Synthesis of xanthone derivates for in vitro and in vivo biological activity studies

Synthesis of xanthone derivatives for in vitro and in vivo biological activity studies J. Siroka Xanthone derivatives are heterocyclic compounds with the dibenzo-γ-pyrone as the main molecular moiety. They contain different types of substituents in different positions, leading to a large variety of pharmacological activities. 3,4-Dihydroxyxanthone was revealed as a hit compound in a study involving the investigation of the inhibitory effect of oxygenated xanthones on several human tumor cell lines. In order to obtain enough quantity for in vivo assays and for further molecular modifications, the synthesis of 3,4-dihydroxyxanthone was accomplished: the condensation of 1,2,3-trimethoxyphenol with the appropriate substituted benzoyl chloride (2-methoxybenzoyl chloride) afforded benzophenone (2-hydroxy-2',3,4- trimethoxy benzophenone) which was further cyclized to give 3,4-dimethoxyxanthone. The 3,4-dimethoxyxanthone was demethylated to furnish 3,4- dihydroxyxanthone. Additionally, the synthesis of reactive formylated derivatives of xanthones, 1- formyl-3,4-dihydroxyxanthone and 1-formyl- 3,4-dimethoxyxanthone, was attempted by Duff formylation. Only 1-formyl-3,4- dihydroxyxanthone was obtained. Due to a small amount of 3,4-dihydroxyxanthone obtained from the first synthesis, the synthesis was repeated..