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  • 1
    Electronic Resource
    Electronic Resource
    Einführung von Sauerstoff-Funktionen in die α-Stellung von β-Diketonen, 41) Direkte Acyloxylierung von 1,3-Cyclohexandionen mit Diacylperoxiden (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1938-1950 
    Details
    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.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140531
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  • 2
    Electronic Resource
    Electronic Resource
    Notizen. 5- und 6-Ring-Reduktone aus 2-Diazo-1,3,dicarbonyl-verbindungen. Eine schonende Alternative zur klassischen “Verkochungsmethode” (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1958-1962 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five- and Six-Membered Ring Reductones from 2-Diazo-1,3-dicarbonyl Compounds. A Smoothful Alternative of the Classic Thermal Dediazotation2-Acyloxy-2-chloro-1,3-dicarbonyl compounds 2, easily obtained from 2-diazo-1,3-dicarbonyl compounds 1, and tert-butyl hypochlorite in formic or acetic acid at room temperature or below, are immediately reduced to the corresponding reductone esters 3, by sodium iodide/disodium pentaoxodisulfate. (Concomitant) Hydrolysis of the reductone esters yields the desired reductones 4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140533
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  • 3
    Electronic Resource
    Electronic Resource
    1,2,3-Cyclohexantrion/2,6-Dihydroxy-2,5-cyclohexadien-1-on Isomerisierung: Eine einfache Synthese für 2,6-dioxysubstituierte 2,5-Cyclohexadien-1-one (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1951-1957 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,2,3-Cyclohexanetrion/2,6-Dihydroxy-2,5-cyclohexadien-1-on-Isomerization: A Facile Synthesis of 2,6-Dioxy-substituted 2,5-Cyclohexadien-1-onesHitherto unknown 1,2,3-cyclohexanetriones masked as chlorohydrins 2 or as chlorohydrin esters 4 are easily rearranged yielding the corresponding 2,6-dihydroxy-2,5-cyclohexadien-1-ones 6 or their esters 8.
    Notes: Die bislang unbekannten 1,2,3-Cyclohexantrione 5 können in Form ihrer Chlorhydrine 2 oder deren Ester 4 leicht in die entsprechenden 2,6-Dihydroxy-2,5-cyclohexadien-1-one 6 oder deren Ester 8 umgelagert werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140532
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  • 4
    Electronic Resource
    Electronic Resource
    Zum Mechanismus einer α-Bromacetal/Ester-Umlagerung (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1109-1115 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Mechanism of an α-Bromoacetal-Ester RearrangementOn heating in the presence of appropriate bases 2-bromo-2-phenylacetaldehyde ethylene acetal (1) undergoes a rearrangement to give 2-bromoethyl phenylacetate (3). The course of this rearrangement is investigated kinetically for carious solvents, temperatures, and bases. The mechanism has been found to be a combination of two component-reactions known from the literature: HBr-elimination with formation of a ketene acetal and its reprotonation followed by the cleavage of the acetal ring.
    Notes: Beim Erhitzen in Gegenwart geeigneter Basen erfährt 2-Brom-2-phenylacetaldehydethylenacetal (1) eine Umlagerung in Phenylessigsäure-2-bromethylester (3). Der Ablauf dieser Umlagerung wird in Abhängigkeit von Lösungsmitteln, der Temperatur und zahlreichen Basen kinetisch untersucht. Als Mechanismus wird eine Kombination zweier literaturbekannter Teilreaktionen - HBr-Eliminierung unter Bildung eines Ketenacetals und dessen Reprotonierung gefolgt von Acetalringspaltung - gefunden.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770706
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