Westphalen's diol diacetate: 19(10→5)-abeo-5β-cholest-9-ene-3β,6β-diyl diacetate

Ramírez Hernández, J.; Sandoval-Ramírez, J.; Meza-Reyes, S.; Vega Báez, J.L.; Bernès, S.

doi:10.1107/S1600536812045278

Volume 68
Part 12
Page o3331
December 2012

Received 28 October 2012
Accepted 2 November 2012
Online 10 November 2012

Key indicators
Single-crystal X-ray study
T = 298 K
Mean (C-C) = 0.004 Å
Disorder in main residue
R = 0.048
wR = 0.136
Data-to-parameter ratio = 9.3
Details

Westphalen's diol diacetate: 19(105)-abeo-5-cholest-9-ene-3,6-diyl diacetate

Johana Ramírez Hernández,^a Jesús Sandoval-Ramírez,^a Socorro Meza-Reyes,^a José Luis Vega Báez ^a and Sylvain Bernès ^b ^*

^aBenemérita Universidad Autónoma de Puebla, Facultad de Ciencias Químicas, Ciudad Universitaria, Puebla, Pue. 72570, Mexico, and ^bUniversidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad S/N, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León CP 66451, Mexico
Correspondence e-mail: sylvain_bernes@hotmail.com

The structure of the title steroid [alternative name: 3 [beta] ,6 [beta] -diacetoxy-5 [beta] -methyl-19-norcholest-9(10)-ene], C₃₁H₅₀O₄, confirms the generally accepted mechanism for the rearrangement of a cholestan-5 [alpha] -ol derivative reported a century ago by Westphalen. The methyl group at position 10 of the starting material migrates to position 5 in the steroidal nucleus, while a [Delta] ⁹ bond is formed, as indicated by the C=C bond length of 1.347 (4) Å. The methyl transposition leaves the 5R configuration unchanged, with the methyl oriented towards the [beta] face. During the rearrangement, the steroidal B ring experiences a conformational distortion from chair to envelope with the C atom at position 6 as the flap. In the title structure, the isopropyl group of the side chain is disordered over two positions, with occupancies of 0.733 (10) and 0.267 (10). The carbonyl O atom in the acetyl group at C3 is also disordered with an occupancy ratio of 0.62 (4):0.38 (4).

Related literature

For the initial report on the Westphalen rearrangement, see: Westphalen (1915). For applications in steroid synthesis, see: Rodig et al. (1961); Knights & Hanson (2004); Pinto et al. (2008, 2009). For mechanistic aspects of this rearrangement, see: Kocovský & Cerný (1977); Kocovský et al. (1979); Kamernitskii et al. (1987).

Experimental

Crystal data

C₃₁H₅₀O₄
M_r = 486.71
Orthorhombic, P 2₁ 2₁ 2₁
a = 9.2846 (15) Å
b = 10.7203 (18) Å
c = 29.982 (4) Å
V = 2984.2 (8) Å³
Z = 4
Mo K radiation
= 0.07 mm^-1
T = 298 K
0.6 × 0.5 × 0.5 mm

Data collection

Siemens P4 diffractometer
4350 measured reflections
3393 independent reflections
2827 reflections with I > 2(I)
R_int = 0.043
3 standard reflections every 97 reflections intensity decay: 0.5%

Refinement

R[F² > 2(F²)] = 0.048
wR(F²) = 0.136
S = 1.05
3393 reflections
364 parameters
57 restraints
H-atom parameters constrained
_max = 0.14 e Å^-3
_min = -0.13 e Å^-3

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FF2087 ).

Acknowledgements

We thank VIEP-BUAP for financial support.

References

Kamernitskii, A. V., Reshetova, I. G. & Chernov, S. V. (1987). Pharm. Chem. J. 21, 736-744.
Knights, S. G. & Hanson, J. R. (2004). J. Chem. Res. pp. 830-831.
Kocovský, P. & Cerný, V. (1977). Collect. Czech. Chem. Commun. 42, 2415-2437.
Kocovský, P., Cerný, V. & Turecek, F. (1979). Collect. Czech. Chem. Commun. 44, 234-245.
Pinto, R. M. A., Ramos Silva, M., Matos Beja, A., Salvador, J. A. R. & Paixão, J. A. (2009). Acta Cryst. C65, o214-o216.
Pinto, R. M. A., Salvador, J. A. R., Le Roux, C., Carvalho, R. A., Ramos Silva, M., Matos Beja, A. & Paixão, J. A. (2008). Steroids, 73, 549-561.
Rodig, O. R., Brown, P. & Zaffaroni, P. (1961). J. Org. Chem. 26, 2431-2435.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Siemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.
Westphalen, T. (1915). Chem. Ber. 48, 1064-1069.

organic compounds