Unusual sesquiterpene lactones from Ligularia virgaurea spp. oligocephala.

Organic letters

PubMedID: 15228267

Wu QX, Shi YP, Yang L. Unusual sesquiterpene lactones from Ligularia virgaurea spp. oligocephala. Org Lett. 2004;6(14):2313-6.
[structure: see text] [structure: see text] Sesquiterpene lactones, ligulolide A (1) and 6beta,8alpha-dihydroxy-1-oxoeremophila-7(11),9(10)-diene-12,8-olide (2), were isolated from Ligularia virgaurea spp. oligocephala. Their structures were established by analysis of one- and two-dimensional NMR data. The relative stereostructures were determined on the basis of NOESY and single-crystal X-ray experiments. 1 represents a novel sesquiterpene carbon framework, and a possible biosynthetic process is proposed. 2 is a novel eremophilane-type sesquiterpene.