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  • Inorganic Chemistry  (704)
  • Cell & Developmental Biology  (419)
  • 1980-1984  (1,123)
  • 1925-1929
  • 1981  (1,123)
Collection
Publisher
Years
  • 1980-1984  (1,123)
  • 1925-1929
Year
  • 1
    ISSN: 0886-1544
    Keywords: videomicroscopy ; differential interference microscopy ; streaming ; reticulopodial motility ; Allogromia ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A new method called Allen Video-enhanced Contrast, Differential Interference Contrast (AVEC-DIC) microscopy is shown to be sufficiently sensitive to detect several new features of microtubule-related motility in the reticulopodial network of the foraminifer, Allogromia. The method takes advantage of the variable gain and offset features of a binary video camera to operate the DIC microscope under conditions highly favorable for video imaging, but in which the optical image is virtually invisible to the eye yet retains its full information when viewed by a suitable video camera. The improvements are made possible by setting a dé Senarmont compensator to λ/9-λ/4 at maximal working aperture of internally corrected planapochromatic objectives. Under these conditions, the offset feature of the video camera can reject so much stray light from the instrument and specimen that contrast compares favorably with that observed in high-extinction images, and polarizing rectifiers offer scarcely any advantage. Freed from the constraints of the light-limited conditions of DIC microscopy, video images can be recorded 60 times per second, or over 1,000 times the rate of photomicrographs at comparable magnifications under high-extinction conditions.Application of this method to the reticulopodial network of Allogromia has shown that cytoplasmic organelles are translocated only in contact with single microtubules or bundles of microtubules, and that these organelles fail to move when separated from microtubules. Microtubules themselves undergo both axial translatory (“sliding”) and lateral “zipping and unzipping” movements that have been suggested to occur during mitosis and other biological processes.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1981), S. 329-347 
    ISSN: 0886-1544
    Keywords: actin ; microfilaments ; heavy meromyosin ; mammary gland ; secretion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytochalasin B, a microfilament-altering drug, inhibits lactose synthesis in lactating guinea pig mammary gland [Biochim. Biophys. Acta 392:20, 1975] but not primarily by inhibiting glucose transport [Eur. J. Cell Biol. 20:150, 1979]. In order to study the possible role of microfilaments in lactose synthesis and secretion, we isolated both the alveolar (milk-secreting) and myoepithelial (contractile) cells from lactating mammary gland. Light microscopy shows that the alveolar cell fraction (viability approximately 71%) is homogenous and that the cells retain strong polarity of secretory structures in the apical region. Two proteins were extracted from the alveolar cell fraction. One (mol wt 42,000) comigrates with skeletal muscle actin on SDS-PAGE gels. The other, a high-molecular-weight (180,000) protein (HMWP) may be analogous to actin-binding protein or clathrin. An extract from the myoepithelial cell fraction also contains a protein that comigrates with actin but no HMWP. Whole tissue extract contains the 42K protein, and a 185K HMWP. Examination of the alveolar cell extract by electron microscopic (EM) negative staining revealed meshworks of multistranded, interconnecting filaments, with attached globular structures (100-200 A) (possibly the HMWP) and single filaments (40-60 A diameter) branching off. To localize these filamentous structures in situ, whole tissue was glycerinated and incubated with rabbit skeletal muscle heavy meromyosin (HMM). Masses of filaments in myoepithelial cells served as convenient standards for HMM decoration. Decorated filaments have cross-arms or projections, unlike the narrow, smooth filaments of control tissue. Decorated filaments in alveolar cells are located beneath the plasma membrane, in close association with secretory vacuoles, and near the Golgi apparatus; filaments near the latter two are often oriented perpendicular to the plasma membrane. Microvesicles are embedded in meshworks under the plasmalemma and near the Golgi apparatus. Intermediate-sized (85-115 A diameter), non-decorated filaments diverge from the meshworks of decorated filaments. Microvesicles are associated with intermediate-sized filaments as well. The association of actin-like filaments with secretory vacuoles and microvesicles and their location in areas of the cell concerned with biosynthetic activities suggest a possible function in the intracellular transport of secretory products.
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  • 3
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1981), S. 455-468 
    ISSN: 0886-1544
    Keywords: intercellular bridge ; intercellular communication ; cytokinesis ; squid ; ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Incomplete cytokinesis followed by the disappearance of the midbody and spindle remnant results in intercellular bridges between the cells of the blastoderm of the squid embryo. An electron microscope study of the morphology of the stages of development of the intercellular bridge is presented. Cytokinesis ceased as the furrow base reached a diameter slightly larger than the midbody. As furrowing stopped, a dense material accumulated to form a cylindrical sheath 50 nm thick, lining the inner surface of the furrow base. Proteolytic enzymes showed this material to have a significant protein component. As the midbody broke down, vesicles lined the inner surface of the bridge sheath. In this configuration, there was cyto-plasmic continuity between the cells, and organelles appeared to pass through the bridge.The intercellular bridge could become temporarily closed. Vesicles entered the channel and fused with the vesicles lining the inner surface of the sheath. The vesicles enlarged until the channel became occluded with a series of transverse cisternae, the edges of which were embedded in the material of the sheath. When the bridge reopened, the transverse cisterna appeared to dissociate from the sheath, move out of the channel, and break down. Occasionally bridges were seen in which the bridge wall appeared distorted into lobes. It is suggested that such bridges might be in the porcess of breaking down, resulting in the final separation of the cells.
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  • 4
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    Cell Motility and the Cytoskeleton 1 (1981), S. 469-483 
    ISSN: 0886-1544
    Keywords: microtubules ; nucleation ; mitosis ; nocodazole ; immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The reassembly of microtubules is described in mitotic cells after release from nocodazole-induced block. The formation of microtubules was followed by light microscopic immunocytochemical staining using the PAP method, combined with to-luidine blue staining of the chromatin. The light microscopic observations on whole cells were compared with ultrastructural observations on thin sections. This step is essential to ascertain complete destruction of microtubules during the nocodazole treatment and to correlate immunocytochemical staining with the presence of microtubules.Removal of nocodazole (10 or 1 μg/ml) after a sufficiently long incubation to induce a complete disappearance of microtubules resulted in the appearance of tubulin staining specifically associated with the centromeres and with one or two isolated points in the cytoplasm. Electron microscopy confirmed that the staining was due to the massive accumulation of small microtubules at the kinetochores and centrosomes. Kinetochore nucleation was seen only in association with condensed metaphase-stage chromosomes and not with the less-condensed prophase chromosomes.In a second type of experiment cells were allowed to enter mitosis in the presence of an incompletely active concentration of nocodazole (0.1 μg/ml). The construction of the mitotic spindle was arrested; however, short microtubules were assembled at the kinetochores and centrosomes.These experiments demonstrate that in living mitotic PTK2 cells the kinetochores, as well as the centrosomes, exert a nucleating action on tubulin assembly.The further elongation of microtubules after removal of nocodazole was seen to occur preferentially along axes between the centrosomes and the kinetochores. This resulted in the construction of normal metaphases that evolved through anaphase and telophase. We have attempted to formulate a hypothesis that may explain the oriented assembly that seems to be essential in the construction of the spindle.
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  • 5
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    Cell Motility and the Cytoskeleton 1 (1981), S. 485-497 
    ISSN: 0886-1544
    Keywords: actin ; tubulin ; nucleotides ; polymerization ; microfilaments ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Both actin and tubulin, the major proteins of the cytoskeleton, bind nucleotide triphosphate (NTP) and exhibit the phenomenon of “polymerization-coupled” NTP hydrolysis. In this report I review the nature of polymerization-coupled NTP hydrolysis, and its possible role in the cellular function of actin and tubulin. Polymerization-coupled hydrolysis may be viewed as simply reflecting differences in the NTPase activity of free subunit as compared to polymer. Making assumptions concerning the values of various rate constants, it is possible to write expressions for the effects of NTP hydrolysis on the kinetics of polymerization. The role of NTP hydrolysis may be viewed in at least three different ways: (1) Hydrolysis alters the kinetics of assembly and disassembly. This leads to a consideration of the role of subunit flow in microtubule and microfilament function. (2) Hydrolysis is an essentially irreversible step that separates the assembly and disassembly reactions. This suggests a role of NTP in the regulation of polymer content during cellular cycles of assembly and disassembly. (3) NTP may allow transient stabilization of intersubunit bonds. This suggests a role of NTP in nucleation and possible regulation of nonequilibrium states of assembly.
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  • 6
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    Cell Motility and the Cytoskeleton 1 (1981), S. 499-515 
    ISSN: 0886-1544
    Keywords: dynein ; tubulin ; axonemes ; microtubules ; microtubule-associated proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule-associated proteins (MAPs), isolated from brain tubulin, bound to and saturated outer fibers of Chlamydomonas flagella. MAPs present on these microtubules prevented the subsequent recombination of dynein. MAPs also bound to intact axonemes and thus did not specifically bind to the dynein binding sites on the A subfiber. A molar ratio of 1 mole MAP2 per 27 moles tubulin dimers at saturation of the outer fibers with MAP2 suggested that MAPs could effectively interfere with dynein recombination only if the MAPs were near the dynein binding sites to sterically prevent binding. However, electron microscopic observations indicated that MAPs were not localized but, instead, were dispersed around the outer fibers. In addition, MAP2 present at saturating amounts on in vitro assembled brain microtubules had no significant effect on dynein binding. Dynein-decorated microtubules contained clusters of arms suggesting that there may be cooperative interaction between the arms during dynein binding. Because the A subfiber of axonemes contains sites to which dynein preferentially attaches, MAPs may prevent recombination by interfering with cooperative binding to these specific sites. Dynein presumably binds with equal affinity to any protofilament on in vitro assembled microtubules, and, therefore, the MAPs may not be capable of effectively interfering with cooperative binding of dynein to these microtubules.
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  • 7
    Electronic Resource
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    Cell Motility and the Cytoskeleton 1 (1981), S. 167-178 
    ISSN: 0886-1544
    Keywords: nerve growth ; actin ; tubulin ; antibodies ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryonic chick nerve cells, from dissociated dorsal root ganglia, were cultured on polylysine substrata and examined for tubulin and actin distribution by indirect immunofluorescence.Antibodies generated against chick brain tubulin produced specific fluorescence in growth cones, neurites, and cell bodies without revealing distribution differences or substructure in the nerve cells. However, at reduced antitubulin concentrations, differences were resolved. Tubulin fluorescence remained uniform and intense in neurites and cell bodies, but exhibited reduced intensity and patterning in growth cones. Nonneuronal cells in the reduced intensity and patterning in growth cones. Nonneuronal cells in the cultures served as controls for typical cytoplasmic tubulin fluorescence distribution. Straining controls demonstrated that fluorescence resulted from tubulin-antitubulin binding.Analogous studies, using antibodies generated against chick brain actin, demonstrated distribution differences at reduced antiactin concentrations, including “hot spots” of intense fluorescence in growth cones and a paucity of fluorescence in neurites.
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  • 8
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    Cell Motility and the Cytoskeleton 1 (1981), S. 237-245 
    ISSN: 0886-1544
    Keywords: centrioles ; symmetry ; triplet blades ; thermal fluctuations ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The paper suggests several principles of construction of a microscopically small device for locating the directions of signal sources in microscopic dimensions. It appears that the simplest and smallest device that is compatible with the scrambling influence of thermal fluctuations as are demonstrated by Brownian motion is a pair of cylinders oriented at right angles to each other. Nine equally spaced blades run in a pitched fashion along the mantle of each cylinder. The blades have a concave cross-section and bend around the circumference of the cylinder in a certain rotational pattern. Considering the striking similarity of this hypothetical device with centrioles, the paper puts forward the conjecture that centrioles locate the direction of hypothetical signals inside cells.
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  • 9
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    Cell Motility and the Cytoskeleton 1 (1981), S. 247-260 
    ISSN: 0886-1544
    Keywords: cilia ; trachea ; ATP-reactivation ; ciliary activity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Evidence for active sliding of microtubules during ciliary activity has been demonstrated in a number of organisms: sea urchin sperm flagella, protozoan cilia, and mollusc gill cilia. Although there is evidence that active sliding also occurs in mammalian sperm flagella, there is little or no information on whether active sliding of microtubules also occurs in the short (5-μm) cilia of the mammalian trachea or oviduct. Since these cilia are important in tracheobronchial clearance and ovum transport, respectively, it has been important to demonstrate that microtubule sliding is also involved in the activity of somatic cilia. Ciliated apical portions (cortices) and cilia were isolated from rabbit trachea and oviduct, using Triton X-100 to demembranate the cilia. Most of the ciliated cortices reactivated upon addition of ATP, whereas isolated cilia reactivated to a lesser extent. When preparations of cilia were digested with trypsin before or after ATP addition, disintegration of axonemal doublets occurred with about the same frequency as reactivation. These events were recorded using Nomarski optics and dark-field microscopy. When isolated cilia which had been digested by trypsin and exposed to ATP were also prepared for electron microscopy by negative staining, telescoping of doublet microtubules from axonemes could be shown. These results demonstrate that mammalian somatic ciliary doublet microtubules actively slide in a manner similar to that described for invertebrate cilia.
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  • 10
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    Cell Motility and the Cytoskeleton 1 (1981), S. 269-272 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 11
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    Cell Motility and the Cytoskeleton 1 (1981), S. 261-268 
    ISSN: 0886-1544
    Keywords: Tetrahymena ; chemotaxis ; temporal-gradient sensing ; modulation of turning frequency ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The motility pattern of Tetrahymena thermophila in a homogeneous attractant field consists of successive “runs” and “turns.” The turning frequency decreases or increases upon an abrupt increase in attractant or repellent concentration, respectively. The dose-response curve for leucine and methionine yields a saturation curve with half maximum modulation of the turning frequency at a concentration of 15 μM and 2 μM, respectively. The turning frequency is modulated at a threshold concentration of 0.02 μM and 0.50 μM for leucine and methionine, respectively. The decrease (increase) in turning frequency in the presence of an attractant (repellent) jump reverts to prestimulus frequency in a time proportional to the concentration jump. Hence, Tetrahymena seem to employ temporal-gradient sensing for chemotaxis. Spatial-gradient taxis is thus exerted by random walk, which is biased in the direction of the gradient.
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  • 12
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    Cell Motility and the Cytoskeleton 1 (1981), S. 273-273 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 13
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    Cell Motility and the Cytoskeleton 1 (1981) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 14
    ISSN: 0886-1544
    Keywords: videomicroscopy ; polarization microscopy ; streaming ; reticulopodial motility ; Allogromia ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A new method is described for recording rapid processes of cell motility in polarized light. The Allen video-enhanced contrast (AVEC-POL) method of polarization microscopy achieves significant improvements in resolution, contrast, and the visibility of fine detail by a combination of novel adjustments to a standard (unrectified) polarizing microscope and video camera. Using the full working aperture of a high-power planapochromatic objective lens and compensator setting of λ/9-λ/4, visible images appear lacking in contrast. However, the same images viewed with an appropriate video camera equipped with an electronic offset adjustment can be made to appear with as much contrast as desired, revealing a significantly greater amount of fine detail in the image than can be seen by high extinction visual microscopy alone. At bias retardations between one-ninth and one-quarter wave, the diffraction anomaly observed near extinction disappears. Consequently, polarizing rectifiers are not required with the AVEC-POL method, and images previously requiring photographic exposures of around 20 seconds are sufficiently bright to be registered on the video monitor in 1/60 second. Using an intensity monitor, quantitative measurements of cellular birefringence can be retrieved from live or videotaped images displaying a linear relationship between contrast and phase retardation due to birefringence. The AVEC-POL method also renders accessible to polarized light analysis a number of objects that scatter or depolarize too much light to be studied by high extinction methods. The method is demonstrated on model objects and applied to the highly motile reticulopodial network of Allogromia laticollaris. Rapid motion in close association with microtubules can now be analyzed in greater detail at a significant reduction in the cost of recording.
