-blooded vertebrates.
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  • 7
    ISSN: 1432-072X
    Keywords: Acetobacterium woodii ; Hydrogen-oxidizing acetate-forming anaerobe ; Fine structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acetobacterium woodii is a Gram-positive anaerobic nonsporeforming bacterium able to grow on H2 and CO2 as sole sources of energy. The product of fermentation is acetic acid. Fine structural analysis showed rod-shaped flagellated cells, and coccoid cells without flagella arranged predominantly in pairs and chains. The cell wall was found to be composed of three layers. The cell surface exhibited a periodic array of particles consisting of subunits. The cytoplasmic membrane showed particles either either in random distribution or in a hexagonal pattern. Intracytoplasmic membranes were rarely observed, whereas inclusion bodies of varying shapes, predominantly in an uncommon disc-shape, could frequently be observed. Their content was dissolved in ultrathin sections indicating hydrophobic nature.
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  • 8
    ISSN: 1432-072X
    Keywords: Defective lysogeny ; Alcaligenes eutrophus ; Simultaneous isolation technique ; Temperate bacteriophages ; Pseudomonas pseudoflava ; Biological characterization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Widespread defective lysogeny was detected in Alcaligenes eutrophus by electron microscopic analysis of cultures. Mitomycin C treatment of the cultures resulted in the production of defective (inco-) particles. Polysheaths were produced both with and without induction. With the simultaneous isolation technique six phages were isolated for hydrogen-oxidizing strains of the new species Pseudomonas pseudoflava. The phages were able to replicate under autotrophic conditions and were found to have a very restricted host range. Electron microscopic analysis allowed classification into two structural groups. Group I contained phages with contractile tails; group II contained phages with flexible, noncontractile tails. All but one (gb) of the new phages were shown to be temperate by isolation of lysogens and induction with mitomycin C.
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  • 9
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    Archives of microbiology 112 (1977), S. 207-218 
    ISSN: 1432-072X
    Keywords: Cryptophyceae ; Algae ; Hemiselmis rufescens ; Chroomonas ; Cryptomonas ; Mitochondrial complex ; Cristae ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The unitary nature of the mitochondrion and the characteristic flattened finger-like morphology of the cristae were demonstrated in the Cryptophyceae. Hemiselmis rufescens contained an unbranched vermi-form mitochondrion in contrast to the variously branched complex, comprising an interconnected peripheral and central reticulum, in Chroomonas sp. and strains of Cryptomonas. The systematic value of the shape and distribution of the mitochondria in the examined genera was suggested.
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  • 10
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    Archives of microbiology 115 (1977), S. 185-198 
    ISSN: 1432-072X
    Keywords: Synechococcus lividus ; Cyanobacteria ; Carbon dioxide ; Electron microscopy ; Bleaching-regreening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of carbon dioxide on pigment and membrane content in Synechococcus lividus was studied by depriving cells of CO2 and examining cell populations biochemically and by electron microscopy. After 120 h of CO2 deprivation, S. lividus lost all detectable chlorophyll a and C-phycocyanin. Such bleached cultures were “mustard yellow”, the result of approximately 1.8 times more carotenoid per cell than green control cultures. Although cells from beached cultures appeared morphologically identical to control green cells when examined by light microscopy, electron microscopic examination revealed them to be devoid of detectable thylakoid membrane. Thylakoid membrane could not be recovered by physical isolation or revealed by freeze etching of bleached S. lividus. In addition, inclusion bodies characteristically found in S. lividus were also absent. Reintroduction of CO2 into bleached cultures resulted in a rapid resynthesis of both chlorophyll a and C-phycocyanin. Electron microscopic examination of these regreening cultures revealed that thylakoid membrane was also rapidly resynthesized. Growth of regreened cultures did not occur until there was the synthesis of a full complement of chlorophyll a, C-phycocyanin, and thylakoid membrane. A time course study of the cytological events occurring during bleaching and regreening is presented.
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  • 11
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    Cell & tissue research 176 (1977), S. 23-36 
    ISSN: 1432-0878
    Keywords: Lateral line organ ; Shark (Mustelus manazo) ; Neuromasts ; Cell types ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lateral line organ of the spotted shark is characterized by its semi-cylindrical shape. Each organ (neuromast) is so closely apposed to the next that the individual neuromasts are almost continuous. The neuromast is composed of receptor cells, supporting cells and mantle cells. The receptor cells bear one kinocilium and up to 40 stereocilia. Bi-directional arrangement of the receptor cells as occurs in teleosts was demonstrated. Afferent and efferent nerve endings were found at the base of the receptor cells. The supporting cells extend from the basal lamina to the free surface. Long microvilli and a cilium-like “ciliary rod” project from the top of each supporting cell. The cell contains relatively few elements of the Golgi apparatus and little rough endoplasmic reticulum, but mitochondria and filaments are abundant. The mantle cell limits the lateral margin of the neuromast. It is distinguished from the supporting cell because of its long crescent-shaped nucleus and scarce, short microvilli. Myelinated nerve fibres are found in the subepithelial connective tissue but not in the epithelium. The fine structure of the shark lateral line organ suggests that this organ is in an intermediated step of evolution between that of lamprey and teleost.
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  • 12
    ISSN: 1432-0878
    Keywords: OsO4 ; Cholesterol ; Symbiotes ; Aphids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. However, the staining of the pea-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. In aphids cultured in vitro with 3H mevalonate in the presence of added cholesterol, the incorporation of label into the cholesterol and lanosterol fractions is significantly reduced. If the dietary cholesterol effects a similar inhibition in vivo, the cholesterol-dependent osmium staining could be due to precursors(s) of cholesterol accumulating in the intracellular sites described. There is also osmium staining of large (normally electron-transparent) vacuoles in mycetocytes, gut and fat body, irrespective of dietary cholesterol.
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  • 13
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    Cell & tissue research 176 (1977), S. 417-429 
    ISSN: 1432-0878
    Keywords: Fat body ; Galleria mellonella ; Basement membrane ; Ruthenium red staining ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fat body lobes of Galleria mellonella are surrounded by basement membrane — a fine granular layer of connective tissue. This membrane has an affinity for ruthenium red. The results obtained after treatment of the fat body with neuraminidase, hyaluronidase, phospholipase C and proteolytic enzymes suggest that glycoproteins and phospholipoproteins are constituents of this basement membrane. The basement membrane also has the ability to bind concanavalin A-peroxidase, which is associated with the presence of mannoside residues.
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  • 14
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Protamine ; Endocytosis ; Autophagic vacuolation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The uptake in vitro of horseradish peroxidase (HRP) in mouse skeletal muscle was examined by electron microscopy and chemical determination. In muscles exposed to an HRP solution for 60 min at +37°C, HRP infiltrated the basal lamina of muscle fibres and caused an intense labelling of their sarcolemma. In addition HRP was found within the transverse tubules. Exposure to HRP for 30 min at +37°C followed by HRP together with a polycationic protein (protamine) for 30 min at +37°C caused an intracellular vesicular uptake of HRP. Intracellular HRP was found in numerous vesicles, membrane limited bodies and vacuoles. Protamine also induced focal autophagic vacuolation with progressive muscle fibre degeneration. An intracellular HRP uptake or muscle cell vacuolation could not be detected in the absence of protamine or when the incubation temperature was + 4°C. Chemical determination of HRP uptake was in general agreement with the morphological results. The uptake of HRP in the presence of protamine was stimulated at +31°C and blocked at +4°C. The results suggest that in skeletal muscle in vitro intracellular uptake of macromolecules occurs by endocytosis.
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  • 15
    ISSN: 1432-0878
    Keywords: Electron dense plaques ; Pancreatic islets ; Parathyroids ; Electron microscopy ; Calcium binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Small electron dense plaques (EDP) were found in the plasma membrane of pancreatic islet A-, B- and D-cells and parathyroid chief cells of mice and gerbils. The identification of the EDP was facilitated by the use of special fixation techniques. The EDP may represent sites of calcium binding in the cell membranes.
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  • 16
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    Cell & tissue research 177 (1977), S. 127-140 
    ISSN: 1432-0878
    Keywords: Microtubules ; Retina ; Electron microscopy ; Rainbow trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the retina of the rainbow trout (Salmo gairdneri, Richardson) two types of microtubular structures are demonstrated. Besides the normal type of microtubules (about 200 Å in diameter), occurring in all cell types of the retina, a second type is described which is termed microtubule-like structure (MLS) because of its extracellular localization. These MLS have a diameter of about 250 Å under the same preparative conditions in which the normal microtubules appear 180–200 Å thick. The interspace between the tubules is smaller than between the microtubules. Specific MLS to membrane associations exist, which are analyzed by serial sectioning and tilting procedures. It is suggested that the MLS have their origin at small membranous extrusions of the plasmalemma. These extrusions could contain nucleation sites for the MLS-formation within the extracellular space. It remains unknown which cell type produces the MLS proteins and which factors are responsible for the aggregation of the subunits to intact MLS.
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  • 17
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    Cell & tissue research 177 (1977), S. 221-226 
    ISSN: 1432-0878
    Keywords: Actin-like filaments ; Myoid cell ; Testis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microfilaments in the myoid cells of the peritubular tissue in the mouse, swine and human testis bind heavy meromyosin (HMM) and form arrowhead complexes. The periodicity of the arrowhead complexes is about 35 nm. Individual filaments show arrowheads that point in the same direction. Opposing polarity of the HMM-bound filaments is also observed. The microfilaments do not bind HMM in the presence of 10 mM ATP. After treatment with the contraction medium of Hoffmann-Berling, the filaments appear to be undulated. These observations indicate that the microfilaments in the myoid cell are actin-like in nature. A small number of thicker filaments (about 10 nm in diameter) which do not bind HMM is also observed in the cell. Microfibrils which have been reported around the human myoid cell are also found in the swine.
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  • 18
    ISSN: 1432-0878
    Keywords: Optic neuropile ; Crustacea ; Catecholamine ; Fluorescence histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The crustacean optic neuropiles, the lamina ganglionaris and especially the medulla externa, show a specific pattern of green fluorescence with the fluorescence histochemical method of Falck-Hillarp. Normally, only the terminals and the cell bodies fluoresce, but in reserpine-treated animals exogenous catecholamines are taken up by the whole adrenergic neuron and are thus visualized as a whole. Incubating crayfish optic neuropiles in dopamine or α-methylnoradrenaline after reserpine treatment demonstrated a tangential neuron connecting the lamina and the medulla externa. The morphology of this tangential neuron differs from the two types of tangential neurons, Tan1 and Tan2, previously characterized with Golgi techniques. The catecholaminergic neuron thus constitutes a third tangential neuron type.
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  • 19
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    Cell & tissue research 182 (1977), S. 401-407 
    ISSN: 1432-0878
    Keywords: Microtubules ; Sciatic nerve (rat) ; Tannic acid ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tannic acid in glutaraldehyde was used to stain microtubules in myelinated and unmyelinated axons of rat sciatic nerve. In the majority of areas the tannic acid failed to penetrate the unmyelinated axons whilst penetrating neighbouring myelinated axons, suggesting a difference in the ability of the two types of nerves to exclude tannic acid. Where tannic acid had penetrated the unmyelinated axons the 13 protofilament substructure and size of the microtubules appeared identical to those seen in the myelinated axons.
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  • 20
    ISSN: 1432-0878
    Keywords: Albinism ; Pigment epithelium ; Tyrosinase ; Electron microscopy ; Carassius auratus L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies, and cytochemical and biochemical determinations of tyrosinase activity were conducted on the pigment epithelium of albino and xanthic goldfish eyes. In eyes of xanthic goldfish, two types of melanosomes are present, spherical and elongated. Melanized melanosomes are absent in the eyes of the albino goldfish, but elongated lamellar premelanosomes are observed. Internal vesicles are present in both melanosome types in the pigment epithelium of the xanthic goldfish but are absent in premelanosomes of the albino. There are also differences in the distribution of lipid droplets, smooth endoplasmic reticulum and Golgi complexes with the latter two being more abundant in the albino. Tyrosinase was not identified cytochemically; however, the enzyme was demonstrated biochemically in the pigment epithelia of both albino and xanthic goldfish. The enzyme is associated with the particulate and soluble fractions of both types of eyes. Particulate albino tyrosinase may be solubilized by triton X-100 treatment. Tyrosinase inhibitors are present in the particulate fractions of both albino and xanthic goldfish eyes. Thus, in the goldfish, ocular albinism appears to be a multiple defect at the molecular and ultrastructural levels.
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  • 21
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    Cell & tissue research 176 (1977), S. 407-416 
    ISSN: 1432-0878
    Keywords: Chick embryo ; Electron microscopy ; Glial differentiation ; Neuron differentiation ; Reaggregation cultures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dissociation and reaggregation cultures from different portions of the chick embryo neural tube were made, and the resulting aggregates were fixed for electron microscopy after 1, 5, 8, 14, 16 and 22 days in vitro. All cultures (pure aggregates of telencephalon, optic lobe or neural retina, and combined aggregates made from mixtures of optic lobe plus neural retina or optic lobe plus telencephalon) show a common timing of neuronal and glial morphological differentiation. During the first week in vitro, some cells developed neuronal characteristics in the absence of morphological evidence of glial differentiation. Numerous axonic processes usually formed fascicles with all the fibers running parallel to each other. Axonic growth cones were abundant and a few immature synapses were also present. The second week in culture was characterized by the disappearance of growth cones and the increase in number and morphological maturation of synapses. Morphologically detectable glial differentiation began by the end of this week, and during the third week almost every neuronal element, including the axonic fascicles, became associated with glial cells showing astrocytic features.
