Die Röntgenstrukturanalyse von 17β‐Bromacetoxy‐ 9β, 10α‐androst‐4‐en‐3‐on

The structure of 17β‐bromacetoxy‐9β, 10α‐androst‐4‐en‐3‐one has been determined by three‐dimensional X‐ray crystallographic methods. The crystals of the restrosteroid belong to the orthorhombic space group P212121 with four molecules per unit cell. The cell constants are a = 11.32 Å, b = 13.71 Å and c = 12.52 Å. The absolute configuration of the molecule has been determined by the anomalous dispersion method. Bond length, bond angles and distances of atoms from ‘best planes’ are given. Ring A represents a distorted half‐chair, ring B and C a chair and ring D an envelope conformation. The molecule shows, contrary to normal 9α, 10β‐steroids, a bent shape.