SYNTHESES OF XANTHONE DERIVATIVES

In the present paper, fourteen derivatives (Ⅱ～Ⅴ, Ⅷ, Ⅸ) of 1,3-dihydroxyxanthone have been synthesized. Compound Ⅱ was obtained by condensation of 1,3-dihydroxyxanthone with the corresponding halides in the presence of base Compounds Ⅲ and Ⅳ were prepared by treating 1,3-dihydroxyxanthone with epichlorohydrin in the presence of piperidine. Amination of Ⅳ gave compound Ⅴ. Passive cutaneous anaphylaxis (PCA) assay in rats showed that compound Ⅱ_c gave 63% protective effect (5 mg/kg iv). In order to facilitate the introduction of electron-withdrawing substituents, unsuccessful attempts have been made to remove the ketonic group of Ⅰ andⅧ_b by zinc amalgam-HCl reduction or of Ⅸ. by Huang Min lon reaction, the latter suffering demethylation under drastic alkaline conditions.