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  • 22
    ISSN: 1432-0878
    Keywords: Gastric mucous cells ; Differentiation ; 3H-thymidine incorporation ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastric surface mucous cells (SMC), mucous neck cells (MNC) and their undifferentiated and immature precursors were studied by light and electron microscopic histochemistry. The secretory granules of SMC were smaller, more electron dense and more reactive to PAS and its analogues than those of MNC. Alcian blue demonstrated that the mucus of SMC was acidic and that of MNC was neutral. The periodic acid —thiocarbohydrazide —silver proteinate method revealed the presence of carbohydrates in the Golgi apparatus, condensing vacuoles, secretory granules, apical vesicles and tubules and cell coat. Maturation of SMC during their migration towards the free surface was reflected by an increase in size and number of secretory granules, an increase of RER and microfilaments, and a decrease of microvilli and apical vesicles and tubules. The secretory granules of older SMC were less acidic and possessed a proteinaceous core. Most MNC were fully differentiated, but some immature MNC containing only a few granules were found. Furthermore, undifferentiated cells and intermediates between SMC and MNC were also observed. The presence of both transitional and intermediate forms indicates that both SMC and MNC arise from the same population of undifferentiated cells. Incorporation of 3H-thymidine revealed that undifferentiated cells, isthmic SMC, MNC and intermediate cells are proliferative. No proliferative activity was found in foveolar SMC, parietal, chief, fibrillovesicular or endocrine cells.
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  • 23
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    Cell & tissue research 177 (1977), S. 159-180 
    ISSN: 1432-0878
    Keywords: Muscle transplantation ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat soleus muscles were autografted from right to left legs, and regeneration following necrosis of all original myofibres was studied after 7 to 250 days. The best regenerates were from grafts replacing all calf muscles and sutured to the tendon stumps. After 30 days the size of such regenerates was equal to those from minced gastrocnemius muscles: the cross sectional area of muscle tissue was 30% (1.7 mm2) and the number of fibres was 180% (4500) of normal soleus muscles; the fibre diameters were 10 to 40 μm. To increase the number of myoblasts before grafting some muscles were injured by Ringer solution of 70° C and transplanted after 2 days. Nevertheless, this did not influence regeneration. After 7 days clusters of myotubes occurred in the periphery of the muscle. These myotubes originated from myoblasts growing like endothelial cells on the inner face of the persisting basal lamina tubes of necrotic fibres. After 30 days the muscles were vascularized. Fibres formed in a common basal lamina detached and so looked “split”. Satellite cells of new fibres came from undifferentiated cells associated with myotubes, i.e. from myoblasts. After 30 days and more regenerates contained three sorts of fibres. 1. Thin (5 to 20 μm) fibres resembling fetal muscle fibres. They were most prominent after 30 days, and probably not yet innervated. 2. Thin (10 μm) degenerating fibres as in long-time denervated muscles. 3. Thick (more than 30 μm) mature looking fibres which were innervated and revealed end-plates. Half of the grafts studied after 30 and 60 days contained unmyelinated and myelinated axons which had grown along strands of surviving Schwann cells. After 250 days, only two muscles were studied which both lacked innervation. Almost all regenerates contained muscle spindles, which, however, were not innervated. Within the persisting spindle capsules new muscle fibres had been formed from satellite cells of the former intrafusal fibres.
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  • 24
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    Cell & tissue research 177 (1977), S. 247-268 
    ISSN: 1432-0878
    Keywords: Adrenal medulla ; In vitro ; Phase contrast microscopy ; Catecholamine histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Explants and enzyme-dispersed cells of adrenal medulla from 10–12 day old rats were studied in culture for up to 3 weeks. Adrenomedullary chromaffin cells, nerve cells and satellite cells were clearly discernible. The nerve cells were few in number and did not show catecholaminespecific fluorescence. Chromaffin cells stored catecholamines, as judged by the Falck and Hillarp method, in varying amounts decreasing with age of the cultures and the distance from the explants. Exocytosis profiles observed with the electron microscope suggested that cultured chromaffin cells also released catecholamines. Moreover, the cells formed processes and frequently migrated into the outgrowth. After 6 days in culture, the great majority of chromaffin cells stored noradrenaline as revealed by electron microscopy with few adrenaline-storing cells being visible. Granular vesicles (∼ 80–240 nm in diameter) with cores of different electron densities were occasionally present in the same cell suggesting the occurrence of mixtures of primary and secondary amines. Apart from “chromaffin” granules, small clear and densecored vesicles (∼ 40–60 nm) were found both in the somata and cell processes. Chromaffin cells and their processes were often closely apposed and occasionally formed specialized attachment zones. As a whole, chromaffin cells in culture resembled small granule-containing cells in sympathetic ganglia. 0.5 mM dbcAMP prevented dedifferentiation of chromaffin cells as judged by the lack of processes, the size and amount of “chromaffin” granules and the high number of adrenaline-storing cells present after 6 days in culture. NGF caused a striking increase in the number of axons growing out from expiants.
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  • 25
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    Cell & tissue research 177 (1977), S. 291-305 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Tupaia ; Gap junctions ; Renin ; Freeze-fracturing ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascular pole of the juxtaglomerular apparatus in Tupaia belangeri was studied with special reference to the intercellular contacts of the periendothelial cells and the endothelium of the vas afferens. The periendothelial cells of the vascular pole of the glomerulum are connected by numerous gap junctions; and the granulated epithelial cells are suggested to form a functional unit. Probably there is a continuity of this system troughout the entire vascular pole including (1) all granulated cells, (2) all lacis cells, (3) the mesangium cells and (4) the adjacent smooth muscle cells of the vas afferens and vas efferens. Analysis of the endothelial junctions shows a zonular arrangement of tight junctions indicating a rather tight blood-tissue barrier next to the glomerular vascular pole. The ultrastructure of the different cell types of the vas afferens is also described, emphasizing the granulated epithelial cells and their innervation.
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  • 26
    ISSN: 1432-0878
    Keywords: Gut epithelium ; Ciona intestinalis, Mytilus edulis ; Endocrinecells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural evidence has been found for the presence of polypeptide hormone-producing cells in the gut of Ciona intestinalis L. and Mytilus edulis L. which do not appear to have been described before. Due to their localization and ultrastructural characteristics, it is suggested that the cells in Mytilus edulis probably produce an insulin-like substance and that some of these cells in Ciona intestinalis may produce 5-HT (5-Hydroxytryptamine). In each species only one granulated cell type can be observed. The granules, which are electron dense and membrane bound, also show a halo. The average diameter of the granules is 100–200 nm for Ciona and 200–400 nm for Mytilus.
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  • 27
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    Cell & tissue research 177 (1977), S. 539-553 
    ISSN: 1432-0878
    Keywords: Sensory receptors ; Peripatopsis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three types of sensilla occurring on the lips and on the antennae of Peripatopsis moseleyi have been investigated by scanning and transmission electron microscopy. On the lips sensory spines can be found which contain numerous cilia originating from bipolar receptor cells. They reach the tip of the spine where the cuticle is modified. The perikarya of the sensory cells, a large supporting cell with a complicated surface and a second type of receptor, form a bud-like structure and are surrounded by a layer of collagen fibrils. The second receptor cell bears apical stereocilia as well as a kinocilium which are directed towards the centre of the animal — thus the cell appears to be turned upside down. The sensilla of the antennae are 1) sensory bristles containing two or three kinds of receptor cells, one of which bears an apical cilium and one kind of supportive cell and 2) sensory bulbs located within furrows consisting of receptor cells with branched cilia and two kinds of supportive cells which are covered by a modified thin cuticle. According to the electron microscopical findings the sensory spines on the lips are presumably chemoreceptors. The sensory bristles on the antennae can be regarded as mechanoreceptors and the sensory bulbs as chemoreceptors.
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  • 28
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    Cell & tissue research 178 (1977), S. 155-167 
    ISSN: 1432-0878
    Keywords: Electromotor system ; Oval nucleus ; Synapses, junctions ; Electron microscopy ; Torpedo marmorata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of the oval nucleus of neonatal Torpedo marmorata is described at the light and electron microscopic level of examination. The nucleus is unique relative to other central electromotor centers of electric fish so far described being bilaterally symmetrical, composed of two nerve cell types, and possessing no gap junctions between neurons and their processes. This particular structural plan presents difficulties in accounting for presumed synchronous discharge since it has been strongly argued that electrotonic coupling by means of gap junctions is the primary process by which synchronization is accomplished. Close membrane apposition and dendritic bundling, common features within the nucleus, are discussed as possible alternative structural correlates.
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  • 29
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    Cell & tissue research 182 (1977), S. 1-16 
    ISSN: 1432-0878
    Keywords: Epithalamus (Rat) ; Supraependymal nerves ; Electron microscopy ; Circumventricular organs ; Medial habenular nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission and scanning electron microscopy of the rat epithalamus shows a regional variation in the distribution of Supraependymal nerves (SN) which correlates well with Supraependymal yellow fluorescence reported by Richards et al. (1974). The medial habenular nucleus, the intercommissural and suprahabenular recesses, the habenular commissure and the fibrae periventriculares thalami have the greatest density of SN/100 μm of ependymal surface. The floor of the suprahabenular and intercommissural recesses is covered by non-ciliated ependyma. The significance of these findings is discussed with respect to (1) a direct functional relationship of SN with ependyma, and (2) a possible participation of the non-ciliated ependyma of the suprahabenular and intercommissural recesses in secretory activity whereby the CSF serves as a vehicle for neuroendocrine communication.
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  • 30
    ISSN: 1432-0878
    Keywords: Ovary ; Oocyte elimination ; Peritoneal epithelium ; Primordial follicle ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Numerous ovarian oocytes of primordial follicles are lost postnatally by their elimination into the peritoneal cavity during days 1–6 in young mice. It is rarely found in animals over 2 weeks old. This phenomenon has been investigated by light and EM techniques. Oocytes that become extruded from the ovary this way appear to pass between the cells of the covering epithelium. The ultrastructural changes that take place during this process are described.
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  • 31
    ISSN: 1432-0878
    Keywords: Gastrin cells ; Electron microscopy ; Fixation ; Granule maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural appearance of gastrin cell (G cell) granules was studied after different fixation procedures. When the pH of prefixation was varied there was greater preservation of the electron density of granule cores after acidic (pH 5.0 and 6.0) than after neutral or alkaline (pH 7.0 and 8.0) prefixation. Increasing duration of prefixation at pH 7.3 resulted in progressive loss of electron density of the granule core with swelling and occasional rupture of the limiting membrane. In tissues where most granules had been rendered electron lucent by fixation, those granules remaining dense cored were preferentially located close to the Golgi zone. These findings indicate that the electron density of G cell granules is profoundly affected by conditions of fixation, and that immature granules are more resistant to loss of core density than mature granules. They also suggest that the gastrin granule in vivo, like other polypeptide granules, may have a “solid”, osmotically inactive core.
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  • 32
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    Cell & tissue research 176 (1977), S. 275-284 
    ISSN: 1432-0878
    Keywords: Neural lamella (wax moth) ; Ruthenium red ; Enzyme digestion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The outer surface of the neural lamella, the connective tissue ensheathing the brain, shows the ability to bind ruthenium red in the wax moth larva. Ruthenium red-positive material is sensitive to neuraminidase, hyaluronidase and to some extent to phospholipase C, what suggests that the negative charge on the external surface of the neural lamella depends on the presence of the anionic groups of sialic and hyaluronic acids and phospholipids.
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  • 33
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    Cell & tissue research 185 (1977), S. 285-288 
    ISSN: 1432-0878
    Keywords: Striated muscle (mammalian) ; Myofilaments ; Actin filaments ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural organization of myofilaments in skeletal muscle was studied in four mammalian species (mouse, rat, hamster, goat). In all these species, myofibrils showing irregularly distributed arrays of a variable number of actin filaments (from 6 to 11) were observed. The proportion of such myofibrils and the predominant patterns of actin filaments varied from one species to another. These results are in agreement with those previously reported for human skeletal muscle.
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    Cell & tissue research 185 (1977), S. 399-408 
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Satellite cells ; Aging ; Regeneration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myosatellite cells were examined and quantified at the fine structural level of resolution during aging of skeletal muscles in mice and rats. Satellite cells in the soleus and gastrocnemius muscles of animals between eight and 30 months of age appeared, according to morphological criteria, metabolically less active than those examined in immature muscles. In the soleus muscle of the mouse, satellite cells decreased in number from 4.6% at eight months of age to 2.4% at 30 months. This decrease appeared to be due to the passage of some satellite cells into the interstitial space as a result of the formation of external lamina material around the entire satellite cell surface.
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  • 35
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    Cell & tissue research 185 (1977), S. 535-545 
    ISSN: 1432-0878
    Keywords: Milk (goat, cow) ; Cell fragments ; Origin ; Triglyceride synthesizing capacity ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Goats' milk includes numerous cell fragments (“christiesomes”) which originate from the mammary secretory cells, contain well preserved endoplasmic reticulum, mitochondria and lipid droplets, and are responsible for the considerable triglyceride synthesising capacity of fresh goat milk. Cows' milk shows a few such particles only after repeated oxytocin-aided milkings. Cows' milk does contain quite different particles which have a dense content with a few small vesicles and numerous microvillus-like protrusions on one side (“sunbursts”). These have not been found in goats milk. Cytoplasmic particles similar to sunbursts have been found on the surface of the mammary secretory epithelium. It is suggested that they are residues of dead cells.
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  • 36
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1-11 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation of Succinimide During the Synthesis of the Insulin A Chain(14-21) OctapeptideDuring the synthesis of insulin A chain (14-21) fragments it was observed that alkaline treatment of Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut and Msc-Tyr-(But)-Gln-Leu-Glu(OBut)Asn-Tyr(But)-Cys(Trt)-Asn-OBut caused quantitative formation of succinimide in position 21.
