Studies on terpenoids and steroids. Part 3. Structure and synthesis of a new phenolic D:A-friedo-24-noroleanane triterpenoid, zeylasterone, from kokoona zeylanica

Abstract

Zeylasterone, the first of a novel series of natural phenolic nortriterpenes from Kokoona zeylanica(Celastraceae) and ‘ kokum soap ’ has been shown to be 29-methyl hydrogen 2,3-dihydroxy-6-oxo-D:A-friedo-24-noroleana-1,3,5(10),7-tetraene-23,29-dioate (3) on the basis of spectroscopic and chemical evidence. Trimethylzeylasterone (8) has been synthesized from pristimerin, a quinone methide present in K. zeylanica and ‘ kokum soap ’. The biosynthetic importance of some triterpenoids of K. zeylanica is discussed.