Multi component reactions (MCRs) have been exploited for the synthesis of Xanthene derivatives using various catalysts under different reaction conditions such as Silica sulfuric acid (SSA) or Amberlyst-15 as an efficient and reusable heterogeneous catalyst has been used for the preparation of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one derivatives from the threecomponent condensation reaction of b-naphthol, cyclic 1,3 dicarbonyl compounds and aromatic aldehydes under solvent-free conditions in good to excellent yields and short reaction times. Microwave Promoted Perchloric Acid catalyzed One Pot Synthesis of 14-aryl –14H - dibenzo[a,j] xanthene and 12-aryl-8, 9, 10, 12-tetrahydrobenzo[a]-xanthen-11-one derivatives by condensation of various substituted benzaldehydes , β-naphthol and dimedone under solvent free conditions. Similarly condensation of β-naphthol, aromatic aldehydes and cyclic 1,3- dicarbonyl compounds in presence of Chlorosulphonic acid (ClSO3H) as a catalyst to furnish 12-Aryl -8,9,10,12-tetrahydrobenzo [a]xanthen-11-ones derivatives in good to excellent yields under ultrasound and solvent free conditions at ambient temperature . All these methodologies are efficient and environmentally benign and can be developed further for industrial application.