    Notes: Bei der Synthese von Teilsequenzen der Insulin-A-Kette (14-21) wurde während der alkalischen Abspaltung der Msc-Gruppe von Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys-(Trt)-Asn-OBut und Msc-Tyr-(But)-Gln-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut in allen Fällen Succinimidbildung in Position 21 beobachtet.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 37-48 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, IX. On the Reaction of Amide Acetals with HeterocumulenesDeprotonation of the (dimethylamino)methoxycarbenium ion (10) by NaH liberated the carbene 2, which was trapped by aryl isocyanate to give the hydantoin 6 and by phenyl isothiocyanate to yield 8. Hence, the carbene 2 is assumed to be also an intermediate in the corresponding reactions of the amide acetal 1 which lead to the hydantoins 6 and 8. The reaction of 1 with phenyl isothiocyanate yielded the products 4, 7, 8, or 12 depending on the reaction conditions. An equilibrium between 1 and the carbene 2 is suggested by the reaction of 1 with sulfur to give 16, and is the basis for mechanistic discussions.
    Notes: Das durch Deprotonierung des (Dimethylamino)methoxy-carbenium-Ions (10) mit NaH freigesetzte Carben 2 addierte sich an-Arylisocyanat zum Hydantoin 6, an Phenylisothiocyanat zu 8. Dies legt nahe, daß auch bei der Umsetzung des Amidacetals 1 mit Heterocumulenen zu den Hydantoinen 6 bzw. 8 das Carben 2 beteiligt ist. Bei der Umsetzung von 1 mit Phenylisothiocyanat entstanden je nach Reaktionsführung die Produkte 4, 7, 8 oder 12. Für deren Bildung werden Mechanismen diskutiert, die von einer Gleichgewichtseinstellung von 1 mit dem Carben 2 ausgehen. Diese Annahme wird durch Umsetzung von 1 mit Schwefel zu 16 gestützt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 67-77 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Perhalomethylthio)heterocycles, VIII. (Perchlorofluoromethylthio)- and (Haloformylthio)-N-heteroaromaticsPyrrole reacts with Cl3-nFnC—SCl (n = 1-3) to give mixtures of 2- and 3-substituted pyrroles 1 a-c and 2a, b; CF3SCFCl—SCl and XC(O)SCl (X = F, Cl) merely yield 2-substituted derivatives 3. In the presence of excess CF3SCl also disubstituted products 4, 5 are available. Analogously pyrrole derivatives can be substituted directly, dependent on their reactivity (6-14). 1a is oxidized by 3-chloroperbenzoic acid to yield the sulfoxide 15 or the sulfone 16; the reaction with bromine and iodine results in the formation of the fully halogenated compounds 17, 18. Indole reacts with CF3SCl to give the 3-substituted 19, while carbazole yields the N-substituted product 20 in a Grignard reaction. 1H and 19F n. m. r. spectra are discussed.
    Notes: Pyrrol setzt sich mit Cl3-nFnC—SCl (n = 1-3) zu Isomerengemischen 2- und 3-substituierter Pyrrole 1a-c bzw. 2a, b, um; CF3SCFCl—SCl und XC(O)SCl (X = F, Cl) liefern lediglich 2-substituierte Derivate 3. In Gegenwart eines CF3SCl-Überschusses sind auch disubstituierte Produkte 4, 5 erhältlich. Analog sind Pyrrol-Derivate, je nach ihrer Reaktivität, einer direkten Substitution zugänglich (6-14). 1 a wird durch 3-Chlorperbenzoesäure zum Sulfoxid 15 bzw. Sulfon 16 oxidiert; die Umsetzung mit Brom bzw. Iod führt zu den vollständig halogenierten Verbindungen 17, 18. Indol reagiert mit CF3SCl zum 3-substituierten 19, während Carbazol in einer Grignard-Reaktion das N-Substitutionsprodukt 20 liefert. 1H- und 19F-NMR-Spektren werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 96-106 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Aldehydes and Ketones with the Makosza Dichlorocarbene ReagentPhase transfer-catalyzed reactions of aldehydes and ketones with trichloromethane and 50 per cent aqueous sodium hydroxide in the presence of benzyltriethylammonium chloride (BTEA) at low temperatures result in the formation of α-(trichloromethyl)carbinols 7; in the presence of dimethyl sulfate the corresponding methyl ethers 8 are obtained. At 56 ± 2°C the α-hydroxy-11, α-chloro- 12 and α,β-unsaturated carboxylic acids 13 are formed. In this reaction the α-(trichloromethyl)carbinols 7 can be excluded as intermediates. An alternative reaction mechanism for the formation of 11, 12, and 13 is discussed, which involves direct addition of dichlorocarbene to the C=O double bond to form the dichlorooxiranes 5 followed by rearrangement and saponification.
    Notes: Aldehyde und Ketone reagieren mit Trichlormethan im Zweiphasensystem mit 50proz. wäßrigem Natriumhydroxid unter Phasentransfer-Katalyse durch Benzyltriethylammonium-chlorid (BTEA) (1) bei tiefer Temperatur zu α-(Trichlormethyl)carbinolen 7, in Gegenwart von Dimethylsulfat zu den entsprechenden Methylethern 8. Bei 56 ± 2°C entstehen α-Hydroxy- 11, α-Chlor- 12 und α,β-ungesättigte Carbonsäuren 13, wobei die α-(Trichlormethyl)carbinole 7 als Zwischen-stufen auszuschließen sind. Als Alternativmechanismus wird die direkte Addition von Dichlor-carben an die C=O-Doppelbindung zu Dichloroxiranen 5 und deren Umlagerung und Verseifung diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 23-36 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, VIII. Selectivity of Nucleophilic Carbenes with Regard to HeterocumulenesThe selectivities of N-methylbenzothiazolinylidene (2) and 1,3-diphenylimidazolidinylidene (3) against aryl isocyanates and phenyl isothiocyanate have been determined. The selectivities increase from dimethoxycarbene (1) over 2 to 3. In contrast all three carbenes display equal selectivity with regard to different aryl isocyanates.
    Notes: Für N-Methylbenzothiazolinyliden (2) und 1,3-Diphenylimidazolidinyliden (3) wurden die Selektivitäten gegenüber verschiedenen Arylisocyanaten einerseits und Phenylisothiocyanat andererseits bestimmt. Diese nehmen vom Dimethoxycarben (1) über 2 zu 3 zu. Dagegen zeigen alle drei Carbene bei 140°C eine übereinstimmende Selektivität gegenüber Arylisocyanaten.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 12-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Metabolites of Microorganisms, XII. Michigazone, a New Phenoxazone Pigment from Streptomyces michiganensis  -  Structure Determination and SynthesisBy spectroscopic methods and chemical degradation michigazone has been shown to possess structure 7. 7 and some further related phenoxazones have been synthesized by the Kehrmann-method.
    Notes: Spektroskopische Untersuchungen und chemischer Abbau führten für Michigazon zur Konstitution 7. 7 und einige weitere bisher noch nicht beschriebene Phenoxazone wurden durch Kehrmann-Synthese dargestellt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 49-52 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, X. Ionic Intermediates in the Reaction of Trimethyl Orthoformate with Aryl IsocyanatesThe ion pair 2/3 is assumed to be the crucial intermediate in the reaction of trimethyl orthoformate with aryl isocyanates. The collapse of the ion pair to 4 is a fast subsequent reaction. The acid base reaction of the ion pair to the carbene 6 proceeds with a comparable rate. Methoxyl transfer of 2/3 to form 1 is considerably slower. Transalkylation of the ion pair to 8 has not been observed.
    Notes: Bei der Umsetzung von Orthoameisensäure-trimethylester mit Phenylisocyanat wird das Ionen-paar 2/3 als zentrale Zwischenstufe angenommen. Eine rasche Folgereaktion dieses Ionenpaares ist die Kombination zu 4. Vergleichbar schnell verläuft die Säure-Basen-Reaktion im Ionenpaar zum Carben 6. Eine Methoxyl-Übertragung aus 2/3 zu 1 ist erheblich langsamer. Die Umalkylierung zu 8 konnte nicht beobachtet werden.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 86-95 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Activated Ethylenes, V. Reaction of Aromatic Compounds with Derivatives of Chloromethylenemalonic Acid. A new Synthesis of Aromatic AldehydesThe derivatives of chloromethylenemalonic acid 3 and 4 react with aromatic compounds in the presence of aluminium chloride to give the arylmethylenemalonic acid derivatives 5a-i and 6a-d. By hydrolysis of the C=C double bond the corresponding dinitriles 2a-g are converted into aldehydes.
    Notes: Chlormethylenmalonsäure-Derivate 3 und 4 lassen sich in Gegenwart von Aluminiumchlorid mit Aromaten umsetzen, wobei die Arylmethylenmalonsäure-Derivate 5a-i und 6a-d entstehen. Die entsprechenden Dinitrile 2a-g lassen sich durch Hydrolyse der C=C-Doppelbindung in Aldehyde überführen.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 107-123 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry of the Norcaradiene-Norcaradiene Rearrangement, I. The Synthesis of Optically Active [Norcaradiene ⇌ Cycloheptatriene] DerivativesAnion 14 derived from treatment of 1,3,5-cycloheptatriene-7-carbonitrile (13) with n-butyllithium or lithium diisopropyl reacts with methyl iodide, deuterium oxide, and carbon dioxide to give the corresponding 7,7-disubstituted derivatives 2, 13-D, and 16. By a sequence of reactions 2 was transformed into the optically pure [norcaradiene ⇌ cycloheptatriene] systems 4 and 10. The equilibrium concentrations of the [norcaradiene ⇌ cycloheptatriene] systems 2-12 were determined by 1H n.m.r. mesurements at low temperatures.
    Notes: Das aus 1,3,5-Cycloheptatrien-7-carbonitril (13) mit n-Butyllithium oder Lithium-diisopropylamid erzeugte Anion 14 reagiert mit Methyliodid, Deuteriumoxid und Kohlendioxid ausschließlich zu den entsprechenden 7,7-disubstituierten Derivaten 2, 13-D, und 16. Aus 2 lassen sich durch eine Folge von Reaktionen die optisch reinen [Norcaradien ⇌ Cycloheptatrien]-Systeme 4 und 10 synthetisieren. Mit Hilfe der Tieftemperatur-1H-NMR-Spektroskopie wurden die Gleichgewichtskonzentrationen der [Norcaradien ⇌ Cycloheptatrien]-Systeme 2-12 ermittelt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 146-153 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 4-Acetoxy-2-cyclopenten-1-oneBy using 4-acetoxy-2-cyclopenten-1-one (8) as a synthone for the non-existent cyclopentadienone (5), Michael additions are performed that give rise to trans-disubstituted cyclopentanone derivatives (11,12). In the case of tert-butyl acetoacetate as Michael donator the addition to 11 is followed by an aldol-cyclisation to the trans-perhydroazulene system 22.
    Notes: Unter Verwendung von 4-Acetoxy-2-cyclopenten-1-on (8) als Synthon für das nicht existenzfähige Cyclopentadienon (5) wurden Michael-Additionen durchgeführt, die zu trans-disubstituierten Cyclopentanon-Derivaten (11, 12) führen. Bei Verwendung von tert-Butyl-acetacetat als Michael-Donator schließt sich an die Addition zu 11 eine Aldolcyclisierung zum trans-Perhydroazulensystem 22 an.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 605-610 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 3,3-Bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. Trapping Reactions of Nitrile Ylides with NitrosobenzeneTrapping reactions of bis(trifluoromethyl)-substituted nitrile ylides 2, generated by thermolysis of 3,3-bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. 1, with nitrosobenzene yield 5,5-bis-(trifluoromethyl)-Δ3-1,2,4-oxadiazolines 3, 3,3-bis(trifluoromethyl)-Δ4-1,2,4-oxadiazolines 4, and 4,4-bis(trifluoromethyl)-1,4-dihydro-1-quinazolinols 5. The compounds 5 are products of a thermal rearrangement of first formed [3 + 2]-cycloadducts. I. r., 1H n. m. r., 19F n. m. r., and mass spectra of the new compounds are described.
    Notes: Abfangreaktionen von bis(trifluormethyl)-substituierten Nitril-yliden 2, die durch Thermolyse aus 3,3-Bis(trifluormethyl)-Δ4-1,4,2λ5-oxazaphospholinen 1 erzeugt werden, mit Nitrosobenzol liefern 5,5-Bis(trifluormethyl)-Δ3-1,2,4-oxadiazoline 3, 3,3-Bis(trifluormethyl)-Δ4-1,2,4-oxadiazoline 4 und 4,4-Bis(trifluormethyl)-1,4-dihydro-1-chinazolinole 5. Die Verbindungen 5 sind das Resultat einer thermisch ausgelösten Umlagerung primär erhaltener [3 + 2]-Cycloaddukte. IR-, 1H-NMR-, 19F-NMR- und Massenspektren der neuen Verbindungen werden beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 619-630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXIV. Benzo[12]annulenes: On the Annulene Character of Dibenzo- and Tribenzo[12]annulenesAs a contribution to the controversial discussion about the antiaromaticity of the [12]annulene system in the di- and tribenzo[12]annulenes 3 and 4 the compounds 5, 8, and 18 were prepared for comparison. The discussion of the 1H n. m. r. spectra with consideration of the anisotropy effect of the triple bonds led to the conclusion that in contrast to earlier assumptions the [12]annulene system in 3 and 4 in spite of the benzo-anellation is paratropic.
