Al2 (SO4)3.18H2O as an Efficient and Environmentally Benign Natural Catalyst for Facile and Solvent-free Synthesis of Xanthene Derivatives

An environmentally friendly, facile and solvent-free synthetic route for aluminum sulfate octadecahydrate (Al2(SO4)3.18H2O) catalyzed one-pot multi-component synthesis of 12-aryltetrahydrobenzo[ α]xanthene-11-ones, 1,8-dioxo-octahydroxanthenes and 14-aryl-14Hdibenzo[ α,j]xanthenes has been developed. The readily, easy to handle, non-toxic, environmental friendly and low-cost catalyst, easily separated with no column chromatographic separation, short reaction times and high to excellent yields is an option for the economical, mild and facile synthesis of these rings.