128SYNTHESIS, CHARACTERISATION AND BIOLOGICAL EVALUATION OF 1-BENZOYL-6- HYDROXY-3,4 DIHYDRO QUINAZOLINE DERIVATIVESA simple and general method has been developed for the synthesis of various 3,4-dihydro quinazolinone derivatives by the treatment of an aldehydes with excess equivalent of urea in ethanol affords Arylideno-bis-ureas 1 which on condensation with p-amino benzoic acid in acidic medium cyclised to 4-aryl-6-hydroxy-2-oxo-3,4-dihydroquinazolines 2. Reaction of 2 with benzoylchloride in 10% NaOH results in 1-benzoyl 4-aryl-6-hydroxy-2-oxo-3,4-dihydroquinazolin-2(H)-one 3. The structures of the compounds were characterized by elemental analysis, IR, 1H-NMR and 13C-NMR spectra. Compounds 3 have been evaluated for their antimicrobial activity.asg_subha@yahoo.comResearch342012Quinazoline,Aldehydes,Antimicrobial activityA. Suba Geetha,B. Vijayakumar,S. Selvakumar,K. Sheeja Devi,S. Narendiran,M. NishanthiDepartment of Pharmaceutical Chemistry, RVS College of Pharmaceutical sciences, Sulur, Coimbatore, Tamilnadu, India.,Department of Pharmaceutical Chemistry, Sri Venkateswara College of Pharmacy, R.V.S Nagar, Chittoor-517127, Andhra Pradesh, India,Department of Pharmaceutical Chemistry, Sir C.R. Reddy College of Pharmaceutical Sciences, Westgothawari (Dist), Eluru, Andhra Pradesh, India,Department of Pharmaceutical Chemistry, Jagan’s College of Pharmacy, Nellore, Andhra Pradesh, India,Department of Pharmaceutical Chemistry, Swami Vivekananda Institute of Pharmaceutical Sciences, Vangapally-508286, Andhra Pradesh, India.,Department of Pharmacognosy, Sri Venkateswara College of Pharmacy, R.V.S Nagar, Chittoor-517127, Andhra Pradesh, India.