Silica Supported Perchloric Acid: An Efficient Catalyst for the Synthesis of 14-Aryl-14H-dibenzo[a,i]xanthene-8,13-diones

The condensation of beta-naphthol with aromatic aldehydes and 2-hydroxynaphthalene-1,4-dione in presence of silica supported perchloric acid under solvent-free media to afford the corresponding 14-aryl-14H-dibenzo[a,i]xanthene-8,13-diones in excellent yields and short reaction times is described. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused several times in subsequent reactions.