Antitumor Activity of Some Prenylated Xanthones.

Pyranoxanthones 6-8 were obtained by dehydrogenation of the respective dihydropyranoxanthones 3-5 with DDQ in dry dioxane. Two prenylated xanthones 10,11 were obtained from the reaction of 1-hydroxyxanthone (9) with prenyl bromide in alkaline medium, or by condensation of xanthone 9 with isoprene in the presence of orthophosphoric acid. The structural elucidation of the two new compounds 6,11, as well as an update of data for the already described prenylated derivatives 7,8,10 were accomplished by IR, UV, HRMS and NMR (¹H, C, HSQC and HMBC) techniques.

1-Hydr-oxy-3-(3-methyl-but-2-en-yloxy)xanthone.

In the title compound, C(18)H(16)O(4), a monoprenylated xanthone, the xanthone skeleton exhibits an essentially planar conformation (r.m.s.

Dihydroxyxanthones prenylated derivatives: synthesis, structure elucidation, and growth inhibitory activity on human tumor cell lines with improvement of selectivity for MCF-7.

The synthesis, structure elucidation, and antitumor activity of 11 xanthones are reported, being the compounds 3, 4, 6-8, and 9 described for the first time. Xanthones 1 and 2 were used as building blocks to obtain the prenylated derivatives 3-8. Prenylation was carried out using prenyl bromide in alkaline medium.