NANO-SILICA PHOSPHORIC ACID: AN EFFICIENT CATALYST FOR ONE-POT SYNTHESIS OF 3, 4-DIHYDROPYRIMIDIN-2 (1 H) -ONES (THIONES) UNDER SOLVENT-FREE OR SONICATION CONDITIONS

چکیده مقاله

Two simple protocols for the synthesis of three-component condensation reaction of an aldehyde, β-ketoester and urea or thiourea to obtain the 3, 4-dihydropyrimidin-2(1H)-ones (thiones) using nano silica phosphoric acid are reported. Short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.