title: 1β,15α-Dihy-droxy-16α,17-ep-oxy-pregn-4-ene-3,20-dione.
abstract: The title mol-ecule, C21H28O5, is composed of three six-membered rings (A/B/C) and a five-membered ring (D). Ring A adopts a 1α-sofa conformation, while rings B and C adopt chair conformations. Cyclo-pentane ring D adopts a 14α-envelope conformation. In the crystal, O-H⋯O hydrogen bonds lead to the formation of ribbons running along the a axis. The structure is further consolidated by C-H⋯O inter-actions, which link the molecules head-to-tail into ribbons along the a axis.
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, People's Republic of China.
authors.forename: Yan-Bing
authors.initials: YB
authors.lastname: Shen
authors.forename: Yi-Bo
authors.initials: YB
authors.lastname: Wang
authors.forename: Jian-Mei
authors.initials: JM
authors.lastname: Luo
authors.forename: Min
authors.initials: M
authors.lastname: Wang