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  • 15
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    Cell Motility and the Cytoskeleton 1 (1981), S. 303-327 
    ISSN: 0886-1544
    Keywords: cilia ; microtubules ; ATPase ; vanadate ; geometry of sliding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A dynein arm attachment cycle produces sliding between adjacent doublet microtubules (N and N + 1) of cilia. In intact axonemes, in the absence of ATP, almost all arms appear attached at both ends (rigor). When ATP is added, most arms detach from doublet N + 1. In ATP and vanadate, the arms do not return to rigor, suggesting that ATP hydrolysis is required for re-extension and reattachment of the dynein arm, but not for detachment. Using solutions containing dynein to decorate dynein-less axonemal doublets, we confirm this interpretation. In the absence of ATP, both sides of each doublet decorate with arms. Addition of ATP, ATP and vanadate or AMP-PNP causes immediate arm detachment, but only in the first instance, where extensive ATP hydrolysis can occur, does decoration eventually reappear. Dynein decorates heterologous axonemal doublets and brain microtubules, as well as homologous doublets, suggesting that this mechanochemical cycle may have general applicability in microtubule-based cell motility.
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  • 16
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    Cell Motility and the Cytoskeleton 1 (1981), S. 433-443 
    ISSN: 0886-1544
    Keywords: Physarum ; acellular slime mold ; calcium ion ; calcium-ionophore ; cytoplasmic contraction ; oscillation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Calcium is now generally thought to play a key role in regulating a variety of cellular movements. When the plasmodium of Physarum polycephalum was treated with the calcium-ionophore A23187 or the quasi-ionophore amphotericin B, Ca2+ leaked out. Ca2+ efflux into the ambient solution from the plasmodial strand segment was measured by the luminescence of a photoprotein aequorin, and the tensile force production was recorded simultaneously. Ca2+ efflux oscillated with the same period as the cycle of tension generation in the strand, but the phase of cyclic changes in Ca2+ efflux was opposite to that of tension generation. That is, Ca2+ efflux fell in the increasing tension phase and rose in the decreasing tension phase. Cyclic changes in efflux of Ca2+ are provisionally interpreted as reflecting corresponding changes in concentrations of free Ca2+ in the cytoplasm.
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  • 17
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    Cell Motility and the Cytoskeleton 1 (1981), S. 445-454 
    ISSN: 0886-1544
    Keywords: taxol ; microtubules ; polymerization ; tubulin ; mitotic inhibitor ; protein self-assembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dissociated bovine brain microtubule protein has been shown to reassemble at 0°C in the presence of the drug taxol. Tubulin polymerization was monitored both by electron microscopy of the polymeric structures and by incorporation of tritiated GTP into filterable polymeric structures. Most of the labeled guanine nucleotide uptake into tubulin polymeric structures occurred in the first 30 minutes of incubation with the drug. The initial polymerization event results in the formation of protofilamentous tubulin ribbons. The first microtubules were noted after 1 hour of incubation with the drug. After 20 hours of incubation at 0°C with taxol, the bulk of the polymerized tubulin appeared to be in the form of microtubules. Cold-stable tubulin rings with a mean diameter of 34 nm were present in the reaction mixture before the addition of taxol and throughout the 20-hour incubation. Most of the rings were apparantly not involved in the taxol-induced microtubule assembly. The results are consistant with a model whereby taxol induces an initial formation of protofilamentous ribbon structures, mostly from free tubulin dimers, and a slower subsequent folding of the ribbon structures into microtubules.
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  • 18
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    Cell Motility and the Cytoskeleton 1 (1981), S. 179-192 
    ISSN: 0886-1544
    Keywords: actin ; echinoderm ; fascin ; filopodia ; actin cross-linking protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Echinoderm coelomocytes transform from petaloid cells with large motile lamellipodia to filopodial forms. During this morphological transformation, actin filaments extensively reorganize from a random meshwork into tight bundles, which become the skeletons or cores of the filopodia. Antibody localization procedures show that fascin, a 58,000 dalton actin cross-linking protein, becomes incorporated into the filament bundles as they form. Isolated filopodial cores have a pronounced transverse striping pattern, which has been previously identified with fascin crosslinks, and gel electrophoresis identifies a protein in the cores that co-migrates with purified egg fascin. A few of the core fragments also have a distinctive “cap,” which we presume is the membrane insertion site for actin filaments.We have developed a radioimmunoassay for fascin and have used it to study the redistribution of this protein during transformation. Data from the assay indicate that fascin constitutes about 5% of the total cell protein and that substantially more fascin, approximately 1.5-2 times more, is found in the Triton-insoluble cytoskeletons of the filopodial cells than in the petaloid cells. Actin, measured by the DNAase I inhibition assay accounts for approximately 10% of the total cell protein. Approximately 65% of this actin is in a soluble non-filamentous form in the petaloid cells. Our results show that actin polymerization must occur during the cell shape change, since we find approximately 25% more actin in the filopodial cytoskeleton than in the petaloid cytoskeleton. The results show a preferential incorporation of fascin into the cytoskeleton as the cells form filopodia.
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  • 19
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    Cell Motility and the Cytoskeleton 1 (1981), S. 193-203 
    ISSN: 0886-1544
    Keywords: polygonal network ; rat aortic smooth muscle cell ; cell culture ; electron microscopy ; amino acid analysis ; elastin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cultured rat aortic smooth muscle cells (SMC) were examined by electron microscopy and found to contain polygonal networks of 75 A° thin myofilament bundles. The cells also had large bundles of longitudinally aligned thin myofilaments with periodically spaced dense bodies. Abundant plasmalemmal vesicles were present at the cell periphery, and the cells were connected by desmosomes. Intercellular spaces contained sparse amounts of elastic fibers, a material generally present in SMC cultures. Analyses of amino acids by automated column-chromatography showed that isodesmosine and desmosine, two amino acid residues unique for elastin, were present. Accordingly, it was concluded that polygonal networks, previously detected solely in cultured nonmuscle cells, were present in SMC.Other findings suggest (1) a change in myofilament arrangement takes place during cell migration, and (2) rat aortic SMC grown in tissue culture flasks is an important experimental tool in the study of cell motility since such myofilament rearrangements were observed to occur up to fourteen days in first passage.
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  • 20
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    Cell Motility and the Cytoskeleton 1 (1981), S. 205-235 
    ISSN: 0886-1544
    Keywords: capping of receptors ; cell locomotion ; cell-surface interactions ; frictional force ; membrane flow ; polymorphonuclear leukocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: As a cell moves over a surface, the distribution of membrane proteins that adhere to the surface will be changed relative to the distribution of these molecules on a static cell. Observations of this redistribution offer, in principle, evidence as to the mechanisms of membrane dynamics during cell locomotion. Toward extracting such information we present and analyze a mathematical model of receptor transport in the membrane by diffusion and convection, as affected by the making and breaking of the bonds between the receptors and the surface as the cell moves.We show that the disruption of receptor-surface bonds at the tail of the cell provides a mechanism by which the frictional force opposing a cell's motion is exerted, and calculate the magnitude of this force as a function of cell velocity. Assuming this to be the major contribution to the frictional force, we show that when the shear force on a cell is above a critical value it is no longer possible for the cell to slide across the surface. For such large forces, it is still possible for the cell to roll; alternatively the cell can be torn free of the surface.Our analysis of existing data on movement of polymorphonuclear leukocytes indicates that cell motion is not accompanied by a bulk flow of membrane from the front to the back of the cell. The data also indicate that cells do not tend to roll as they move over a surface under normal conditions. The data are most consistent with a model where the membrane as a whole is stationary but where receptors that bind to the surface become coupled to sub-membrane contractile proteins.
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  • 21
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    Cell Motility and the Cytoskeleton 1 (1981), S. 387-397 
    ISSN: 0886-1544
    Keywords: birefringence ; polarizing microscope ; sea urchin egg ; cortex ; mitosis ; cleavage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Birefringence (BR) at the cell surface of fertilized eggs of the sand-dollar, Clypeaster japonicus, during mitosis and cleavage was determined with a photoelectric BR detection apparatus [Hiramoto et al, 1981a]. The cortex of about 2 μm thickness is birefringent positive with respect to the normal to the cell surface. The hyaline layer is negatively birefringent. The halo-layer consisting of a row of microvilli surrounding the egg is positively birefringent in normal Ca-free sea water, while it is negatively birefringent in Ca-free sea water with high refractive index. The BR of the cortex gradually increases over the entire surface during mitosis until the onset of cleavage. The BR of the cortex at the polar region reaches a maximum shortly after the onset of cleavage and then decreases, while the BR of the cortex at the equatorial region begins to decrease shortly before the onset of cleavage, reaches a minimum shortly after the cleavage starts, and then increases again as the cleavage furrow advances. The coefficient of birefringence of the cortex is about 2.5 × 10-5 at the maximum. The BR change of the cortex during mitosis and cleavage is interpreted as a passive deformation caused by the constriction of the contractile ring as well as an active structural change of the cortex occurring in the dividing cell.
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    Cell Motility and the Cytoskeleton 1 (1981) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Cell Motility and the Cytoskeleton 1 (1981), S. 417-431 
    ISSN: 0886-1544
    Keywords: spindle poles ; centrioles ; cell center ; scaffold ; electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: I have used fluorescence microscopy and antibodies to 10nm filaments and tubulin labelled with contrasting fluorochromes to compare the distribution of these proteins in endothelial cells during cell division. During interphase the two filament systems have entirely different distributions: The bulk of the 10nm filaments form a ring that surrounds the cell center and nucleus and remains parallel to the substrate, while the microtubules radiate from the cell center to the cell's border. When the mitotic spindle replaces the radial microtubule pattern in mitosis, the spindle poles remain within - and in close proximity to - the ring of 10nm filaments. This was confirmed by electron microscopy which showed the ring and centrioles in the same plane separated by a distance of 300-400 nm.
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  • 24
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    Cell Motility and the Cytoskeleton 1 (1981), S. 399-416 
    ISSN: 0886-1544
    Keywords: myosin heavy chain ; avian muscular dystrophy ; adult and embryonic fast white fibers ; slow red fiber ; rod ; subfragment-1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Avian muscular dystrophy is characterized by the degeneration of fast white skeletal muscle fibers, with onset during development. Using a one-dimensional peptide mapping technique, we have detected two forms of the myosin heavy chain in the fast white fibers of adult domestic chickens, one form characteristic of birds homozygous for muscular dystrophy, the other of their normal controls. Four dystrophic strains carrying the same gene for muscular dystrophy were examined.No differences were detected in the embryonic heavy chain peptide maps of normal and dystrophic chickens, consistent with the developmental onset of the condition. Differences were also absent from the peptide maps of heavy chains from slow red fibers, which are unaffected in dystrophy. No dystrophy-specific peptide map differences were detected in the three light chains. Analysis of peptide maps of rod and the heavy chain component of subfragment-1 from normal and dystrophic heavy chains indicates the presence of amino acid sequence differences in the two proteins.
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    Cell Motility and the Cytoskeleton 1 (1981) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 26
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    Cell Motility and the Cytoskeleton 1 (1981), S. 349-362 
    ISSN: 0886-1544
    Keywords: Ca2+ ; flagella ; symmetry ; vanadate ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Increased Ca2+ concentration causes a reversible increase in asymmetry of the flagellar bending waves of “potentially symmetric” demembranated sea urchin spermatozoa. When these flagella are immobilized with 5 μM vanadate, increased Ca2+ concentration causes a reversible increase in the total bend angle between the tip and the base of the immobilized flagella. These effects of Ca2+, and the movement which can be activated by CaATP2-, can be inhibited by vanadate, but in both cases, high concentrations of vanadate, of the order of 100 μM, are required. These observations suggest that ATP, possibly in the form of CaATP2-, is required for the Ca2+-induced change in shape of the flagella, but other observations suggest that the magnitudes of asymmetry and total bend angle are more closely related to Ca2+ concentration than to CaATP2- concentration.
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    Cell Motility and the Cytoskeleton 1 (1981), S. 363-370 
    ISSN: 0886-1544
    Keywords: Ca2+ ; Mg2+ ; symmetry ; flagella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Potentially asymmetric spermatozoa are obtained when spermatozoa are demembranated in the presence of a low Ca2+/Mg2+ ion concentration ratio. They swim with asymmetric bending waves even when reactivated at low Ca2+ concentrations, and become more asymmetric when Ca2+ is increased. Potentially symmetric spermatozoa, which swim with symmetric bending waves at low Ca2+ and become asymmetric as the Ca2+ is increased, can be obtained by exposing the flagella to a high Ca2+/Mg2+ ratio, either during or subsequent to demembranation. The rate of this conversion is an increasing function of temperature and Triton concentration. Potentially symmetric spermatozoa can be reconverted to potential asymmetry, if the exposure to high Ca2+/Mg2+ is brief, and is terminated by addition of EGTA and Mg2+ before diluting the spermatozoa. The conversion to potential symmetry may involve removal of a labile component from the axoneme.
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  • 28
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    Cell Motility and the Cytoskeleton 1 (1981), S. 371-385 
    ISSN: 0886-1544
    Keywords: rotating filaments ; cytoplasmic streaming ; Nitella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Our knowledge about the actin-containing characean filaments on the basis of light and electron microscopical investigations is reviewed. Dynamic filamentous networks, known already from isolated droplets, were detected in Nitella rhizoidal cells using light microscopical techniques. Earlier light microscopic observations in cytoplasmic droplets are confirmed and complemented by new model experiments with rotating helices. The motile phenomena occurring at the filament bundles (ring formation, wave propagation, particle translocation, net dynamics, rolling motions, formation of side arms) can, in this way, be imitated in detail. Thus, the concept of cytoplasmic streaming as a translocation along bundles of rapidly rotating helical filaments is supported. In order to explain unidirectional cytoplasmic streaming, a periodic winding up and unwinding of fine filaments is postulated by which ions are periodically bound and displaced. The formation of side arms which is favored during unwinding results in a screw-mechanical different behavior of the filaments in the two directions of rotation and therefore causes permanent particle transport in one direction.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1-13 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Sulfur Ylide Complexes, IX1) π-Complexes of 1-Alkyl-3,5-diphenylthiabenzene 1-Oxides with Dicarbonylnitrosylchromium, -molybdenum, and -tungsten1-Alkyl-3,5-diphenylthiabenzene 1-oxide chromium complexes 2a-f1) are oxidized by NOPF6 in CH2Cl2 at -70°C, yielding the cationic dicarbonylnitrosyl complexes 3a-f. Stable analogous complexes of molybdenum and tungsten can be isolated if the sulfur atom of the ring is substituted by electron releasing and bulky groups such as CH(CH2Ph)2 or CH(SiMe3)2.
