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Volume 69 
Part 2 
Page o302  
February 2013  

Received 24 October 2012
Accepted 23 January 2013
Online 31 January 2013

Key indicators
Single-crystal X-ray study
T = 293 K
Mean [sigma](C-C) = 0.003 Å
R = 0.050
wR = 0.158
Data-to-parameter ratio = 15.5
Details
Open access

Desoxyhemigossypol 6-methyl ether

aInstitute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, M. Ulugbek str. 83, Tashkent, 100125 Uzbekistan, and bSouthern Plains Agricultural Research Center, Agricultural Research, Service, USDA, College Station, TX 77845, USA
Correspondence e-mail: via74@yandex.ru

The title sesquiterpene [systematic name: 6-methoxy-10-methyl-7-(propan-2-yl)-2-oxatricyclo[6.3.1.04,12]dodeca-1(11),4,6,8(12),9-pentaen-5-ol], C16H18O3, was isolated from pathogen-infected stele tissue of Gossypium barbadense. There are two molecules in the asymmetric unit and the dihedral angle between their naphthofuran systems is 86.48 (2)°. In the crystal, O-H...O hydrogen bonds between the hydroxy groups and etheric O atoms link the molecules into centrosymmetric tetramers. These tetramers are assembled into (010) layers via stacking interactions between the naphthofuran systems [interplanar distance 3.473 (3) Å] and short C-H...O contacts.

Related literature

For the isolation and chemical structure determination of related cotton sesquiterpenoid phytoalexins and their intermediates, see: Bell et al. (1975[Bell, A. A., Stipanovic, R. D., Howell, C. R. & Fryxell, P. A. (1975). Phytochemistry, 14, 225-231.]); Stipanovic et al. (1975[Stipanovic, R. D., Bell, A. A. & Howell, C. R. (1975). Phytochemistry, 14, 1809-1811.]). For the role of terpenoid aldehydes as phytoalexins (active defense agents) in response to infection by wilt fungi, see: Mace (1978[Mace, M. E. (1978). Physiol. Plant Path. 12, 1-11.]). For information on the mechanism of action, see: Mace et al. (1995[Mace, M. E. & Stipanovic, R. D. (1995). Pestic. Biochem. Physiol. 53, 205-209.]). For the mechanism of O-methylation of desoxyhemigossypol, see: Liu et al. (2002[Liu, J., Benedict, C. R., Stipanovic, R. D., Magill, C. W. & Bell, A. A. (2002). J. Agric. Food Chem. 50, 3165-3172.]). For general information about antimicrobial compounds produced by cotton, see: Bell (1995[Bell, A. A. (1995). in Challenging the Future: Proceedings of the World Cotton Research Conference-1, edited by G. A. Constable & N. W. Forrester, pp. 225-235. Melbourne: CSIRO.]).

[Scheme 1]

Experimental

Crystal data
  • C16H18O3

  • Mr = 258.30

  • Triclinic, [P \overline 1]

  • a = 10.0275 (5) Å

  • b = 11.1058 (6) Å

  • c = 13.2938 (8) Å

  • [alpha] = 107.797 (5)°

  • [beta] = 103.896 (5)°

  • [gamma] = 90.435 (4)°

  • V = 1363.08 (13) Å3

  • Z = 4

  • Cu K[alpha] radiation

  • [mu] = 0.69 mm-1

  • T = 293 K

  • 0.40 × 0.34 × 0.28 mm

Data collection
  • Oxford Diffraction Xcalibur Ruby diffractometer

  • Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]) Tmin = 0.925, Tmax = 1.000

  • 10119 measured reflections

  • 5476 independent reflections

  • 3775 reflections with I > 2[sigma](I)

  • Rint = 0.027

Refinement
  • R[F2 > 2[sigma](F2)] = 0.050

  • wR(F2) = 0.158

  • S = 1.04

  • 5476 reflections

  • 354 parameters

  • H-atom parameters constrained

  • [Delta][rho]max = 0.45 e Å-3

  • [Delta][rho]min = -0.22 e Å-3

Table 1
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
O2-H2A...O3 0.82 2.28 2.723 (2) 114
O2-H2A...O4i 0.82 2.11 2.809 (2) 144
O5-H5...O3 0.82 2.13 2.7843 (19) 137
O5-H5...O6 0.82 2.27 2.719 (2) 115
C12-H12B...O2ii 0.97 2.48 3.445 (3) 171
Symmetry codes: (i) -x+2, -y+1, -z; (ii) -x+2, -y+1, -z+1.

Data collection: CrysAlis PRO (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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: XP in 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: GK2530 ).


Acknowledgements

This work was supported by the CRDF project UZB2-31001-TA02.

References

Bell, A. A. (1995). in Challenging the Future: Proceedings of the World Cotton Research Conference-1, edited by G. A. Constable & N. W. Forrester, pp. 225-235. Melbourne: CSIRO.
Bell, A. A., Stipanovic, R. D., Howell, C. R. & Fryxell, P. A. (1975). Phytochemistry, 14, 225-231.  [CrossRef] [ChemPort]
Liu, J., Benedict, C. R., Stipanovic, R. D., Magill, C. W. & Bell, A. A. (2002). J. Agric. Food Chem. 50, 3165-3172.  [CrossRef] [PubMed] [ChemPort]
Mace, M. E. (1978). Physiol. Plant Path. 12, 1-11.  [CrossRef] [ChemPort]
Mace, M. E. & Stipanovic, R. D. (1995). Pestic. Biochem. Physiol. 53, 205-209.  [CrossRef] [ChemPort]
Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]
Stipanovic, R. D., Bell, A. A. & Howell, C. R. (1975). Phytochemistry, 14, 1809-1811.  [CrossRef] [ChemPort]


Acta Cryst (2013). E69, o302  [ doi:10.1107/S1600536813002304 ]

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