Synthesis and antimicrobial study of new tetrazole, benzimidazole and N3-functionalized quinazolinone derivatives

Reactions of 4H-3,1-benzoxazin-4-one 3 with various nitrogen nucleophiles; sodium azide, hydroxylamine hydrochloride, ammonium acetate, and formamide afforded new N-heterocyclic compounds 4-7. The synthesized quinazolinone derivative 7 was used as a useful building block for further synthesis of new series of N3-functionalized quinazolinone compounds 8-12. The chemical structures of all synthesized heterocyclic compounds were deduced from their spectroscopic analyses. The antimicrobial activity of the new compounds was evaluated against several pathogenic microorganisms, and most of them showed remarkable activity comparable to the antibacterial Ciprofloxacin and antifungal Clotrimazole