ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Heterocycles Starting from Bis(alkoxycarbonyl)ketene Ethylene Acetals ( = Dialkyl 2-(1,3-Dioxolan-2-ylidene)propane-1,3-dioate). Synthesis and Properties of a New Class of Pyrazolium BetainesThe readily available bis(alkoxycarbonyl)ketene ethylene acetals 1 react with bifunctional nucleophiles to give heterocycles 2-5 (Scheme 1). Their reactions with N,N-dialkylhydrazines lead to the pyrazolium betaines 7a-f (Scheme 4). Cyclic N,N-dialkylhydrazines give spiro compounds 7d-f. The reaction of thioketene acetal 12 and of the derivative 15 of methanetricarboxylic acid with N,N-dimethylhydrazine results in the formation of 3-(methylthio)- and 3-methoxypyrazolium betaine 7g and 7h, respectively (Scheme 4). The chemical reactivity of the synthesized pyrazolium betaines 7 was tested. The structure of the 3-(methylthio) derivative 7g was determined by X-ray analysis.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19920750407
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