1-(2-Hydroxy-3,5-dimethoxyphenyl)ethanone

In title compound, C10H12O4, all of the non-H atoms lie approximately in a plane with the largest deviation being 0.061 (2) Å. An intramolecular O—H⋯O hydrogen bond generates an S(6) ring motif. No classical intermolecular hydrogen bonding occurs, with only van der Waals forces stabilizing the crystal structure.

In title compound, C 10 H 12 O 4 , all of the non-H atoms lie approximately in a plane with the largest deviation being 0.061 (2) Å . An intramolecular O-HÁ Á ÁO hydrogen bond generates an S(6) ring motif. No classical intermolecular hydrogen bonding occurs, with only van der Waals forces stabilizing the crystal structure.

Comment
Soy isoflavone is secondary metabolite during its growth period. As it could be extracted from plants and have a similar structure of estrogen, people usually call it phytoestrogen. Due to the manifested biological activity, such as antitumor, cardiovascular protection, anti-oxidant, anti-inflammatory, osteoporosis improvement, dual effect on estrogen, isoflavone has been paid more attention in social and academic area (Wang & Murphy, 1994;Yoshio et al., 1989). During the development of our own isoflavone derivatives, the title compound, 1-(2-hydroxy-3,5-dimethoxyphenyl)ethanone, was prepared as an intermediate. The crystallographic analysis of the title compound described herein further confirms the molecular structures of the title compound and isoflavones.
In title compound, C 10 H 12 O 4 , all bond lengths and angles in the molecule are normal (Allen et al., 1987). All of atoms (C1-C10/O1-O4, except H atoms)lie in a plane with the largest deviation 0.061 (2) Å for C10. The intramolecular O3-H3···O4 hydrogen bonds generate S(6) ring motif (Bernstein et al., 1995). There is no classical intermolecular hydrogen bond found in the structure with only Van der Waals forces stabilizing the crystal.

Experimental
Under ice bath, a solution of 2-hydroxyacetophenone(100 g, 0.734 mol) in CH 3 OH(1.2L) was added N-bromosuccinimide(392 g, 2.203 mol). Then the reaction mixture was stirred overnight at room temperature. The mixture was added 1L water to form yellow precipitation then filtered. The filtered cake was washed with a little amount of CH 3 OH/H 2 O=1/1 to yield 80 g light yellow crystals, which is 1-(3,5-dibromo-2-hydroxyphenyl)ethanone. Under ice bath, sodium methoxide(73 g, 1.360 mol) was dissolved in CH 3 OH (1L). Then under nitrogen protection, 1-(3,5-dibromo-2-hydroxyphenyl)ethanone (80 g, 0.272 mol) and CuCl(27 g,0.272 mol) was added to the solution quickly followed by DMF(0.5L). The brown suspension was heated to 363 K overnight until LC-MS showed complete. The mixture was neutralized with concentrated HCl to pH5-6, filtered through celite. Then it was extracted with ethyl acetate three times. The combined organic phase was washed with brine, dried over Na 2 SO 4 and evaporated in vacuo to obtain crude product. Pure title compound was obtained by column chromatography. Crystals suitable for X-ray diffraction were obtained through slow evaporation of a solution of the pure title compound in ethyl acetate/n-hexane (1/4 by volume) (Aalten et al., 1989).

Refinement
All H atoms were found on difference maps, with C-H = 0.95 or 0.98, O-H = 0.84 Å and included in the final cycles of refinement using a riding model, with U iso (H) = 1.2U eq (C) and 1.5U eq (C, O) for the methyl and hydroxyl H atoms.
supplementary materials sup-2 Figures   Fig. 1. View of the title compound, with displacement ellipsoids drawn at the 40% probability level. 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 > σ(F 2 ) is used only for calculating Rfactors(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.