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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3097-3111 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Addition Reactions of 2-Phenyl-1-cyclopropene-1-carboxylatesFrom the olefins 1,2, and 4-7 the 1-chloro-1-cyclopropanecarboxylic acids 15-20 are prepared via the dichlorocyclopropanes 8, 9, and 11-14. The trans-isomers 15a-20a were readily separated. Spiropentane 10 undergoes anionic ring cleavage with BuLi to give finally the ester 33. The tert-butyl esters 21-26 yield with KOtBu the cyclopropene esters 27-32. The trans-esters 21a-26a react much faster than the cis-esters b. At C-3 unsubstituted chlorocyclopropane esters, e.g. 34, do not give stable cyclopropene esters even with lithium dialkylamides. Diazomethane adds to the esters 27-32 to give the pyrazolines 38-43, their isomers a and b being separable. With traces of base the bicyclic pyrazolines are cleaved to 1,4-dihydropyridazines 44-46. Cyclopropenes 27-30 react with thiophenolate to from the isomeric products 47-50; malonate adds to 28 and 31 to give 51, 52. With malononitrile via subsequent reactions the cyclopentadienes 55-57 are obtained.
    Notes: Aus den Olefinen 1, 2 und 4-7 werden über die Dichlorcyclopropane 8, 9 und 11-14 die 1-Chlor-1-cyclopropancarbonsäuren 15-20 erhalten, deren trans-Isomeren a leicht abtrennbar sind. Das Spiropentan 10 erleidet mit BuLi anionische Ringöffnung und ergibt schließlich den Ester 33. Die tert-Butylester 21-26 bilden mit KOtBu die Cyclopropenester 27-32, wobei die trans-Ester 21a-26a viel schneller reagieren als die cis-Ester b. An C-3 unsubstituierte Chlorcyclopropanester, z. B. 34, ergeben auch mit Lithium-dialkylamiden keine stabilen Cyclopropenester. Diazomethan addiert sich an die Ester 27-32 zu den Pyrazolinen 38-43, deren Isomeren a und b trennbar sind. Mit Spuren Base werden die bicyclischen Pyrazoline zu 1,4-Dihydropyridazinen 44-46 geöffnet. Mit Thiophenolat reagieren 27-30 zu den isomeren Additionsprodukten 47-50, Malonester addiert sich an 28 bzw. 31 zu 51 und 52. Die Addition von Malonodinitril führt nach Folgereaktionen zu den Cyclopentadienen 55-57.
    Type of Medium: Electronic Resource
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