3β-Acetoxy-5α-cholestan-6-one 2-cyanoacetylhydrazone

The asymmetric unit of the title compound, C32H51N3O3, consists of two crystallographically independent molecules, A and B; the 2-methylpentane group of molecule A and the propane group of molecule B are each disordered over two sets of sites, with refined site-occupancies of 0.825 (5):0.175 (5) and 0.630 (18):0.370 (18), respectively. In both molecules, the three cyclohexane rings in the steroid fused ring systems adopt chair conformations while the cyclopentane rings adopt envelope and twist conformations in molecules A and B, respectively. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds link the two independent molecules together, generating R 2 1(7) and R 2 2(8) ring motifs.

The asymmetric unit of the title compound, C 32 H 51 N 3 O 3 , consists of two crystallographically independent molecules, A and B; the 2-methylpentane group of molecule A and the propane group of molecule B are each disordered over two sets of sites, with refined site-occupancies of 0.825 (5):0.175 (5) and 0.630 (18):0.370 (18), respectively. In both molecules, the three cyclohexane rings in the steroid fused ring systems adopt chair conformations while the cyclopentane rings adopt envelope and twist conformations in molecules A and B, respectively. In the crystal, N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds link the two independent molecules together, generating R 2 1 (7) and R 2 2 (8) ring motifs.
The asymmetric unit of the title compound consists of two crystallographically independent molecules A and B (Fig. 1).
The 2-methylpentane group of molecule A and the propane group of molecule B are disordered with refined site-occupancies On the other hand, the cyclopentane ring of the steroid fused ring system in both molecules adopts a different ring conformation (Cremer & Pople, 1975). The cyclopentane (C12A-C16A) ring of molecule A is in an envelope conformation with puckering parameters Q= 0.469 (3) Å and φ= 351.6 (4)° with atom C12A at the flap. Meanwhile, molecule B is in a twist conformation where the cyclopentane (C12B-C16B) ring is twisted about C16B-C12B bonds, with puckering parameters Q= 0.464 (3) Å and φ= 350.2 (4)°. The bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to the related structures (Khan et al., 2011;Ketuly et al., 2011).

Experimental
To a solution of steroidal ketone, 3β-acetoxy-5α-cholestan-6-one, (5 mmol) in absolute ethanol (10 ml) was added cyanoacetichydrazide (10 mmol) followed by few drops of triethylamine. The reaction mixture was refluxed for 24 h. The progress of reaction was monitored by thin layer chromatography. After completion of the reaction, reaction mixture was concentrated under reduce pressure. The obtained solid, was extracted with ether and ethereal layer was washed with water, NaHCO 3 solution (5%) and dried over anhydrous sodium sulfate. The solvent was evaporated and the product was recrystallized from ethanol resulting in shiny crystals.

Refinement
The propane group of molecule A was disordered over two positions with refined site-occupancies of 0.825 (5):0.175 (5).
The minor disordered components were refined isotropically. For molecule B, the 2-methylpentane group was disordered over two positions with refined site-occupancies of 0.630 (18):0.370 (18). N-bound H atoms was located from the difference map and refined freely, [N-H = 0.85 (3) and 0.88 (3) Å]. The remaining H atoms were positioned geometrically [C-H = 0.96-0.98 Å] and refined using a riding model with U iso (H) = 1.2 or 1.5 U eq (C). A rotating group model was applied to the methyl groups. Since there are not sufficient anomalous dispersion to determine the absolute configuration, 8296 Friedel pairs were merged for the final refinement. The same U ij parameter was used for atoms pair C30X/C31X. Similarity and rigid bond restraints was also used in the final refinement. Fig. 1. The molecular structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. All disordered components are shown.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance mat-