Task-specific ionic liquid catalyzed efficient microwave-assisted synthesis of 12-alkyl or aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones under solvent-free conditions

Abstract

The green, mild, and efficient synthesis of 12-alkyl or aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones has been achieved by a three-component coupling of 2-naphthol, aldehydes, and cyclic1,3-dicarbonyl compounds in the presence of a sulfonic acid functionalized ionic liquid without any solvent under microwave irradiation. The catalyst can be reused at least eight times without any noticeable decrease in catalytic activity. © 2011 Taylor & Francis.