Synthesis and Antimicrobial Activity of 2-Aryl-4H-3,1-benzoxazin-4-ones

Twenty derivatives of 2-aryl-4H-3,1-benzoxazin-4-one synthesized and their potential therapeutically significance tested against two strains of Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and four strains of Gram negative bacteria (Shigella flexnari, Escherichia coli, Salmonella typhi and Pseudomonas aeruginsoa) by agar well diffusion method. The 2-(3-nitrophenyl)-4H-3,1-benzoxazin-4-one (3f) recorded significant antibacterial activity against Bacillus subtilis whereas 2-(4-bromophenyl)-4H-3,1-benzoxazin-one (3o) exhibited weak antibacterial activity against Staphylococcus aureus. Further 2-(2-methylphenyl)-4H-3,1-benzoxazin-4-one (3b) showed significant activity against Shigella Flexnari, Escherichia coli, Pseudomonas aeruginsoa and Salmonella typhi. The antibacterial activity of synthesized derivatives of 2-aryl-4H-3,1-benzoxazin-4-one was compared to reference standard antibiotics amoxycillin, streptomycin, kanamycin and ciprofloxacin. The present study revealed that 2-aryl-4H-3,1-benzoxazin-4-ones possess good bactericidal activity against a panel of bacteria causing common bacterial diseases and therefore opens the possibility of finding latest clinically useful antibacterial compounds. The synthesized compounds were characterized by H-1 NMR, EI, FT-IR and elemental analysis.