Oxidation of xanthenes with manganese (II1) acetate in the presence of active methylene compounds such as 1, 3-dicarbonyl compounds, malononitrile derivatives, acetone, and nitromethane selectively gives 9-substituted xanthene derivatives in good yields. A similar oxidation of thioxanthene also yields 2-(9-thioxanthenyl)-1, 3-dicarbonyl compounds in 57- 91% yields. The obtained 2-(9-xanthenyl)-l, 3-dicarbonyl compounds are readily ...