Crystal structure of 6-nitro-cholest-5-ene

The crystal structure of the title compound (C27H45NO2) has been determined by X-ray crystallographic techniques. The compound crystallizes in the mon oclinic space group P2(1) with unit cell parameters a = 12.143(2), b = 10.8 35(2), c = 19.747(4) Angstrom, beta = 101.29(1)degrees. The structure has b een solved by direct methods and refined to R=0.064. There are two crystall ographically independent molecules, I and II, in the asymmetric unit. In bo th the molecules, rings A, B and C are conformationally very similar, howev er pronounced differences are observed in the D ring which assumes a distor ted envelope conformation in molecule I and a distorted half-chair conforma tion in molecule II. The A/B ring junction is quasi-trans while ring system s B/C and CID are trans fused in both the molecules I and II. Two bifurcate d intramolecular hydrogen bonds have been observed. Molecules are held toge ther by intermolecular C-H . . .O hydrogen bonds.