    Notes: Als Beitrag zu der kontroversen Diskussion über die Antiaromatizität des [12]Annulen-Systems in den Di- und Tribenzo[12]annulenen 3 und 4 wurden die Vergleichsverbindungen 5, 8 und 18 dargestellt. Die Diskussion der 1H-NMR-Spektren unter Berücksichtigung des Anisotropieeffektes der Dreifachbindungen ergab, daß entgegen früherer Auffassung das [12]Annulen-System in 3 und 4 trotz der Benzo-Anellierung paratrop ist.
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  • 49
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 631-637 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXV. Benzo[12]annulenes: Synthesis and Properties of a Benzo-naphtho[12]annuleneThe benzo-naphtho[12]annulene 4, where in contrast to 1, 2, and 3 a planar twelve-membered ring is present, has been synthesized via 6-9. 1H n. m. r. absorption of the internal hydrogen is observed at δ = 13.13 ppm. The allotment of this considerable down-field shift to the paratropic effect of the annulene system and the anisotropy of the triple bonds is discussed. For this purpose, the twelve-ring system 5 in which the macrocyclic conjugation is interrupted has been synthesized from 9 via 10 and 11.
    Notes: Das Benzo-naphtho[12]annulen 4, bei dem im Gegensatz zu den Verbindungen 1, 2 und 3 eine ebene Zwölfring-Struktur fixiert ist, wurde über 6-9 synthetisiert. Die 1H-NMR-Absorption des inneren Wasserstoffatoms wird bei δ = 13.13 ppm beobachtet. Die Aufteilung dieser beträchtlichen Tieffeld-Verschiebung in den Paratropie-Effekt des Annulen-Systems und den Anisotropie-Effekt der Dreifachbindungen wird diskutiert. Hierzu wurde das Zwölfring-System 5, bei dem die makrocyclische Konjugation unterbrochen ist, von 9 über 10 und 11 synthetisiert.
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  • 50
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 651-655 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XV. Reactions of trans,trans-1,3-Diphenyl-2-azaallyllithium with Heterocumulenestrans,trans-1,3-Diphenyl-2-azaallyllithium (1) reacts with phenylisocyanate, phenylisothiocyanate, and methylisothiocyanate to give an imidazolidine-4-one (2a) or imidazolidine-4-thione (2b, c), respectively. When reacting with carbon disulfide or dicyclohexylcarbodiimide (symmetrical heterocumulenes) the cycloaddition is followed by a fast secondary reaction (→ 4, 7).
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich regiospezifisch an die CN-Doppel-bindung des Phenylisocyanats sowie Phenyl- und Methylisothiocyanats unter Bildung eines Imidazolidin-4-ons (2a) bzw. -4-thions (2b, c). Bei entsprechenden Umsetzungen mit den symmetrischen Heterokumulenen Schwefelkohlenstoff und Dicyclohexylcarbodiimid folgt der Cycloaddition jeweils eine schnelle Sekundärreaktion (→4, 7).
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  • 51
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 667-676 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of trans-[Pt(CO2R)(CO)(PPh3)2]+BF4- with Alkynes: Formation of Alkynyl- and Alkenylplatinum(II) ComplexesThe alkoxycarbonyl complexes [Pt(CO2R)(CO)(PPh3)2]+ BF4- 1 react with alkynes HC≡CR to give the acetylides 2a-c. On the other hand, cationic β-methoxyvinyl 3 or β-hydroxyvinyl complexes 4, respectively, are obtained from the reactions of 1 with disubstituted acetylenes R1C≡CR2 under participation of the nucleophiles methanol and water. Compounds 3 and 4 are converted into neutral derivatives (5, 6, 8) by methoxide or azide ions. The synthesis of Ir(CO2CH3)(CO)(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 is described. Bonding is discussed for the new complexes by means of n. m. r. and i. r. data.
    Notes: Die Alkoxycarbonyl-Komplexe [Pt(CO2R)(CO)(PPh3)2]+BF4- 1 setzen sich mit Alkinen HC ≡ CR zu den Acetyliden 2a-c um. Dagegen entstehen aus 1 und disubstituierten Acetylenen R1C≡CR2 unter Beteiligung der Nucleophile Methanol und Wasser kationische β-Methoxyvinyl- 3, bzw. β-Hydroxyvinyl-Komplexe 4. Die Verbindungen 3 und 4 werden mit Methylat- oder Azid-Ionen in neutrale Derivate (5, 6, 8) umgewandelt. Ferner wird die Synthese von Ir(CO2CH3)(CO)-(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 beschrieben. Die Bindungsverhältnisse werden mit Hilfe von NMR- und IR-Daten diskutiert.
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  • 52
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 703-716 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Bridged 5,6-Diamino-4,7-dialkyl-1,3-benzodioxoles as Intermediates for the Synthesis of Molecules with Knot StructureIn a reaction sequence involving metalation with butyllithium followed by alkylation. cyclohexanone pyrocatechol acetal 4 is converted to the 3,6-dialkylpyrocatechol 11. By subsequent acetalisation with 1,25-dichloro-13-pentacosanone (14), followed by nitration (19), reduction (20), acylation (26), renewed reduction (27), and cyclization, the double bridged benzodioxole 28 is obtained. The compound represents an intermediate in the projected synthesis of a molecule with knot structure.
    Notes: Ausgehend vom Cyclohexanon-brenzcatechinacetal 4 wird durch Metallierung mit Butyllithium und nachfolgende Alkylierung in einer mehrstufigen Reaktionsfolge das 3,6-Dialkylbrenzcatechin 11 synthetisiert. Durch nachfolgende Acetalisierung mit 1,25-Dichlor-13-pentacosanon (14), gefolgt von Nitrierung (19), Reduktion (20), Acylierung (26), erneuter Reduktion (27) und Cyclisierung wird das zweifach überbrückte Benzodioxol 28 erhalten. Es stellt ein Zwischenprodukt in der geplanten Synthese eines Moleküls mit Knotenstruktur dar.
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  • 53
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 463-467 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XIV Sulfinato-O,S Complexes of Palladium(II) and Rhodium(III)The directed preparation of the sulfinato-O,S complexes {R(O)OS}nM (2a, b; 5a, b) was successful for the first time by elimination of coordinated water from the sulfinato-S complexes {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] by 2,2-dimethoxypropane. The O,S-linkage is unequivocally shown from their chemical behaviour and the i. r. spectra. The criteria necessary for the formation of sulfinato-O,S complexes are discussed.
    Notes: Durch Abspaltung von koordiniertem Wasser aus den Sulfinato-S-Komplexen {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] mit 2,2-Dimethoxypropan gelang erstmals die gezielte Darstellung der Sulfinato-O,S-Komplexe {R(O)OS}nM (2a, b; 5a, b). Die O,S-Verknüpfung ergibt sich eindeutig aus dem chemischen Verhalten und den IR-Spektren. Die für die Bildung von Sulfinato-O,S-Komplexen notwendigen Kriterien werden diskutiert.
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  • 54
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 474-486 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 78 Further Constituents of South African Senecio SpeciesFrom representatives of the section Rigidi besides already known compounds four new benzofurans (3, 5, 6, and 10) as well as six new furanoeremophilanes (13, 15, 19-21, and 23) are isolated. From Senecio pterophorus a new type of a pyrrolizidine derivative (25) is isolated. Senecio cissampelinus contains similar compounds (34-37). The structures are elucidated by spectroscopic methods as well as by some chemical reactions. The chemotaxonomical aspects are discussed.
    Notes: Aus Vertretern der Sektion Rigidi werden neben bereits bekannten Verbindungen vier neue Benzofurane (3, 5, 6 und 10) sowie sechs neue Furanoeremophilane (13, 15, 19-21 und 23) isoliert. Aus Senecio pterophorus wird ein neuer Typ eines Pyrrolizidin-Derivats (25) isoliert. Ähnliche Verbindungen (34-37) enthält Senecio cissampelinus. Die Konstitutionen werden durch spektroskopische Methoden sowie durch einige chemische Reaktionen geklärt. Die chemotaxonomischen Aspekte werden diskutiert.
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 491-499 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Monohydrazones of Dicarbonyl Compounds, IV. New Syntheses of Pyrroles and PyrrolinesKetones and aldehydes with an active methylene group condense easily with monohydrazones of glyoxal (1 + 2 → 3). The hydrazonoethylidene derivatives thus obtained can be reduced to give pyrroles, pyrrolines, pyrrolidines, or N-aminopyrroles.
    Notes: Methylenaktive Ketone und Aldehyde lassen sich mit Monohydrazonen des Glyoxals zu Hydrazonoethyliden-Derivaten umsetzen (1 + 2 → 3). Durch Reduktion dieser Produkte sind Pyrrole, Pyrroline, Pyrrolidine sowie N-Aminopyrrole darstellbar.
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  • 56
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 522-539 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 78. Additions of C-(2,2′-Biphenylylene)-Nα-(4-chlorophenyl)-Nβ-cyano-azomethine Imine to Styrene, Alkenes, Enol Ethers and EnaminesThe cycloaddition of the title compound 1 to styrene at 70°C produces 95% of a pyrazolidine; the hydrogenolytic degradation to 9-phenethylfluorene as well as the n. m. r. spectrum reveal the addition direction. The 1-cyanopyrazolidine derivative shows reactions typical for cyanamides. - The azomethine imine 1 likewise accepts many nonconjugated alkenes, cycloalkenes and derivatives of styrene in high yield. The cycloadducts of butyl vinyl ether, cis- and trans-propenyl propyl ether, β-methoxystyrene and vinyl acetate suffer with dilute acids elimination of alkoxide or acetate, respectively, and of the N-cyano group to yield 2-pyrazolines. The electrophilicity of the azomethine imine carbon center determines the addition direction; substituents on the ethylenic dipolarophile which stabilize positive charge in the transition state of cycloaddition show up in position 5 of the pyrazolidine.
    Notes: Die Cycloaddition der Titelverbindung 1 an Styrol bei 70°C ergibt 95% eines Pyrazolidins; die Additionsrichtung geht aus der Hydrogenolyse zu 9-Phenethylfluoren ebenso wie aus dem NMR-Spektrum hervor. Das 1-Cyanpyrazolidin zeigt für Cyanamide typische Reaktionen. - Das Azomethin-imin 1 addiert viele nichtkonjugierte Alkene, Cycloalkene und Derivate des Styrols in hoher Ausbeute, wobei spektroskopische Daten die Addukt-Strukturen sichern. Die Cycloaddukte des Butylvinylethers, cis- und trans-Propenylpropylethers, β-Methoxystyrols und Vinylacetats erleiden schon mit verdünnter Säure eine Eliminierung des Alkoxyls bzw. Acetats und des N-Cyans unter Bildung von 2-Pyrazolinen. Die Additionsrichtung des 1,3-Dipols wird von der Elektrophilie des Azomethin-imin-Kohlenstoffs bestimmt; Substituenten am ethylenischen Dipolarophil, die positive Ladung im Übergangszustand der Cycloaddition zu stabilisieren vermögen, erscheinen in 5-Stellung des Pyrazolidins.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 611-618 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 2,2,2-Trifluor-4,4,5,5-tetrakis(trifluormethyl)-1,3,2λ5-dioxaphospholanePF5 and PhPF4 react with 2-[bis(trimethylsilyl)amino]-2,2-difluoro-4,4,5,5-tetrakis (trifluoromethyl)-1,3,2λ5-dioxaphospholane (1b) to yield the trifluorophosphorane 2 or 3, respectively. 3 is the first known example of a stable fluorophosphazophosphorane. 2 reacts with methoxytrimethylsilane to give the thermally stable difluoromethoxyphosphorane4; with hexamethyldisiloxane 5 is obtained. PF5 easily converts 5 into 2. Diphenyl(trimethylsilyl)phosphine reduces 2 to the cyclic fluorophosphite 6, which displaces the coordinated cycloolefin in (C7H8)Mo(CO)4 (C7H8 = norbornadiene) with formation of the cis-complex 7. The spectroscopic data are discussed.
    Notes: Die Reaktion von PF5 bzw. PhPF4 mit 2-[Bis(trimethylsilyl)amino]-2,2-difluor-4,4,5,5-tetrakis-(trifluormethyl)-1,3,2λ5-dioxaphospholan (1b) ergibt das Trifluorphosphoran 2 bzw. 3, das erste stabile Fluorphosphazophosphoran. 2 setzt sich mit Methoxytrimethylsilan zu dem thermisch beständigen Difluormethoxyphosphoran 4 um, mit Hexamethyldisiloxan entsteht 5, das mit PF5 leicht in 2 umgewandelt werden kann. Diphenyl(trimethylsilyl)phosphin reduziert 2 zu dem cyclischen Fluorphosphit 6, das in (C7H8)Mo(CO)4 (C7H8 = Norbornadien) das Cycloolefin unter Bildung des cis-Komplexes 7 substituiert. Die spektroskopischen Daten werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 638-644 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XIII. endo-exo-Isomeric Cycloadducts of trans,trans-1,3-Diphenyl-2-azaallyllithium and Acenaphthylenetrans,trans-1,3-Diphenyl-2-azaallyllithium adds at O or -70°C to acenaphthylene with retention of configuration to give a mixture of N-lithio-syn- and N-lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrole (3a, 4a, R = Li) (ca. 1:1). The syn-isomer (endo-cycloadduct) rearranges to the anti-isomer (exo-cycloadduct) at +35°C.
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich bei O oder -70°C unter Retention an Acenaphthylen zu einem Gemisch von N-Lithio-syn- und N-Lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrol (3a, 4a, R = Li) (ca. 1:1). Das syn-Isomere (endo-Cycloaddukt) lagert sich bei +35°C in das anti-Isomere (exo-Cycloaddukt) um.
