3,17-Dioxoandrost-4-en-4-yl acetate

The title compound, C₂₁H₂₈O₄, has a 4-acet­oxy substituent positioned on the steroid [alpha] face. The six-membered ring A assumes a conformation inter­mediate between 1[alpha],2[beta]-half chair and 1[alpha]-sofa. A long Csp³-Csp³ bond is observed in ring B and reproduced in quantum-mechanical ab initio calculations of the isolated mol­ecule using a mol­ecular-orbital Hartree-Fock method. Cohesion of the crystal can be attributed to van der Waals inter­actions and weak C-H...O hydrogen bonds.