Constituents of Dipterocarpaceae Resins. IV. Triterpenes of Shorea acuminata and S. resina-nigra

Abstract

Application of N.M.R. methyl resonance data led to revision of the structures given to the two cis 2,3-diols resulting from osmium tetroxide oxidation of methyl oleana-2,12-dien-28-oate (10). 2α,3α-Dihydroxyolean-l2-en-28-oic acid (6a), a new natural product, occurs in Shorea acuminata resin. Other constituents are 2α-hydroxy-ursolic acid (14a), mangiferonic acid (15b), and asiatic acid (14c). S. resina-nigra contains β-amyrin (16a), ursolaldehyde (14f), and Ψ-taraxesterol(17a).