A wide variety of 2,3-dihydroquinazolin-4(1H)-ones has been prepared via one-pot three-component condensation of isatoic anhydride, aldehydes and primary amines or ammonium acetate in the presence of a catalytic amounts of l-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate (supported on silica gel), as green, non-toxic and reusable catalyst, in water at 80 A degrees C.
