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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2814-2820 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Olefination Reactions with Phosphorous ylids, II. β-Oxido Phosphorus ylids in the Presence and Absence of Soluble Alkaline Metal Saltstrans-Stereoselective olefin synthesis by means of the modified Wittig reactions cannot be achieved in salt-free medium, since only in the presence of soluble lithium salts do the phosphorous betaines exist predominantly in the threo form.
    Notes: Phosphor-Betaine bevorzugen nur dann ganz eindeutig die threo-Form und können somit stereoselektiv in trans-Olefine übergeführt werden, wenn lösliche Lithiumsalze im Reaktions-gemisch zugegen sind.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 690-693 
    ISSN: 0749-1581
    Keywords: NMR ; 13C NMR ; 15N NMR ; 1,2,4-triazines ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C and 15N NMR spectra of eight substituted 1,2,4-triazines were measured and assigned. The assignments of the 13C NMR spectra were based on the substituent chemical shifts and nJ(C,H) coupling constants. 15N NMR chemical shifts generally showing well separated ranges were assigned by the proton coupled 15N NMR spectra. 15N NMR chemical shifts of N-4 in 3- and 5-methoxy or -thiomethyl-substituted 1,2,4-triazines were found to be related significantly (confidence level 〉99%) with the π-charge at N-4 calculated by a semi-empirical molecular orbital (AM1) procedure. For the 15N NMR chemical shifts of N-1 and N-2, no reliable correlations with the molecular electronic properties such as AM1 π-charges and ionization potentials ( - EHOMO) were found.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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