6β,8β-Dihy-droxy-eremophil-7(11)-en-8α,12-olide.
The title compound, C(15)H(22)O(4), an eremophilane sesquiternoid, was isolated from the roots of Ligularia virgaurea. Both six-membered rings (A and B) adopt chair conformations and the five-membered ring is almost planar (r.m.s. deviation = 0.016 Å). The two methyl and two hy-droxy groups adopt a syn conformation and the A/B ring junction is cis-fused. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into [100] chains.
School of Pharmacy, Lanzhou University, Lanzhou 730000,  People's Republic of China.
Zhan-Xin
ZX
Zhang
Dong-Qing
DQ
Fei