Schiff Bases and Triazolothiadiazines Derived from A Thiophene-Substituted 4-Amino-3-Mercapto-1,2,4-Triazole

Abstract 4-Amino-5-(thiophen-2-ylmethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione was synthesized and converted into the corresponding Schiff bases using several aromatic aldehydes. Reaction of this aminotriazolethione with phenacyl bromides lead to triazolothiadiazines, which were subsequently reduced with NaBH4 to dihydrotriazolothiadiazines. The latter type of fused heterocycle has been also obtained directly by reacting one of the previously obtained Schiff base with phenacyl bromides. NMR analysis confirmed the structures of the synthesized compounds.