Trinuclear cis–[MoVIO2] complexes catalyzed efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one based biomolecules via one-pot-three-components Biginelli reaction under solvent-free condition

Abstract

The tricompartmental ligands tris(H2ONO) [H6L1-3 (I–III)] having C3 symmetry, obtained from the condensation of benzene-1,3,5-tricarbohydrazide and 3-acetyl-2-hydroxy-6-methyl-4H-pyran-4-one (I), 3-acetyl-4-hydroxy-2H-chromene-2-one (II) and 3-hydroxy-5-(hydroxymethyl)-2-methylpyridine-4-carbaldehyde (III) react with [MoVIO2(acac)2] in refluxing methanol to give tris-{cis-[MoO2]2+} complexes [{MoVIO2(H2O)}3L1] (1), [{MoVIO2(H2O)3}L2] (2), and [{MoVIO2(H2O)3}L3] (3), respectively. These ligands and complexes were characterized by elemental analyses, FT-IR, UV/Vis, NMR (1H and 13C), thermal studies and DFT optimized structure for 1. These complexes show potential catalytic activity towards the one-pot three-components [alkyl acetoacetate, benzaldehyde (or its derivatives) and urea] synthesis of biologically active 3,4-dihydropyrimidine (DHMP) based molecules via Biginelli reaction under mild and solvent free conditions in the presence of H2O2, a green oxidant. Density functional theory computations were performed to provide a suitable reaction pathway for this catalytic reaction which was further supported by spectroscopic study.