Abstract The behaviour of the aminopyrazole derivatives 1a-c, 2-amino-4-phenylthiazole (2) and 2-amino-5-phenyl-1, 3, 4-thiadiazole (3) toward the action of ethoxycarbonyl and benzoyl iso-thiocyanate is reported. The data clearly demonstrates the dependence of the nature of the products obtained from the reaction of isothiocyanates with cyclic amidines on the nature of the substituents on the heterocyclic ring.
