Y. Tominaga, N. Yoshioka, R. Castle
Mar 1, 1997
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Influential Citations
4
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Journal
Journal of Heterocyclic Chemistry
Abstract
The reaction of 5-amino-1-phenylpyrazole-4-carbonitriles 1a-c with dimethyl acetylenedicarboxylate in the presence of potassium carbonate in dimethyl sulfoxide gave trimethyl 4,5,5a,8-tetrahydro-1-phenyl-4,8-dioxo-1H-pyrazolo[3,4-e]indolizine-5,5a,6-tricarboxylate derivatives 3a-c from the basic solution. The products were formed by a double Michael reaction of 1 with dimethyl acetylenedicarboxylate followed by cyclization to the cyano group. The structure of product 3a was established by X-ray crystallography.