21-Hydroxypregna-1,4-diene-3,20-dione

The title compound, C21H28O3, is a fungal transformed metabolite of decoxycorticosterone acetate, consisting of four fused rings A, B, C and D. Ring A is nearly planar, with a maximum deviation of 0.010 (3) Å from the least-squares plane, while the trans-fused rings B and C adopt chair conformations. The five-membered ring D is in an envelope conformation. The orientation of the side chain is stabilized by an intramolecular O—H...O hydrogen bond. In the crystal, adjecent molecules are linked by C—H...O hydrogen bonds into extended zigzag chains along the a axis