A practical and green method for the synthesis of 5H-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3′-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (CSA) under solvent-free conditions at 100 °C is described. The significant features of this procedure are high yields of the products, simple […]
Functionalized indeno[1,2-b]chromene derivatives have been synthesized via condensation reaction of 1H-indene-1,3(2H)-dione with benzaldehyde and cyclization with 2-hydroxynaphthalene-1,4-dione in the presence of a catalytic amount of triethylamine (Et3N) in EtOH at room temperature. It was observed that benzaldehyde bearing electron donating group gave high yield of product, whereas, benzaldehyde having electronic withdrawing substituent does not participate […]
