Molecular conformations. Part IV. X-Ray analysis of 3β,6β-dimethoxy-5β,19-cycloandrostan-17-one N-acetyl-p-bromobenzenesulphonylhydrazone

Abstract

Crystals of 3β,6β-dimethoxy-5β,19-cycloandrostan-17-one N-acetyl-p-bromobenzenesulphonylhydrazone are orthorhombic, space-group P212121, with four molecules in a unit cell of dimensions a= 17·81, b= 11·48, c= 14·46 A. The atomic co-ordinates were determined by Fourier and least-squares calculations. Ring A of the steroid exhibits the expected half-chair conformation with atoms 2 and 3 displaced by 0·36 and –0·42 A, respectively, from the plane through atoms 1, 4, 5, and 10. Ring B is distorted away from a half-chair towards an envelope conformation, for the displacement of atom 7 from the plane defined by atoms 5, 6, 9, and 10 is appreciably smaller than that of atom 8. Ring C adopts a chair conformation, and ring D is intermediate between a half-chair form and an envelope form in which C(14) is the out-of-plane atom.