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  • 1975-1979  (8)
  • 1890-1899
  • 1977  (8)
  • 1
    Electronic Resource
    Electronic Resource
    Bacterial metabolism of substituted phenols (1977)
    Springer
    Archives of microbiology 114 (1977), S. 25-33 
    Details
    ISSN: 1432-072X
    Keywords: Substituted phenols ; Insecticides ; “Meta”fission ; Nocardia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 4-(Methylmercapto)-phenol (MMP) and 4-(methylsulfinyl)-phenol (MSP) are oxidized by the soil isolate Nocardia spec. DSM 43251, which is closely related to Nocardia calcarea. The rate of degradation depends on the capability of a substrate to support growth and is strongly enhanced in the presence of a second carbon source under the conditions of cooxidation. MMP and MSP are cometabolized by hydroxylation of the benzene ring with the formation of the substituted catechol following by ring cleavage between carbon atoms 2 and 3 (“meta”fission) to give 2-hydroxy-5-methylmercapto-or 2-hydroxy-5-methylsulfinylmuconic semialdehyde. Oxidation of MMP to MSP represents a bypath of MMP-oxidation. The intermediates were identified on the basis of their physical properties. The enzymes responsible for the metabolism of MMP and MSP are induced by growth with MMP or MSP, but not with glucose. MMP- and MSP-induced cells catalyze the oxidation of a variety of substituted phenols. This indicates a rather low substrate specificity of the enzymes induced by MMP and MSP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429626
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  • 2
    Electronic Resource
    Electronic Resource
    29Si NMR spectroscopy of cyclosiloxanes (1977)
    Springer
    Journal of structural chemistry 18 (1977), S. 463-470 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00753093
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Steric effects in 29Si and 13C n.m.r. spectra of trimethylsiloxy-substituted benzenes (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 237-238 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 29Si and 13C NMR spectra of trimethylphenoxysilane and three bis(trimethylsiloxy)benzenes have been investigated. Crowding in the ortho derivative leads to a small but observable deshielding of both silicon and carbon nuclei of the trimethylsiloxy group. In comparison to analogous effects observed in trimethylsilyl-substituted benzenes the oxygen link appears to increase the susceptibility of silicon to this steric effect but to decrease that of the methyl carbons. It is suggested that the operative steric interaction might not be that between the terminal methyl groups but involves the oxygen atom.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270090413
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  • 4
    Electronic Resource
    Electronic Resource
    Steric gamma effect on 29Si shielding in (CH3)3Si—O—C—R groups (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 239-240 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that a γ-methyl group causes approximately a 3 ppm upfield shift of the silicon resonance in (CH3)3Si—O—C—CH3 fragments. It is estimated that polar effects contribute about 0.8 ppm to this shift leaving a net steric γ upfield shift of 2 ppm. Variations around these average values are interpreted by different conformer populations, the importance of which are illustrated by the shifts in trimethylsiloxy derivatives of adamantane.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270090414
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  • 5
    Electronic Resource
    Electronic Resource
    Steroide. LIII. 1H-NMR-Untersuchungen. Konfigurationszuordnung von 16-substituierten 17-Hydroxy-Steroiden (1977)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 419-431 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Steroids. LIII. 1H N.M.R.-Investigations. Configurational Assignment of 16-Substituted 17-Hydroxy SteroidsThe 1H n.m.r. spectra of epimeric 16-substituted 17β-hydroxy-3-methoxy-estra-1,3,5(10)-trienes can be used for configurational assignment. The values of the coupling constants J16,17 allow the elucidation of the configuration, when all of the four epimeric compounds with the same 16-substituent are available. When only one compound is available, a reliable configurational assignment by J16,17 is only possible, when J ≤ 2 cps (16β,17α-configuration of the substituents) or when J 〉 8 cps (16β,17β-configuration). Further parameters for configurational assignment are the chemical shifts of the 13β-methyl protons and the 17-proton, the downfield shifts of the 17-proton signals, caused by acetylation or by “in situ” reaction with trichloroacetyl isocyanate, and the chemical shift as well as the sum of the coupling constants of the 16-protons. The contributions of the 16-substituents to the chemical shift of the 17-proton are compared with similar values, obtained from 1-substituted acenaphthenes. Equations for the calculation of these contributions are presented for the trans compounds.
