Synthesis and biological activity of mono- and diamides of 2,3-secotriterpene acids

Amides of four types were synthesized derived from 2,3-seco-18αH-oleanane and 2,3-secolupane mono- and dicarboxylic acids. The spectrum of diamide derivatives was expanded with C3-C3′ and C28-C28′ biscondensed amides with two A-secotriterpene backbones obtained by the interaction of monocarboxylic A-seco acids with lysine. Among the synthesized monoand diamide derivatives, potential inhibitors of herpes simplex virus type 1 replication were found, namely, some compounds with an ethyl β-alaninate fragment (EC 50 8.7 and 4.1 μM). The ethyl β-alaninate diamide was shown to combine antiherpetic and anti-HIV activity (EC 50 5.1 μM). For the active compounds, the ratios of maximum tolerable concentrations to EC 50 ranged from 9.7 to 40.8. The synthesized amides did not show any marked cytotoxic effects against human rabdomiosarcoma RD TE32, A549 lung carcinoma, and melanoma MS cell lines.