Synthesis of 1,3-thiazolidin-4-ones; Reactivity of the thiosemicarbazone function towards dimethyl acetylenedicarboxylate

Abstract

Aryl thiosemicarbazones react rapidly in a facile procedure with dimethyl acetylene-dicarboxylate to give substituted (ylidene) hydrazono(4-oxothiazolidin-5-ylidene) acetates in high yields. The synthesised compounds were characterised by spectroscopic methods and the structures confirmed by single crystal X-ray crystallography. Several mechanistic options involving nucleophilic interaction are presented.