17βH-Periplogenin, a cardiac aglycone from the root bark of Periploca sepium Bunge

The title compound {systematic name: 4-[(3S,5S,8R,9S,10R,13R,14S,17S)-3,5,14-trihy-droxy-10,13-dimethyl-hexa-deca-hydro-1H-cyclo-penta-[a]phenanthren-17-yl]furan-2(5H)-one}, C(23)H(34)O(5), was isolated from the roots of Periploca sepium Bunge, a famous Chinese traditional herbal medicine. The three six-membered rings adopt chair conformations, the cyclo-pentane ring displays an approximate envelope conformation (with the C atom bearing the methyl substituent at the flap) and the five-membered lactone ring adopts an essentially planar [maximum deviation of 0.004 (8) Å] conformation. In the crystal, mol-ecules are linked into helical chains along [010] by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. Two intra-molecular O-H⋯O hydrogen bonds are also present.