    Notes: Die 1-Alkyl-3,5-diphenylthiabenzol-1-oxid-Chromkomplexe 2a-f1) werden durch NOPF6 in CH2Cl2 bei -70°C unter Bildung der kationischen Dicarbonylnitrosyl-Spezies 3a-f oxidiert. Die Isolierung analoger stabiler Komplexe von Molybdän und Wolfram gelingt, wenn sich am Schwefel stark elektronenspendende und sperrige Substituenten wie CH(CH2Ph)2 oder CH(SiMe3)2 befinden.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Topics: Chemistry and Pharmacology
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  • 31
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 14-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dynamic 1H-NMR-Investigation of the Iminophosphorane-Benzoxazaphospholine TautomerismThe Synthesis of many (alkyl-2-hydroxyphenylimino) Phosphoranes is described. These compounds are useful to determine by dynamic 1H-NMR investigations the activation parameters of the observed equilibrium earlier supposed. The lifetimes obtained of the tautomers A und B at 298 K have a range of 0.1 to 10 s.
    Notes: Die Synthese zahlreicher (Alkyl-2-hydroxyphenylimino)phosphorane wird beschrieben. Für das bei diesen Verbindungen zu beobachtende und früher diskutierte Gleichgewicht zwischen zwei tautomeren Formen A und B können durch 1H-NMR-Untersuchungen die Aktivierungsparameter bestimmt werden. Die Lebensdauern von A und B liegen bei 298 K zwischen 0.1 und 10 s.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 61-66 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Pyrimido[6,1-a]isoquinolines with FormaldehydeThe isoquinolin-1-ylidenacetonitrile derivative 1 reacts with formaldehyde and hydrazine, acylhydrazines or hydroxylamine to give the 3,3′-bi(pyrimidoisoquinoline) 5 and the 3-amino-and 3-hydroxypyrimido[6,1-a]isoquinolines 6 and 8, respectively. 8 was transformed into 12, 14, and 15 which are unsubstituted at N-3 and have various oxidation levels in the pyrimidine moiety.
    Notes: Aus dem Isochinolin-1-ylidenacetonitril 1 wurden mit Formaldehyd und Hydrazin, Acylhydrazinen oder Hydroxylamin das 3,3′-Bi(pyrimidoisochinolin) 5 bzw. die 3-Amino und 3-Hydroxypyrimido[6,1a]isochinolin-Derivate 6 und 8 dargestellt. 8 ließ sich in die an N-3 unsubstituierten Derivate 12, 14 und 15 überführen, die verschiedene Oxidationsgrade im Pyrimidinring aufweisen.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 398-399 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Boron, 1141) A Convenient Synthesis of Diboron TetrabromideTetramethoxydiborane (4) and boron tribromide react at ambient temperature with formation of diboron tetrabromide (yield 50%), methyl bromide and diboron trioxide. This makes B2 Br4 readily accessible for further studies.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981) 
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    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 423-432 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transanular Interactions of the Azo Chromophore in Isodrin-type Systems1)The unusual transanular photoreactivity of the azo-compound 5 is also reflected in its photoelectron spectrum. The investigation of compounds 5, 13 and 14 reveals an effective interaction in 5 (through-bond and through-space) with H ij = -0.62 eV between πNN and πCC. This experimental value fits in well with known parameters of analogous isodrin-type systems. The excited states are looked into by means of semiempirical calculations with model compounds 17 and 19. Both the n-π+* and (at shorter wavelength) the π-π+* transition are conducive to an intramolecular photocycloaddition. X-ray diffraction has been used to determine the πNN,πCC-transanular distance (2.91Å).
    Notes: Die ungewöhnliche transanulare Photoreaktivität der Azoverbindung 5 spiegelt sich auch im Photoelektronenspektrum wider. Die Untersuchung der Verbindungen 5, 13 und 14 läßt eine effektive Wechselwirkung (through-bond und through-space) von Hij = -0.62 eV zwischen πNN und πNN in 5 erkennen. Dieser experimentelle Wert steht in ausgezeichneter Übereinstimmung mit bekannten Parametern analoger isodrinartiger Systeme. An den Modellverbindungen 17 und 19 werden die angeregten Zustände mit Hilfe semiempirischer Rechnungen untersucht. Sowohl der n-;π+* - als auch der kurzwellige π-π+* Übergang sind einer intramolekularen Photocycloaddition förderlich. Durch Röntgenbeugung wird der πNN, πCC-Transanularabstand zu 2.91 Å ermittelt.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 173-189 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, I Syntheses of Amino Acids from Halocarboxylic Alkyl Esters and Alkali Metal Cyanates1)α- and ω-halo- as well as α,ω-dihalocarboxylic alkyl react with potassium cyanate in the presence of alcohol at 80-120°C in dipolar aprotic solvents to yield α- and ω(alkoxycarbonyl-amino)- and α, ω-bis(alkoxycarbonylamino)carboxylic alkyl esters, respectively, in good yields. Hydrolytic cleavage of these mono- or diurethanes with an aqueous solution of hydrochloric acid/formic acid leads to the corresponding amino acid hydrochlorides in nearly quantitative yields.
    Notes: α- und ω-Halogen- sowie α,ω-Dihalogencarbonsäure-alkylester reagieren mit Kaliumcyanat in Gegenwart von Alkoholen in dipolaren aprotischen Lösungsmitteln bei 80-120°C in guten Ausbeuten zu α- und ω-(Alkoxycarbonylamino)- bzw. α,ω-Bis(alkoxycarbonylamino)carbonsäurealkylestern (Mono- bzw. Diuerthane). Die hydrolytische Spaltung dieser Verbindungen mit einem wäßrigen Salzsäure/Ameisensäure-Gemisch führt in meist quantitativen Ausbeuten zu den entsprechenden Aminosäure-hydrochloriden.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 214-219 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycyclic Compounds, XX1) A Simple Synthesis of OrchinolThe phytoalexin orchinol (3a) is available in gram amounts starting from 2-(3,5-dimethoxyphenyl) ethyliodide and 2,5-dimethoxybenzoic acid. Key steps are the synthesis of a mixture of the tetrhydrophenanthrenones 2a/2b and their direct dehydrogenation with pyridinium hydrobromide perbromide followed by a subsequent treatment with n-butyllithium.
    Notes: Das Phytoalexin Orchinol (3a) ist ausgehend von 2-(3,5-Dimethoxyphenyl)ethyliodid und 2,5-Dimethoxybenzoesäure im Gramm-Maßstab zugänglich. Zentrale Schritte sind die Synthese des Gemische der Tetrahydrophenanthrenone 2a und 2b und deren direkte Dehydrierung zu 3a mit Pyridiniumhydrobromid-perbromid und nachfolgender Butyllithium-Behandlung.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 240-245 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 2,3-Dialkylpyrazines2,3-Dialkylquinoxalines (4), which are available from the reaction of benzofuroxan (1) with ketones and subsequent reduction of the 2,3-dialkylquinoxaline N, N′-dioxides (3), are converted to 2,3-dialkylpyrazines (6) by oxidation-decarboxylation steps.
    Notes: 2,3-Dialkylchinoxaline (4), die durch Umsetzung von Benzofuroxan (1) mit Ketonen und nachfolgende Reduktion der erhaltenen 2,3-Dialkylchinoxalin-N,N′-dioxide (3) gut zugänglich sind, werden durch Oxidation und Decarboxylierung in 2,3-Dialkylpyrazine (6) übergeführt.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 227-231 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occuring Terpene Derivatives, 3061) Synthesis of a Furan Sesquiterpene from Eumorphia prostataStarting with 5-methyl-2-cyclohexen-1-one (1) through the intermediate 4 the cyclopentene carbaldyhydes 5 und 6 were synthesized. Wittig reaction led to the epimeric nitriles 7 und 8, which after conversion to the aldehydes 9 and 10 on reaction with β-furyllithium afforded the carbinols 11 and 12. Manganese dioxide oxidation yielded the ketones 13 and 14, their spectral data being in agreement with those of the natural compounds.
    Notes: Ausgehend von 5-Methyl-2-cyclohexen-1-on (1) werden über das Zwischenprodukt 4 die Cyclopentancarbaldehyde 5 und 6 synthetisiert. Wittig-Reaktion führt zu den epimeren Nitrilen 7 und 8, die nach Überführung in die Aldehyde 9 und 10 durch Reaktion mit β-Furyllithium die Carbinole 11 und 12 liefern. Mangandioxid-Oxidation gibt die Ketone 13 und 14, deren spektroskopischen Daten mit denen der Naturstoffe übereinstimmen.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 232-239 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Procedure for an α-Glycoside Synthesis of 3-Amino-2,3,6-trideoxyhexopyranoses from GlycalsThe anomeric mixture of the hex-2-enopyranosyl azides 2 und 3, either of which adopts an equilibrium with the 3-azidoglycals 5 and 6, reacts with cyclohexanol and N-iodosuccinimide to give the 3-azido-2-iodo derivatives having α-D-altro- (4) and α-D-manno configuration (9). By reductive work-up and subsequent acetylation the synthesis of 3-acetylamino-2,3-dideoxy-α-glycosides of D-ribo (7) and of D-arabino structure (8) is achieved. By a corresponding reaction sequence starting with di-O-acetyl-L-rhamnal (10) a three step synthesis of both α-L-ristosaminide (16) as well as α-L-acosaminide (17) is realized.
    Notes: Das Anomerengemisch der Hex-2-enopyranosylazide 2 und 3, die jeweils mit den 3-Azidoglycalen 5 bzw. 6 im Gleichgewicht stehen, wird mit Cyclohexanol und N-Iodsuccinimid zu den 3-Azido-2-iod-Derivaten mit α-D-altro- (4) und α-D-Manno-Konfiguration (9) umgesetzt. Deren reduktive Aufarbeitung nebst Acetylierung ermöglicht die Synthese von 3-Acetylamino-2,3-didesoxy-α-glycosiden der D-ribo- (7) und der D-arabino-Struktur (8). In einer vergleichbaren Reaktionssequenz wird aus Di-O-acetyl-L-rhamnal (10) in nur drei Stufen die Synthese des α-L-Ristosaminids (16) sowie des α-L-Acosaminids (17) realisiert.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 564-580 
    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, XXV1) Syntheses and Reactions of Branched Tricarbonyl CompoundsThiazolium salt-catalyzed addition of aldehydes to arylidene- und alkylidene-β-dicarbonyl compounds as well as to 3-acylacrylic esters leads to branched tricarbonyl compounds (1-26), which are useful reagents for the synthesis of heterocyclic compounds. Furthermore a new simple procedure for the preparation of aromatic substituted 1,4-diketones is described.
    Notes: Unter thiazoliumsalz-Katalyse werden Aldehyde an Aryliden- und Alkyliden-β-dicarbonylverbindungen sowie an 3-Acylacrylsäureester zu verzweigten Tricarbonylverbindungen (1-26) addiert, die zu heterocyclischen Ringsystemen umgesetzt werden. Weiterhin wird eine neue einfache Darstellung aromatisch Substituierter 1,4-Diketone beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 620-629 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrazino-bridged [14]Annulenes1)Starting with [1,1-bipyrrole]-2,2′-dicarbaldehyde (6b), 4,9-diphenyl-10b,10c-diazadicyclopenta[ef,kl]heptalene-3,8-dione(4) has been obtained by Knoevenagel-condensation (to give 7b) and cyclization in boiling boron trifluoride-ether. A strong interaction between the carbonyl groups and the rest of the π-systeme is indicated by the IR spectrum (4a). The synthesis of 4.5.9.10-tetra-hydro-10b,10c-diazadicyclopenta[ef,kl]heptalene-3,8-dione (3) has been achieved from 6b by condensation to 7e, reduction to 10 using DIBAH as well as cyclization and decarboxylation. Treatment of 7a and b with DIBAH leads to the unstable dialdehydes 8 and 9, respectively.
    Notes: Ausgehend von [1,1′-Bipyrrol]-2,2′-dicarbaldehyd (6b) wird über eine Knoevenagel-Kondensation (zu 7b) und Cyclisierung in siedendem Bortrifluorid-Ether 4,9-Diphenyl-10b, 10c-diazadicyclopenta[ef,kl]heptalen-3,8-dion (4) erhalten. Das IR-Spektrum deutet auf eine starke Wechselwirkung zwischen den Carbonylgruppen und dem restlichen π-System (4a). Die Synthese des 4,5,9,10-Tetrahydro-10b,10c-diazadicyclopenta[ef,kl]heptalen-3,8-dions(3) gelang aus 6b durch Kondensation zu 7e, Reduktion mit DIBAH zu 10 und anschließende Cyclisierung und Decarboxylierung. Behandlung von 7a und b mit DIBAH führte zu den instabilen Dialdehyden 8 und 9.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 638-651 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New ChromoionophoresThe synthesis and spectroscopic properties, especially shifts in light absorption upon addition of salts, of the new ionophore dyes 1, 3, 4, 10 and 11 of the anthraquinone-, naphthoquinone-, and phenol blue type are described. The observed hypsochromic and bathochromic shifts are discussed in view of the crown ether complexation in the donor or acceptor part, resp., or with 3 and 4 in view of the coordination at both donor and acceptor. Influences of the ion size and of the charge density as well as the influence of changes of the cyanine and polyene character are explained.
    Notes: Synthese und spektroskopische Eigenschaften, insbesondere Lichtabsorptions-Verschiebungen bei Salzzusatz, der neuen Ionophor-Farbstoffe 1, 3, 4, 10 und 11 vom Anthrachinon-, Naphthochinon- und Phenolblau-Typ werden beschrieben. Die hypso- und bathochromen Verschiebungen werden im Hinblick auf die Kronenether-Komplexierung im Donor- und Acceptorteil bzw. bei 3 und 4 am Donor und Acceptor erötert. Einflüsse der Ionengröße und Ladungsdichte sowie von Änderungen des Cyanin- und Polyen-Charakters werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 699-706 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleosides, XXXIV1) Ribosylations of 5,6-Dihydro-6-oxolumazine and its 1,3-Dimethyl Derivative5,6-Dihydro-6-oxolumazine (1) and its 1,3-dimethyl derivative (2) have been ribosylated as their trimethylsilyl derivatives 9 and 3 with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose (8) under BF3-etherate catalysis. 2 leads to an anomeric mixture of 1,3-dimethyl-6-(2,3,5-tri-O-benzoyl-α-and -β-D-ribofuranosyloxy)lumazine (4,5) which have been separated chromatographically. Starting from 1 5,6-dihydro-6-oxo-1,3-bis(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)lumazine (10) was the main reaction product besides small amounts of the corresponding anomeric 6-O-α- and-β-triribosides 12 and 13.
    Notes: 5,6-Dihydro-6-oxolumazin (1) und sein 1,3-Dimethyl-Derivat (2) werden als Trimethylsilyl-Derivate 9 bzw. 3 mit 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose (8) unter BF3-Etherat-Katalyse ribosidiert. 2 ergibt ein Anomerengemisch aus 1,3-Dimethyl-6(2,3,5-tri-O-benzoyl-α-und-β-D-ribofuranosyloxy)lumazin (4, 5), das chromatographisch getrennt wird. Aus 1 wird als Hauptprodukt 5,6-Dihydro-6-oxo-1,3-bis(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)lumazin (10) erhalten neben kleinen Mengen der entsprechenden anomeren 6-O-α- und -β-Tririboside 12 und 13.
