New Synthetic Analogs of Natural 5Z,9Z-Dienoic Acids—Hybrid Molecules Based on Oleanolic Acid: Synthesis and Study of Antitumor Activity

<b>Objectives</b>: A series of synthetic analogs of natural (5Z,9Z)-diene acids were synthesized for the first time in the form of hybrid molecules containing an oleanolic acid fragment. This fragment was simultaneously linked by an amide bond to various hetero- and carbocyclic amines and a complex ester bond to (5Z,9Z)-tetradeca-5,9-dienecarboxylic acid, which was synthesized by a new reaction of Ti-catalyzed homocyclomagnification of 1,2-dienes. <b>Results</b>: Among the synthesized hybrids, the highest cytotoxic activity was observed for compound <b>9a</b> in the series of Jurkat, K562, U937, and HEK293, with IC50 values of 4.5; 3.1; 2.8; and 26.17 μM/L, respectively. Furthermore, the synthesized compound <b>9a</b> has been observed to induce apoptosis and exhibit genotoxicity in Jurkat culture, which suggests that it may be a promising candidate for further investigation as an antitumor agent.