Background: Oleanolic acid (OA) is a known natural compound with many important biological activities. Thirteen oleanolic acid derivatives linked at C-3 and C-28 were synthesized and their structures were confirmed by H-1- and C-13 NMR and mass spectral analyses. Among them, compounds 4, 6, 8-10, 12, 13 were synthesized for the first time. They were evaluated for their cytotoxic activity. They showed proliferative effect at low concentrations while cytotoxic effect was observed at high concentrations in a dose dependent manner.