14,15-Didehydro-hellebrigenin.
The title compound, C(24)H(30)O(5), is the didehydro product of the steroid hellebrigenin (systematic name: 3β,5,14-trihy-droxy-19-oxo-5β-bufa-20,22-dienolide). It consists of three cyclo-hexane rings (A, B and C), a five-membered ring (D) and a six-membered lactone ring (E). The stereochemistry of the ring junctions are A/B cis, B/C trans and C/D cis. Cyclo-hexane rings A, B and C have normal chair conformations. The five-membered ring D with the C=C bond adopts an envelope conformation. Lactone ring E is essentially planar with a mean derivation of 0.006 (4) Å and is β-oriented at the C atom of ring D to which it is attached. There is an O-H⋯O hydrogen bond in the mol-ecule involving the hy-droxy groups. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into chains propagating along [010]. The chains are linked by C-H⋯O contacts into a three-dimensional network.
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.
Tong
T
Yu
Hai-Yan
HY
Tian
Xiao-Feng
XF
Yuan
Shu-Zhi
SZ
Hu
Ren-Wang
RW
Jiang