Titanium dioxide supported on MWCNTs as an eco-friendly catalyst in the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones accelerated under microwave irradiation

Abstract

Some transition metal oxides supported on MWCNTs were prepared as novel heterogeneous catalysts using the facile processes. Then, the catalytic behaviour of transition metal oxide–MWCNT nanocomposites was investigated in the Biginelli one-pot cyclocondensation of aldehydes, β-dicarbonyl compounds and urea (thiourea) in solvent-free media under microwave irradiation as the energy source. The experimental results showed that TiO₂–MWCNTs were the most efficient nanocatalyst for the Biginelli reaction among the studied transition metal oxide–MWCNTs. This study provides new insights to develop this three components methodology using microwave-assisted dry media technology. The current catalytic process is an environmentally friendly, sustainable and economically acceptable synthetic tool because it operates under solvent-free conditions with high chemical efficiency, easy work-up procedures and feasible reusability of the nanocomposites.