title: [Syntheses of nitrogen-containing triterpenes. I. Derivatives of ursolic acid and oleanolic acid].
mesh_terms: D002264:Carboxylic Acids / Q000138:chemical synthesis; D009584:Nitrogen; D013729:Terpenes / Q000138:chemical synthesis*
chemical_list: D002264:Carboxylic Acids; D013729:Terpenes; D009584:Nitrogen