Silica‐bonded S‐sulfonic acid as recyclable catalyst for the synthesis of 1,8‐dioxo‐decahydroacridines and 1,8‐dioxo‐octahydroxanthenes

Abstract magnified image Silica‐bonded S ‐sulfonic acid (SBSSA) has been found to be an efficient catalyst for the synthesis of 1,8‐dioxo‐decahydroacridines and 1,8‐dioxo‐octahydroxanthenes in excellent yields. The former have been synthesized from aromatic aldehydes, amines, and 5,5‐dimethyl‐1,3‐cyclohexanedione, whereas the latter from this mixture without amines. The method is an easy access to functionalized acridine and xanthene derivatives. The catalyst can be reused. J. Heterocyclic Chem., (2010).