Triterpenes of Lantana tiliaefolia. 24-Hydroxy-3-oxours-12-en-28-oic acid, a new triterpene

Abstract

The known triterpenes ursonic acid, oleanonic acid, ursolic acid, oleanolic acid and 24-hydroxy-3-oxoolean-12-en-28-oic acid occur in Lantana tiliaefolia Cham., together with a new triterpene,24-hydroxy-3-oxours-12-en-28-oic acid. A detailed 13C n.m.r. study has been made of a number of olean-12-enes and urs-12-enes, and the 1H n.m.r. signals from the secondary methyl groups in urs-12-enes have been investigated. N.m.r. evidence shows significant conformational differences in ring A between a number of 3-oxo derivatives that differ in their ring A substituents. Methyl ursonate and methyl oleanonate have been separated on columns of Spherosorb A5Y alumina.