Synthesis of 12-epi-ent-polyalthenol an antitumour indole sesquiterpene alkaloid

The synthesis of 12-epi-ent-polyalthenol, 10, and its epimer at C-19, 11, from ent-halimic acid as starting material has been carried out. The structure of the natural product polyalthenol 1 is confirmed in this way. The synthesized indole sesquiterpenes 10 and 11 and their acetylderivatives 32 and 33 inhibited cellular proliferation of a number of human leukaemic and solid tumour cell lines.

12-Epi-ent-polyalthenol has been synthesized from ent-halimic acid. The indole sesquiterpenes synthesized inhibit proliferation of several human tumour cells, including leukemic and solid tumour cells, with an IC50 in the range of 25 μM.