Structure of 3-hydroxy-17-oxoestra-1,3,5(10)-trien-11 beta-yl acetate

C20H24O4, Mr = 328.41, orthorhombic, P2(1)2(1)2(1), a = 11.688 (3), b = 15.377 (5), c = 9.466 (2) A, V = 1701 (1) A3, Z = 4, Dx = 1.282 g cm-3, lambda (Mo K alpha) = 0.71073 A, mu = 0.823 cm-1, F(000) = 704, T = 298 K, R = 0.063 for 1921 reflections with F greater than 2 sigma (F). The structure was determined to observe the effect of the 11 beta-acetate substituent on the conformation of the molecule. The 3-hydroxy is hydrogen bonded to O19 at 2.86 A. The B ring has a 7 alpha, 8 beta-half chair conformation, the most commonly observed B ring conformation in estrogen analogues.