Synthesis of novel heterocyclic oleanolic acid derivatives with improved antiproliferative activity in solid tumor cells.

A series of new oleanane imidazole carbamates, N-acylimidazoles or N-alkylimidazoles were synthesized, characterized and evaluated for their antiproliferative activity in AsPC-1 pancreatic cancer cells. Structure-activity relationship analysis revealed that the N-alkylimidazole 27 was the most active compound with apoptosis induction abilities correlated with upregulation of NOXA and downregulation of Bcl-xL. The antiproliferative activity of compound 27 was further tested in more solid tumor cell lines with IC(50) values lower than 1 μM.