Titanium tetrachloride incorporated crosslinked polystyrene copolymer as an efficient and recyclable polymeric Lewis acid catalyst for the synthesis of Β-amino carbonyl compounds at room temperature

Abstract

An efficient and eco-friendly procedure for one-pot synthesis of β-amino carbonyl compounds by three-component reaction of aromatic aldehydes, acetophenone, and aromatic amines via a Mannich type reaction using a stable tightly bound complex, titanium tetrachloride incorporated crosslinked polystyrene copolymer (PS/TiCl4), as a water tolerant, recoverable, and reusable polymeric Lewis acid catalyst in ethanol at room temperature is reported. The complex of the polystyrene and TiCl4 provides a shelf-stable acidic, water tolerant material, and it is not easily hydrolyzed by water. Our findings thus show a novel and improved modification of the Mannich type reaction in terms of mild reaction conditions, clean reaction profiles, applicability to various substrates using a simple workup procedure which makes this reaction an interesting alternative to previously applied procedures. The recyclability of the catalyst makes this protocol environmentally benign.