Task specific dicationic acidic ionic liquids catalyzed efficient and rapid synthesis of benzoxanthenones derivatives

A rapid and straightforward approach to the synthesis of dibenzo[a,j]xanthenes and 1,8-dioxo-octahydroxanthenes using task specific dicationic acidic ionic liquids as a highly efficient and readily available catalyst under solvent-free condition have been developed. A series of Brønsted-Lewis acidic ionic liquid were prepared and investigated their catalytic activity for synthesis of various xanthenes derivatives from aldehydes and 2-naphthol or dimedone. The ease of the product separation without organic solvent and column chromatography and reusability of acidic ionic liquid catalyst makes this method economically affordable for large-scale synthesis.