CRYSTAL-STRUCTURE OF THE SOLVATE SPIRONOLACTONE-ACETONITRILE (2-1)

7-alpha-Acetylthio-3-oxo-17-alpha-pregn-4-ene-21, 17-beta-carbolactone acetonitrile solvate, 2C24H32-O4S.C2H3N, M(r) = 874.38, monoclinic, P2(1), a = 11.858 (4), b = 19.665 (3), c = 11.346 (3) angstrom, beta = 118.17 (3)-degrees, V = 2332 (2) angstrom-3, Z = 2, D(x) = 1.24 Mg m-3, lambda-(Mo K-alphaBAR) = 0.7107 angstrom, mu = 0.16 mm-1, F(000) = 940, T = 294 (1) K, final R = 0.036 for 3196 unique reflections. Bond lengths and angles are consistent with values found in analogous steriods. The two independent spironolactone molecules have the same A, B and C rings but different D and E rings. One D ring is intermediate between a beta-envelope and a half-chair (DELTA = 15.4, phi-m = 46.1-degrees) and the other is practically a half-chair (DELTA = -1.6, phi-(m) = 45.3-degrees). C(20) in the first molecule, and C(20) and C(21) in the second molecule statistically occupy two positions. Therefore, the E ring has two conformations in each molecule: a beta- or alpha-envelope in the first case and two opposite half-chairs in the second case. The cohesion of the structure is due to van der Waals interactions.