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 677-682 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Simple Phosphorus and Arsenic Ylides with Methylgermanium, -tin, and -lead SubstituentsThe syntheses of the ylides (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2, and (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 are reported. The relative substituent effect of all IVb elements on the carbanionic function of ylides is discussed in the light of the 13C and 31P n. m. r. spectra of these compounds and their Si and Sn analogues.
    Notes: Die Darstellung der Ylide (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2 und (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 wird beschrieben. Der relative Substituenteneffekt aller IVb-Elemente auf die Carbanion-Funktion von Yliden wird an Hand der 13C- und 31P-NMR-Spektren dieser Verbindungen und ihrer Si- und Sn-Analoga diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 717-720 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Alkyl and Aryl Compounds, XIX. Preparation and Crystal Structure of Methylrubidium and MethylcaesiumCH3Rb and CH3Cs are prepared from CH3Li and rubidium tert-butoxide or caesium 2-methyl-2-pentanolate, respectively. As shown by X-ray diffraction of the crystal powders the compounds possess a hexagonal structure of the NiAs type with isolated methyl anions and alkali cations like CH3K investigated earlier.
    Notes: CH3Rb und CH3Cs werden durch doppelte Umsetzung von CH3Li mit Rubidium-tert-butylat bzw. Caesium-2-methyl-2-pentanolat dargestellt. Nach röntgenographischen Untersuchungen der Kristallpulver besitzen die Verbindungen wie das bereits früher untersuchte CH3K eine hexagonale Struktur vom NiAs-Typ mit isolierten Methyl-Anionen und Alkali-Kationen.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 730-736 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometrical Investigations of Dicarbonyl(cyclopentadienyl)(thioamidato) Complexes of Molybdenum and TungstenThe mass spectra of several dicarbonyl(cyclopentadienyl)(thioamidato) complexes of Mo and W and of the corresponding free thioamides are reported and the fragmentation processes are discussed. The fragmentation modes of the ionized complexes reveal structural rearrangements of the organic ligands, which cannot be observed in the spectra of the free thioamides.
    Notes: Die Massenspektren einiger Dicarbonyl(cyclopentadienyl)(thioamidato)-Komplexe von Mo und W und die der zugehörigen freien Thioamide werden angegeben und die Fragmentierungsprozesse diskutiert. Der organische Ligand unterliegt im ionisierten Komplex tiefgreifenden strukturellen Umlagerungen, für die sich in den Spektren der freien Thioamide keine Parallele finden läßt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 744-748 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Interactions of Triple Bonds, XVI. The Crystal and Molecular Structure of 5,6,12,13-Tetradehydro-8,9,10,11-tetrahydro-7H-dibenzo-[a,c]cyclotrideceneThe crystal structure of the title compound was solved by direct methods and has been refined to R = 0.056. The triple bonds are crossed by an angle of 64.0°. Their centres have a distance of 3.174 Å. Because of transannular repulsion within the thirteen-membered ring system the acetylene group deviates by 4.1° and 4.6° respectively in a cisoid manner from a linear arrangement. The other angles are enlarged. In the present conformation the length of the [CH2]5-bridge corresponds the length of the CH2—S—S—CH2-group. The chiral molecule lies on a crystallographic twofold axis.
    Notes: Die Kristallstruktur der Titelverbindung wurde mit direkten Methoden gelöst und bis zu einem R-Wert von 0.056 verfeinert. Die Dreifachbindungen sind unter einem Winkel von 64.0° gekreuzt angeordnet und zeigen einen Mittelpunktsabstand von 3.174 Å. Auf Grund der transannularen Abstoßung innerhalb des dreizehngliedrigen Ringsystems ist die Acetylengruppe um 4.1° bzw. 4.6° aus der linearen Anordnung cisoid deformiert. Die übrigen Winkel sind aufgeweitet. Die Länge der [CH2]5-Brücke entspricht in der vorliegenden Konformation der einer CH2—S—S—CH2-Gruppe. Das chirale Molekül liegt auf einer zweizähligen kristallographischen Achse.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 693-702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Question of Inner Hexacoordination with Pentaarylphosphoranes; Phosphorane Rearrangements at the Level of Coordination Number 5The spirocyclic pentaarylphosphoranes 13 and 18b containing hydroxy groups in the direct neighbourhood of the molecule centre, isomerize more or less readily to the oxyphosphoranes 14 and 22, resp., with retention of coordination number 5. Inner onium-ate complexations could not be detected with the starting materials.
    Notes: Die spirocyclischen Pentaarylphosphorane 13 und 18b, die in unmittelbarer Nachbarschaft zum Molekülzentrum Hydroxylgruppen aufweisen, isomerisieren mehr oder weniger leicht unter Beibehaltung des Koordinationsniveaus 5 zu den Oxyphosphoranen 14 bzw. 22. Innere Onium-At-Komplexierungen konnten bei den Ausgangsverbindungen nicht nachgewiesen werden.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 683-692 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 1,3,5-Trifluoro-1,3,5-trioxo-1λ6,3λ6,5λ6,2,4,6-trithiatriazine (Sulfanuric Fluoride) with AminesWhereas the reaction of the trithiatriazine 1 with diethylamine yields only mono- and disubstituted derivatives (2b, 3), the reaction with dimethylamine results in the replacement of one, two, or three fluorine atoms (→ 2a, 3a, 4). On the other hand, only mono- or trisubstituted compounds (5a, b or 9a, b, resp.), are formed by the reactions of 1 with primary amines such as methylamine and ethylamine. Ammonia reacts with 1 to give 10·NH3. The free compound 10 is formed by treatment with HCl gas. 10 reacts with P(C6H5)4Cl to yield the ionic compound 11 and with benzaldehyde to form the Schiff base 12. With secondary diamines 1 preferentially undergoes intermolecular linkage with formation of 13, but a bicyclic compound 14 could also be prepared in low yield. 1 reacts with silylamines such as RN(SiMe3)2 (R = CH3, C2H5) only after addition of RNH(SiMe3) (→ 15a, b). Sn—N cleavage reactions with 1 occur more readily. Only monosubstituted products (e. g. 16) are formed. Reaction of 1 with phenylhydrazine results in reduction of a sulfur atom and formation of the anion 17. A substituted anion (18) was also prepared from 2a by this method. The reaction behavior of 1 is discussed in detail.
    Notes: Während das Trithiatriazin 1 mit Diethylamin nur zu Mono- und Disubstitutionsderivaten (2b, 3b) reagiert, kann Dimethylamin ein, zwei oder auch drei Fluoratome austauschen (→2a, 3a, 4). Die Reaktion von 1 mit primären Aminen wie Methylamin und Ethylamin liefert hingegen nur Mono- und Trisubstitutionsprodukte (5a, b bzw. 9a, b). Ammoniak reagiert mit 1 zu 10·NH3, die freie Verbindung 10 entsteht nach Behandeln mit HCl-Gas. Mit P(C6H5)4Cl gibt 10 die ionische Verbindung 11, mit Benzaldehyd die Schiffsche Base 12. Mit sekundären Diaminen setzt sich 1 bevorzugt unter intermolekularer Verknüpfung (13) um, aber auch eine bicyclische Verbindung 14 ist in geringer Ausbeute darzustellen. Mit Silylaminen wie RN(SiMe3)2 (R = CH3, C2H5) reagiert 1 erst nach Zusatz von RNHSiMe3 (→ 15a, b). Sn-N-Spaltungsreaktionen mit 1 verlaufen erheblich leichter, wobei ausschließlich Monosubstitutionsprodukte (z. B. 16) gebildet werden. 1 gibt mit Phenylhydrazin unter Reduktion eines Schwefelatoms das Anion 17. Auch ein substituiertes Anion (18) konnte auf diesem Wege aus 2a dargestellt werden. Das Reaktionsverhalten von 1 wird ausführlich diskutiert.
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  • 65
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the 8-, 4′-, and 7-Monomethyl Ethers of Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavone) and Structure of Ranupenin from Ranunculus repens L.By synthesis of 8-, 4′- and 7-O-monomethylgossypetin via a modified Allan-Robinson condensation as well as directly from gossypetin (3,3′,4′,5,7,8-hexahydroxyflavone), it is shown that ranupenin from Ranunculus repens L., which occurs in the plant as an O-monogalactoside, has the structure not of 8-O-monomethyl- but of 7-O-monomethylgossypetin.
    Notes: Durch die Synthese von 8-, 4′- und 7-O-Monomethylgossypetin über eine modifizierte Allan-Robinson-Kondensation bzw. direkt aus Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavon) konnte geklärt werden, daß dem als O-Monogalactosid natürlich vorliegenden Ranupenin aus Ranunculus repens L. nicht die Konstitution eines Gossypetin-8-, sondern -7-methylethers zukommt.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 773-777 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molecular Mechanics Calculations on the Stability of Bridgehead OlefinsEmpirical force field calculations were used to determine the limits of application of the rules proposed by Fawcett Wiseman and Köbrich for the stability of bridgehead olefins (Bredt compounds). The stability is ruled by the size of the trans-cycloolefin unit, whereas the sum of the number of atoms in the three bridges is of minor importance. With a given skeleton the double bond was found less favourable in the largest bridge than in the second largest in most cases studied.
    Notes: Mittels empirischer Kraftfeldrechnungen wird der Gültigkeitsbereich der Regeln von Fawcett, Wiseman und Köbrich zur Vorhersage der Stabilität von Brückenkopfolefinen (Bredt-Verbindungen) untersucht. Die Größe der trans-Cycloolefineinheit ist für die Stabilität ausschlaggebend, die Summe der Ringgliederzahl in den drei Brücken ist von untergeordneter Bedeutung. Bei gegebenem Gerüst ist in der Mehrzahl der untersuchten Moleküle die Doppelbindung in der größten Brücke weniger günstig als in der zweitgrößten.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 816-819 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Borabenzene Derivatives, IX. Paramagnetic Chromium Complexes of 1-Methylborinate and 1-Phenylborinate IonsPotassium borinates, K[C5H5B-R] (R = CH3, C6H5), react with CrCl3 or CrCl2·THF to give paramagnetic bis(borinato)chromium complexes, Cr(C5H5B-R)2 (R = CH3, C6H5). For these a sandwich structure with a 16-electron valence shell is proposed.
    Notes: Durch Umsetzung von Kaliumborinaten, K[C5H5B-R] (R = CH3, C6H5), mit CrCl3 oder CrCl2·THF werden paramagnetische Bis(borinato)chrom-Komplexe, Cr(C5H5B-R)2 (R = CH3, C6H5), erhalten. Für diese wird eine Sandwich-Struktur mit einer 16-Elektronen-Valenzschale vorgeschlagen.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 994-999 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Reactions of Hydroxy-N,N-dimethylcarboxamides3-Hydroxy-N,N-dimethyl-1-carboxamides (2, 7) are converted into the corresponding γ-butyrolactones (3, 8) by treatment with an acidic ion-exchange resin in acetone or by thermolysis. 2-Hydroxy-N,N-dimethyl-1-carboxamides (10, 12, 14, 16b, 18) on the contrary form the corresponding carbonyl compounds (9, 11, 13, 15b, 17).
    Notes: 4-Hydroxycarbonsäure-dimethylamide (2, 7) lassen sich durch Behandlung mit saurem Ionenaustauscher in Aceton oder durch Thermolyse in die entsprechenden γ-Butyrolactone(3,8) überführen. 3-Hydroxycarbonsäure-dimethylamide (10, 12, 14, 16b, 18) bilden hingegen beim Erwärmen die entsprechenden Carbonylverbindungen (9, 11, 13, 15b, 17) zurück.
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  • 69
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, XIV. The Reactions of Aliphatic Diazo Compounds with the Tricarbonyl(cyclopentadienyl) Hydrides of Molybdenum and TungstenDepending on their constitution, aliphatic diazo compounds 3 behave differently in their reactions with tricarbonyl(cyclopentadienyl)hydridomolybdenum (1) and -tungsten (2). Diazomethane (3a), diazoethane (3b), and 2-diazopropane (3c) are stabilized as alkane diazo ligands in complexes of the type C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7). Phenyl-, (4-nitrophenyl)-, (4-methoxyphenyl)diazomethane (3d, e, f), and 9-diazofluorene (3g) form in clean reactions the carbene insertion products C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), whereas ω-diazoacetophenone (3h) and diazodimedone (3i) yield the binuclear diazo complexes C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10). Diethyl diazomalonate (3h) is coordinated as an imino-amido ligand in the coordination compound 14 which arises from a 1,1-insertion of 3k into the polar tungsten-hydrogen bond of 2.
    Notes: In ihrer Reaktivität gegenüber Tricarbonyl(cyclopentadienyl)hydridomolybdän (1) und -wolfram (2) weisen Diazoalkane 3 starke konstitutionsbedingte Unterschiede auf: Diazomethan (3a), Diazoethan (3b) und 2-Diazopropan (3c) werden als Alkandiazo-Liganden in Komplexen vom Typ C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7) stabilisiert; Phenyl-, (4-Nitrophenyl)-, (4-Methoxyphenyl)diazomethan (3d, e, f) sowie 9-Diazofluoren (3g) bilden in glatten Reaktionen die Carben-Insertionsprodukte C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), während ω-Diazoacetophenon (3h) wie auch Diazodimedon (3i) die zweikernigen Diazoketon-Komplexe C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10) ergeben. Diazomalonsäure-diethylester (3k) wird im Zuge einer zur Koordinationsverbindung 14 führenden 1,1-Insertion in die polare Wolfram-Wasserstoff-Bindung von 2 als Imino-amido-Ligand komplexiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 948-953 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XXI. On Dehydro Amino Acids, VIII. N-Acyl-α,β-dehydro Amino Acids by Rearrangement of N-Acyl-α-imino AcidsAcetylation of 2-iminoisovaleric acid ester 1 gives the acetyl imino derivative 2. By addition of nucleophilic reagents the α-substituted valine esters 5 and 6 are obtained; base catalyzed rearrangement affords acetyl-α,β-dehydrovaline ester 7. The latter reaction opens a general approach to Boc-α,β-dehydroamino acids 11a-d and esters 9a-d.
