Sulfamic acid as a reusable and green catalyst for efficient and simple synthesis of 2-substituted-2

A series of 2,3-dihydroquinazolin-4(1H)-ones have been synthesized in good to excellent yields through direct cyclocondensa-tion of anthranilamide and aryl aldehydes or ketones in water or methanol under mild conditions. The reaction was efficiently promoted by 10 mol% sulfamic acid (SA, H2NSO3H) and the catalyst could be recovered easily after the reactions and reused without evident loss of reactivity.