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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 459-465 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkaline Carboxylic Acid Elimination by Neighbouring Group Participation3-(2-Hydroxy-3,4,5-trimethylphenyl)-3-methylphthalide (1) und 3-(2-Hydroxyphenyl)-3-methylphthalide (2) react in alkali by way of intramolecular carboxylic acid elimination to give the 1,1-diphenylethylenes 3 and 4 in high yields. It is shown that this elimination reaction dominates over the saponification of the lactone ring by the neighbouring group effect of the phenolate oxygen. Only with higher concentrations of hydroxylic ions the saponification reaction becomes faster in the case of 2. This neighbouring group effect, though in a slow reaction, Causes β-elimination of water in the tert. alcohols 11 c, e yielding the 1,1-diphenylethylenes 12c, e.
    Notes: 3-(2-Hydroxy-3,4,5-trimethylphenyl)-3-methylphthalid (1) und 3-(2-Hydroxyphenyl)-3-methylphthalid (2) geben in Alkali unter intramolekularer Carbonsäure-Eliminierung in hohen Ausbeuten die 1,1-Diphenyläthylene 3 bzw. 4. Es wird gezeigt, daß diese Eliminierungsreaktionen durch den Nachbargruppeneffekt des Phenolat-Sauerstoffes schneller ablaufen als die Verseifung der Lactonringe. Erst bei höheren Hydroxylionen-Konzentrationen wird im Falle von 2 die Verseifungsreaktion schneller. Dieser Nachbargruppeneffekt ermöglicht ferner - wenn auch in langsamer Reaktion - alkalische β-Eliminierung von Wasser aus den tert. Alkoholen 11c, e unter Bildung der 1,1-Diphenyläthylene 12c, e.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1974 (1974), S. 1167-1182 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Quinones, V1). - Experiments on the Preparation of l,lO-Anthraquinone2)An attempt has been made on the basis of calculated and experimental results to stabilize the very reactive 1,10-anthraquinone by stepwise and directed introduction of methyl groups. The 2,3,4,5,8-pentamethyl-1,10-anthraquinone (12) could be prepared, but only isolated as hemiketal 19. - It could be shown that the electron affinities of anthraquinones are probably a good measure of their stability.
    Notes: Aufgrund rechnerischer und experimenteller Befunde wurde versucht, das sehr reaktive 1,10-Anthrachinon durch schrittweise und gezielte Einfuhrung von Methylgruppen zu stabilisieren. Das 2,3,4,5,8-Pentamethyl-1,10-anthrachinon (12) konnte dargestellt, aber nur als Halbketal 19 isoliert werden. - Wie sich zeigte, lassen sich die Elektronenaffinitäten der Anthrachinone wahrscheinlich zur Beurteilung ihrer Stabilität heranziehen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 9 (1970), S. 164-165 
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 1969-01-01
    Print ISSN: 0040-4039
    Electronic ISSN: 1873-3581
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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