    Notes: Die 1H-NMR-Spektren epimerer 16-substituierter 17-Hydroxy-3-methoxyöstra-1,3,5(10)-triene werden zur Konfigurationsbestimmung herangezogen. Aus der Kopplungskonstante J16,17 kann die Konfiguration eindeutig ermittelt werden, wenn die vier möglichen Epimeren mit gleichem 16-Substituenten vorliegen. Liegt nur eine Verbindung vor, ist eine sichere Zuordnung allein durch J16,17 nur möglich, wenn J ≤ 2 Hz ist (16β,17α-Konfiguration der Substituenten) oder wenn J 〉 8 Hz ist (16β,17β-Konfiguration). Weitere zur Konfigurationsbestimmung geeignete Parameter sind die chemische Verschiebung der 13β-Methylprotonen und die des 17-Protons, die Tieffeldverschiebung dieses Signals nach Acetylierung oder nach „in situ“-Reaktion mit Trichloracetylisocyanat sowie chemische Verschiebung und Gesamtaufspaltung des 16-Protonensignals. Die Beiträge der 16-Substituenten zur chemischen Verschiebung des 17-Protons werden mit den aus 1-substituierten Acenaphthenen erhaltenen Werten verglichen. Gleichungen zur Berechnung dieser Beiträge für die trans-Verbindungen werden angegeben.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19773190310
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  • 6
    Electronic Resource
    Electronic Resource
    Derivate des Phosphorsäure-o-phenylenesters. XV [1]. Synthese von Tris-(o-phenylendioxy)-phosphorat(V)Herrn Prof. Dr. Dr. h. c. mult. Alfred Rieche zum 75. Geburtstag gewidmet (1977)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 188-194 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Derivatives of o-Phenylenephosphate. XV. Synthesis of Tris-(o-phenylenedioxy)-phosphorate(V)The structure of an orthophosphate which had been supposed earlier to represent type 1, has been proven to be a compound having only one P-nucleus in the molecule, with a penta(4) resp. hexacoordinated (5) structure depending on the solvent. The triethyl-ammonium salt 8 of this first example of a hexacoordinated phosphoric acid with 6 P—O-bonds (5) is formed simply from tri- als well as from tetra- and pentacoordinated derivatives of phosphorous resp. phosphoric or thiophosphoric acid.
    Notes: Die Struktur eines früher als 1 angesehenen Orthophosphorsäureesters erwies sich als einkernige Phosphorverbindung, die in Abhängigkeit vom Lösungsmittel in penta-(4) bzw. hexacoordinierter (5) Form vorliegt. Das Triäthylammoniumsalz 8 dieser ersten hexacoordinierten Phosphorsäure mit sechs P—O-Bindungen 5 ist überraschend leicht aus tri-, tetra- und pentacoordinierten Verbindungen der phosphorigen bzw. Phosphorsäure oder Thiophosphorsäure zugänglich.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19773190203
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  • 7
    Electronic Resource
    Electronic Resource
    29Si-NMR-Spektroskopie an Silicatlösungen. IV. Untersuchungen zur Kondensation der Monokieselsäure (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 428 (1977), S. 43-52 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 29Si-NMR Spectroscopy of Silicate Solutions. IV. Investigations on the Condensation of Monosilicic AcidCondensation reactions of the monosilicic acid prepared by hydrolysis of Si(OCH3)4 in diluted HCl are investigated by 29Si-n.m.r. spectroscopy. It is shown that the first product of the condensation, which is stable for some time, is not di- but cyclotrisilicic acid. The condensation then proceeds via higher monocyclic and polycyclic acids to branched and crosslinked polymer products. The kinetics of the condensation reactions is investigated in the dependence on SiO2 concentration and pH value. The mechanism of the condensation, particularly that in the low molecular range, is discussed.
    Notes: Die Kondensationsreaktionen der Monokieselsäure, die durch Hydrolyse von Si(OCH3)4 in verd. HCl hergestellt wurde, werden mit Hilfe der 29Si-NMR-Spektroskopie untersucht. Es wird gezeigt, daß als erstes, über längere Zeit stabiles Kondensationsprodukt nicht Di-, sondern Cyclotrikieselsäure gebildet wird. Der weitere Verlauf der Kondensation führt über höhere mono- und polycyclische Kieselsäuren zu verzweigten und vernetzten hochmolekularen Produkten. Die Kinetik der Kondensationsreaktionen wird in Abhängigkeit von SiO2-Konzentration und pH-Wert untersucht und der Kondensationsmechnismus besonders im niedermolekularen Bereich diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19774280105
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  • 8
    Electronic Resource
    Electronic Resource
    29Si-NMR-Spektroskopie an Silicatlösungen. V. über die 29Si-NMR-Spektren niedermolekularer Kieselsäuren (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 437 (1977), S. 249-252 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 29Si-N.M.R. Spectroscopy of Silicate Solutions. V. On the 29Si-N.M.R. Spectra of Low-molecular Silicic AcidsThe 29Si-n.m.r. signals of the end groups of di- and trisilicic acid (each in 0,5 M aqueous solution) are lying in a very close neighbourhood (Δδ = 0,03 ppm). In more concentrated solutions (1.5M) the end group signals approach to oneanother and overlap respectively in such a strong manner, that their unambiguous assignment and, hence, the identification of the low-molecular condensation products of monosilicic acid are up to now not possible.
    Notes: 29Si-NMR-Untersuchungen an 0,5 m Di- und Trikieselsäurelösungen zeigen, daß die Resonanzsignale für die Endgruppen-Si-Atome der beiden Kieselsäuren sehr eng benachbart sind (Δδ = 0,03 ppm). In konzentrierten 1,5 m Lösungen nähern bzw. überlagern sich die Endgruppensignale derart, daß eine eindeutige Zuordnung der Resonanzsignale und die Identifizierung nieder-molekularer Kondensationsprodukte der Monokieselsäure bisher nicht möglich ist.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19774370136
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