Two oleanane triterpenoids from gordonia ceylanica and their conversions to taraxarane triterpenoids.

Chemical investigation of the hot hexane extract of the stem bark of Gordonia ceylanica afforded two new oleanane triterpenoids, 3beta-acetoxy-11alpha, 13beta-dihydroxyolean-12-one and 3beta,11alpha-diacetoxy-13beta-hydroxyolean-12-one (2) The attempted acid hydrolysis of these two compounds resulted the dehydration and subsequent methyl group migration to afford the taraxarane triterpenoids 3beta,11alpha-dihydroxytaraxer-14-en-12-one (4) and 3beta-hydroxy-11alpha-acetoxytaraxer-14-en-12-one (5), respectively. These taraxaranes have not been previously reported.