Oxidative cyclization of arylhydrazones of chalcones and benzalacetones to pyrazoles by thianthrene cation radical

AC Kovelesky, HJ Shine

Index: Kovelesky, Albert C.; Shine, Henry J. Journal of Organic Chemistry, 1988 , vol. 53, # 9 p. 1973 - 1979

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Citation Number: 25

Abstract

Phenyl-,@-nitropheny1)-, and (2, 4-dinitrophenyl) hydrazones of chalcone (benzalacetophenone), benzalacetone, and of some of their derivatives undergo oxidative cyclization in reactions with thianthrene cation radical perchlorate. The products are, respectively, 1, 3, 5-triaryl-(3) and 3-methyl-l, 5-diarylpyrazoles (4) and are formed in excellent yields. Cyclization appears to occur by way of the arylhydrazone cation radical ...