Abstract An application of ultrasonic irradiation in the one-pot synthesis of N-acetyl-2-aryl-1, 2-dihydro-(4H)-3, 1-benzoxazin-4-ones from the condensation reaction between aromatic aldehydes and anthranilic acid in the presence of excess amount of acetic anhydride has been explored. The reactions proceed smoothly under mild and solvent-free conditions at room temperature in the absence of any catalyst to afford the products in good to excellent ...