Acetic acid as an efficient catalyst for synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines

1,8-Dioxo-octahydroxanthenes have been synthesized in good yields by reaction of arylaldehydes and dimedone in the presence of a catalytic amount of acetic acid, without use of any additional co-catalyst, under solvent-free, thermal conditions. We also report preparation of 1,8-dioxo-decahydroacridines by reaction of arylaldehydes, dimedone, and amines or ammonium acetate under solvent-free, thermal conditions in the presence of the same catalyst.