A novel method for the one-pot three-component synthesis of 2,3-dihydroquinazolin-4(1H)-ones

One-pot three-component condensation of isatoic anhydride with primary amines or ammonium carbonate and aromatic aldehydes in refluxing ethanol in the presence of catalytic amounts of silica sulfuric acid afforded the corresponding 2.3-dihydroquinazolin-4(1H)-ones in high yields. The catalyst is reusable and can be applied several times without any decrease in product yield.