Heterocyclic compounds. Part V. Reactions of phenyl and benzoyl isocyanates and benzoyl isothiocyanate with hydrazones

Abstract

Reactions of phenyl and benzoyl isocyanate with ketone hydrazones gave s-triazolidines in good yields, whereas benzaldehyde phenylhydrazone simply gave semicarbazones. With benzoyl isothiocyanate ketone hydrazones and benzaldehyde phenylhydrazone gave oxatriazepinethiones. These reactions are all thought to proceed via betaines, and their mechanisms are discussed in the light of semi-empirical INDO calculations.