    Notes: Durch Acetylierung von 2-Iminoisovaleriansäureester 1 wird die Acetyliminoverbindung 2 erhalten. Addition von nucleophilen Reagentien führt zu den α-substituierten Valinestern 5 und 6, basenkatalysierte Umlagerung zu Acetyl-α,β-dehydrovalinester 7. Letztere Reaktion eröffnet einen allgemeinen Weg zu Boc-α,β-Dehydroaminosäuren 11a-d und ihren Estern 9a-d.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 979-984 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Natural Dibenzo-α-pyrones, II. Synthesis of Alternariol and Alternariol 9-Methyl EtherThe synthesis of 3,7,9-trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-one (alternariol, 1) and the first synthesis of its 9-methyl ether (2) as well as an extension of the Hurtley condensation to o-bromobenzamides are reported.
    Notes: Die Synthese von 3,7,9-Trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-on (Alternariol, 1), die erste Synthese von Alternariol-9-methylether (2) und eine Erweiterung der Hurtley-Kondensation auf o-Brombenzamide wird beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1020-1026 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylchlorobis(tri-tert-butylphosphine)rhodium(I)Tri-tert-butylphosphine reacts with tetracarbonyl-μ-dichlorodirhodium (1) to form carbonylchlorobis(tri-tert-butylphosphine)rhodium(I) (2), existing in an equilibrium with dicarbonyl-μ-dichlorobis(tri-tert-butylphosphine)dirhodium (3) in pentane solution, which can be seen in the i. r. and 31P-n. m. r. spectra. The crystal structure of 2 has been determined from single crystal X-ray data. The compound crystallizes with 4 molecules in a unit cell of symmetry P21/n in the monoclinic system.
    Notes: Tri-tert-butylphosphin reagiert mit Tetracarbonyl-μ-dichlorodirhodium (1) unter Bildung von Carbonylchlorobis(tri-tert-butylphosphin)rhodium(I) (2), das in Pentanlösung mit Dicarbonyl-μ-dichlorobis(tri-tert-butylphosphin)dirhodium (3) im Gleichgewicht steht, was sich im IR- und 31P-NMR-Spektrum verfolgen läßt. Die Kristallstruktur von 2 wurde röntgenographisch aus Diffraktometer-Einkristalldaten bestimmt. Die Verbindung kristallisiert mit 4 Molekülen in der Elementarzelle der Symmetrie P21/n im monoklinen System.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1042-1046 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stable Mercury(I)-Sulfur Compounds, 3. Investigations on the Donor Capacity of Sulfur at the Mercury(I) IonNew mercury(I)-sulfur compounds have been prepared by reactions between mercury(I) nitrate, perchlorate or hexafluorosilicate solutions with methanol, water/benzene or water/methylene chloride solutions of the following sulfur donor ligands: 1,3-dithiolane, 2-phenyl-1,3-dithiolane, 2,2′-trimethylenebis(1,3-dithiolane), bis(benzylthio)methane, dibenzylsulfide. With mercury(I)-dinitrate, the products are the 1:1 adducts (1a), (4a), (6a), and (11a). With mercury(I)-perchlorate the 1:2 adducts (1b),(4b),(6b) or the 1:1 adducts (5b) and (11b) have been obtained. Dibenzylsulfide forms a 1:1 adduct (11c) with dimercury(I)-hexafluorosilicate.
    Notes: Neue Quecksilber(I)-Schwefel-Verbindungen wurden durch Umsetzung von Quecksilber(I)-nitrat, -perchlorat bzw. -hexafluorosilicat-Lösungen mit folgenden Schwefel-Donor-Liganden in methanolischen Lösungen bzw. im Zweiphasensystem wäßrige Lösung/Benzol oder Methylenchlorid hergestellt: 1,3-Dithiolan, 2-Phenyl-1,3-dithiolan, 2,2′-Trimethylenbis(1,3-dithiolan), Bis-(benzylthio)methan, Dibenzylsulfid. Mit Quecksilber(I)-nitrat werden 1:1-Addukte (1a), (4a), (6a) und (11a), mit Quecksilber(I)-perchlorat 1:2-Addukte (1b), (4b) und (6b) bzw. 1:1-Addukte (5b) und (11b) erhalten. Mit Diquecksilber(I)-hexafluorosilicat bildet das Dibenzylsulfid ein 1:1-Addukt (11c).
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1069-1085 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of Thiacyclanone-1,1-dioxides with DiazoalkanesThiacyclanone-1,1-dioxides 1a-e, 9, 13, 15a react with diazomethane and diazoethane to give the enol ethers 2a-j, epoxides 4c, h, 10a, 14a, 17a, α-alkyl-β-ketosulfones 3d, e, j, and ring-enlarged ketosulfones 5h, i, 7h, 11b, 12b, 15b, 16b and 18a, depending on the size of the ring and the position of the carbonyl and sulfonyl group to each other. The enol ethers are easily hydrolysed with mineral acids forming the β-ketosulfones 1a-e. In the presence of lewis acids ethyl diazoacetate yields ethoxycarbonylmethoxy compounds 2k, I, and ring-enlarged β-ketoesters 5k-o, 7m, n, 15c, 16c, and 18c. Only the γ-ketosulfone 9 with ethyl diazoacetate gives, in addition to the ring-enlarged product 11c, the glycidic ester 10c. The β-ketoesters undergo hydrolysis and decarboxylation to the ketosulfones in very good yield. In the ring-expansion of ketosulfones with diazoethane and ethyl diazoacetate the preferred insertion of the diazo compound occurs between the C-3 and C-4 atoms.
    Notes: In Abhängigkeit von der Ringgliederzahl und der Lage von Carbonyl- und Sulfonylgruppe zueinander reagieren Thiacyclanon-1,1-dioxide 1a-e, 9, 13 und 15a mit Diazomethan bzw. -ethan zu Enolethern 2a-j, Epoxiden 4c, h, 10a, 14a, 17a, α-Alkyl-β-ketosulfonen 3d, e,j oder zu ringerweiterten Ketosulfonen 5h,i, 7h, 11b, 12b, 15b, 16b und 18a. Die Enolether spalten leicht mit Mineralsäure zurück zu den β-Ketosulfonen 1a-e. Mit Diazoessigester in Gegenwart von Lewis-Säuren entstehen die Ethoxycarbonylmethoxy-Verbindungen 2k, I bzw. die ringerweiterten β-Ketoester 5k-o, 7 m, n, 15c, 16c und 18c; lediglich das γ-Ketosulfon 9 gibt mit Diazoessigester neben dem Ringerweiterungsprodukt 11c den Glycidester 10c. Die β-Ketoester lassen sich in guten Ausbeuten zu den Ketosulfonen verseifend decarboxylieren. Bei den Ringerweiterungen der Ketosulfone mit Diazoethan und Diazoessigester ist eine bevorzugte Insertion des Diazoalkanrestes zwischen C-3 und C-4 festzustellen.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1124-1129 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Four- and Five-membered Phosphorus Heterocycles, 15. The Products of Carbohydrazide/Phosphonic Chloride Reaction: 2,2′-Spirobi(1,3,4,2λ5-oxadiaza-phospholines)The products of the 2:1-condensation of carbohydrazides 1 with phosphonic dichlorides 2 are not cyclic anhydrides 4 of the phosphonic bis(acylhydrazides), as has been assumed until now. Instead they possess the structure of the spirocyclic phosphoranes 9 named in the title. Their formation is due to the unusual reaction of a P = O-bond involving elimination of water. With dimethylphosphinic chloride (14) the hydrazides 1 react in quite the same sense to give the dimers 17 of oxadiazaphospholes in which the pentacoordinate phosphorus (as a bridgehead) is again part of two small rings. The phosphoranes 9 are also obtained from the reaction of 1 with tetrachloro-phosphoranes 5 or thiophosphonic dichlorides 18 or even bis(dimethylamino)phosphines 19.
    Notes: Die 2:1-Kondensationsprodukte aus Carbonsäurehydraziden 1 und Phosphonyldichloriden 2 stellen nicht - wie bisher angenommen - durch Anhydridbildung cyclisierte Phosphonsäure-bis(acylhydrazide) 4 dar, sondern die im Titel genannten spirocyclischen Phosphorane 9. Ihr Entstehen beinhaltet das „Aufrichten“ einer P = O-Bindung unter Wasserabspaltung. Mit Di-methylphosphinylchlorid (14) reagieren die Hydrazide 1 im gleichen Sinn zu Oxadiazaphosphol-Dimeren 17 mit ebenfalls bicyclisch (als Brückenkopf) eingebautem Phosphoranphosphor. Die Phosphorane 9 entstehen auch aus 1 und Tetrachlorphosphoranen 5 oder Thiophosphonyl-dichloriden 18 oder auch Bis(dimethylamino)phosphinen 19.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1684-1690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Hydronium Tetrachloroaurate(III)-2,2-dimethyl-2H-benzimidazole 1,3-Dioxide, (C9H10N2O2)H3O+ [AuCl4]-1,2-Benzoquinone dioxime (1) reacts with tetrachlorogold(III) acid-trihydrate in dialkyl ketones as solvents to yield solids 5-7 which contain H3O+ and [AuCl4]- ions and neutral 2,2-dialkyl-2H-benzimidazole 1,3-dioxides (2-4). The organic, neutral molecule can easily be isolated from this solid by means of an ion-exchanger. The structure of hydronium tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazole 1,3-dioxide (5), which can be obtained from acetone solutions, is obtained by X-ray analysis.
    Notes: Die Reaktion von 1,2-Benzochinondioxim (1) mit Tetrachlorogold(III)-säure-trihydrat in Dialkyl-ketonen als Lösungsmittel führt zu Festkörpern 5-7, die aus H3O+- und [AuCl4]--Ionen sowie aus neutralen 2,2-Dialkyl-2H-benzimidazol-1,3-dioxiden (2-4) aufgebaut sind. Daraus läßt sich das organische neutrale Molekül mittels eines Ionenaustauschers abtrennen und in Substanz isolieren. Die Struktur des aus Aceton erhältlichen Hydronium-tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazol-1,3-dioxids (5) wird durch Röntgenstrukturanalyse ermittelt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1744-1747 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Photochemistry of Two Tribenzo-(CH)12-Valence IsomersA new synthesis of the tribenzo[12]annulene 1 and the photochemical transformations of 1 and of its valence isomer 2 are described. A reaction mechanism is proposed.
    Notes: Eine neue Synthese des Tribenzo[12]annulens 1 und die photochemischen Umwandlungen von 1 und seines Valenzisomeren 2 werden beschrieben. Ein Reaktionsmechanismus wird vorgeschlagen.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1759-1762 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 94. New Furanoeremophilanes from Ligularia vorobierii Worosh.L. vorobierii contains besides already known five new furanoeremophilane derivatives (5 and 7-10). Their structures have been elucidated by spectroscopic methods. The constituents show again a close relationship to the neighbouring genus Senecio.
    Notes: L. vorobierii enthält neben bereits bekannten fünf neue Furanoeremophilan-Derivate (5 und 7-10), deren Konstitutionen durch spektroskopische Methoden geklärt werden. Die Inhaltsstoffe zeigen erneut eine enge Verwandtschaft zu der Nachbargattung Senecio.
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Reactivity of Metal π-Complexes, XXII. Sandwich-like Dinuclear (Pd-Pd)-Complexes with Bridging Cyclopentadienyl and Allyl LigandsThe reaction of C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-allyl) with tertiary phosphines or phosphites in the molar ratio of 1:1 produces in practically quantitative yields the dinuclear complexes (C5H5)(2-RC3H4)Pd2L2 (4-20) in which palladium has the oxidation state +1. The crystal structure analysis of 5 (R = CH3, L = P(C6H5)3) and 12 (R = CH3, L = P(OC6H4-o-CH3)3) shows that the cyclopentadienyl as well as the allyl ligand is bonded in a sandwich manner to the Pd-Pd unit. The Pd-Pd distance of 267.9 (in 5) or 268.9 pm (in 12) is suggestive of a metal-metal bond. It is not possible to determine whether the cyclopentadienyl ring in 4-20 exists as a pentahapto- or trihapto-bonded ligand on the basis of the 1H- and 13C n. m. r. data. The reactivity of the dinuclear complexes is in agreement with square planar coordination of the metal atoms.
    Notes: Bei den Reaktionen von C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-Allyl) mit tertiären Phosphinen oder Phosphiten im Molverhältnis 1:1 entstehen in praktisch quantitativer Ausbeute die Zweikernkomplexe (C5H5)(2-RC3H4)Pd2L2 (4-20), in denen Palladium in der Oxidationszahl +1 vorliegt. Wie die Kristallstrukturanalysen von 5 (R = CH3, L = P(C6H5)3) und 12 (R = CH3, L = P(OC6H4-o-CH3)3) zeigen, sind sowohl der Cyclopentadienyl- als auch der Allyl-Ligand sandwichartig an die Pd2-Einheit gebunden. Der Pd-Pd-Abstand von 267.9 (in 5) bzw. 268.9 pm (in 12) weist auf das Vorliegen einer Metall-Metall-Bindung hin. Aufgrund der 1H- und 13C-NMR-Daten ist nicht zu entscheiden, ob in 4-20 der Cyclopentadienylring als pentahapto-oder trihapto-gebundener Ligand vorliegt. Die Reaktivität der Zweikernkomplexe steht mit einer quadratisch-planaren Koordination der Metallatome in Einklang.
