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Volume 69 
Part 1 
Page o91  
January 2013  

Received 28 November 2012
Accepted 10 December 2012
Online 15 December 2012

Key indicators
Single-crystal X-ray study
T = 298 K
Mean [sigma](C-C) = 0.005 Å
R = 0.052
wR = 0.152
Data-to-parameter ratio = 13.7
Details
Open access

(E)-2-Hydroxy-4-methoxy-3-(3-methylbut-2-enyl)-6-styrylbenzoic acid

aInstitute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China
Correspondence e-mail: l-z-r@263.net

The title compound, C21H22O4, also known as cajanine, features an intramolecular O-H...O hydrogen bond between the adjacent carboxy and hydroxy groups. The benzene rings make an interplanar angle of 175.4 (2)°. In the crystal, molecules are linked by pairs of O-H...O hydrogen bonds, forming inversion dimers.

Related literature

Cajanine is an important component of the herb Cajanus cajan L., which is used in traditional Chinese medicine to treat osteonecrosis of the femoral head. For the total synthesis of cajanine, see: Ji et al. (2011[Ji, X.-Y., Xue, S.-T., Zheng, G.-H., Han, Y.-X., Liu, Z.-Y., Jiang, J.-D. & Li, Z.-R. (2011). Acta. Pharm. Sin. B, 1, 93-99.]). For the bioactivity of cajanine, see: Fu et al. (2009[Fu, Y.-J., Zhu, Y.-G., Wu, N., Kong, Y., Liu, W. & Hua, X. (2009). Chin. Patent CN 101485649.]); Ji et al. (2011[Ji, X.-Y., Xue, S.-T., Zheng, G.-H., Han, Y.-X., Liu, Z.-Y., Jiang, J.-D. & Li, Z.-R. (2011). Acta. Pharm. Sin. B, 1, 93-99.]); Luo et al. (2008a[Luo, Q.-F., Sun, L., Si, J.-Y. & Chen, D.-H. (2008a). Phytomedicine, 15, 932-939.],b[Luo, Q.-F., Sun, L., Si, J.-Y., Chen, D.-H. & Du, G.-H. (2008b). Yao Xue Xue Bao, 43, 145-149.]); Zheng et al. (2007a[Zheng, Y.-Y., Yang, J., Chen, D.-H. & Sun, L. (2007a). Yao Xue Xue Bao, 42, 386-391.],b[Zheng, Y.-Y., Yang, J., Chen, D.-H. & Sun, L. (2007b). Yao Xue Xue Bao, 42, 562-565.]); Inman & Hopp (2002[Inman, W. D. & Hopp, D. C. (2002). US Patent 20020058701A1.]); Ruan et al. (2009[Ruan, C.-J., Si, J.-Y., Zhang, L., Chen, D.-H., Du, G.-H. & Sun, L. (2009). Neurosci. Lett. 467, 159-63.]).

[Scheme 1]

Experimental

Crystal data
  • C21H22O4

  • Mr = 338.39

  • Triclinic, [P \overline 1]

  • a = 6.9790 (3) Å

  • b = 9.9975 (8) Å

  • c = 13.8202 (11) Å

  • [alpha] = 77.899 (1)°

  • [beta] = 78.956 (2)°

  • [gamma] = 78.507 (2)°

  • V = 912.58 (11) Å3

  • Z = 2

  • Mo K[alpha] radiation

  • [mu] = 0.08 mm-1

  • T = 298 K

  • 0.35 × 0.32 × 0.31 mm

Data collection
  • Bruker SMART APEX diffractometer

  • 4547 measured reflections

  • 3138 independent reflections

  • 1735 reflections with I > 2[sigma](I)

  • Rint = 0.024

Refinement
  • R[F2 > 2[sigma](F2)] = 0.052

  • wR(F2) = 0.152

  • S = 1.06

  • 3138 reflections

  • 229 parameters

  • H-atom parameters constrained

  • [Delta][rho]max = 0.15 e Å-3

  • [Delta][rho]min = -0.18 e Å-3

Table 1
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
O1-H1...O2i 0.82 1.85 2.667 (2) 176
O3-H3...O2 0.82 1.82 2.546 (2) 147
Symmetry code: (i) -x+2, -y+1, -z+1.

Data collection: SMART (Bruker, 1999[Bruker (1999). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 1999[Bruker (1999). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: SHELXTL.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: NG5309 ).


Acknowledgements

This work was supported by the National S&T Major Special Project on Major New Drug Innovation (2012ZX09301002-001). We also thank Professor Su-na Wang at Liaocheng University for assistance with the crystallography and help with the X-ray experiment.

References

Bruker (1999). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.
Fu, Y.-J., Zhu, Y.-G., Wu, N., Kong, Y., Liu, W. & Hua, X. (2009). Chin. Patent CN 101485649.
Inman, W. D. & Hopp, D. C. (2002). US Patent 20020058701A1.
Ji, X.-Y., Xue, S.-T., Zheng, G.-H., Han, Y.-X., Liu, Z.-Y., Jiang, J.-D. & Li, Z.-R. (2011). Acta. Pharm. Sin. B, 1, 93-99.  [ChemPort]
Luo, Q.-F., Sun, L., Si, J.-Y. & Chen, D.-H. (2008a). Phytomedicine, 15, 932-939.  [ISI] [CrossRef] [PubMed] [ChemPort]
Luo, Q.-F., Sun, L., Si, J.-Y., Chen, D.-H. & Du, G.-H. (2008b). Yao Xue Xue Bao, 43, 145-149.  [PubMed]
Ruan, C.-J., Si, J.-Y., Zhang, L., Chen, D.-H., Du, G.-H. & Sun, L. (2009). Neurosci. Lett. 467, 159-63.  [ISI] [CrossRef] [PubMed] [ChemPort]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]
Zheng, Y.-Y., Yang, J., Chen, D.-H. & Sun, L. (2007a). Yao Xue Xue Bao, 42, 386-391.  [PubMed]
Zheng, Y.-Y., Yang, J., Chen, D.-H. & Sun, L. (2007b). Yao Xue Xue Bao, 42, 562-565.  [PubMed]


Acta Cryst (2013). E69, o91  [ doi:10.1107/S1600536812050258 ]

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