Received 7 December 2011
aCEMDRX, Department of Physics, Faculty of Sciences and Technology, University of Coimbra, P-3004-516 Coimbra, Portugal,bCentre for Neuroscience and Cell Biology, University of Coimbra, P-3004-517 Coimbra, Portugal, and cFaculty of Pharmacy, University of Coimbra, P-3000-548 Coimbra, Portugal
Correspondence e-mail: email@example.com
The title cholestan, C28H46O3, was prepared by epoxidation of 7-norcholest-5-en-3-yl acetate and crystallized by slow evaporation from an ethanolic solution. All rings are trans fused. The 3-acetate and the 17-cholestane side chain are in equatorial positions. The molecule is highly twisted due to its B-nor characteristic. A quantum chemical ab-initio Roothaan Hartree-Fock calculation of the equilibrium geometry of the isolated molecule gives values for bond lengths and valency angles in close agreement with the experimental ones.
For the chemistry of the title compound, see: Carvalho et al. (2009a, 2010a). For studies of biological activity of steroids, see: Carvalho et al. (2009b, 2010b). For the influence of structural characteristics of B-nor steroids on the outcome of many reactions, see: Uyanik & Hanson (2009). For asymmetry parameters, see: Duax & Norton (1975); Altona et al. (1968). For reference bond-length data, see: Allen et al. (1987). For puckering parameters, see: Cremer & Pople (1975). For the melting point of the title compound, see: Joska et al. (1963). For the software used in ab-initio calculations, see Schmidt et al. (1993).
Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IM2347 ).
This work was supported by funds from FEDER via the COMPETE (Programa Operacional Factores de Competitividade) programme and by the FCT (Fundação para a Ciência e a Tecnologia) (project PEst-C/FIS/UI0036/2011). We gratefully acknowledge the LCA-UC for a grant of computer time in the Milipeia cluster.
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.
Altona, C., Geise, H. J. & Romers, C. (1968). Tetrahedron, 24, 13-32.
Bruker (2003). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Carvalho, J. F. S., Silva, M. M. C., Moreira, J. N., Simões, S. & Sá e Melo, M. L. (2009a). J. Med. Chem. 52, 4007-4019.
Carvalho, J. F. S., Silva, M. M. C., Moreira, J. N., Simões, S. & Sá e Melo, M. L. (2010a). J. Med. Chem. 53, 7632-7638.
Carvalho, J. F. S., Silva, M. M. C. & Sá e Melo, M. L. (2009b). Tetrahedron, 65, 2773-2781.
Carvalho, J. F. S., Silva, M. M. C. & Sá e Melo, M. L. (2010b). Tetrahedron, 66, 2455-2462.
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.
Duax, W. L. & Norton, D. A. (1975). Atlas of Steroid Structure. New York: Plenum Press.
Flack, H. D. (1983). Acta Cryst. A39, 876-881.
Joska, J., Fajkos, J. & Sorm, F. (1963). Collect. Czech. Chem. Commun. 28, 82-99.
Schmidt, M. W., Baldrige, K. K., Boatz, J. A., Elbert, S. T., Gordon, M. S., Jensen, J. J., Koseki, S., Matsunaga, N., Nguyen, K. A., Sue, S., Windus, T. L., Dupuis, M. & Montgomery, J. A. (1993). J. Comput. Chem. 14, 1347-1363.
Sheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Spek, A. L. (2009). Acta Cryst. D65, 148-155.
Uyanik, C. & Hanson, J. R. (2009). J. Chem. Res. 12, 713-719.