title: (25R)-5a-Spiro-stane-3,12-dione.
abstract: The title compound, C(27)H(40)O(4), was obtained from the oxidation of (25R)-3b-hydr-oxy-5a-spiro-stan-12-one (Hecogenin) by Jone's reagent. The mol-ecule contains six alicyclic and heterocyclic rings, all trans-fused, among which four six-membered rings adopt similar chair conformations while two five-membered rings assume an envelope conformation.
authors.forename: Tie-Ying
authors.initials: TY
authors.lastname: Zi
authors.forename: Zhi-He
authors.initials: ZH
authors.lastname: Zang
authors.forename: Ming-Yong
authors.initials: MY
authors.lastname: Yuan
authors.forename: Ling-Li
authors.initials: LL
authors.lastname: Zheng