A simple, efficient, and general method has been developed for the synthesis of various 3-alkylquinazolin-4-one derivatives from quinazolin-4-one treated with alkyl bromides under phase transfer catalysis condition. The structures of the compounds were characterized by elemental analysis, IR, (1)H-NMR and (13)C-NMR spectra. Title compound 6-bromo-3-propylquinazolin-4-one (3h) was found to possess good antifungal activity.