Abstract A simple, efficient and convenient one-pot synthesis of 2, 3-dihydroquinazolin-4 (1H)-one derivatives under solvent-free and catalyst-free conditions by the reaction of aromatic aldehydes, isatoic anhydride, and ammonium acetate was reported. The advantages of this protocol include short reaction time, mild reaction conditions, easy work- up, high yields, and environmental friendliness. J. Heterocyclic Chem.,(2011).