Crystal structure of hydro-cortisone 17-butyrate.

In the title compound, C25H36O6, the two central cyclo-hexane rings exhibit a chair conformation. The terminal cyclo-hexene and cyclo-pentane rings are in half-chair and envelope conformations (with the C atom bearing the methyl substit-uent as the flap), respectively. The methyl group of the butyrate chain is disordered over two orientations, with a refined occupancy ratio of 0.742 (6):0.258 (6). Intra-molecular O-H⋯O and C-H⋯O hydrogen bonds are observed. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds into chains running parallel to the a axis.