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Volume 69 
Part 8 
Pages o1237-o1238  
August 2013  

Received 20 June 2013
Accepted 2 July 2013
Online 10 July 2013

Key indicators
Single-crystal X-ray study
T = 200 K
Mean [sigma](C-C) = 0.005 Å
R = 0.049
wR = 0.121
Data-to-parameter ratio = 13.4
Details
Open access

Tenulin 0.25-hydrate, a sesquiterpene lactone isolated from Helenium amarum

aDepartment of Chemistry, The University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA, and bCrystallographic Systems, Bruker AXS Inc., 4565 East Cheryl Parkway, Madison, WI 53711, USA
Correspondence e-mail: kyle-knight@utc.edu

The asymmetric unit of the title compound, C17H22O5·0.25H2O [systematic name: 2-hydroxy-2,2a,6,9a-tetramethyl-2a,4a,5,6,6a,9a,9b,9c-octahydro-2H-1,4-dioxadicyclopent[cd,f]azulene-3,9-dione 0.25-hydrate], a natural product isolated from Helenium amarum, contains two independent tenulin molecules and half a water molecule of crystallization situated on a twofold rotation axis. The hydroxy group of the hemiketal moiety is in a [beta]-position. In the crystal, each water molecule interacts with four tenulin molecules via O-H...O hydrogen bonds. The two independent tenulin molecules (A and B) differ only in the character of their participation in hydrogen bonding. Specifically, while A is an acceptor of Owater-H...OA and a donor of OA-H...OB hydrogen bonds, molecule B is an acceptor of the latter hydrogen bond and the donor of an OB-H...Owater hydrogen bond. In the crystal, these O-H...O hydrogen bonds link the tenulin and water molecules into layers parallel to the ac plane.

Related literature

For the discovery and structural identification of tenulin, see: Clark (1939[Clark, E. P. (1939). J. Am. Chem. Soc. 61, 1836-40.]); Herz & Sharma (1975[Herz, W. & Sharma, R. P. (1975). J. Org. Chem. 40, 2557-2559.]); Braun et al. (1956[Braun, B. H., Herz, W. & Rabindran, K. (1956). J. Am. Chem. Soc. 78, 4423-4429.]); Barton & De Mayo (1956[Barton, D. H. R. & De Mayo, P. (1956). J. Chem. Soc. pp. 142-149.]). For the biological activity of tenulin and its analogs, see: Lee et al. (1977[Lee, K. H., Hall, I. H., Mar, E. C., Starnes, C. O., ElGebaly, S. A., Waddell, T. G., Hadgraft, R. I., Ruffner, C. G. & Weidner, I. (1977). Science, 196, 533-536.]); Waddell et al. (1979[Waddell, T. G., Austin, A. M., Cochran, J. W., Gerhart, K. G., Hall, I. H. & Lee, K. H. (1979). J. Pharm. Sci. 68, 715-718.]); Hwang et al. (1996[Hwang, D., Fischer, N. H., Jang, B. C., Tak, H., Kim, J. K. & Lee, W. (1996). Biochem. Biophys. Res. Commun. 226, 810-818.]); Li & Zhang (2008[Li, X.-J. & Zhang, H.-Y. (2008). Trends Mol. Med. 14, 1-2.]); Hodge & Waddell (1995[Hodge, J. S. & Waddell, T. G. (1995). J. Nat. Prod. 58, 149-151.]) and references therein. For the crystal structure of bromoisotenulin, see: Mazhar et al. (1974[Mazhar Ul, H., Rogers, D. & Caughlan, C. N. (1974). J. Chem. Soc. Perkin Trans. 2, pp. 223-228.]).

[Scheme 1]

Experimental

Crystal data
  • C17H22O5·0.25H2O

  • Mr = 310.86

  • Orthorhombic, P 21 21 2

  • a = 10.5508 (16) Å

  • b = 28.371 (4) Å

  • c = 10.5228 (14) Å

  • V = 3149.9 (8) Å3

  • Z = 8

  • Mo K[alpha] radiation

  • [mu] = 0.10 mm-1

  • T = 200 K

  • 0.42 × 0.32 × 0.26 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.818, Tmax = 1.000

  • 19558 measured reflections

  • 5543 independent reflections

  • 4678 reflections with I > 2[sigma](I)

  • Rint = 0.041

Refinement
  • R[F2 > 2[sigma](F2)] = 0.049

  • wR(F2) = 0.121

  • S = 1.26

  • 5543 reflections

  • 415 parameters

  • 1 restraint

  • H-atom parameters constrained

  • [Delta][rho]max = 0.32 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
O3-H3...O10i 0.84 1.87 2.711 (3) 175
O8-H8...O1Wii 0.84 2.17 2.945 (5) 153
O1W-H1W...O5 0.99 (3) 1.94 (3) 2.897 (4) 162 (6)
Symmetry codes: (i) -x+1, -y+1, z; (ii) x, y, z+1.

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2 and SAINT. 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: OLEX2 (Dolomanov et al. 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: OLEX2.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV5419 ).


Acknowledgements

Acknowledgements are made to the National Science Foundation MRI Program (CHE-0951711) and the Grote Chemistry Fund at the University of Tennessee at Chattanooga for their generous support of our work.

References

Barton, D. H. R. & De Mayo, P. (1956). J. Chem. Soc. pp. 142-149.  [CrossRef]
Braun, B. H., Herz, W. & Rabindran, K. (1956). J. Am. Chem. Soc. 78, 4423-4429.  [CrossRef] [ChemPort] [Web of Science]
Bruker (2008). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Clark, E. P. (1939). J. Am. Chem. Soc. 61, 1836-40.  [CrossRef] [ChemPort]
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.  [Web of Science] [CrossRef] [ChemPort] [IUCr Journals]
Herz, W. & Sharma, R. P. (1975). J. Org. Chem. 40, 2557-2559.  [CrossRef] [ChemPort]
Hodge, J. S. & Waddell, T. G. (1995). J. Nat. Prod. 58, 149-151.  [CrossRef] [ChemPort] [Web of Science]
Hwang, D., Fischer, N. H., Jang, B. C., Tak, H., Kim, J. K. & Lee, W. (1996). Biochem. Biophys. Res. Commun. 226, 810-818.  [CrossRef] [ChemPort] [PubMed]
Lee, K. H., Hall, I. H., Mar, E. C., Starnes, C. O., ElGebaly, S. A., Waddell, T. G., Hadgraft, R. I., Ruffner, C. G. & Weidner, I. (1977). Science, 196, 533-536.  [CrossRef] [PubMed] [ChemPort] [Web of Science]
Li, X.-J. & Zhang, H.-Y. (2008). Trends Mol. Med. 14, 1-2.  [Web of Science] [CrossRef] [PubMed]
Mazhar Ul, H., Rogers, D. & Caughlan, C. N. (1974). J. Chem. Soc. Perkin Trans. 2, pp. 223-228.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [ChemPort] [IUCr Journals]
Waddell, T. G., Austin, A. M., Cochran, J. W., Gerhart, K. G., Hall, I. H. & Lee, K. H. (1979). J. Pharm. Sci. 68, 715-718.  [CrossRef] [ChemPort] [PubMed] [Web of Science]


Acta Cryst (2013). E69, o1237-o1238   [ doi:10.1107/S1600536813018369 ]

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