The structure of 2-oxo-8α-angeloyloxy-11α-acetoxy-5βH,6αH,7αH-guai-1(10),3-dien-6,12-olide, a sesquiterpenic lactone from Laserpitium prutenicum L. revision of the stereostructures of native 2-oxoguai-1(10),3-dien-6,12-olides from the species of the Umbelliferae family

Abstract

On the basis of an analysis of its NMR spectra and X-ray analysis the stereostructure of the so-called 4-acetoxypruteninone-(10) (laferin) has been corrected to that of formula I. The stereostructures of almost all so far described native 2-oxoguai-1(10),3-dien-6,12-olides isolated from the species of Umbelliferae have been corrected on the basis of 1H NMR parameters.