Structural characterization and dynamic NMR studies of a new peracylated macrocyclic diterpene

Abstract

A heptaester of a new diterpene alcohol was isolated from the dichloromethane extract of the whole plant of Euphorbia esula L. A detailed NMR and mass spectral analysis revealed that its structure is (E)-(2R*, 3R*, 4S*, 5R*, 7S*, 8R*, 9S*, 13R*, 15R*)-2,3,5,8,9-pentaacetoxy-7-isobutanoyloxy-14-oxojatropha-6(17),11-diene. Its conformation was studied in three different solutions. The temperature dependence of the spectral parameters revealed conformational changes through internal rotation of the macrocycle part of the molecule. Copyright © 1999 John Wiley & Sons, Ltd.