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  • 1
    Electronic Resource
    Electronic Resource
    Norbornanes. Part 18. Inductive Charge Dispersal in the Solvolyses of 4- and 5-Substituted 2-Norbornyl p-Toluenesulfonates (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 2098-2107 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solvolysis rates and products of 4- and 5-exo-substituted 2-exo- and 2-endo-norbornyl tosylates 9 and 10, respectively, are reported. The logarithms of the rate constants (log k) correlate linearly with the inductive constants σIq for the substituents. A comparison of the reaction constants p1 for the 4-, 5-, 6-, and 7-substituted 2-exo- and 2-endo-tosylates 9, 10, 1, and 2 respectively, indicates that inductivity is higher for 2-exo-ionization than for 2-endo-ionization in all series. This observation is attributed to the more favorable alignment of neighbouring C-atoms for dorsal participation in exo-ionization, especially, in the case of C(6).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690834
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  • 2
    Electronic Resource
    Electronic Resource
    Polar Effects. Part 14. Inductive Charge Dispersal in Bicyclo[2.2.2]oct-1-yl Cations (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 2158-2164 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate constants (log k) for solvolysis of 2-, 3-, and 4-substituted bicyclo[2.2.2]octyl p-nitrobenzenesulfonates 10, 11 and 12, respectively, correlate linearly with the corresponding inductive substituent constants s̰Iq. The formation of the ion pairs 9 is, therefore, controlled by the I effect of neighboring substituents. It follows from the corresponding reaction constants ρ1 of -1.54, -1.12, and -1.22 that inductivity is highest at the positions α to C(1). It is lower and practically equal at the β- and γ-positions. Therefore, charge dispersal is similar to that previously observed in the quinuclidinium ion 7.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680810
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  • 3
    Electronic Resource
    Electronic Resource
    Characterization of symmetrical and unsymmetrical thiol-disulfide interchange reactions by one-and two-dimensional magnetization transfer NMR spectroscopy (1992)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 30 (1992), S. 746-753 
    Details
    ISSN: 0749-1581
    Keywords: NMR Two-dimensional NMR ; Thiol-disulfide ; Glutathione ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One- and two-dimensional magnetization transfer NMR methods were used to characterize symmetrical and unsymmetrical thiol-disulfide interchange reactions in the glutathione-cysteamine system. The chemical system consists of four symmetrical and two unsymmetrical thiol-disulfide interchange reactions. In terms of the magnetization transfer experiment, these reactions can be treated as two three-site exchange networks, one for exchange of the cysteamine moiety among cysteamine, cystamine and the cysteamine part of the glutathione-cysteamine mixed disulfide and another for exchange of the glutathione moiety among glutathione, glutathione disulfide and the glutathione part of the mixed disulfide. Two-dimensional 13C—{1H} EXSY NMR spectroscopy was used to identify specific exchange reactions which take place on the time scale of the magnetization transfer experiment at a given pD. The kinetics of the interchange reactions were quantitatively characterized using an overdetermined version of the one-dimensional 13C—{1H} EXSY experiment and a 13C—{1H} selective inversion-transfer experiment with a linear-least-squares analysis of the time course data. Second-order rate constants were calculated for all six of the thiol-disulfide interchange reactions from the pseudo-first-order rate constants obtained from the selective inversion-transfer experiments.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260300810
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  • 4
    Electronic Resource
    Electronic Resource
    Study of 13C-19F and 1H-19F couplings in some fluorinated aromatic compounds using two-dimensional 13C-1H chemical shift correlation spectroscopy with proton homonuclear decoupling (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 75-79 
    Details
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The magnitudes and relative signs of 13C-19F and 1H-19F coupling constants in 6-F-indole, 5- and 6-F-tryptamine, 5-F-indole-3-carboxaldehyde, 2- and 4-F-biphenyl, droperidol, flusperilene, 1-F-naphthalene and 3-F-fluroanthene (F = fluoro) have been determined using two-dimensional 13C-1H chemical shift correlation spectroscopy with proton homonuclear decoupling. Except for one long-range 1H-19F coupling constant, all the other observed 1H-19F couplings in these compounds were found to be of the same sign as the corresponding 13C-19F coupling constants. The variation of the magnitude of tlfe coupling constants due to substitution is relatively insignificant.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260240115
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