Nano-Fe3O4 encapsulated-silica particles bearing sulfonic acid groups as an efficient, eco-friendly and magnetically recoverable catalyst for synthesis of various xanthene derivatives under solvent-free conditions

This report describes an efficient method for the synthesis of 1,8-dioxo-octahydroxanthene, 14H-dibenzo[a,j]xanthene, 12-aryl-tetrahydrobenzo[a]xanthenes-11-one and 13-aryl-5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraone derivatives in the presence of a catalytic amount of nano-iron oxide encapsulated silica particles bearing sulfonic acid groups. Results present an efficient, environmentally friendly and magnetically recoverable catalyst under solvent-free conditions at 110-130 °C.