Abstract The cyclothiomethylation of carboxylic acid hydrazides RCONHNH 2 (R= C 5 H 4 N, Ph, 2-MeOC 6 H 4, or 4-HOC 6 H 4 CH 2) with formaldehyde and H 2 S at 70° C affords predominantly the corresponding N-(1, 3, 5-dithiazinan-5-yl) amides, whereas this reaction at 0–− 50° C gives a mixture of the latter compounds with 3-acyl-1, 3, 4-thiadiazolidines. N- (1, 3, 5-Dithiazinan-5-yl)-amides were selectively synthesized by the reaction of carboxylic ...
