(4S,8S,9R,12E)-8,9,16,18-Tetrahydroxy-4-methyl-3-oxabicyclo[12.4.0]octadeca-12,14,16,18-tetraen-2-one monohydrate

The asymmetric unit of the title compound, C18H24O6·H2O, contains a 14-membered macrolide molecule and a water molecule. In the crystal structure, intramolecular C—H⋯O and O—H⋯O hydrogen bonds help to stabilize the molecular conformation, while intermolecular O—H⋯O hydrogen bonds link the molecules, forming an infinite network. The absolute configuration was assigned by comparison with related zearalenone compounds, but needs verification.

The asymmetric unit of the title compound, C 18 H 24 O 6 ÁH 2 O, contains a 14-membered macrolide molecule and a water molecule. In the crystal structure, intramolecular C-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds help to stabilize the molecular conformation, while intermolecular O-HÁ Á ÁO hydrogen bonds link the molecules, forming an infinite network. The absolute configuration was assigned by comparison with related zearalenone compounds, but needs verification.

Comment
The title compound, (I), 5'-hydroxyzearalenol is a new natural β-resorcylic macrolide which has recently been isolated (Zhao et al., 2008) from the culture of a marine-derived fungus Fusarium sp. 05ABR26. It is closely related in structure to the zearalenone series compounds (Zinedine et al., 2007), which show attractive cytotoxic and genotoxic effects. As a continuation of our studies on the secondary metabolites of Fusarium sp. 05ABR26, we report here the crystal structure of 5'-hydroxyzearalenol monohydrate.
The structure of (I) is built up from the self-assembly of the molecules of 5'-hydroxyzearalenol with water molecules via hydrogen-bond interactions. The water molecule is involved as a donor and accepter of hydrogen bonds. The crystal structure is stabilized by intermolecular O-H···O hydrogen bonds ( Fig. 2 and Table 1).
It was not possible to accurately determine the absolute configuration of (I) by anomalous dispersion effects in the case of using Mo K/a radiation (0.71073 Å). However, the naturally occurring compounds of the zearalenone series all had the same C3S configuration (Zinedine et al., 2007), thereofore leading to the assignment of the absolute configurations of C7 and C8 to be S and R, respectively. Nevertheless, this absolute configuration of the molecule needs further verifcatio.
Experimental 5'-hydroxyzearalenol was isolated from 1L culture of a marine-derived fungus 05ABR26 (a Fusarium sp.), affording 9.1 mg by repeated column chromatography on Sephadex LH-20 and Silica gel. Single crystals suitable for X-ray analysis were grown by slow evaporation of a solution of 5'-hydroxyzearalenol in n-hexane:acetone (3:1 v/v) at room temperature.