Synthesis of Xanthones and Benzophenones as Inhibitors of Tumor Cell Growth

The synthesis of two new sulfated xanthones and two O-substituted benzophenones was carried out to evaluate for their inhibitory effect on growth of human tumor cell lines. The sulfation of 3,6-(2) and 3,4-dihydroxyxanthone (3) was accomplished using sulfur trioxide-pyridine to give, respectively, xanthone-3,6-O,O-bis(sulfate) (4) and xanthone- 3,4-O,O-bis(sulfate) (5). Treatment of 2,2',4,4'-tetrahydroxybenzophenone (6) with acetic acid and prenyl bromide furnished 2,2',4,4'- tetraacetoxybenzophenone (7) and (5-hydroxy-2,2-dimethylchroman-6-yl)(2'-hydroxy-4'-(tertpentyloxy) phenyl)methanone (8), respectively. Compounds 2-8 were tested for their effect on the in vitro growth of four representative human tumor cell lines: MCF-7 ER(+) (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), SF-268 (glioma), and A375-C5 (melanoma). Compounds 2 and 7-8 showed an inhibitory activity in the μM range.`