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 (EC₅₀ 8.7 and 4.1 μM). The ethyl β-alaninate diamide was shown to combine antiherpetic and anti-HIV activity (EC₅₀ 5.1 μM). For the active compounds, the ratios of maximum tolerable concentrations to EC₅₀ 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.