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  • 80
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1833-1851 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Metallation of Benzyl- and Allylmercaptanes; the Thiobenzaldehyde and Thioacrolein DianionsDouble deprotonation of benzyl, allyl and 2-methylallyl mercaptane furnishes thiocarbonyl dianiones 2, 12, and 15, respectively. The novel nucleophiles react with alkyl halides, epoxides, and carbonyl derivatives to give good yields of products of type 3, 13/14, and 16/17, respectively. The doubly lithiated allyl mercaptanes are preferentially attacked by all of the employed electro-philes in the γ-position (60/40-90/10 γ/α-ratio) to lead to cis-vinyl sulfides 13 and 16. These can be converted into sulfur-free propanal derivatives 22-26 in high yields. 12 resembles synthetically the otherwise not available 3-lithiopropionaldehyde (18′, homoenolate).
    Notes: Thiocarbonyl-Dianionen lassen sich quantitativ durch doppelte Deprotonierung aus Benzyl-(→2), Allyl- (→12) und 2-Methylallylmercaptan (→15) erzeugen. Die neuen Nucleophile setzen sich mit Alkylhalogeniden, Epoxiden und Carbonylverbindungen in guten Ausbeuten zu Produkten vom Typ 3, 13/14 bzw. 16/17 um. Die doppelt metallierten Allylmercaptane reagieren mit allen bisher getesteten Elektrophilen bevorzugt in γ-Stellung (60/40—90/10 für γ/α) zu cis-Vinyl-sulfiden 13 und 16, die in guten Ausbeuten in schwefelfreie Propionaldehydderivate 22-26 übergefuhrt werden konnten. 12 entspricht damit synthetisch dem nicht direkt zugänglichen 3-Lithio-propionaldehyd (18′, Homoenolat).
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1896-1907 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched-chain Sugars, XV. Glycoside Syntheses with L-StreptoseThe halogeno derivatives of the cyclic carbonates 11 a and 11 b are most suitably used in the synthesis of L-streptose β-glycosides. α-Glycosides are obtained from the benzylidene compound 20. The benzylidene group can be subsequently removed by catalytic hydrogenation. Using the glycosyl halide 16 a also α-glycosides are formed in high yields. However, it is difficult to cleave the isopropylidene group under acidic conditions. Acetylated halides of type 4 are very labile and therefore not useful in glycoside synthesis.
    Notes: Zur Herstellung β-L-glycosidischer Verknüpfungen der L-Streptose sind die Halogenide des cyclischen Carbonats 11 a und 11 b am besten geeignet. α-L-Glycosidische Verknüpfungen der L-Streptose werden am günstigsten mit der Benzylidenverbindung 20 erhalten. Die Benzylidengruppe ist anschließend hydrogenolytisch abspaltbar. Auch das Halogenid 16 a liefert hohe Anteile an α-Glycosid. Die Isopropylidengruppe ist aber schwierig sauer abspaltbar. Acetylierte Halogenide wie 4 sind wegen ihrer Empfindlichkeit zur Glycosidsynthese weniger geeignet.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1925-1930 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, VI. Synthesis of StreptobiosamineA synthesis of 5-deoxy-2-O-(2-deoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-streptobiosamine) is described. The same synthesis was repeated with the corresponding L-sugars. It leads to 5-deoxy-2-O-(2-deoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-streptobiosamine), the disaccharide portion of streptomycin.
    Notes: Eine Synthese der 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-Streptobiosamin) wird beschrieben. Die gleiche Synthese wurde auch mit den entsprechenden L-Zuckern durchgeführt. Sie lieferte 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-Streptobiosamin), das den Disaccharidbaustein des Streptomycins darstellt.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1971-1977 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XIV. The Catalysed Reaction of Aldehydes with Mannich BasesAlkali cyanide- and thiazolium salt-catalysed addition of aldehydes to Mannich bases of saturated and unsaturated ketones leads to the formation of 1,4-diketones (1-6, 9-22).
    Notes: Alkalicyanid- und thiazoliumsalz-katalysierte Additionen von Aldehyden an Mannich-Basen von gesättigten und ungesättigten Ketonen führen zu 1,4-Diketonen (1-6, 9-22).
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  • 84
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mechanism of the Aluminium Chloride-catalysed Rearrangement of 7 H-Dibenzo[c,g]carbazole to 7 H-Dibenzo[a,g]carbazole and of Related Aromatic Skeleton RearrangementsOn an experimental basis a mechanism for the aluminium chloride-catalysed rearrangement of 7 H-dibenzo[c,g]carbazole (1) to 7 H-dibenzo[a,g]carbazole (2) is derived, that involves in the first step formation of the 5,6-dihydro derivatives 3 and 9 which rearrange via a spiro cation 14. This mechanism should also be valid for topologically analogous systems.
    Notes: Für die aluminiumchlorid-katalysierte Skelettumlagerung von 7 H-Dibenzo[c,g]carbazol (1) in 7 H-Dibenzo[a,g]carbazol (2) wird aus Experimenten ein Mechanismus abgeleitet, nach dem zunächst Bildung der 5,6-Dihydro-Derivate 3 und 9 erfolgt, die über ein Spirokation 14 umlagern. Dieser Mechanismus sollte auch für topologisch analoge Systeme zutreffen.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2019-2027 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclophosphates, III. Synthesis and Properties of Uridine 3′,5′-Cyclophosphate EstersThe uridine 3L′,5′-cyclophosphate esters 4-11 were synthesized by reaction of the free acid of uridine 3′,5′-cyclophosphate (1-3) with the appropriate diazoalkane. The configuration of the isomeric 1,3,2λ5-dioxaphosphorinanes is assigned on the basis of an X-ray analysis with the aid of 31P n. m. r. The stereoselectivity was influenced in part by the degree of reactivity of the diazo compound, by steric hindrance in the 2′-position of the ribose, and by variation in the reaction temperature. The newly synthesized compounds were characterized by u. v. and 31P n. m. r. spectra.
    Notes: Die Uridin-3′,5′-cyclophosphat-ester 4-11 wurden durch Reaktion der freien Säure des Uridin-3′,5′-cyclophosphates (1-3) mit den entsprechenden Diazoalkanen erhalten. Die Zuordnung der stereoisomeren 1,3,2λ5-Dioxaphosphorinane läßt sich mit Hilfe der 31P-NMR-Spektren aufgrund einer Röntgenstrukturanalyse zeigen. Eine stereoselektive Beeinflussung durch Variation der Reaktivität der Diazokomponente oder durch sterische Hinderung an der 2′-Position der Ribose, sowie in Abhängigkeit von der Temperatur, konnte partiell erzielt werden. Sämtliche synthetisierten Verbindungen wurden durch UV- und 31P-NMR-Spektren charakterisiert.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1462-1469 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mannich Reaction at 2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one, the Chromophore of the Ribonucleoside “Q”2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (6a) reacts with dimethylamine and cyclopentylamine in the presence of formaldehyde to form the Mannich bases 6c and d. From 6c the amine moiety was split off on hydrogenation under pressure. The degradation product was identical with 2-amino-6-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (6b), which was obtained by unambiguous synthesis. This shows that in contrast to 3,7-dihydropyrrolo[2,3-d]-pyrimidin-4-one, Mannich reaction involving 6a leads to substitution at C-6.
    Notes: 2-Amino-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-on (6a) reagiert mit Dimethylamin und Cyclo-pentylamin in Gegenwart von Formaldehyd zu den Mannich-Basen 6c und d. Aus 6c ließ sich durch Druckhydrierung das Amin abspalten. Das Abbauprodukt war identisch mit 2-Amino-6-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-on (6b), das auf eindeutigem Syntheseweg erhalten worden war. Damit wird gezeigt, daß die Mannich-Reaktion bei 6a im Gegensatz zu 3,7-Dihydropyrrolo[2,3-d]pyrimidin-4-on zur Substitution an C-6 führt.
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  • 87
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1492-1496 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: as-Triazines and Condensed Derivatives, XVIII. Ring-Chain Tautomerism in 3-Hydroxythiazolo[3,2-b]-as-triazin-7-onesThe hydroxyl groups of the most stable conformer (y) of 3-hydroxythiazolo[3,2-b]-as-triazin-7-one (2a) as well as of the related compound 4 are axial.  -  At elevated temperatures, the AB signal of the CH2 group in the 1H-NMR spectrum of compound 2b collapses, as a result of tautomerization to 3b, into a singlet. ΔG≠ is 17.0 kcal/mole at the coalescence temperature (68°C). In agreement with the decreasing order of the +I effect in the series CH3 〉 CH2Cl 〉 H, no similar tautomerizations take place up to 130°C in the case of compounds 2a and 2c. Compound 4, however, exists at elevated temperatures as an equilibrium mixture with the corresponding “open-chain” form 5.  -  The singlet of the CH2Cl group of compound 2c is transformed, at elevated temperatures, into an AB quadruplet. An explanation for this apparent anomaly is suggested.
    Notes: Das stabilste Konformere (y) des 3-Hydroxythiazolo[3,2-b]-as-triazin-7-ons (2a) enthält eine axiale OH-Gruppe, ebenso wie das der verwandten Verbindung 4.  -  Bei Erhöhung der Temperatur fällt das AB-Signal der CH2-Gruppe im 1H-NMR-Spektrum von 2b als Folge der Tautomerisierung zu 3b in ein Singulett zusammen. Der ΔG≠-Wert bei der Koaleszenztemperatur (68°C) beträgt 17.0 kcal/mol. Im Einklang mit der Abnahme des +I-Effektes in der Reihenfolge CH3 〉 CH2Cl 〉 H erfolgt bei den Verbindungen 2a und 2c bis 130°C keine ähnliche Tautomerisierung. Die Verbindung 4 liegt jedoch bei erhöhter Temperatur im Gleichgewicht mit der „offenkettigen“ Form 5 vor.  -  Bei steigender Temperatur wandelt sich das Singulett der CH2Cl-Gruppe von 2c in ein Quadruplett um. Eine Erklärung für diese scheinbare Anomalie wird gegeben.
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  • 88
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Seven-Membered Ring Systems, XV. Organolithium Derivatives of the Conformationally Rigid Tetraphenyltribenzocycloheptariene (1,2,3,4-Tetraphenyl-9H-tribenzo[a,c,e]cycloheptene)Quasi-axial substituents (e. g. hydrogen and chlorine) at C-9 of 1,2,3,4-tetraphenyl-9H-tribenzo-[a,c,e]cycloheptene (1) are easily exchanged with formation of quasi-axial organometallic compounds. Only in the case of the 9-lithio-9-methyl derivative 17 an equilibrium 17A ⇄ 17B between a quasi-equatorial and a quasi-axial lithium compound was found. Various stereospecific reactions of the new organometallics are reported and the reactivity differences of conformational origin are discussed.
    Notes: Quasi-axiale Substituenten (z. B. Wasserstoff und Chlor) am C-9 von 1,2,3,4-Tetraphenyl-9H-tribenzo[a,c,e]cyclohepten (1) werden leicht unter Bildung quasi-axialer Organometall-Verbindungen ausgetauscht. Lediglich im Fall des 9-Lithio-9-methyl-Derivates 17 konnte ein Gleichgewicht 17A ⇄ 17B zwischen einer quasi-äquatorialen und einer quasi-axialen Lithium-Verbindung nachgewiesen werden. Zahlreiche stereospezifisch verlaufende Abwandlungen der neuen Organometalle werden beschrieben und die konformativ bedingten Reaktivitätsunterschiede diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1576-1585 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Methyl-1-methylene-1λ5-phosphorinane and Cyclopropyl(dimethyl)methylenephosphorane: Two Different Types of Ylides from an Analogous Reaction, and their ComplexesThe reaction of NaNH2 with (4-bromobutyl)- or (3-bromopropyl)-trimethylphosphonium bromide in THF under reflux yields the two title compounds 1 and 8, resp. At room temperature imide-bridged double ylides 2 and 10 are generated. The reaction path is interpreted. With copper, silver, and gold(I) chloride, the dimeric coinage metal complexes of these ylides are obtained. In the first case (with 1) the complexes are assigned a double spirocyclic structure (7a-c).
    Notes: Die Reaktion von NaNH2 mit (4-Brombutyl)- oder (3-Brompropyl)-trimethylphosphonium-bromid in siedendem THF liefert die beiden Titelverbindungen 1 bzw. 8. Bei Raumtemperatur entstehen imid-verbrückte Doppel-Ylide 2 bzw. 10. Der Reaktionsverlauf wird gedeutet. Mit Kupfer-, Silber- und Gold(I)-chlorid werden die dimeren Münzmetall-Komplexe der Ylide erhalten, denen im ersteren Fall (mit 1) eine doppelt spirocyclische Struktur zukommt (7a-c).
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1597-1600 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 91
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 820-832 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions of Heterocumulenes, IX. 1:1-, 2:1-, and 3:1-Adducts from the Reaction of Isothiocyanates with 3-Dimethylamino-2,2-dimethyl-2H-azirineTreatment of the azirine 1 with the activated isothiocyanates 2a, b leads to 1,3-cleavage of the ring and formation of the dipoles 5, which can be characterized by hydrolysis, protonation and methylation to give 6-8. In the reaction of 1 with the sterically hindered alkyl isothiocyanates 2f-i the ring of 5 is split to form the carbodiimides 10. 10f-i hydrolyze via 5 to give the thioureas 11, from which 11f, g easily cyclize to yield the 2-thiohydantoins 12. Cycloaddition reactions of 10f lead to the heterocycles 14, 15, and 17. The alkyl isothiocyanates 2c-e react with 1, depending on the reaction conditions, to give the 3:1-adducts 14 or the dipolar 2:1-adducts 21. The hydrolysis of 21e leads to the thiazolinone 26 with the acyclic product 25 as intermediate.
