(Z)-3α-(1,3-Dioxoisoindolin-2-yl)-17(20)-pregnene.

The title compound, C(29)H(37)NO(2), crystallized with two independent mol-ecules in an asymmetric unit in which the conformation of the cyclo-hexyl ring of the pregnene moiety bonded to the 3α-(1,3-dioxoisoindolin-2-yl)- ring system differs: in one mol-ecule it is in a chair conformation, while in the other it exhibits a half-chair conformation. The other six-membered rings in the pregnene moiety are in chair conformations and the five-membered rings are in envelope forms in both mol-ecules. In both mol-ecules, the 3α-(1,3-dioxoisoindolin-2-yl)- ring systems are individually approximately planar, with r.m.s. devtaions 0.0148 and 0.0264 Å. The structure is consolidated by inter-molecular C-H⋯O hydrogen-bonding inter-actions involving the carbonyl O atoms and methyl, methyl-ene and methyl-idyne groups, resulting in a two-dimensional structure.