Crystal structure of quinestrol hemiethanolate

The X-ray crystal structure of the synthetic sex steroid quinestrol (3-O-cyclopentyl-17 alpha-ethynylestradiol) as crystallized from ethanolic solution is determined. The asymmetric unit contains two steroid and one ethanol molecules. The conformation of the two steroid molecules differs in the orientation of the cyclopentane ring. The cocrystallized ethanol molecule facilitates formation of cooperative O-H . . . O hydrogen bonding. The title compound crystallizes in the monoclinic space group P2(1), with a = 13.950(6), b = 6.5945(8), c = 25.403(8) Angstrom, beta = 104.78(4)degrees and D-calc = 1.136 g cm(-1) for Z = 4.