(20S,2′′S)-20-[4′-(3′′-Hydroxy-2′′-methyl­prop­yl)-3′-methylisoxazol-5-yl]-5β-preg­nan-3β,16β-diol

The title steroidal compound, C(29)H(47)NO(4), was prepared in a one-pot reaction starting from a sarsasapogenin derivative of known configuration. The isoxazole heterocycle is oriented towards the α face of the steroid nucleus and, although fully functionalized on C atoms, does not provoke steric hindrance with the adjacent D ring. The absolute configuration observed for chiral centers is as expected, and shows that no epimerization occurred in the precursors. In the crystal, the three OH groups serve as donors for hydrogen bonding with O and N atoms. The isoxazole N atom is involved in O-H⋯N hydrogen bonds, forming chains along [100]. These chains are further connected via O-H⋯O and weak C-H⋯O contacts, giving rise to a three-dimensional supra-molecular network.