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  • 45
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 727-732 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Anionic Lewis Bases to Arsinidene ComplexesThe chloroarsinidene complex CLAs[(CO)5Cr]2 (1) reacts with ammonium salts of halide and pseudohalide ions CL-, Br-, I-, CN-, N3-, and SCH- to give anionic 1:1 adducts. Syntheses and properties of these compounds as well as the results of an X-ray structure analysis of HPy+(CL2As[(CO)5Cr]2- will be described.
    Notes: Der Chlorarsinidenkomplex CLAs[(CO)5Cr]2 (1) reagiert mit Ammoniumsalzen der Halogenid- und Pseudohalogenid-Ionen Cl-, Br-, I-, CN-, N3 und SCN- unter Bildung von anionischen 1 : 1-Addukten. Darstellung und Eigenschaften aller Komplexe sowie die an der Verbindung HPy+ (CL2As[(CO)5Cr]2)- durch Röntgenstrukturanalyse belegte Konstitution werden beschrieben.
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  • 46
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 740-745 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Acetals of L-Rhamnose with Lithium-organic Compounds New Syntheses of Mycaral, Olivomycal, and Methyl 2,3,6-Trideoxy-α-L-erythro-hex-2-enopyranosideMethyl α-L-mycaroside (6a) is obtained from the dideoxy-uloside 2) by Grignard addition. the benzylidene rhamnoside (1a) reacts with methyllithium to give in only one step mycaral (4) (21%) and olivomycal (5) (72%). With lithiumdiisopropylamide 1a yields the unsaturated sugar 3a.
    Notes: Methyl-α-L-mycarosid (6a) wird aus dem Didesoxy-ulosid 2 durch Grignard-Addition erhalten. Das Benzylidenrhamnosid 1a reagiert mit Methyllithium in einem schritt zu Mycaral (4) und Olivomycal (5). Mit Lithiumdiisopropylamid erhält man hingegen aus 1a den ungesättigten Zucker 3a.
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  • 47
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 774-786 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiaziridine 1,1-Dioxides1)Experiments towards a 1,3-elimination of hydrogen halides from α-chlorosulfonamides, α-bromosulfonamides, andN-chlorosulfonamides did not yield isolable thiaziridine 1,1-dioxides 4. Therefore, at -78°C, the diazoalkanes 10 were allowed to react with N-sulfonylamines 14 generated in situ by hydrogen chloride elimination from sulfamoylchlorides with triethylamine. If the work-up temperature was kept below -30°C, from tert-alkyldiazomethanes and tert-alkylsulfamoyl-chlorides the 2,3-di-tert-alkylthiaziridine 1,1-dioxides 4f-i were obtained in 32-47% yield. They form colorless, thermally labile crystals. Their structure was based on IR, UV and 1H-NMR spectra as well as on the quantitative thermal decomposition into sulfur dioxide and aldimines. The disubstituted diasomethanes 23 reacted with tert-butylsulfonylamine affording, besides N-tert butylketimines (the decomposition products of intermediate trisubstituted thiaziridine 1,1-dioxides 21), tert-butylsulfinylamine 25 and ketones 26. The latter products presumably resulted from the cheletropic decomposition of the oxathiiranes 24.
    Notes: Da Versuche zur 1,3-Eliminierung von Halogenwasserstoff aus α-Chlorsulfonamiden, α-Brom-sulfonamiden oder N-Chlorsulfonamiden nicht zu isolierbaren Thiaziridin-1,1-dioxiden 4 führten, wurden bei -78°C Diazoalkane 10 mit N-Sulfonylaminen 14 umgesetzt, die durch Chlorwasserstoff-Eliminierung mit Triethylamin aus Sulfamoylchloriden 13 in situ erzeugt wurden. Unterhalb von -30°C erhielt man aus tert-Alkyldiazomethanen und tert-Alkylsulfamoylchloriden die 2,3-Di-tert-alkylthiaziridin-1,1-dioxide 4f-i in 32-47 proz. Ausbeute als farblose, thermisch labile Kristalle. Ihre Konstitution wurde durch IR,- UV- und 1H-NMR-Spektren sowie durch ihren quantitativen thermischen Zerfall in Schwelfeldioxid und Aldimin 9 gesichert. Disubstituierte Diazomethane 23 gaben mit tert-Butylsulfonylamin neben N-tert-Butylketiminen, den Zerfallsprodukten intermediärer, trisubstituierter Thiaziridin-1,1-dioxide 21, tert-Butylsulfinylamin 25 und Keton 26, die vermutlich durch cheletropen Zerfall von Oxathiiranen 24 entstanden.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 814-817 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Correlation of Melochinine with CassineMelochinine (1) was transferred into the pyridine derivative 3, a degradation product of Cassine (2). Thus it is proven that the substitutents in melochinine have the same arrangement as in cassine.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 825-828 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four- and Five-membered Phosphorus Heterocycles, 521) Pentacyclic Diphosphoranes from the Reaction 2H-1, 2, 4, 3λ3-Triazaphosphole/Azodicarboxylic EstersAzodicarboxylic ester react with 2-methyl-5-phenyl-2H-1, 2, 4, 3λ3-triazaphosphole (1) as heterodienes in an oxidative [4 + 1] cycloaddition at the σ2-phosphorus and a concomitant [2 + 2] dimerization of the supposed intermediate spirocyclic phosphazene 3. The resulting diphosphoranes 4 may also be synthesized from the dichlorotriazaphosphole dimer 5 and hydrazinedicarboxylic esters 6.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 829-831 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses of (Trifluoromethylseleno)phosphoryl Dichloride and Thiocarbonyl Bromide FluorideIn the presence of SbCL5 or BCl3 CF3SeCl reacts with CH3OPCl2 to form Cf3SeP(O)Cl2 (1). Halogen exchange reactions of SCFCI occur with OPCl3 or SPBr3 to give OPFnCl3-n or SPClnBr3-n (n = 1-3) as well as SPBrClF. The reaction of SCFCl with PBr3 leads to SCBrF(2).
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 837-842 
    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, XXV. Selective Degradation of Sisomicin to SisaminePeriodate oxidation of 1,2′,3,6′-tetra-N-acetylsisomicin (2) directly leads in high yield to tetra -N-acetylsisamine (16). At periodate splitting of 1 and 3 to 14 and 17 additional Barry-degradation seems to be favourable.
    Notes: Periodatoxidation von 1,2′,3,6′-Tetra-N-acetylsisomicin (2) liefert in hohen Ausbeuten direkt Tetra-N-acetylsisamin (16). Bei der Periodatspaltung von 1 und 3 to 14 and 17 ist ein zusätzlicher Barry-Abbau zweckmäßig.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 843-857 
    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, XXVI. Syntheses of Sisomicin D, Sisomicin B, and 5″-C-Methyl-Sisomicin BModified sisomicins can be synthesized by selective glycoside syntheses with the sisamine derivative 17. Coupling of 18 with 17 yields via 19 sisomicin D (21). Sisomicin B (26) can be obtained from 23 with 17 via 25 and from 34 with 17 via 35 5″-C-methylsisomicin B (36) is obtainable.
    Notes: Durch selektive Glycosidsynthesen mit dem Sisamin-Derivat 17 lassen sich modifizierte Sisomicine darstellen. Kupplung von 18 mit 17 liefert über 19 Sisomicin D (21). Aus 23 ist mit 17 über 25 Sisomicin B (26) und aus 34 mit 17 über 35 5″-C-Methyl-Sisomicin B (36) erhältlich.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 877-890 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Double-Bridged 2,5-Diamino-1,4-dialkyl-3,6-dimethoxybenzene Derivatives as [2]-PrerotaxanesStarting with 2,5-dimethoxyterephthaldialdehyde (1) and the triphenylphosphorane 2 the double bridged 2,5-diaminohydroquinone derivative 20 is synthesised in a multistep reaction with triphenylmethyllithium.
    Notes: Ausgehend von 2,5-Dimethoxyterephthaldialdehyd (1) und dem Triphenylphosphoran 2 wird in einer mehrstufigen Reaktionsfolge das zweifach überbrückte 2,5-Diaminohydrochinon-Derivat 20 synthetisiert. Über das Dibromid 21 wird hieraus durch Umsetzung mit Triphenylmethyllithium das [2]-Praerotaxan 22 erhalte.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 926-936 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acylation of Benzenes with Carboxylic Dihalophosphoric AnhydridesAryl ketones 4,9 are formed in good yields without the addition of Friedel-Crafts catalysts from activated arenes (e. g. alkylbenzenes, anisole) and aryl- and alkylcarboxylic dihalophosphoric anhydrides 1,2 and 7,8 respectively. The anhydrides 7,8 may be prepared in situ by mixing the respective carboxylic and dihalophosphoric anhydrides. This procedure is especially advantageous in care of the less stable compounds.
    Notes: Aryl-und Alkylcarbonsäure-dihalogenphosphorsäure-anhydride 1,2 bzw. 7,8 reagieren mit aktivierten Aromaten (Alkylbenzolen, Anisol) auch ohne Zugabe von Friedel-Crafts-Katalysatoren in guten Ausbeuten zu Arylketonen 4,9. Die gemischten Anhydride 7,8 können auch in situ durch Mischen der Carbonsäureanhydride mit den Dihalogenphosphorsäure-anhydriden hergestellt und umgesetzt werden, was insbesondere für die weniger stabilen gemischten Anhydride von Nutzen ist.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 937-945 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 2,4,6-Tris(alkylamino)-3-pyridinecarbonitriles by Dimroth Rearrangement2,4,6-Tris(alkylamino)-3-pyridinecarbonitriles 8 are prepared in a three step synthesis starting from N-Alkylcyanoacetamides 5. Key-step in this sequence is the Dimroth rearrangement of the 2(1H)-Pyridinimines 7 which leads in high yield to 8.
    Notes: 2,4,6-Tris(alkylamino)-3-pyridincarbonitrile 8 können in einer dreistufigen Synthese aus den N-Alkylcyanessigsäureamiden 5 erhalten werden. Der Schlüsselschritt ist dabei die in hohen Ausbeuten verlaufende Dimroth-Umlagerung der 2(1H)-Pyridinimine 7 zu 8.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 959-967 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Trimethylsilyl Cyanide - A Reagent for Umpolung, VII. Nucleophilic Acylation of Carbonyl Compounds with α,β-Unsaturated AldehydesThe addition products 9-12 of trialkylsilyl cyanide with conjugated aldehydes react as their aminons 9A-12A exclusively in the α-position with ketones and aldehydes, accompanied by a 1,4-O, O-silyl rearrangement (13,15,18,19). The formation of 2:1 adducts (20 from 9A and pivalic aldehyde) can be supressed by the slower rearranging triethylsilyl group (12A→23). With 9A and mesityloxide 1,2-addition occurs in THF (24, however, 1,4-addition in ether (25). Michaeladdition to α, β-unsaturated esters is possible also. Here, the halo ester 38 yields the cyclopropane 40. Similar methods from the literature are discussed.
    Notes: Die Additionsprodukte 9-12 von Trialkylsilylcyanid an konjugiert ungesättigte Aldehyde reagieren als Anionen 9A-12A ausschließlich in α-Stellung mit Ketonen und Aldehyden, jeweils unter 1,4-O,O-Silylwanderung (13,15,18,19). Die Bildung von 2:1-Addukten (20 aus 9A und Pivalinaldehyd) kann durch die langsamer wandernde Triethylsilylgruppe unterdrückt werden (12A→23). 9A addiert sich an Mesityloxid in THF in 1,2-Stellung zu 24, in Ether jedoch in 1,4-Stellung zu 25. Michael-Additionen an α,β-ungesättigte Ester gelingen ebenfalls, wobei der Halogenester 38 zum Cyclopropan 40 weiterreagiert. Vergleichbare literaturbekannte Methoden werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1004-1014 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectra of Three-and Four-Membered Ringsystems Containing PhosphorusThe He(I) photoelectron (PE) spectra of 1-9 have been investigated. Based on semiemperical calculations (MINDO/3 and Extended Hückel method) the first bands could be assigned to linear combinations of the phosphorus lone pairs and to Walsh-orbitals. Due to the low symmetry of the compounds a strong mixing of lone pairs and Walsh-orbitals is predicted.
    Notes: Die He(I)-Photoelektronen (PE-Spektren der Verbindungen 1-9 wurden gemessen. Die Zuordnung der ersten Banden zu Linearkombinationen der einsamen Elektronenpaare am Phosphor bzw, zu Walsh-Orbitalen basiert auf semiempirischen Rechnungen (MINDO/3, Extended Hückel-Methode). Infolge der niedrigen Symmetrie der Verbindungen sagen die Rechnungen eine starke Mischung zwischen einsamen Elektronenpaaren und Walsh-Orbitalen voraus.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1027-1047 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Thermolysis, and Photolysis of Substituted 3,4-Epoxy-cycloalkenesThe substituted epoxy-cycloalkenes 5-7 are transformed thermally at 200-250°C into the benzene derivatives 10,15, and 18 after initial C/O-bond cleavage of the oxirane ring. At temperatures higher than 300°C (short time pyrolysis) 6 and 7 give, in addition to the aromatic compounds 15/18, the furans 16 and 19, respectively. On photochemical excitation 5-7 react with C/C-ring opening to the annelated 2,3-dihydrofurans 11,17, and 20, respectively. The epoxycycloheptene 8 undergoes analogous ring expansion leading to 21 on electronic as well as thermal activation (ca. 80% yield). Whereas 21 does not form any defined product up to 380°C, and the monosubstituted bicyclus 11 suffers fragmentation affording methyl 3-furancarboxylate (12) and ethylene, both dihydrofurans 17 and 20 are quantitatively converted back into the epoxy-cycloalkenes 6 and 7, respectively, at temperatures below 200°C the cycloreversion reaction affording 16/19 competes only above 300°C. The cyclic dipoles of type IV, assumed to occur as intermediates during the 2,3-dihydrofuran-vinyloxirane isomerisations 17→6/20→7, can be trapped with dimethyl acetylenedicarboxylate or N-phenylmaleimide at significantly lower temperature (150/120°C) to give the 1:1-cycloadducts 38-40. However, because no such products could be obtained in case of the photoreactions of 5-8, a concerted [1,3]-C-migration has to be considered as a mechanistic alternative of the light-induced formation of 11, 17, 20, and 21.
