Received 5 September 2012
The title compound, 3C7H10O6·H2O, is the enantiomerically pure product of a multi-step synthesis from the enantiomerically pure natural shikimic acid. The asymmetric unit contains three molecules of the acid and one molecule of water. The cyclohexene rings of the acids have half-chair conformations. The carboxylate, the four hydroxide groups and the additional water molecule form a complex three-dimensional hydrogen-bonding network.
A series of antitumor-active marine natural carbasugars has been isolated in the last two decades with a cyclohexene-1-carboxylate core structure and four contiguous stereogenic centers (Numata et al., 1997). The relative configuration of these compounds, the pericosines, has been a matter of debate since the first reports on the isolation (Usami et al., 2008, 2009). By means of detailed NMR analysis of the natural compound pericosine D0 and comparison with the NMR data published for the 6-hydroxy-5-epishikimic acid described herein, the absolute and relative configuration was established (Usami et al., 2006, 2011). This reveals the importance of this X-ray crystallographic determination that finally proves the assignments that resulted from spectroscopic analyses. For the synthesis, see: Griesbeck et al. (2007).
Data collection: COLLECT (Hooft 1998); cell refinement: DENZO (Otwinowski & Minor 1997); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SCHAKAL99 (Keller 1999); software used to prepare material for publication: PLATON (Spek 2009).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: GG2099 ).
This research was supported by the Deutsche Forschungsgemeinschaft and by University start-up funding (2004-2005).
Griesbeck, A. G., Miara, C. & Neudörfl, J. (2007). Arkivoc, 8, 216-223.
Hooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.
Keller, E. (1999). SCHAKAL99. University of Freiburg, Germany.
Numata, A., Iritani, M., Yamada, T., Minoura, K., Matsumura, E., Yamori, T. & Tsuruo, T. (1997). Tetrahedron Lett. 38, 8215-8218.
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Spek, A. L. (2009). Acta Cryst. D65, 148-155.
Usami, Y., Horibe, Y., Takaoka, I., Ichikawa, H. & Arimoto, M. (2006). Synlett, 10, 1598-1600.
Usami, Y. & Mizuki, K. (2011). J. Nat. Prod. 74, 877-881.
Usami, Y., Mizuki, K., Ichikawa, H. & Arimoto, M. (2008). Tetrahedron Asymmetry, 19, 1461-1464.
Usami, Y., Ohsugi, M., Mizuki, K., Ichikawa, H. & Arimoto, M. (2009). Org. Lett. 11, 2699-2701.