Efficient preparation of 9-aryl-1,8-dioxo-octahydroxanthenes catalyzed by nano-TiO2 with high recyclability

9-Aryl-1,8-dioxo-octahydroxanthene derivatives are synthesized by the reaction of arylaldehydes with dimedone (5,5-dimethyl-1,3- cyclohexanedione) in the presence of nano-TiO2 as an efficient and heterogeneous catalyst under solvent-free conditions. Simple methodology, easy workup procedure, clean reaction, short reaction time, reusability of the catalyst up to 12 times and high yields are some advantages of this work.