    Notes: Die substituierten Epoxy-cycloalkene 5-7 reagieren thermische bei 200-250°C unter einleitender C/O-Ringspaltung zu den Benzol-Derivaten 10,15 und 18. Im Falle von 6 und 7 werden oberhalb von ca. 300°C (Kurzzeitpyrolyse-Bedingungen) neben den Aromaten 15/18 die Furane 16 bzw. 19 isoliert. Photochemisch wandeln sich 5-7 unter C/C-Ringöffnung in die anellierten 2,3-Dihydrofurane 11, 17 bzw. 20 um. Eine analoge Ringerweiterung (zu 21) geht das Epoxycyclohepten 8 sowohl bei thermischer als auch bei elektronischer Anregung in Ausbeuten von ca. 80% ein. Während 21 bis ca. 380°C keine definierten Folgereaktionen eingeht und der monosubstituierte Bicyclus 11 unter diesen Bedingungen zu 3-Furancarbonsäure-methylester (12) und Ethylen zerfällt, bilden die beiden Dihydrofurane 17 und 20 schon unterhalb von 200°C die Epoxy-cycloalkene 6 bzw. 7 quantitativ zurück; die Fragmentierung zu den Furanen 16/19 konkurriert hier erst oberhalb von 300°C. Die als Zwischenstufen der 2,3-Dihydrofuran-Vinyloxiran-Isomerisierungen 17→6/20→7 postulierten cyclischen Dipole vom Typ IV können schon bei deutlich niedrigeren Temperaturen (150/120°C) mit Acetylendicarbonsäure-dimethylester oder N-Phenylmaleinimid als 1:1-Cycloaddukte (38-40) abgefangen werden. Da entsprechende Hinweise für das Auftreten solcher Zwischenstufen bei den Photoumwandlungen von 5-8 fehlen, wird als mechanistische Alternative der lichtinduzierten Bildung von 11,17,20 und 21 eine konzertierte [1,3]-C-Verschiebung diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 707-715 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleosides, XXXV1) Synthesis, Properties, and Reactivity of Lumazine 5-Oxide RibosidesVarious lumazine-1-mono- and -1,3-diribosides (1-6) have been converted by H2O2-oxidation in trifluoroacetic acid nto the corresponding 5-oxides 7-12. Deacylation led to free 1-(β-D-ribo-furanosyl)lumazine 5-oxide (13) and its 6, 7-dimethyl- (14) and 6, 7-diphenyl derivative (15), respectively. Treatment of the acylated lumazine riboside 5-oxides 7, 11, and 12 with acetyl chloride in TFA yielded the corresponding 6-chloro derivatives 16-18. 17 was deblocked to 6-chloro-1-(β-D-ribofuranosyl)lumazine (19) and 11 showed an interesting reaction on treatment with methanolic HCL, forming 6-methoxy-1-(β-D-ribofuranosyl)lumazine (20).
    Notes: Verschiedene Lumazin-1-mono-und-1,3-diriboside (1-6) werden durch H2O2-Oxidation in Trifluoressigsäure in die entsprechenden 5-Oxide 7-12 übergeführt. Durch Deacylierung werden das freie 1-(β-D-Ribofuranosyl)lumazin-5-oxid (13) sowie sein 6,7-Di-phenyl-Derivat (15) gewonnen. Durch Behandlung der geschützten Lumazin-ribosid-5-oxide 7, 11 und 12 mit Acetylchlorid in Trifluoressigsäure entstehen die entsprechenden 6-Chlor-Derivate 16-18. 17 wird zu 6-Chlor-1-(β-D-ribofuranosyl)lumazin (19) entacetyliert, und 11 liefert mit methanolischer HCL 6-Methoxy-1-(β-D-ribofuranosyl)lumazin (20).
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 733-739 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of Methyl Digilanidobioside and DigilanidobialBy modified Königs-Knorr reactions of reactions of acyl-α-bromoglucoses 1 and 2 with the allo-epoxide 3 the β, 1 → 4-linked disaccharide derivatives 4 and 5 are obtained. By opening of the epoxide ring in 4 employing lithium iodide, in addition to minor amounts of the isomer 6 predominantly the 2-iodohydrine 7 with altro-configuration in the reducing ring is prepared. Reductive dehalogenation of 7 leads to methyl digilanidobioside (8), further characterized by the acetylated derivatives 11 and 12. By reaction of 7 with methyllithium the synthesis of digilanidobial, isolated in the acetylated forms 9 and 10, is achieved. The condensation of the disaccharide glycal 9 with 3 is effected by use of the N-iodosuccinimide procedure yielding the trisaccharide derivative 13.
    Notes: Modifizierte Königs-Knorr-Reaktionen der Acyl-α-bromglucosen 1 und 2 mit dem allo-Epoxid 3 führen zu den β, 1 → 4-verknüpften Disaccharid-Derivaten 4 und 5. Durch Umsetzung von 4 mit Lithiumiodid wird neben dem Isomeren 6 vorwiegend das 2-Iodhydrin 7 mit altro-Konfiguration im reduzierenden Ring gebildet. Reduktive Dehalogenierung von 7 liefert Methyl-digilanidobiosid (8), das durch die Acetyl-Derivate 11 und 12 charakterisiert wird. Methyllithium erzeugt aus 7 Digilanidobial, das in Form der Acetyl-Verbindungen 9 und 10 isoliert wird. Kondensation von 3 mit dem Disaccharidglycal 9 nach dem N-Iodsuccinimid-Verfahren führt zum Trisaccharid-Derivat 13.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 746-756 
    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 Substitution at the Cyclopropane RingStarting from 2a the bicyclic chlorolactone 14a is obtained via 3a and 11a. Reaction of 14a with KOtBu gives the lactone 17b which also is formed from 14b. These results can be explained by a mechanism via the intermediate E. Additional evidence is given by the failure of 15a and b to react with KOtBu and by the product distribution of the reaction of deuterated compound 16a.
    Notes: Ausgehend von 2a wird über 3a und 11a das bicyclische Chlorlacton 14a erhalten. Dessen Reaktion mit KOtBu ergibt das Lacton 17b, das auch aus 14b gebildet wird. Diese Ergebnisse werden mit einem Mechanismus über die Zwischenstufe E erklärt. Zusätzliche Beweise sind das Ausbleiben einer Reaktion von 15a und b mit KOtBu sowie die Produktverteilung bei der Reaktion der deuterierten Verbindung 16a.
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  • 62
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: trans-2,3-D-tert-butylthiirane 1,1-Dioxide and 2,5-Di-tert-butyl-2,5-dihydro-1,3,4-thiadiazole 1,1-Dioxides from tert-Butyldiazomethane and Sulfur Dioxide Solvent Effects and Mechanisms of the Staudinger-Pfenninger-Reaction1)When allowed to react with sulfur dioxide tert-butyldiazomethane formed not only trans-di-tert-butylthiirane 1,1-dioxide (3) but also the diastereomeric 2,5-dihydro-1,3,4-thiadiazole 1,1-dioxides 7e which under base-catalysis rearranged to the 2,3-dihydro-1,3,4-thiadiazole 1,1-dioxide 11. The structures were deduced from IR, UV, and 1H-NMR spectra, and from the products obtained after loss of sulfur dioxide. Whereas increase of the solvent polarity favoured 3 over 7e, the diastereomer ration cis-7e/trans-7e remained virtually unaffected. The ration of thiirane 1,1-dioxide 3 to dihydrothiadiazole 1,1-dioxides did not depend on whether the intermediate tert-butylsulfene 6e had been generated from 5e and sulfur dioxide or from 2,2-dimethylpropane sulfonylchloride (14) and triethylamine. In contrast to reports in the literature, the reaction of the phenyldiazoalkanes 5f and 5h with sulfur dioxide afforded cis/trans ratios of the thiirane 1.1-dioxides 9f and 9h, respectively, which were only slightly influenced by the solvent. Apparently, the dihydrothiadiazole 1.1-dioxides 7 and hence their decomposition products, the azines 8 (as far as these do not arise from the direct decomposition of the diazo compounds), are the result of a [3 + 2]cycloaddition between the diazoalkane 5 and the sulfene 6. In contrast, the thiirane 1.1-dioxides 9 seem to originate via the zwitterions 20 the formation of which is favoured over the [3 + 2]cycloaddition by solvents of high polarity, by the presence of aryl substituents at the sulfene. as well as by the lack of alkyl groups. The dichotomy in the behaviour of sulfenes towards diazoalkanes can be traced back to the existence of two low-lying sulfene MO′s, only one of which exhibits π-symmetry.
    Notes: tert-Butyldiazomethan (5e) bildete mit Schwefeldioxid sowohl trans-Di-tert-butylthiiran-1,1-di-oxid (3) als auch die diastereomeren 2,5-Dihydro-1,3,4-thiadiazol-1,1-dioxide 7e, die sich basen-katalysiert in das 2,3-Dihydro-1,3,4-thiadiazol-1,1-dioxid 11 umlagerten. Die Konstitutionen wurden durch IR-, UV- und 1H-NMR-Spektren und die Produkte der Schwefeldioxid-Abspaltung gesichert. Während höhere Solvenspolarität 3 gegenüber 7e begünstigte, wurde das Diastereomerenverhältnis cis-7e/trans-7e davon praktisch nicht beeinflußt. Das Verhältnis des Thiiran-1,1-dioxids 3 zu den Dihydrothiadiazoldioxiden hing nicht davon ab, ob das intermediäre tert-Butylsulfen (6e) aus 5e und Schwefeldioxid oder aus 2,2-Dimethylpropansulfonylchlorid (14) und Triethylamin erzeugt wurde. Im Gegensatz zu Literaturangaben ergab die Umsetzung der Phenyldiazoalkane 5f und 5h mit Schwefeldioxid cis/trans-Verhältnisse der Thiiran-1,1-dioxide 9f bzw. 9h, die nur wenig vom Lösungsmittel beeinflußt wurden. Die Dihydrothiadiazoldioxide 7 und damit auch ihre Zerfallsprodukte, die Azine 8 (soweit diese nicht durch direkte Zersetzung der Diazoalkane entstehen), sind offenbar das Ergebnis einer [3 + 2]Cycloaddition zwischen Diazoalkan 5 und Sulfen 6, Thiiran-1,1-dioxide 9 scheinen dagegen aus Zwitterionen 20 zu entstehen, die gegenüber der [3 + 2]Cycloaddition durch höhere Polarität des Lösungsmittels, durch Arylsubstituenten des Sulfens und die Abwesenheit von Alkylgruppen begünstigt werden. Die Dichotomie im Verhalten von Sulfenen gegenüber Diazoalkanen läßt sich auf die Existenz zweier tiefliegender Sulfen-MO′s zurückführen, von denen nur eines π-Symmetrie aufweist.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 822-824 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Compounds, VII1) Mild and Efficient Deoxygenation of sulfoxides by Means of the System Chlorotrimethylsilane/ZincAliphatic, Cycloaliphatic, and aromatic sulfoxides are readily deoxygenated by treatment with the system chlorotrimethylsilane/zinc. Reaction conditions are extremely mild, yields of products are good.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 909-915 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Synthetic Methods, 3. Tetrahydrothiopyran-3-one 1,1-Dioxide, a Usefull 4 C Synthon for the Stereoselective Synthesis of (Z)- (E)-γ,δ-Unsaturated Carboxylic AcidsBy alkylation and ring opening together with bromination, tetrahydrothiopyran-3-one 1,1-dioxide (2) is converted into α-halosufone intermediates, which can be transformed stereoselectively by Ramberg-Backlund rearrangement to (Z)-or (E)-γ,δ-unsaturated carboxylic acids 5.
    Notes: Tetrahydrothiopyran-3-on-1,1-dioxid (2) wird durch Alkylierung und Ringöffnung unter Bromierung zu α-Halosulfon-Zwischenstufen umgesetzt, die durch Ramberg-Backlund-Umlagerung stereoselektiv in γ,δ-ungesättigte Carbonsäuren 5 übergeführt werden.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 916-925 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Carboxylic Dihalophosphoric AnhydridesThe mixed anhydrides 3,4,6 and 7 are prepared in good yields by conproportionation of the respective carboxylic Dihalophosphoric Anhydrides 1 and 2. The aryl derivatives 3 and 4 can be isolated in neat form, the alkyl compounds 6 and 7 undergo further reactions upon destillation. For the combination of trihaloacetic and dihalophosphoric anhydrides, the equilibrium is shifted to the side of the symmetrical anhydrides (5d, e and 2).
    Notes: Aryl-3,4 und Alkylcarbonsäure-dihalogenphosphorsäure-anhydride 6,7 sind durch Konproportionierung entsprechender Carbonsäure. 1 und Dihalogenphosphorsäure-anhydride 2 im allgemeinen in guten Ausbeuten zugänglich. Die Arylverbindugen 3, 4 können in der Regel in Substanz isoliert werden, während eine Destillation der Alkylderivate 6, 7 wegen Zersetzungsreaktionen nicht gelang. Bei den perhalogenierten Anhydriden 6e, f und 7e, f liegt das Gleichgewicht überwiegend auf Seite der symmetrischen Anhydride 5d, e und 2.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 946-958 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Selective Blocking of Primary or Secondary Hydroxyl Groups with Electroactive Protecting GroupsIn a diol such as 17, at first the primary OH-group is blocked with an electroactive protecting group (→ 18). Then the secondary OH-group is protected with a second group (→ 19), that is reduced at more negative potentials. Controlled potential electrolysis selectively deblocks the primary OH-group. As protecting groups the tritylone ( = 9,10-dihydro-10-oxo-9-phenyl-9-anthracenyl-) and 4-cyanobenzyl residue were suitable. With the help of a combination of these groups 1-dodecyloxy-3-octadecyloxy-2-propanol (27) was prepared starting with 1,2-O-isopropylideneglycerol (21).
    Notes: In Diolen wie 17 wird zunächst die primäre OH-Gruppe mit einer kathodisch abspaltbaren Schutzgruppen (→18), danach die sekundäre mit einer zweiten Gruppe geschützt (→ 19), die bei negativerem Potential abspaltbar ist. Potentiostatische Elektrolyse setzt nur die primäre Hydroxylgruppe frei. Als Schutzgruppen waren der Tritylon- (= 9,10-Dihydro-10-oxo-9-phenyl-9-anthracenyl-) und 4-Cyanbenzylrest geeignet. Mit Hilfe dieser Schutzgruppenkombination wurde 1-Dodecyloxy-3-octadecyloxy-2-propanol (27) ausgehend von 1,2-O-Isopropylidenglycerin (21) dargestellt.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 990-993 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermolysis of cis-and trans-1,3-DivinylcyclobutaneAt 300°C cis-1,3-Divinylcyclobutane (4) gives butadiene (5) and 4-vinyl-1-cyclohexene (6) as well as trans-1,3-divinylcyclobutane (2) in small quantity. 2 has been synthesized in an independent way and yields the same products as 4. The diradical 3 is considered as an intermediate.
    Notes: cis-1,3-Divinylcyclobutan (4) reagiert um 300°C zu Butadien (5) und 4-Vinyl-1-cyclohexen (6), wobei trans-1,3-Divinylcyclobutan (2) in geringer Menge auftritt. 2 wird unabhängig hergestellt und liefert die gleichen Produkte sowie 4. Das Diradikal 3 wird als Zwischenstufe angesehen.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 982-989 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of cis-1,3-DivinylcyclobutaneThe title compound 7 is obtained by ozonolysis of bicyclo [2.1.1]hex-2-ene (5) and Wittig reaction of the dialdehyde 6. There was no intramolecular photo-cycloaddition observed by irradiation of 7 but rearrangement to cis-and trans-allylvinylcyclopropanes 10 and 11. With the esters 12-14 the light energy is wasted in cis-trans-isomerisations. In comparison, the cis-1,3-cyclopentane derivatives 16 and 17 give some [2+2] cycloaddition.
