Silica sulfuric acid-catalyzed Claisen-Schmidt condensation of 1,3,4 trisubstituted pyrrole 2,5 dione to chalcones

A series of 11 chalcones was synthesized from 1-(4-acetylphenyl)-3,4-dibromo-1H-pyrrole-2,5-dione with various substituted benzaldehyde under solvent-free conditions using silica-sulphuric acid as a catalyst. The yields of chalcones are more than 90 %. All the compounds were characterized by physical, spectroscopic, and elemental analysis.