    Notes: Die aktivierten Isothiocyanate 2a, b reagieren mit dem Azirin 1 unter öffnung der 1,3-Bindung zu den Dipolen 5, die sich durch Hydrolyse, Protonierung und Methylierung zu 6-8 charakterisieren lassen. Im Falle der sterisch gehinderten Alkylisothiocyanate 2f-i tritt Ringöffnung von 5 zu Carbodiimiden 10 ein. 10f-i hydrolysieren über 5 zu den Thioharnstoffen 11, die für 11f, g leicht zu den 2-Thiohydantoinen 12 cyclisieren. Cycloadditionsreaktionen mit 10f führen zu den Heterocyclen 14, 15 und 17. Die Alkylisothiocyanate 2c-e bilden mit 1 je nach den Reaktionsbedingungen die 3:1-Addukte 14 oder die dipolaren 2:1-Addukte 21. Die Hydrolyse von 21e führt über das ringoffene Produkt 25 zum Thiazolinon 26.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 852-866 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Generation of and Olefination with α-S-, -Se-, -Si-, and -Sn-perheterosubstituted (Trimethylsilyl)-methyllithium DerivativesThe Peterson-olefination reaction of equation (1) is used to prepare ketenedithio- 5, ketenediseleno acetals 8, trimethylsilyl- 11, 1,1-bis(trimethylsilyl)- 12, 1-alkylthio- and 1-arylthio-1-silyl- 16, as well as 1-alkylthio- and 1-arylthio-1-stannyl olefins 19 from the α-silyllithium compounds 4, 7b, 9, 10, 15, and 18, respectively. New or improved productive methods of generation of these olefinating reagents are described. The scope and limitations of the present olefinations are discussed.
    Notes: Mit der Peterson-Olefinierungsreaktion der Gl. (1) werden aus den α-Silyllithium-Verbindungen 4, 7b, 9, 10, 15 und 18 Ketendithio- 5 bzw. Ketendiselenoacetale 8, Trimethylsilyl- 11, 1,1-Bis(trimethylsilyl)- 12, 1-Alkylthio- und 1-Arylthio-1-silyl- 16, sowie 1-Alkylthio- und 1-Arylthio-1-stannylolefine 19 hergestellt. Für die Olefinierungsreagentien 7b, 9, 10, 15 und 18 werden neue oder verbesserte, ergiebige Erzeugungsmethoden beschrieben. Die Grenzen der Anwendbarkeit der Olefinierungsreaktionen werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 921-941 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XVII. On Dehydroamino Acids, IV. Ring Closure of DehydropeptidesSix- or five-membered cyclic compounds (amino-piperazinediones: 2, 14-19, 21, 24, or imidazolidinones 28, 29) are obtained under basic conditions from dehydropeptides by α-addition of an amide function to the acylaminoacrylic unit. Sterical conditions, scope, and limitations of this cyclisation have been investigated up to the dehydrotetrapeptide amide 20. Formation of six-membered rings is preferred. Five-membered rings only result, if reaction to six-membered rings is excluded either by the structure of the dehydropeptide (no NH-function available) or by its conformation (s-trans amide function). Ring closure to the cyclodipeptides 2a, 14, 15, 18, 19, 21, and 24 proceeds stereoselectively.
    Notes: Dehydropeptide bilden in alkalischer Lösung durch α-Addition einer Amidgruppe an das Acylaminoacrylsäuresystem sechs- oder fünfgliedrige Ringe (Amino-piperazindione: 2, 14-19, 21, 24 bzw. Imidazolidinone: 28, 29). Reaktionsbedingungen, räumlicher Ablauf und Grenzen der Cyclisierung wurden bis zum Ringschluß des Dehydrotetrapeptidamids 20 untersucht. Der Sechsring wird bevorzugt. Ein Fünfring bildet sich nur dann, wenn die Cycloaddition zum Sechsring infolge der Struktur (keine NH-Funktion zur Addition) oder der Konformation (s-trans-Fixierung einer Amidbindung) des Dehydropeptids nicht möglich ist. Der Ringschluß zu den Cyclodipeptiden 2a, 14, 15, 18, 19, 21 und 24 verläuft stereoselektiv.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 965-978 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dyotropic Rearrangements, XI. Mechanism of the Thermal Rearrangement of Allyl (Silymethyl) EthersThe study of the mechanism of the thermal rearrangement of allyl (silylmethyl) ethers 1a-e has been extended to include crossover and trapping experiments, secondary kinetic deuterium isotope effects, solvent influence and an investigation of the stereochemistry of the migrating silyl group. The rate determining step appears to be the coordination between the silyl group and the oxygen atom, causing the allyl-α-C-O bond to be loosened. In the following, kinetically not measurable step the allyl groups either migrate concertedly with allyl inversion or split off into radicals, depending upon the nature of the substituents R1,R2.
    Notes: Die Studie über den Mechanismus der thermischen Umlagerung von Allyl-(silymethyl)-ethern 1a-e wird mit Hilfe von Kreuzungs- und Abfangsversuchen, sekundären kinetischen Deuterium-Isotopeneffekten, Löungsmitteleinflüssen und einer Untersuchung zur Stereochemie der wandernden Silylgruppe vertieft. Danach scheint der geschwindigkeitsbestimmende Schritt die Koordinierung zwischen dem Silylrest und dem Sauerstoff zu sein, die eine Lockerung der Allyl-α-C-O-Bindung bewirkt. Im anschließenden, kinetisch nicht faßbaren Schritt lagern die Allylgruppen entweder konzertiert mit Allylumkehrung um oder zerfallen in Radikale, je nach Natur der Substituenten R1, R2.
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  • 95
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2180-2188 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of 2-Diazopropane to Allene. Asymmetric Destruction of 1-Pyrazolines with Circularly Polarized Light1,3-Dipolar cycloaddition of 2-diazopropane to allene leads to 1 and the spiropyrazoline 2. The thermal and photochemical decomposition reactions of 1 and 2 are investigated. Irradiation of 2 with circularly polarized light produces a sample which displays optical acitivity and has a strong Cotton effect in the CD. The possibility of applying circularly polarized light for the solution of mechanistic problems in the decomposition of 1-pyrazolines is discussed.
    Notes: Die 1,3-dipolare Cycloaddition von 2-Diazopropan an Allen liefert 1 und das Spiropyrazolin 2, deren thermische und photochemische Zersetzungsreaktionen untersucht werden. Die Bestrahlung von 2 mit circular polarisiertem Licht ergibt eine Anreicherung von optisch aktivem 2, das einen starken Cotton-Effekt im CD zeigt. Die Möglichkeit der Anwendung von circular polarisiertem Licht zur Lösung mechanistischer Fragen beim Zerfall von 1-Pyrazolinen wird diskutiert.
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  • 96
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2222-2235 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Functional Derivatives of Trimethylphosphine, IV. Hydrido(phosphine)iron(II) ComplexesTetrakis(trimethylphosphine)iron, L4Fe (L = P(CH3)3) (3), reacts with HCl to give L2FeCl2 (1a). As an intermediate of this reaction covalent L4(H)FeCl (4a) can be isolated. Its formation by cleavage of the Fe—C bond in L3(H)[(CH3)2PCH2]Fe which is in equilibrium with 3 is established with DCl. With HX (H = NH4⊕, (CH3)3PH⊕; X = Cl⊖, Br⊖, I⊖, PF6⊖) as reagents, L4(H)FeX (X = Cl, Br, I) (4a-c) and [L5(H)Fe]⊕X⊖ (X = Cl, Br, I, PF6) (6a-d) are prepared or their formation in solution is proved. In these solutions two further species, [L4(H)Fe]⊕[X ⊖ solvent]⊕ and [L4(H)(solvent)Fe]⊖ X⊖, are characterized by spectroscopy. Substitution reactions using P(OCH3)3, CO, or isoprene yield the complexes [L5-nL′n(H)Fe]⊕PF⊖ (n = 1. L′ = CO; n = 2, L′ = CO, P(OCH3)3, ½ isoprene; n = 3, L′ = P(OCH3)3), which are also obtained by the direct reaction of the iron(0) complexes L5-nL′nFe with NH4PF6. The isoprene substituted hydridoiron complex (8c) is found to be in an equilibrium with its π-allyl form. As starting materials the tetrahedral complexes L2FeX2 (L = Cl, Br, I) (1a-c) and octahedral L4FeI2 (2c) are characterized.
    Notes: Tetrakis(trimethylphosphin)eisen, L4Fe (L = P(CH3)3) (3), reagiert mit HCl zu L2FeCl2 (1a). Dabei läßt sich kovalentes L4(H)FeCl (4a) als Zwischenstufe fassen, dessen Bildung durch Fe—C-Bindungsspaltung des mit 3 im Gleichgewicht stehenden L3(H)[(CH3)2PCH2]Fe mit DCl nachgewiesen wird. Mit HX (H = NH4⊕. (CH3)3PH⊕; X = Cl⊖, Br⊖, I⊖, PF6⊖) werden L4(H)FeX (X = Cl, Br, I)(4a-c) und [L5(H)Fe]⊕X⊖ (X = Cl, Br, I, PF6) (6a-d) dargestellt bzw. ihre Bildung in Lösung nachgewiesen. In diesen Lösungen werden daneben [L4(H)Fe]⊕[X · Solvens]⊖ und [L4(H)(Solvens)Fe]⊕ X⊖ spektroskopisch charakterisiert. Substitutionsreaktionen mit P(OCH3)3, CO oder Isopren führen zu der Komplexreihe [L5-nL′n(H)Fe]⊕ PF6⊖ (n = 1. L′ = CO; n = 2. L′ = CO, P(OCH3)3, ½ Isopren; n = 3. L′ = P(OCH3)3). Diese Komplexe werden auch durch direkte Reaktion der Eisen(0)-Komplexe L5-nL′nFe mit NH4PF6 erhalten, wobei der isoprensubstituierte Hydridoeisenkomplex (8c) ein Gleichgewicht mit einer π-Allylform erkennen läßt Als Ausgangskomplexe werden die tetraedrischen L2FeX2-Komplexe (X = Cl, Br, I) (1a-c) sowie L4FeI2 (2c) charakterisiert.
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  • 97
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2254-2275 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Verdazyls, 25. N-1′-Linked Bisverdazyls with Phenylene and Naphthylene Bridges, Thermochromism and Magnetic PropertiesThe synthesis of the bisverdazyls 1a-14a starts either from a monoverdazyl and uses 1-cyano-1-methylethyl as protecting group for the free valence (1 a) or from the corresponding bisformazans. 1a with the 1,4-phenylene bridge is diamagnetic up to 300 K, J 〉 3000 cal/mol. In 6a, 2a, and 7a the thermally populated triplet state is separated from the singlet ground state by 1500, 600, or 400 cal/mol. 3a-5a and 10a-13a have almost degenerate singlet triplet states. The magnetic properties, the zero field parameters D, and the thermochromic effects of the absorption spectra are discussed with respect to the structure of 1a-14a and the distorsion around the bridge axis.
    Notes: Die Darstellung der Bisverdazyle 1a-14a entweder stufenweise aus einem Monoverdazyl unter Verwendung der 1-Cyan-1-methylethyl-Gruppe als Schutzfunktion der freien Valenz (1a) oder aus den entsprechenden Bisformazanen wird beschrieben. 1a mit der 1,4-Phenylenbrücke liegt bis 300 K diamagnetisch vor, J 〉 3000 cal/mol. In 6a, 2a und 7a ist der thermisch besetzte Triplett-zustand vom Singulett-Grundzustand durch 1500, 600 bzw. 400 cal/mol getrennt. 3a-5a und 10a-13a besitzen praktisch entartete Singulett-Triplett-Zustände. Die magnetischen Eigenschaften. die Nullfeldparameter D und die Thermochromie-Erscheinungen der Absorptions-spektren werden im Zusammenhang mit der Struktur von 1a-14a und der Verdrillung um die Brückenachse diskutiert.
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  • 98
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2368-2373 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition Reaction of N,N-Dialkylsulfamides, Tertiary Amines, and Phosphines with Fluorosulfonyl IsocyanateFluorosulfonyl isocyanate (2) reacts with N,N-dialkylsulfamides 1a-c or amidosulfonic methyl ester (1d) to afford the N-fluorosulfonyl-N′-(dialkylsulfamoyl)ureas 3a-d. Thermal decomposition of 3a-c leads to the formation of sulfamidie fluorides 4a-c. With tertiary amines and phosphines fluorosulfonyl isocyanate forms 1:1 adducts. Their structure can be proved by i. r. and 13C n. m. r. analysis.
    Notes: Durch Umsetzung von Fluorsulfonylisocyanat (2) mit N,N-Dialkylsulfamiden 1a-c bzw. Amidosulfonsäure-methylester (1d) werden N-Fluorsulfonyl-N′-(dialkylsulfamoyl)harnstoffe 3a-d erhalten, die beim Erhitzen leicht in die Sulfamidsäurefluoride 4a-c zerfallen. Mit tertiären Aminen und Phosphinen bildet Fluorsulfonylisocyanat 1:1-Addukte, deren Struktur durch IR- und 13C-NMR-Untersuchungen aufgeklärt wird.
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  • 99
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2385-2387 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 100
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. XXVII 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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