Solvent free one-pot multi-component synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by mesoporous NH4H2PO4/MCM-41 as an environmentally friendly, cheap, and effective catalyst

A green and efficient method is described for the solvent free synthesis of 3,4-dihydropyrimidin-2(1H)-ones through one-pot three-component condensation of ethyl acetoacetate, an aryl aldehyde, and urea using mesoporous MCM-41 supported ammonium dihydrogen phosphate (NH4H2PO4/MCM-41) as catalyst. The present methodology offers several advantages such as high yields, relatively short reaction times, mild reaction condition, easy work up, and using a highly recyclable catalyst. Some mechanistic studies revealed that the reaction would be achieved via formation of an acyliminium ion, followed by an acid-catalyzed cyclodehydration step.