Titanium tetrachloride immobilized on cross-linked poly(N-vinyl-2-pyrrolidone) as a recyclable heterogeneous catalyst for one-pot three component synthesis of 3, 4-dihydropyrimidin-2(1H)-ones/thiones

Abstract

A new catalytic application of titanium tetrachloride immobilized on the cross-linked poly(N-vinyl-2-pyrrolidone) carrier as beads, TiCl4/PNVP, as a recoverable and heterogeneous macromolecular Lewis acidic catalyst is developed. This catalytic system allowed for the facile and cleaner synthesis of 3,4-dihydro pyrimidin-2(1H)-ones/thiones in high yields with TON up to 23.2 through the Biginelli three-component cyclocondensation reaction in ethanol. The reusability test ascertained that this heterogeneous titanium catalyst can be easily separated from the reaction mixture by simple filtration and reused several times with no great decline of activity.