A new eudesmenolide and 2-hydroxycostic acid from Sphaeranthus indicus linn. X-Ray molecular structure of 4α,5α-epoxy-7α-hydroxyeudesmanolide

Abstract

A new sesquiterpene lactone, 7α-hydroxyeudesm-4-en-6,12-olide (1), and a new sesquiterpene acid, 2-hydroxycostic acid (2), along with the known compounds β-eudesmol (3) and ilicic acid (4) have been isolated from the acetone extract of Sphaeranthus indicus L. The structure and relative stereochemistry of compound (1) has been established by a combination of chemical and spectral data including the X-ray crystallographic studies of its derivative (9). The structure of compound (2) has been deduced mainly by spectral studies.