    Notes: Die Titelverbindung 7 wird aus Bicyclo [2.1.1]hex-2-en (5) durch Ozonolyse und Wittig-Reaktion des Dialdehyds 6 hergestellt. Beim Belichten geht 7 keine intramolekulare Cycloaddition ein, vielmehr erfolgt Umlagerung zu cis-und trans-Allylvinylcyclopropan 10 und 11. Auch bei den entsprechenden Dicarbonsäureestern 12-14 wird die Anregungsenergie hauptsächlich zu cis-trans-Isomerisierungen verbraucht. Bei den ringhomologen cis-1,3-Cyclopentanderivaten 16 und 17 wird zum Vergleich sehr wohl photochemische [2 + 2]-Cycloaddition beobachtet.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1015-1026 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Aminoethynyl)metallation, VIII. Reactions of β-Silylated Ynamines with Ketene; Competition of (Aminoethynyl)silylation and [2 + 2]-CycloadditionSilylethynyl)amines 1 react with ketene (2) to yield according to the principle of the [2 + 2]-cycloaddition preferentially the 2-silyl-2,3-butadienamides 6 and the 3-amino-2-silyl-2-cyclobuten-1-ones. 7. The latter ones hydrolyze easily to the corresponding silyl-free cyclobutenones 8. In some cases one can isolate besides these compounds (see the reactions of 1a and 1e) or exclusively (see the reaction of 1d) 1:2-and 1:3-adducts, the formation of which can be explained via the non detectable (3-siloxy-3-buten-1-ynyl)amines 4 [“(aminoethynyl)silylation”]. These enynamines add to their C/C triple bond a second molecule of ketene (2) to give the allene carboxamides (see 5d) and cyclobutenones 9. The compounds 9 easily hydrolyze to the corresponding acetylcyclobutenones 10 and they react with exceeding ketene (2) to form the 1:3-adducts 11. The cyclobutenone 9d isolable in substance adds diphenyl ketene and tert-butylcyanoketene in the same way to give the analogous chain prolongation products 14 and 15.
    Notes: (Silylethinyl)amine 1 reagieren mit Keten (2) bevorzugt nach dem Prinzip der [2 + 2]-Cycloaddition zu 2-Silyl-2,3-butadienamiden 6 und zu 3-Amino-2-silyl-2-cyclobuten-1-onen 7. Letztere hydrolysieren leicht zu den entsprechenden silylfreien Cyclobutenonen 8. In einigen Fällen isoliert man zusätzlich (s. Umsetzung von 1a und 1e) oder ausschließlich (s. Umsetzung von 1d) 1:2-und 1:3-Addukte, deren Bildung über die hier nicht nachweisbaren (3-Siloxy-3-buten-1-inyl)amine 4 erklärt wird [„(Aminoethinyl)silylierung“]. Diese Eninamine addieren an ihre C/C-Dreifachbindung ein weiteres Ketenmolekül zu entsprechend substituierten Allencarboxamiden (s. 5d) und Cyclobutenonen 9. Die Verbindungen 9 hydrolysieren leicht zu den entsprechenden Acetylcyclobutenonen 10 und reagieren mit überschüssigem Keten (2) zu den 1:3-Addukten 11 weiter. Das in Substanz isolierbare Cyclobutenon 9d addiert in gleicher Weise Diphenylketen bzw. tert-Butylcyanketen zu analogen Kettenverlängerungsprodukten 14 bzw. 15.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1065-1073 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: syn/anti-Conformers and-Rearrangements of Intra- and Extraanularly Substituted Dithia[3.3]metacyclophanesNew dithia[3.3]metacyclophanes (Table 2) have been synthesized and their conformations determined. The dependence of extra-and intraanular substituents, especially methoxy, amino and phenyl groups, are discussed. The barriers of the thermal rearrangement of syn-22 and -24 to the anti-conformers A have been measured kinetically (135 and 131 kJ/mol, resp.). The intraanularly azo-substituted [3.2.3](1,2,3)phane 32 is described.
    Notes: Neue Dithia[3.3]metacyclophane (Tab.2) wurden synthetisiert und ihre Konformation zugeordnet. Ihre Abhängigkeit von extra- und intraanularen Substituenten, insbesondere Methoxy-, Amino-und Phenyl-Gruppen wird erörtert. Die Barrieren der thermischen Umlagerung von syn-22 und 24 in die anti-Konformeren (A) wurden kinetisch zu 135 kJ/mol und 131kJ/mol bestimmt. Das intraanular azo-substituierte [3.2.3](1,2,3)Phan 32 mit fixierter syn-Konformation wird beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1091-1098 
    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, 322. Synthesis of Sesquiterpenes from Heterotheca SpeciesSeven sesquiterpenes (7a, b, 8, 18a, 20b, 21, 23) isolated from two Heterotheca species have been synthesized. While 7a, b and 8 with an anomalous carbon skeleton were prepared via the 2-iso-propyltetralone 6, the synthesis of the four others, all being cadinane derivatives, was achieved via ethyl dihydro-1-naphthalenecarboxylate 15.
    Notes: Sieben aus zwei Heterotheca-Arten isolierte Sesquiterpene (7a, b, 8, 18a, 20b, 21, 23) werden synthetisch dargestellt. Während 7a, b und 8 mit anomalem Kohlenstoffgerüst ausgehend vom 2-Isopropyltetralon 6 aufgebaut werden, gelingt die Synthese der vier anderen, die alle Cadinan-Derivate sind, über den Dihydro-1-naphthalincarbonsäureester 15.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1132-1136 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiocarbonyl Dithiocyanate and Its S-OxideThe preparation of thiocarbonyl dithiocyanate (1), its S-oxide 11, and thiocarbonyl chloride thiocyanate (2) is described. 1 reacts with alcohols and amines to give the compounds 5 and 6. With chlorine 1 forms the sulfenyl chloride 7 and dichlorodithiocyanatomethane (8), resp. From 7 the sulfenyl thiocyanate 9 was prepared.
    Notes: Die Synthese von Thiocarbonyl-dithiocyanat (1), seines S-Oxids 11 und von Thiocarbonyl-chlorid-thiocyanat (2) wird beschrieben. 1 reagiert mit Alkoholen und Aminen zu den Verbindungen 5 und 6. Mit Chlor setzt sich 1 zum Sulfenyl-chlorid 7 bzw. zum Dichlordithiocyanatomethan (8)) um. Aus 7 konnte das Sulfenyl-thiocyanat 9 erhalten werden.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1074-1081 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Cyclopropenes, IV. Synthesis and Structure of 2:1-Adducts from Spirocyclopropenes with Carbon DisulfideIn benzene solution at 140°C in a steel bomb the spirocyclopropenes 1a-d from 2:1-adducts 2a-d with carbon disulfide, the constitution of which has been elucidated by X-ray structure analysis of 2c. Thus, the 2:1-adducts have the structure 2 containing the spiro[thiophene-2(3H), 2′(5′H)-thiophene] as basic system. Possible mechanistic pathways for the selective formation of 2 are discussed.
    Notes: Die Spirocyclopropene 1a-d bilden mit Kohlenstoffdisulfid in benzolischer Lösung bei 140°C im Autoklaven die 2:1-Addukte 2a-d, deren Konstitution durch eine Röntgenstrukturanalyse von 2c ermittelt wurde. Danach besitzen die 2:1-Addukte die Struktur 2, in der das Spiro[thiophen-2(3H), 2′(5′H)-thiophen] als Grundsystem enthalten ist. Mechanistische Vorstellungen zur selektiven Bildung von 2 werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1907-1925 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Indole Derivatives, XLIII1) The Stereochemistry of Michael Additions to α-Methylene-lactamsThe stereoselectivity of Michael additions to α-methylene-lactams 1 leading to the derivatives 6, 7 is investigated in dependence on Michael donors. The influence of a neighbouring substituent proves to be important. Intramolecular additions are not observed.
    Notes: Die Stereoselektivität der Michael-Addition von α-Methylenlactamen 1 zu den Derivaten 6,7 wird in Abhängigkeit vom Michael-Donator überprüft. Auch der Einfluß eines benachbarten Substitutenten erweist sich als wichtig. Sterische wie elektronische Effekte können zu hoher Stereoselektivität Anlaß geben. Intramolekulare Additionen sind nicht durchführbar.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1938-1950 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Introduction of Oxygen Functions into the α-Position of β-Diketones, 41) Direct Acyloxylation of 1,3-Cyclohexanediones by Diacyl PeroxidesDirect acyloxylation of 1,3-cyclohexanediones 1, leads only by way of exception to the formation of monoacyloxylated products 4. However, their sodium salts 5 yield exclusively the immediate reaction products 8 of a bisacyloxylation. On the other hand, these products are unstable in the presence of base, and they experience a migration of an acyl group and loss of one mol of carboxylic acid yielding cyclohexadienones 9. The mechanism of this new rearrangement is described. Starting from products of a benzyloxycarbonyloxylation a convenient synthesis of reductones is described.
    Notes: Die direkte Acyloxylierung der 1,3-Cyclohexandione 1 führt nur in Ausnahmefällen zu den Monoacyloxylierungsprodukten 4. Ihre Natriumsalze 5 dagegen liefern die unmittelbaren Folgeprodukte 8 einer Bisacyloxylierung. Diese sind jedoch in Gegenwart von Base instabil und erfahren unter Abspaltung molarer Menge Carbonsäure eine Umacylierung zu den Cyclohexadienonen 9. Der Mechanismus dieser Umacylierung wird aufgeklärt. Ausgehend von den Folgeprodukten einer Benzyloxycarbonyloxylierung wird eine bequeme Reduktonsynthese beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1976-1979 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-AcylketeniminesThe title compounds 3 are prepared via Wittig reaction from disubstituted methylenephosphoranes 1 and acyl isocyanates 2. compounds 3 react with aromatic amines, carbodiimides, and isonitriles to afford N-Acyl-enamines 8, alkyliden-oxadiazinimines 9, or alkyliden-Oxazolimines 10, respectively.
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1203-1205 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rearrangement of 1-phenyl-β-lactams by aluminium chloride catalysisThe attempted synthesis of 1 by intramolecular alkylation failed. Treatment of the β-lactams 3 and 6 with aluminium chloride yields the dihydroquinolinones 7 and 8.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1210-1215 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Applications of Phase Transfer Catalysis, 15. Phase Transfer Catalytic Preparation of Carbonic Esters Without the Use of PhosgeneCarbonic esters can be prepared in a phase-transfer catalytic reaction from primary alkyl halides and a mixture of dry potassium hydrogen carbonate and dry potassium carbonate in non-polar solvents. The conversion is ineffective inthe absence of hydrogen carbonate and catalyst.
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  • 79
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1610-1623 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleosides, 381) Die Ribonucleoside des Allopurinols2)Von den verschiedenen Ribonucleosiden des Allopurinols wurden die N-1-, N-2-und N-5-Isomeren (9c-11c) sowie die 1,5- und 2,5-bis-ribosylierten Derivate 6c und 7c durch snCl4- induzierte Glycosylierung von Bis(trimethylsilyl)allopurinol 4 mit acylierten Ribofuranosen (5) dargestellt. Trimethylsilyl-triflat als Katalysator bildete zusätzlich das O4-ribosylierte Isomere 8a. Die Konstitutionen der Produkte wurden aus UV-, 1H-NMR- und 13C-NMR-Daten abgeleitet. Die Fähigkeit der Produkte, Xanthin-Oxidase zu inhibieren, wurde untersucht.
    Notes: Of the various conceivable ribonucleosides of allopurinol, the N-1-, N-2-, and N-5-isomers (9c-11c) as well as the 1, 5-and 2,5-bis-ribosylated derivatives 6c and 7c have been prepared via stannic chloride-induced glycosylation of bis (trimethylsilyl)allopurinol 4 with acylated ribofuranoses (5). Trimethylsilyl triflate as catalyst in addition produced the O4-ribosylated isomer 8a. - The structures of the products were secured from UV, 1H, and 13 C NMR data. -Their xanthine oxidase inhibitory activity was evaluated.
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  • 80
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1649-1655 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Cyclopropenes, V1) Cyclooligomerisations of 3,3-Dialkylcyclopropenes at Palladium (0) CatalystsAt Phosphane free palladium(0) catalysts 3,3-dialkylcyclopropenes [3-ethyl-3-methylcyclopropene (2), 3,3-diethylcyclopropene (3), and spiro[4.2]hept-1-ene (4)] are cyclooligomerised to give the trans-tricyclo[3.1.0.02,4]hexane derivatives 6, 7, and 9, and the pentacyclo[9.1.0.02,4.05,7.08,10]-dodecane derivatives 10, 11, and 12. Contrary to this at triisopropylphosphane modified palladium(0) catalysts the tetracyclo[6.1.0.02,4.05,7]nonane derivatives 14, 15 and 16 are formed selectively in more than 80% yield.
    Notes: 3,3-Dialkylcyclopropene [3-Ethyl-3-methylcyclopropen (2), 3,3-Diethylcyclopropen (3) und Spiro 4.2]hept-1-en (4) reagieren an phosphanfreien Palladium (0)-Katalysatoren zu den entsprechenden trans-Tricyclo[3.1.0.02,4]hexan-Derivaten 6, 7 bzw. 8 und zu den Pentacyclo-[9.1.0.02,4.05,7.08,10]dodecan-Derivaten 10, 11 und 12. Triisopropylphosphan-haltige Palladium-(0)-Katalysatoren liefern dagegen selektiv die Tetracyclo[6.1.0.02,4.05,7]nonan-Derivate 14, 15 und 16 mit über 80% Ausbeute.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1679-1696 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Cross-Conjugated Bond Systems, 371) The Vinylogous SesquifulvaleneAs a model study the tricycloheptenone 8 (“masked tropone”) - obtained from quadricyclanone 7 - is used for the synthesis of the tricyclic fulvene 9, which upon Ag⊕-catalysis or upon direct irradiation is quantitatively isomerized to the highly reactive sesquifulvalene 2. Applying the same scheme to the synthesis of the vinylogous sesquifulvalene 5, the tricyclic aldehyde 16 serves as precursor for the tricyclic fulvene 17, isomeric with 5. 17 is uniformly transformed into 5 in the presence of Ag⊕. The isomeric fulvenes 25 and 26 are exclude as precursors of 5. contrary to literature reports 5 is also obtained from 8-formylheptafulvene but only in very limited yield (max. 10%). 5 can be isolated in crystalline form and shows typical fulvalene-type spectral behavior.
