Design, synthesis and biological evaluation of Schiff bases of 4-amino-1,2,4-triazole derivatives as potent angiotensin converting enzyme inhibitors and antioxidant activities

This work reports a novel and highly efficient methodology for the synthesis of Schiff bases of 4-amino-1,2,4-triazole derivatives (3a-h) by the condensation of 4-amino-5-methyl-3-oxo-2-tosyl-1,2,4-triazol-3-one (2) derivative with various aromatic aldehydes under ultrasound irradiation. The major advantages of the reported method are its operational simplicity, extremely mild reaction conditions, short reaction times, and excellent yields. The structures of the synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analysis, and the X-ray crystallography (for compound 3f).