Nano isopolyoxomolybdate catalyzed Biginelli reaction for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and 3,4-dihydropyrimidin-2(1H)-thiones under solvent-free conditions

Abstract

The Biginelli reaction of β-ketoesters with aryl aldehyde and urea or thiourea in the presence of a Keplerate type giant nanoporous isopolyoxomolybdate, (NH₄)₄₂[Mo₇₂^VIMo₆₀^VO₃₇₂(CH₃COO)₃₀(H₂O)₇₂], presented as {Mo₁₃₂}, as an efficient catalyst under solvent free conditions is reported. The catalyst was synthesized according to the earlier published procedure using inexpensive and readily available starting materials. The catalyst could be recovered and reused efficiently in six cycles. Other beneficial features of this new synthetic approach include short reaction time, high yields, clean reaction profiles, and a simple work-up procedure.