    Notes: In einer Modellstudie wird aus dem Tricycloheptenon 8 (“maskiertes Tropon”) - erhältlich aus Quadricyclanon 7 - das tricyclische Fulven 9 hergestellt, welches unter Ag⊕-Katalyse bzw. unter direkter Belichtung einheitlich zum hochreaktiven Sesquifulvalen 2 isomerisiert. In einem analog konzipierten Zugang zum vinylogen Sesquifulvalen 5 dient der tricyclische Aldehyd 16 als Vor stufe für das mit 5 isomere tricyclische Fulven 17. Die Ag⊕-katalysierte isomerisierung liefert einheitlich 5. Die mit 17 isomeren Fulvene 25 und 26 kommen als Vorstufen für 5 nicht in Frage. In mäßiger Ausbeute (max. 10%) ist 5 entgegen Literaturhinweisen auch aus dem Formylheptafulven 23 erhältlich. Das kristallisiert isolierbare 5 ist durch die Spektren als typisches Fulvalen ausgewiesen.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1752-1766 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermal Rearrangements of 1-Allyloxy- and 1-Propargyloxy-λ5-phosphorin DerivativesThe thermal rearrangements of 1-allyloxy-λ5-phosphorin derivatives 1 affords - contrary to the formally similar Claisen rearrangement of allyl phenyl ethers - in the irreversible step an “anti-Woodward-Hoffmann” [3s5s] allyl shift to 4-allyl-1,4-dihydro-λ5-phosphorin derivatives 2. - The reaction is, as cross experiments prove, intramolecular and stereospecific according to 1st order law. It is accelerated by electron donating substituents in position 4 and by electron attracting substituent at the phosphorus, but is not much solvent-dependant. In a next step, again with allyl-inversion, a [3s3s] Cope rearrangement follows to give 2-allyl-1,2-dihydro-λ5-phosphorin derivatives 3. At somewhat higher temperature, by an intramolecular [4 + 2]-cycloaddition from 3j a tricyclus 4 is formed. Besides the experiments with deuterium marked compounds, the X-ray analysis of 4 proves the uniform stereochemic way of all these rearrangements. Steric and electronic influences on some analogous rearrangements are studied, the mechanism is discussed.
    Notes: Die thermische Umlagerung von 1-Allyloxy-λ5-phosphorin-Derivaten 1, führt im Gegensatz zu der formal ähnlichen Claisen-Umlagerung von Allylphenylethern im irreversiblen Primärschritt in einer“ anti-Woodward-Hoffmann”-[3s5s]-Allylwanderung zu 4-Allyl-1,4-dihydro-λ5-phosphorin-Derivaten 2. -Die Reaktion verläuft, wie Kreuzungsexperimente beweisen, intramolekular und stereospezifisch nach einer Reaktion 1. Ordnung. Sie wird durch elektronenabgebende Substituenten in R4 und elektronenanziehende substituenten am Phosphor gefördert, ist jedoch wenig löungsmittelabhängig. Ihr folgt in einem irreversiblen Schritt unter erneuter Allyl-Umkehr eine [3s3s]-Cope-Umlagerung zu 2-Allyl-1,2-dihydro-λ5-Phosphorin-Derivaten 3. Bei etwas höherer Temperatur gehen diese eine intramolekulare [4 + 2]-Cycloaddition zum Tricyclus 4 ein. Dessen Röntgenstrukturanalyse sowie die eindeutigen Deuterierungsergebnisse sprechen für einen stereochemisch einheitlichen verlauf der Umlagerungen. Sterische und elektronische Einflüsse auf einige analoge Umlagerungen werden untersucht, der Mechanismus wird diskutiert.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2158-2185 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Reversible Rearrangement of the trans-Erythrinane Ring System, IV1) Investigations Concerning the Reaction MechanismThe labelled β-lactame carboxylic acid 10a is prepared via the [7,8-14C2]diol-A-7. The products of thermal decarboxylation 11a and 12a include the whole activity of the original carboxylic acid 10a. On the other hand, decarboxylation of 10a with sulfuric acid yields the enoldihydroisoquinoline 30a via the carboxylic acid 18a with the loss of half of the activity. The active CO2 stems from the labelled lactame group of 10a, whereas the enol group of 30a is generated from the unlabelled carboxylic group of 10a or 18a. The position of the residual 14C-atom of 30a is determined by ring opening to 33a, a consecutive acetylation yielding a mixture of two olefins 62a/63a, followed by oxidative degradations to [1-14C]succinic acid and a final Schmidt degradation of this acid to ethylenediamine and labelled CO2. - The exchange of the two substituents and the structure of the rearranged skeleton 3 are confirmed by X-ray analysis of diol-A*6-acetat-7-bromoacetat. Independent synthesis ensures that the constitutions of the compounds 28,30 and 33, emerging during the rearrangement processes, are correct. - Thus it is demonstrated, that the reversible skeleton rearrangement operates by a concerted fourcenter mechanism with stereospecific 1,2-shift of all groups in question.
    Notes: Aus [7,8-14C2]Diol-A* 7 wird über das Diol-A-Derivat 8a die aktive β-Lactamcarbonsäure 10a dargestellt. Bei der thermischen Decarboxylierung von 10a verbleibt praktisch die gesamte Aktivität in den Folgeprodukten 11a und 12a. Dagegen führt der Abbau von 10a mit Schwefelsäure über die Carbonsäure 18a unter Verlust der halben Aktivität zum Enoldihydroisochinolin 30a. Das abgespaltene aktive Kohlendioxid stammt aus der markierten Lactamgruppe von 10a, während die Enolgruppe von 30a aus der inaktiven Carboxylgruppe von 10a bzw. 18a hervorgeht. Die Stellung des noch verbleibenden 14C-Atoms in 30a wird durch Ringöffnung zum Methylester 33a, dessen Überführung in das acetylierte Olefingemisch 62a/63a und durch einen nachfolgenden oxidativen Abbau zur [1-14 C]Bernsteinsäure und schließlich deren Schmidt-Abbau zu Ethylendiamin und aktivem Kohlendioxid nachgewiesen. - Die Vertauschung der Substituenten und die Struktur des umgelagerten Gerüstes 3 werden durch eine Röntgenstrukturanalyse von Diol-A*-6-acetat-7-bromacetat bewiesen. Die Konstitutionen der im Verlauf der Umlagerungsprozesse auftretenden Verbindungen 28, 30 und 33 werden durch unabhängige Synthesen gesichert. - Für die umkehrbare Gerüstumlagerung wird ein konzertierter Vierzentrenmechanismus mit stereospezifischer 1,2-Verschiebung aller Partner nachgewiesen.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2217-2237 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,2-Photoadditions of Stilbenes and Diarylacetylenes to Bicyclic 1,4-Cyclohexadienes: Propellanes and Substitutive 1,2-AdductsThe photoreactions of stilbene, 4,4′-dichloro-, 4,4′-dicyano-, 4,4′-dimethoxystilbene, diphenylacetylene, and bis(4-cyanophenyl)acetylene with 2,3,4,7-tetrahydroindene and 1,4,5,8-tetrahydronaphthalene have been investigated. Despite severe steric hindrance and because of electrostatic support the propellanes 3, 12, 23, 26 are formed as the major [2 +2]-cycloadducts. The products of dehydrogenation 41, 44, 45 and hydrogenation 29 are obtained from them. Further major products of the photolyses are the substitutive 1,2-adducts 4, 5, 14, 15, 24, 27, whereas the ene-adducts 25, 28 occur only in trace amounts. The mechanistic grounds are discussed in terms of diradicals with consideration of exciplex emissions and with the aid of comparative reactions involving 1,4-cyclohexadiene and methyl cinnamate. The photolyses of several propellanes with varying degrees of hydrogenation are described (decomposition, dehydrocyclization, intramolecular cycloaddition, and 1,5-shift). The structures of the products have been determined spectroscopically (IR, UV, fluorescence, 1H-NMR, 13C-NMR) and in part by chemical degradation and independent synthesis.
    Notes: Die Photoreaktionen von Stilben, 4,4′-Dichlor-, 4,4′-Dicyan-, 4,4′-Dimethoxystilben, Diphenyl-acetylen und Bis(4-cyanphenyl)acetylen mit 2,3,4,7-Tetrahydroinden und 1,4,4,8-Tetrahydronaphthalin werden untersucht. Durch [2 + 2]-Cycloaddition enstehen trotz sterischer Hinderung elektrostatisch gefördert überwiegend die Propellane 3, 12, 23, 26, aus denen Dehydrierungsprodukte (41, 44, 45) und das Hydrierungsprodukt 29 gewonnen werden. Weitere Hauptprodukte bei den Photolysen sind 1,2-Substitutionsaddukte (4, 5, 14, 15, 24, 27), während En-Addukte (25, 28) nur spurenweise auftreten. Die mechanistischen Gründe werden anhand von Exciplex-Emissionsspektren und unter Zuhilfenahme von Vergleichsreaktionen mit 1,4-Cyclohexadien sowie Zimtsäure-methylester auf der Grundlage von Diradikalen diskutiert. Die Photolysen mehrerer Propellane unterschiedlichen Hydrierungsgrads werden beschrieben (Zerfall, Dehydrocyclisierung, intramolekulare Cycloaddition und 1,5-Verschiebung). Die Konstitutionen der Produkte werden spektroskopisch (IR, UV, Fluoreszenz, 1H-NMR, 13C-NMR) und zum Teil durch chemischen Abbau und unabhängige Synthesen aufgeklärt.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2238-2244 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Synthesis of 7, 8, 9,10-Tetrahydrocyclohept[b]indol-6(5H)-onesp-Benzoquinone (5a) and methyl-p-benzoquinone (5b) reacts with N-aryl- and N-alkyl derivatives (4a-f) of 2-(aminomethylene)cyclohexanone to yield 2-hydroxy-5-alkyl- or -aryl-cyclohept-indol-6(5H)-ones 6a-j, the structure of which is proved by spectroscopic and chemical methods. A pathway for the reaction is given. By Fischer Cyclisation of the phenylhydrazone cyclohepta[2,1-b:3,4-b′]diindole 16 is prepared from 6h.
    Notes: p-Benzochinon (5a) und Methyl-p-benzochinon (5b) wurden mit N-Aryl- und N-Alkyl-monosubstituierten 2-(Aminomethylen)cyclohexanonen 4a-f umgesetzt. Die 2-Hydroxy-5-alkyl- bzw. -aryl-cyclohept-indol-6(5H)-on-Struktur 6a-j der Reaktionsprodukte wird spektroskopisch und chemisch bewiesen und ein Reaktionsverlauf angegeben. Durch Fischer-Cyclisierung eines Phenylhydrazons von 6h gelingt die Darstellung des Cyclohepta[2,1-b:3,4-b′]diindols 16.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2245-2260 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Spectra of Two Novel CatenanesIn multi-step reaction sequences the precatenanes 23b, c are synthesised. After breaking the chemical bonds between the aromatic nuclei and the bridge head atoms of the double bridged system the [2]-catenanes 25b, c are obtained. The 13C NMR and mass spectra of the precatenanes and catenanes are discussed.
    Notes: In mehrstufigen Reaktionsfolgen werden die Praecatenane 23b, c synthetisiert. Nach Spaltung der chemischen Bindungen zwischen den aromatischen Kernen und den Brückenkopfatomen des Doppelbrücken-Systems werden hieraus die [2]-Catenane 25b, c hergestellt. Die 13C-NMR- und Massenspektren der Praecatenane und Catenane werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2293-2299 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 3,4-Bis(trimethylsilyl)-1-pyrazolines1,2)1,3-Dipolar cycloaddition of diazomethane to the trans-1,2-bis(trimethylsilyl)ethenes 1a-c affords the trans-3,4-bis(trimethylsilyl)-1-pyrazolines 2a-c. Thermolysis of 2a-c yields stereospecifically the trans-1,3-bis(trimethylsilyl)propenes 7b, c and d. The pyrazoline 2c is dehalogenated with Zn to give 3(5),4-bis(trimethylsilyl)pyrazole (8). Reaction of 2a with tetrachloro-o-benzoquinone and of 2b and c with methanolic NaOH leads to dehydrosilylation and elimination of halogenotrimethylsilane, respectively, with formation of the pyrazoles 9-11. 10 and 11 can be desilylated by treatment with acid to yield 12 and 13, resp.
    Notes: Durch die 1,3-dipolare Cycloaddition von Diazomethan an die trans-1,2-Bis(trimethylsilyl)ethene 1a-c werden die trans-3,4-Bis(trimethylsilyl)-1-pyrazoline 2a-c gewonnen. Die Thermolyse von 2a-c führt stereospezifisch zu den trans-1,3-Bis(trimethylsilyl)propenen 7b, c und d. Das Pyrazolin 2c wird durch Reaktion mit Zn zu 3(5),4-Bis(trimethylsilyl)pyrazol (8) dehalogeniert. Bei der Einwirkung von Tetrachlor-o-benzochinon auf 2a und von methanolischer NaOH auf 2b und c tritt Dehydrosilylierung bzw. Halogentrimethylsilan-Eliminierung zu den Pyrazolen 9-11 ein. 10 und 11 lassen sich protolytisch zu 12, 13 entsilylieren.
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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: Transannular Interactions Between Acetylenes - Photoelectron Spectroscopic Investigations on 1,8-Diethynylnaphthalene and Cyclic Derivatives of 2,2′-DiethynylbiphenylThe He(I) photoelectron (PE) spectra of 1,8-diethynylnaphthalene (3), 2,2′-diethynylbiphenyl (6) and the cyclic derivatives of 6 (4 and 5) as well as 1-ethynyl-, 2-ethynyl-, 1,5-diethynyl-, 1-vinyl-, and 1,8-divinylnaphthalene have been recorded. The first bands in the PE spectra of these compounds can be assigned using correlation techniques and semiempirical MO calculations. In case of 3 the resonance integral for the transannular interaction has been found to be β = -0.48 eV. For 4 and 5 the evaluation of β was not possible due to the strong interaction between biphenyl and ethynyl units.
    Notes: Die He(I)-Photoelektronen (PE)-Spektren von 1,8-Diethinylnaphthalin (3), 2,2′-Diethinylbiphenyl (6), der cyclischen Derivate von 6 (4 und 5) sowie von 1-Ethinyl-, 2-Ethinyl-, 1,5-Diethinyl-, 1-Vinyl- und 1,8-Divinylnaphthalin wurden durch Korrelation bzw. semiempirische MO-Rechnungen interpretiert. Bei 3 wurde das Resonanzintegral β für die transannulare Wechselwirkung zu -0.48 eV ermittelt, bei 4,5 und 6 ist wegen der starken Wechselwirkung zwischen Biphenylteil und Acetyleneinheiten eine Ermittlung von β nicht möglich.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2355-2356 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple Synthesis of Nortricyclyl ChlorideIn the presence of titanium tetrachloride the mixture of 5-exo-chloro-2-norbornene (2) and nortricyclyl chloride (3), obtained by HCl addition to norbornadiene (1), reacts completely to form 3. Thus, a simple synthesis of 3 is possible for the first time.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2360-2364 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydridoiridium(III) Complexes with Terminal and Bridging Thio- and Selenocyanate1)The thio- and selenocyanato complexes (Ph3P)2(CO)(Cl)(H)IrX 1 (X = SCN) and 2 (X = SeCN) and 2 (X = SeCN) have been prepared from the corresponding tetrafluoroborato- and trifluoromethanesulfonato-compounds (X = BF4, CF3SO3). The SCN ligand in 1 is S-bonded. 2 was obtained as a mixture of linkage isomers. The reaction of 2 with the tetrafluoroborato-complex (Ph3P)2(CO)(Cl)(H)IrFBF3 gives the salt [(Ph3P)2(OC)(Cl)(H)Ir—SeCN—Ir(H)(Cl)(CO)(PPh3)2]+BF-4 which contains the selenocyanate-bridged cation as a mixture of stereoisomers.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2369-2374 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of a Six-membered Ring with the Elements Sulfur, Nitrogen, and TinA new inorganic six-membered ring 3, containing the elements sulfur, nitrogen, and tin, is prepared by the reaction of CF3SO2N = S = O with [CF3SO2NSn(CH3)2]3 (2a). 3 was characterized on the basis of an X-ray analysis.
    Notes: Ein neuer anorganischer sechsgliedriger Ring 3, der aus den Elementen Schwefel, Stickstoff und Zinn besteht, wird durch Reaktion von CF3SO2N = S = O mit [CF3SO2NSn(CH3)2]3 (2a) dargestellt. Die Konstitution von 3 wird durch die Röntgenstrukturanalyse bestätigt.
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  • 92
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2392-2398 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Molecular Structure of a Spirocyclic Trisepoxide6-Bromo-2,3-epoxycyclohexanone (2) and 6-bromo-2,3-epoxy-2,3-dimethylcyclohexanone (6) were treated with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Whereas 6 afforded 5,6-epoxy-5,6-dimethyl-2-cyclohexen-1-one (7) in the expected elimination process, the analogous reaction with 2 led to the spirocyclic trisepoxide 4, by way of a Darzens reaction. The structures of the compounds prepared were characterized with the help of their 1H NMR, 13C NMR, and IR spectra. The unambiguous structure determination of 4 was achieved by an x-ray study.
    Notes: 6-Brom-2,3-epoxycyclohexanon (2) und 6-Brom-2,3-epoxy-2,3-dimethylcyclohexanon (6) wurden mit 1,8-Diazabicyclo[5.4.0]undec-7-en (DBU) umgesetzt. Während 6 in der erwarteten Eliminierungsreaktion zu 5,6-Epoxy-5,6-dimethyl-2-cyclohexen-1-on (7) reagiert, führt die analoge Umsetzung von 2 gemäß einer Darzens-Reaktion zum spirocyclischen Trisepoxid 4. Die Konstitutionen der dargestellten Verbindungen wurden anhand ihrer 1H-NMR-, 13C—NMR- und IR-Spektren charakterisiert. Von 4 wurde eine Röntgenstrukturanalyse durchgeführt.
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  • 93
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2064-2074 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonyl Isocyanate IsothiocyanateA synthesis of carbonyl isocyanate isothiocyanate (1) is described. 1 reacts with H2O, H2S, or HCl to give the thiadiazines 3,6, and 14, resp. With one mol equivalent of alcohol the isothiocyanates 7 are obtained which form with further alcohol or amines compounds 8-10. With one mol equivalent of amine 1 gives the carbamoyl isothiocyanates 11 which form compounds 12 and 13 with further amine. Compound 1 can be chlorinated to carbonyl isocyanate isocyanide dichloride 18. Partial hydrolysis of 18 leads to carbamoyl isocyanide dichloride (19) yielding with aliphatic amines the stable carbamoyl carbodiimides 16. With alcohols 18 reacts to give the (dichloromethylene)allophanic esters 20.
    Notes: Es wird eine Synthese von Carbonyl-isocyanat-isothiocyanat (1) beschrieben. 1 reagiert mit H2O, H2S oder HCl zu den Thiadiazinen 3,6 und 14. Mit einem Moläquivalent Alkohol erhält man die Isothiocyanate 7, die mit weiterem Alkohol bzw. mit Aminen zu den Verbindungen 8-10 reagieren. Mit einem Moläquivalent Amin reagiert 1 zu den Carbamoyl-isothiocyanaten 11, aus denen mit weiterem Amin die Verbindungen 12 und 13 gebildet werden. 1 läßt sich zum Carbonyl-isocyanat-isocyaniddichlorid (18) chlorieren. Die partielle Hydrolyse von 18 führt zu Carbamoylisocyaniddichlorid (19), welches mit aliphatischen Aminen zu den stabilen Carbamoyl-carbodi-imiden 16 reagiert. Mit Alkoholen reagiert 18 zu den (Dichlormethylen)allophansäureestern 20.
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  • 94
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2116-2131 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2-Methyl-1-phenyl-1-propenyllithium. A vinyllithium Derivative Showing Catalyzed TransmetalationFull preparative and kinetic details are given for the apparent vinyl-to-allyl anion rearrangement1)of the title compound 1. The rapid and quantitative formation of the allyllithium derivative 7 is shown to be catalyzed by 2-methyl-1-phenyl-1-propene (2). An intermolecular transmetalation mechanism with de-aggregation and ionization steps is suggested to explain the orders of reaction, parameters of activation, and solvent dependency.
    Notes: Die rasche und vollständige Umwandlung der Vinyllithium-Verbindung 1 in die Allyllithium-Verbindung 7 wird 1H-NMR-spektroskopisch verfolgt und durch chemische Umsetzungen belegt. Diese scheinbare Umlagerungsreaktion erfolgt unter katalytischer Mitwirkung des 2-Methyl-1-phenyl-1-propens(2). Aus den Reaktionsordnungen, Aktivierungsparametern und der Solvensabhängigkeit wird auf einen intermolekularen Ummetallierungsmechanismus mit deaggregierten und ionisierten Zwischenstufen geschlossen.
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  • 95
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2138-2145 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polar Substituent Effects in Additions of Alkyl radicals to AlkenesReduction of cyclohexylmercuric salts (7) with NaBH4 yields cyclohexyl radicals (8). Their rel rates of addition to substituted styrenes 4, acrylic esters 5 and acrylonitriles 6 have been measured. Comparison with Hammet σ-values show, that substituents at the non attacked vinylic carbon atom show polar effects mainly (Table 1). The effect of a substituent variation increases with increase of the reactivity of the alkenes (Table 2). Mesomeric and steric effects play only a minor role.
    Notes: Die Reduktion von Cyclohexylquecksilbersalzen (7) mit NaBH4 liefert Cyclohexyl-Radikale (8), deren rel. Geschwindigkeitskonstanten der Addition an substituierte Styrole 4, Acrylsäureester 5 und Acrylonitrile 6 gemessen wurden. Der Vergleich mit Hammettschen σ-Werten zeigt, daß die Substituenten am nicht angegriffenen vinylischen Kohlenstoffatom im wesentlichen polare Effekte auf die Additionsgeschwindigkeit ausüben (s. Tab. 1). Der Substituenteneinfluß nimmt dabei mit steigender Reaktivität der Alkene zu (s. Tab. 2). Mesomere und sterische Effekte spielen nur eine untergeordnete Rolle.
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  • 96
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2186-2207 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Optically Active Transition Metal Complexes, LXXIII1) Stereochemistry at the Fe Atom in Rearrangement, Epimerization, and Ligand Exchange Reactions of the Complexes C5H5Fe(CO)(COR)LHeating of the optically active complexes C5H5Fe(CO)(COR)L (1-6) with L = P(C6H5NR′R* leads to rearrangement with formation of C5H5Fe(CO)2CH3 and L before a change in the configuration at the iron atom is observed. The dependence of these reactions on the groups R and R′, and on the concentrations of complex and ligand was investigated. Addition of ligands L′ results in ligand exchange with predominant retention of configuration at the iron atom. The reactions were also carried out with the 13C-labelled compounds C5H5Fe(CO)(13COCH3)L (13, 14) and the cyclopentadienyl-acyl bridged compounds C5H4CH2CH2COFe(CO)L (15, 16). - The results require the assumption of a chiral intermediate C5H5Fe(CO)(COCH3) (Z) on L dissociation from the complexes C5H5Fe(CO)(COCH3)L, which can be trapped by L′ with formation of substitution products. Z also can rearrange to C5H5Fe(CO)2CH3 or invert to its mirror image. With high ligand concentrations a bimolecular inversion mechanism seems to participate.
    Notes: Beim Erhitzen der optisch aktiven Komplexe C5H5Fe(CO)(COR)L (1-6) mit L = P(C6H5)2NR′R* tritt zunächst Umlagerung zu C5H5Fe(CO)2 CH3 und L ein, bevor Konfigurationsänderung am Eisenatom zu beobachten ist. Die Abhängigkeit dieser Reaktionen von den Resten R und R′ sowie von der Komplex- und Ligandenkonzentration wurde untersucht. Bei Zusatz von Liganden L′ erfolgt Ligandensubstitution unter bevorzugter Konfigurationserhaltung am Fe-Atom. Die Reaktionen wurden auch mit den 13C-markierten Verbindungen C5H5Fe(CO)(13COCH3)L (13, 14) und den cyclopentadienyl-acyl-verbrückten Verbindungen C5H4CH2CH2COFe(CO)L (15, 16) durchgeführt. - Die Ergebnisse erfordern die Annahme einer chiralen Zwischenstufe C5H5Fe(CO)-(COCH3) (Z) bei der L-Dissoziation aus den Komplexen C5H5Fe(CO)(COCH3)L, die mit L′ unter Bildung von Substitutionsprodukten abgefangen werden kann. Z kann sich auch zu C5H5Fe(CO)2CH3 umlagern oder in sein Spiegelbild umklappen. Bei hohen Ligandenkonzentrationen scheint auch ein bimolekularer Inversionsmechanismus mitbeteiligt zu sein.
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  • 97
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Open-chain and Cyclic Bis-phosphoranes from α,ω-Dinitriles, Diisobutylaluminium Hydride, and MethylenetriphenylphosphoraneThe reaction of subero-, azelao-, and sebaconitrile (4, n = 6,7, and 8) with diisobutylaluminium hydride (to give 5) and subsequently with methylenetriphenylphosphorane leads to the openchain bis-phosphoranes 8a-c, which have been characterized by the Wittig reaction. The same reaction sequence applied to adiponitrile produces the cyclic bis-phosphorane 9a. The previously unknown hydrocarbon 1,3,9,11-cyclohexadecatetraene (12) has been prepared from 8a and adipoaldehyde.
    Notes: Die Reaktion von Subero-, Azelao- bzw. Sebaconitril (4, n = 6,7 bzw. 8) mit Diisobutylaluminiumhydrid (zu 5) und anschließend mit Methylentriphenylphosphoran führt zu den offenkettigen Bis-phosphoranen 8a-c, die durch die Wittig-Reaktion charakterisiert wurden. Im Falle des Adiponitrils führt die gleiche Reaktionsfolge zu einem cyclischen Bis-phosphoran 9a. Aus 8a und Adipoaldehyd wurde der bisher unbekannte Kohlenwasserstoff 1,3,9,11-Cyclohexadecatetraen (12) synthetisiert.
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  • 98
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2272-2286 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparative and Kinetic Investigations about the Isomerism between (Acyloxy)diorganylphosphanes and Acyldiorganylphosphane OxidesThe (acyloxy)diorganylphosphanes RC(O)OPR′2 (2a-d, 2b′) can be obtained either by reaction of XPR′2 (1) (X = Cl, R′ = Ph) with CH3CO2Na or by the action of 1 (X = Cl, Br; R′ = CH3, Ph) on the perfluorocarboxylic anhydrides [RC(O)]2O [eq. (1)]. 2b-d are thermally labile and rearrange irreversibly to the (perfluoroacyl)diphenylphosphane oxides 3b-d [eq. (2)]. On the basis of kinetic investigations the isomerizations 2b,c → 3b,c follow a first-order rate. The (acyloxy)diorganylphosphanes (2a-d, 2a′, 2b′) can be stabilized on transition metal carbonyl systems [eq. (3)]. The complexes LnMPR′2OC(O)R (5ax,z, 5a′x, 5bx-z, 5b′x, 5cx) [LnM = (OC)5Cr (x), (OC)5Mo (y), (η4-C5H5)Mn(CO)2 (z)] are obtained for 5ax, z, 5a′x from LnMPR′2X (4x,z) and Hg(O2CCH3)2, for 5bx-z, 5b′x from 4x-z and AgO2CCF3 and for 5cx by the reaction of 4x with [C2F5C(O)]2O. 5ax, 5bx and 5b′x are also formed by the trapping reaction of 2a, 2b, 2b′ with (OC)5Cr(THF) (6x) [ed. (4)]. Oxidation of 2a with molecular oxygen generates (acetoxy)-diphenylphosphane oxide (7a), whereas the corresponding perfluoro derivative CF3C(O)OP(O)Ph2 (7b) results from Ph2P(O)OH and [CF3C(O)]2O [eq. (5)].
    Notes: Die (Acyloxy)diorganylphosphane RC(O)OPR′2 (2a-d, 2b′) erhält man entweder durch Umsetzung von XPR′2 (1) (X = Cl, R′ = Ph) mit CH3CO2Na oder bei der Einwirkung von 1(X = Cl, Br; R′ = CH3, Ph) auf die Perfluorcarbonsäureanhydride [RC(O)]2O[Gl. (1)]. 2b-d sind thermolabil und wandeln sich irreversibel in die (Perfluoracyl)diphenylphosphanoxide 3b-d um [Gl. (2)]. Nach kinetischen Untersuchungen folgen die Isomerisierungen 2b,c → 3b,c dem Geschwindigkeitsgesetz 1. Ordnung. Die (Acyloxy)diorganylphosphane (2a-d, 2a′,2b′) lassen sich an Übergangsmetallcarbonylsystemen stabilisieren [Gl. (3)]. So erhält man die Komplexe LnMPR′2OC(O)R (5ax,z, 5a′x, 5bx-z, 5b′x, 5cx) [LnM = (OC)5Cr (x), (OC)5Mo (y), (η5-C5H5)Mn(CO)2 (z)] für 5ax,z, 5a′x aus LnMPR′2X (4X,Z und Hg(O2CCH3)2, für 5bx-z, 5b′x aus 4x-z und AgO2CCF3 und für 5cx durch Reaktion von 4x und [C2F5C(O)]2O. 5ax, 5bx und 5b′x bilden sich auch bei der Abfangreaktion von 2a, 2b, 2b′ mit (OC)5Cr(THF) (6x) [Gl. (4)]. Während 2a bei der Oxidation mit molekularem Sauerstoff das (Acetoxy)diphenylphosphanoxid (7a liefert, entsteht das entsprechende perfluorierte Derivat CF3C(O)OP(O)Ph2 (7b) durch Reaktion von Ph2P(O)OH und [CF3C(O)]2[Gl. (5)].
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  • 99
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2357-2359 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Total Synthesis of Epifenchone and DehydrocampheniloneA new and simple method with good yields for the total synthesis of the title substances 5 and 9 is described. Methylation of 3, 4, and 8 with CH3I/LCIA in THF under reflux yields the geminal dimethylnorbornanones 5, 6 and 9.
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  • 100
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2365-2368 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chirale Butadiene, 91) Präparative Anreicherung enantiomerer 2,3,4,5-Tetrabrom-2,4-hexadiene durch Flüssigkeits-ChromatographieDie Enantiomeren des Diols 1 wurden durch Flüssigkeits-Chromatographie an Triacetylcellulose teilweise getrennt (Enantiomere Reinheiten P = 29% und 24%), während die Diether (+)- und (-)-2 mit P = 80% (Tab. 1) erhalten wurden. Ihre Schwellen der Teilrotation um die zentrale Einfachbindung wurden durch thermische Racemisierung gemessen und mit denen entsprechender Tetrachlordiene 3 und 4 verglichen (Tab. 3).
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