Abstract The behavior of ethyl 2-phenylthiocarb-amoyl acetate 1 toward a variety of several α-halo-carbonyl compounds was investigated. Thus, reaction of 1 with α-bromoketones, hydrazonoyl bromides, and 2-chloro-N-arylacetamides afforded the corresponding dihydrothiazole, 1, 3, 4-thiadiazole, and thiophene derivatives, respectively. The synthesis of thiazolidin-4-one 11, thiazolidin-5-one 12, and some azo derivatives of thiazolidin-5-one ...