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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 [sigma](C-C) = 0.004 Å
Disorder in main residue
R = 0.048
wR = 0.136
Data-to-parameter ratio = 9.3
Details
Open access

Westphalen's diol diacetate: 19(10[rightwards arrow]5)-abeo-5[beta]-cholest-9-ene-3[beta],6[beta]-diyl diacetate

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[Westphalen, T. (1915). Chem. Ber. 48, 1064-1069.]). For applications in steroid synthesis, see: Rodig et al. (1961[Rodig, O. R., Brown, P. & Zaffaroni, P. (1961). J. Org. Chem. 26, 2431-2435.]); Knights & Hanson (2004[Knights, S. G. & Hanson, J. R. (2004). J. Chem. Res. pp. 830-831.]); Pinto et al. (2008[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.], 2009[Pinto, R. M. A., Ramos Silva, M., Matos Beja, A., Salvador, J. A. R. & Paixão, J. A. (2009). Acta Cryst. C65, o214-o216.]). For mechanistic aspects of this rearrangement, see: Kocovský & Cerný (1977[Kocovský, P. & Cerný, V. (1977). Collect. Czech. Chem. Commun. 42, 2415-2437.]); Kocovský et al. (1979[Kocovský, P., Cerný, V. & Turecek, F. (1979). Collect. Czech. Chem. Commun. 44, 234-245.]); Kamernitskii et al. (1987[Kamernitskii, A. V., Reshetova, I. G. & Chernov, S. V. (1987). Pharm. Chem. J. 21, 736-744.]).

[Scheme 1]

Experimental

Crystal data
  • C31H50O4

  • Mr = 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[alpha] radiation

  • [mu] = 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[sigma](I)

  • Rint = 0.043

  • 3 standard reflections every 97 reflections intensity decay: 0.5%

Refinement
  • R[F2 > 2[sigma](F2)] = 0.048

  • wR(F2) = 0.136

  • S = 1.05

  • 3393 reflections

  • 364 parameters

  • 57 restraints

  • H-atom parameters constrained

  • [Delta][rho]max = 0.14 e Å-3

  • [Delta][rho]min = -0.13 e Å-3

Data collection: XSCANS (Siemens, 1996[Siemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.]); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); 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.  [CrossRef]
Knights, S. G. & Hanson, J. R. (2004). J. Chem. Res. pp. 830-831.  [CrossRef]
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.  [CrossRef] [ChemPort] [details]
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.  [CSD] [CrossRef] [PubMed] [ChemPort]
Rodig, O. R., Brown, P. & Zaffaroni, P. (1961). J. Org. Chem. 26, 2431-2435.  [CrossRef] [ChemPort]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]
Siemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.
Westphalen, T. (1915). Chem. Ber. 48, 1064-1069.  [ChemPort]


Acta Cryst (2012). E68, o3331  [ doi:10.1107/S1600536812045278 ]

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