Synthesis and characterisation of new sulfonamide chalcones containing an azo group

The synthesis and characterisation of a new type of chalcone bearing a -N=N- bond is reported using an environmentally benign approach. The synthesis consists of two steps. (E)-4-((5-acetyl-2-hydroxyphenyl)diazenyl) benzenesulfonamide was synthesised by an easy structural modification of sulfanilamide. The key step then involved the solvent-free Claisen-Schmidt condensation of benzaldehydes to form the chalcones. The structures of all compounds were confirmed by FTIR, NMR and MS spectroscopy.