XY-16-HYDROXYIMINO-3-METHOXYESTRA-1,3,5(10)-TRIENE

The asymmetric unit of the title compound, 17 alpha-benzyl- 16-hydroxy imino-3-methoxyestra-1,3,5(10)-trien-17 beta-ol, C26H31NO3, contains t wo molecules which differ in the orientations of the methoxy groups at C(3). The 17-hydroxy and 16-hydroxyimino moieties are involved in int ramolecular N ... O and intermolecular N ... O and O ... O hydrogen bo nds. The hydrogen-bond network accounts for the differences in bond an d torsion angles of the alpha-hydroxyimino moieties of the symmetry-in dependent molecules. This has been confirmed by molecular-mechanics ca lculations on the individual molecules which indicate that they have t he same geometry in their energy minimum states.