Structure of 3-hydroxy-1-methyl-1,3,5(10)-estratriene-11,17-dione

C19H22O3, Mr = 298.39, orthorhombic, P2(1)2(1)2(1), a = 11.332 (6), b = 14.596 (7), c = 9.567 (4) A, V = 1582.6 (5) A3, Z = 4, D chi = 1.252 Mg m-3, lambda(Mo K alpha) = 0.71073 A, mu = 0.0778 mm-1, F(000) = 640, T = 273 K, R = 0.067 for 1762 unique observed reflections where F greater than 2 sigma (F). The structure was studied to observe the effect of 1-methyl and 11-keto substitution. The 3-hydroxyl is hydrogen bonded to O11 at 2.76 A. The B ring is in a 7 alpha, 8 beta half-chair conformation. The molecule twists about the C(9)--C(10) bond to relieve the steric interaction between the 1-methyl and 11-keto groups. The C1--C10--C9--C11 torsion angle is 55 vs 33.5 degrees, the average of 38 estradiol analogue structures.