Iodine-catalyzed the reaction of substituted methyl ketone N-tosylhydrazones with elemental sulfur has been developed. The cyclizations of the ester-substituted N-tosylhydrazone substrates proceeded smoothly under optimal reaction conditions, and the corresponding products 4-alkyl-1, 2, 3-thiadiazoles are obtained. For the reaction of 4-arylbutan-2-one of N-tosylhydrazone substrates, (E)-4-styryl-1