SONOCHEMICAL SYNTHESIS OF SOME NOVEL 6-IMINOBENZOXAZOLINONES WITH POTENTIAL ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES

An environmentally benign protocol for the synthesis of a novel series of imine derivatives containing 2-oxo-3H-benzoxazole scaffold was successfully developed. Thus benzoxazolinone-6-carbaldehyde (3) was carried out by the formylation of 3-methyl-2-oxo-3H-benzoxazole (1) using hexamethylenetetramine (HMTA) in polyphosphoric acid (PPA). The designed compounds were prepared by the treatment of compound (3) with primary amines in the presence of methanol as solvent, by using ultrasonic-assisted method under catalyst-free conditions and conventional heat in methanol at reflux in presence of catalytic amount of acetic acid, to afforded the pure desired 6-imino-2-oxo-3H-benzoxazoles (4a-4f) in appreciable yields; their purity was confirmed by melting point as well as thin layer chromatography (TLC). The chemical structures of the new synthesized compounds were elucidated on the basis of the FT-IR, H-1 and C-13-NMR spectroscopic techniques.