Clean synthesis of 1,8-dioxo-octahydroxanthene derivatives catalyzed by p-dodecylbenezenesulfonic acid in aqueous media

An efficient and convenient approach to the synthesis of 3,3,6,6-tetramethyl-9-aryl-1,8-dioxo-octahydroxanthene derivatives using p-dodecylbenezenesulfonic acid (DBSA) as the catalyst (10 mol%) is described. This method provides several advantages such as being environmentally friendly, processing high yields and simple work-up procedure. In addition, water was chosen as a green solvent.