TERPENOIDS: II. CEANOTHENIC ACID: A C29 A-NORLUPANE DERIVATIVE

Abstract

Extraction of Ceanothus americanus (Jersey Tea) has afforded a new pentacyclic triterpenoid of the empirical formula C29H42O4. It is a dicarboxylic acid containing two ethylenic linkages. The environment of one carboxyl group and one ethylenic linkage has been shown by diagnostic transformations characteristic of ring E of the lupeol–betulin series. The other ethylenic linkage has been shown to be present in a contracted ring A from which one carbon atom has been lost. The position of the second carboxyl group has been established by introduction of the 11-oxo-12-ene system, when monodecarboxylation occurred under mild conditions. This and other evidence establishes ceanothenic acid to be A-norlupa-1,22-diene-14,17-dicarboxylic acid.