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.

nano-sbcl5.sio2 and sbcl5.sio2 are bench-top catalysts which are reusable, readily available, versatile andefficient for promotion of many acid catalyzed organic reactions. these catalysts do not need specialprecautions for preparation, handling or storage, and they can be stored at an ambient temperature for monthswithout losing their catalytic activity. 4-dihydropyrimidin-2(1h)-ones(thiones) ...

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.

cuo-ceo2 nanocomposite is reported as a green and highly efficient recyclable catalyst for the multicomponent  synthesis of 3,4-dihydropyrimidin-2(1h)-ones/thiones under solvent-free conditions. the catalyst was synthesized by co-precipitation method and characterized by xrd, bet specific surface area, fesem and eds analysis.

in this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1h)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using al-mcm-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. the advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions.