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Volume 65 
Part 9 
Page o2113  
September 2009  

Received 31 July 2009
Accepted 1 August 2009
Online 8 August 2009

Key indicators
Single-crystal X-ray study
T = 100 K
Mean [sigma](C-C) = 0.002 Å
R = 0.037
wR = 0.095
Data-to-parameter ratio = 11.1
Details
Open access

Methyl 3-dehydroxy-3-oxoursolate

aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, and bMedicinal Plant Division, Forest Research Institute Malaysia, 52100 Kepong, Selangor Darul Ehsan, Malaysia
Correspondence e-mail: seikweng@um.edu.my

Four of the five six-membered rings of the title pentacylic triterpene, C31H48O3, adopt chair conformations; the fifth, which has a C=C double bond, adopts an approximate envelope conformation.

Related literature

The structure was previously refined to an R-index of 0.043 but atomic coordinates were not published. The reported room-temperature cell [8.109 (1), 8.618 (1), 39.148 (1) Å] is slightly larger; see: de Vivar et al. (1985[Vivar, A. R. de, González, J. M., Perez, C. & Ana, L. (1985). Rev. Latinoam. Quim. 16, 51-52.]). For the synthesis, see: Honda et al. (1997[Honda, T., Finlay, H. & Gribble, G. W. (1997). J. Nat. Prod. 60, 1174-1177.]); Ma et al. (2005[Ma, C.-M., Cai, S.-Q., Chui, J. R., Wang, R.-Q., Tu, P.-F., Hattori, M. & Daneshtalab, M. (2005). Eur. J. Med. Chem. 40, 582-589.]); Zhao et al. (2007[Zhao, L.-X., Liu, N.-N., Pei, X.-J., Liu, D.-F. & Liu, D.-Z. (2007). Liaoning Shifan Daxue Xuebao, Ziran Kexueban, 30, 476-479.]).

[Scheme 1]

Experimental

Crystal data
  • C31H48O3

  • Mr = 468.69

  • Orthorhombic, P 21 21 21

  • a = 8.0298 (2) Å

  • b = 8.4775 (2) Å

  • c = 39.0492 (7) Å

  • V = 2658.2 (1) Å3

  • Z = 4

  • Mo K[alpha] radiation

  • [mu] = 0.07 mm-1

  • T = 100 K

  • 0.25 × 0.15 × 0.10 mm

Data collection
  • Bruker SMART APEX diffractometer

  • Absorption correction: none

  • 18588 measured reflections

  • 3500 independent reflections

  • 3188 reflections with I > 2[sigma](I)

  • Rint = 0.041

Refinement
  • R[F2 > 2[sigma](F2)] = 0.037

  • wR(F2) = 0.095

  • S = 1.05

  • 3500 reflections

  • 315 parameters

  • H-atom parameters constrained

  • [Delta][rho]max = 0.27 e Å-3

  • [Delta][rho]min = -0.18 e Å-3

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELX97 (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: X-SEED (Barbour, 2001[Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.]); software used to prepare material for publication: publCIF (Westrip, 2009[Westrip, S. P. (2009). publCIF. In preparation.]).


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU2575 ).


Acknowledgements

We thank the University of Malaya for supporting this study.

References

Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.  [CrossRef] [ChemPort]
Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Honda, T., Finlay, H. & Gribble, G. W. (1997). J. Nat. Prod. 60, 1174-1177.  [CrossRef] [ChemPort] [ISI]
Ma, C.-M., Cai, S.-Q., Chui, J. R., Wang, R.-Q., Tu, P.-F., Hattori, M. & Daneshtalab, M. (2005). Eur. J. Med. Chem. 40, 582-589.  [ISI] [CrossRef] [PubMed] [ChemPort]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]
Vivar, A. R. de, González, J. M., Perez, C. & Ana, L. (1985). Rev. Latinoam. Quim. 16, 51-52.
Westrip, S. P. (2009). publCIF. In preparation.
Zhao, L.-X., Liu, N.-N., Pei, X.-J., Liu, D.-F. & Liu, D.-Z. (2007). Liaoning Shifan Daxue Xuebao, Ziran Kexueban, 30, 476-479.


Acta Cryst (2009). E65, o2113  [ doi:10.1107/S1600536809030669 ]

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