Brusatol.
The title compound, C(26)H(32)O(11), is composed of an α,β-unsaturated cyclo-hexa-none ring (A), two cyclo-hexane rings (B and C), a six-membered lactone ring (D) and tetra-hydro-furan ring (E). Ring A exists in a half-chair conformation with a C atom displaced by 0.679 (2) Å from the mean plane through the remaining five atoms. Ring B exists in a normal chair conformation. Both rings C and D exist in a twisted-chair conformation due to the O-atom bridge and the carbonyl group in rings C and D, respectively. Ring E shows an envelope conformation with a C atom displaced by 0.761 (1) Å from the mean plane through the remaining five atoms. The ring junctions are A/B trans, B/C trans, C/D cis and D/E cis. An intra-molecular O-H⋯O hydrogen bond occurs. In the crystal, O-H⋯O hydrogen bonds involving the hy-droxy, lactone and ester groups and C-H⋯O inter-actions are observed.
Guangdong Province Key Laboratory of Pharmacodynamic Constituents of, Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632,  People's Republic of China.
Shu-Zhi
SZ
Hu
Lu
L
Jin
Tong
T
Yu
Hai-Yan
HY
Tian
Ren-Wang
RW
Jiang