Microwave-promoted facile and rapid solvent-free synthesis procedure for the efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones and -thiones using ZrO2/SO42- as a reusable heterogeneous catalyst

Sulfated zirconia (ZrO2/SO42-) solid superacid has been proved to be an efficient reusable heterogeneous catalyst for three-component one-pot cyclocondensation reaction of beta-dicarbonyl compounds and urea/thiourea with structurally diverse aromatic aldehydes in solvent-free conditions to furnish the corresponding 3,4-dihydropyrimidin-2(1H)-ones and -thiones in good to excellent yields both under microwave irradiation and thermal conditions.