Date Published: June 01, 2012
Publisher: International Union of Crystallography
Author(s): Tong Yu, Hai-Yan Tian, Xiao-Feng Yuan, Shu-Zhi Hu, Ren-Wang Jiang.
The title compound, C24H30O5, is the didehydro product of the steroid hellebrigenin (systematic name: 3β,5,14-trihydroxy-19-oxo-5β-bufa-20,22-dienolide). It consists of three cyclohexane 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. Cyclohexane 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 molecule involving the hydroxy groups. In the crystal, O—H⋯O hydrogen bonds link the molecules into chains propagating along . The chains are linked by C—H⋯O contacts into a three-dimensional network.
For previous isolations of hellebrigenin, see: Urscheler et al. (1955 ▶); Yang et al. (2010 ▶); Zhao et al. (2010 ▶). For its inhibitory activity against adenosinetriphosphatase of the 3-acetate, 3,5-diacetate, 3-iodoacetate and 3-bromoacetate of hellebrigenin, see: Ruoho et al. (1968 ▶). For the treatment of hellebrigenin with sodium hydroxide, see: Kupchan et al. (1969 ▶). For the stereochemistry of bufalin and secohellebrigeninamide, see: Rohrer et al. (1982 ▶); Yuan et al. (2012 ▶).