An efficient and novel synthesis of chromonyl chalcones using recyclable Zn(l-proline)2 catalyst in water

A novel approach was adopted for the synthesis of a series of chromonyl chalcones (3a-o) from 3-formylchromones (1a-c) and different cyclic active methyl compounds (2a-e), employing Zn(l-proline)₂ as a recyclable Lewis acid catalyst in water. In each conversion, the catalyst was successfully recovered and reused several times without significant loss in yield and selectivity. All the newly synthesized compounds were characterized using elemental analysis and spectral data (IR, ¹H NMR, ¹³C NMR and mass spectrometry).