A triterpene from Rubus pinfaensis.

A new pentacyclic triterpene, pinfaensin, was isolated from the roots of Rubus pinfaensis and the structure elucidated by 13C NMR methods. This triterpene, a glycoside of pinfaensic acid (glucosyl 23-formyl-2 alpha,3 beta,19 alpha-trihydroxyurs-12-en-28-oate), in order to achieve purification and characterization, was hydrolysed to previously unreported pinfaensic acid which on acetylation and methylation gave methyl diacetoxypinfaensate (methyl 2 alpha,3 beta-diacetoxy-23-formyl-19 alpha-hydroxyurs-12-en-28-oate).