3-Hydroxymethyl-6,8-dimethoxy-2H-chromen-2-one

The asymmetric unit of the title compound, C12H12O5, contains four independent molecules. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link the molecules into one-dimensional infinite chains. They are arranged in a nearly parallel fashion along the b axis and stabilized by π–π interactions [3.443 (2) Å].


Comment
The title compound was isolated from the endophytic fungus No. 2090 of the mangrove tree from the South China Sea coast. This substance was previously isolated from the organic extracts of the fungus Verticilliumdahliae Kleb (Ayer et al., 1978). However, the structure of the title compound, (I), was previously elucidated on the basic of spectroscopic analysis.
For further confirming the analytical results, we report herein its crystal structure.
The asymmetric unit of (I) (Fig. 1) contains four independent molecules.
In the crystal structure, intermolecular O-H···O hydrogen bonds (Table 1) link the molecules into one-dimensional infinite chains (Fig. 2). Morover, they are arranged in nearly parallel fashion along the b axis and stabilized by the π-π interactions.
Experimental A strain of fungus (No. 2090) was deposited in the Department of Applied Chemistry, Zhongshan University, Guangzhou, People's Republic of China. Culture conditions: GYT medium (glucose 10 g /L, peptone 2 g /L, yeast extract 1 g /L, NaCl 2.5 g /L) and incubation at 298 K for 24 d. For the extraction and separation of the metabolite, the cultures (70 L) of the title compound were filtered through cheesecloth. The filtrate was concentrated to 3 L below 323 K, then extracted five times by shaking with an equal volume of ethyl acetate. The extract was evaporated under reduced pressure below 323 K. The combined organic extracts were subjected to silica-gel column chromatography, eluting with petroleum ether/ethyl acetate, to yield the title compound. Crystals were obtained through evaporation of a methanol solution.     Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.