Synthesis of ethyl ester of acetic acid containing 5-oxo-[1,2,4] triazole ring (2) was achieved by the condensation of 3-substituted-4-amino-1H-1,2,4-triazol-5(4H)-one (1) with ethyl bromoacetate in basic medium. Compound 2, was then further reacted with hydrazine hydrate to form acid hydrazide, which is 2-(4-amino-3-substituted-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetohydrazide (3). Compound 3 was later treated with three different diverse coumarin aldehydes (6, 12, 18) resulted in the formation of arylidene hydrazides as cis–trans conformers (7, 8, 13, 14, 19, 20). In conclusion, we synthesized 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-1,2,4-triazole-5-on and formylhydroxy-4-methylcoumarin derivatives, which have been characterized by, spectroscopic measurements (IR, 1H-NMR, 13C-NMR and elemental analysis).
Binary heterocyclic systems containing the ethylideneamino linkage: synthesis of some new heterocyclic compounds bearing the naphtho-[2,1-b]furan moiety