Synthesis, characterization and biological activity of new 3(4H)-quinazolinone derivatives

Quinazolinylbenzoic acid 1 was used as a precursor for synthesis of many heterocyclic systems. Ethyl 4-[4-oxo-2-phenylquinazolin-3(4H)-yl]benzoate 2 upon reaction with hydrazine hydrate gave 4-[4-oxo-2-phenylquinazolin-3(4H)-yl]benzoate benzoylhydrazide 3. Compound 3 on treatment with 3-nitrobenzaldehyde, acetyl acetone, ethyl acetoacetate, and ammonium thiocyanate yielded compounds 4–8, respectively. Isothiocyanate 8 was used for the synthesis of other quinazoline derivatives 9–16 via the reactions with various reagents. All newly synthesized quinazolinone derivatives have been characterized by 1H NMR, IR, and mass spectroscopy. Most of the synthesized products were evaluated for their antibacterial and antifungal activities and some of those demonstrated high activity.