An access to a library of novel triterpene derivatives with a promising pharmacological potential by Ugi and Passerini multicomponent reactions.

The promising combination of natural product leads and their derivatization by isocyanide-based multicomponent reactions (IMCRs) has gained interest in accessing diversity-oriented libraries with auspicious pharmacological potential. Therefore, a set of 34 Ugi and 3 Passerini products was successfully synthesized starting from naturally occurring triterpenoids, i.e. oleanolic acid (OA) and maslinic acid (MA), followed by a biological evaluation of the novel α-acylamino carboxamides and the α-acyloxy carboxamides in colorimetric SRB assays to determine their cytotoxic potential. Especially, the MA-Ugi products 6a, 6b and 7b showed a remarkable cytotoxicity for A2780 ovarian carcinoma cells in a low μM range. Compounds 6a and 7b induced programmed cell death in part through the apoptosis pathway.