A highly efficient and improved synthetic methodology for the preparation of 3,4-dihydropyrimidin-2(1H)-one derivatives in good to excellent yield via Biginelli reaction of β-ketoesters/β-diketone, urea/thiourea and various aldehydes using new, efficient and recyclable sulfated polyborate catalyst under the solvent-free condition is reported.
One-pot Reductive Amination of Carbonyl Compounds with NaBH 4 -B(OSO 3 H) 3 /SiO 2 in Acetonitrile and in Solvent-free Condition