Methyl 3-acet­oxy-3-dehydroxy­ursolate

Abdullah, N.H.; Awang, K.; Thomas, N.F.; Ng, S.W.

doi:10.1107/S1600536809030657

Volume 65
Part 9
Page o2114
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 (C-C) = 0.002 Å
R = 0.036
wR = 0.099
Data-to-parameter ratio = 11.3
Details

Methyl 3-acetoxy-3-dehydroxyursolate

Nor Hayati Abdullah,^a Khalijah Awang,^b Noel F. Thomas ^b and Seik Weng Ng ^b ^*

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

Four of the five six-membered rings of the title pentacyclic triterpene, C₃₃H₅₂O₄, adopt chair conformations; the fifth, which has a C=C double bond, adopts an approximate envelope conformation.

Related literature

For the synthesis, see: Ma et al. (2005). The crystal structure of ursolic acid is known from its ethanol solvate; see: Simon et al. (1992). For methyl uroslate-3-bromoacetate, see: Stout & Stevens (1963). For methyl ursolate-3-p-bromobenzoate, see: Paton & Paul (1979).

Experimental

Crystal data

C₃₃H₅₂O₄
M_r = 512.75
Orthorhombic, P 2₁ 2₁ 2₁
a = 6.8245 (1) Å
b = 13.4874 (2) Å
c = 32.2233 (5) Å
V = 2965.99 (8) Å³
Z = 4
Mo K radiation
= 0.07 mm^-1
T = 100 K
0.30 × 0.15 × 0.05 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: none
28565 measured reflections
3886 independent reflections
3612 reflections with I > 2(I)
R_int = 0.034

Refinement

R[F² > 2(F²)] = 0.036
wR(F²) = 0.099
S = 1.07
3886 reflections
343 parameters
H-atom parameters constrained
_max = 0.35 e Å^-3
_min = -0.18 e Å^-3

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2009).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU2574 ).

Acknowledgements

We thank the University of Malaya for supporting this study.

References

Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.
Bruker (2008). APEX2 nd SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
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.
Paton, W. F. & Paul, I. C. (1979). Cryst. Struct. Commun. 8, 207-211.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Simon, A., Delage, C., Saux, M., Chulia, A. J., Najid, A. & Rigaud, M. (1992). Acta Cryst. C48, 726-728.
Stout, G. H. & Stevens, K. L. (1963). J. Org. Chem. 28, 1259-1262.
Westrip, S. P. (2009). publCIF. In preparation.

organic compounds