Phosphate impregnated titania: an efficient reusable heterogeneous catalyst for aza-michael reactions under solvent-free condition

Abstract

The aza-Michael reactions of amines with α,β-unsaturated compounds have efficiently been carried out using phosphate impregnated titania containing 84.5% of TiO₂ and 15.5% of [Ti₄H₁₁(PO₄)₉].nH₂O (n = 1-4) as a heterogeneous catalyst. Solvent-free condition, recyclability of the catalyst, very good yield and scaling up of the reactions are important attributes in this catalysis. Aromatic amines do not participate effectively in the reaction.