Synthesis of Triterpene A-Condensed Azoles

Lupane and 18αH-oleanane α-hydroximino ketones were used to synthesize derivatives condensed at ring A with a substituted azole fragment, namely, C(2)–C(3)-fused oxazoles and 1,2,3-triazoles. Triterpene isoxazoles fused at the C(1)–C(2) bond are described for the first time. An optimized method was proposed for the synthesis of unsubstituted 1,2,3-triazoles, displaying cytotoxic activity (IC50 8.4-40.7 μM) relative to rhabdomyosarcoma, lung carcinoma, and MS melanoma cell lines.