Microwave induced, solvent-free Knoevenagel condensation of 4-oxo-(4H)-1-benzopyran -3 -carbaldehyde with Meldrum's acid using alumina support

A rapid, solvent-free and environmentally friendly Knoevenagel condensation reaction of 4-oxo-(4H)-1-bcnzopyran-3-carbaldehyde 1 with Meldrum's acid 2 has been carried out under microwave irradiation. The structures of condensed products 3a-g have been characterized on the basis of IR and 1 H NMR spectral data.