(E)-3-(4-Hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one

In the title compound, C16H14O4, there is an intramolecular O—H⋯O hydrogen bond. The benzene rings are inclined to one another by 13.89 (9)°. The prop-2-en-1-one group is twisted slightly, the O=C—Car—Car (ar = aromatic) and C=C—C=O torsion angles being −10.4 (3) and −7.4 (3)°, respectively. In the crystal, molecules are linked by O—H⋯O hydrogen bonds, forming chains along [100]. These chains are further linked by O—H⋯O hydrogen bonds, forming corrugated sheets lying parallel to (010). There are C—H⋯π interactions present within the sheets.

In the title compound, C 16 H 14 O 4 , there is an intramolecular O-HÁ Á ÁO hydrogen bond. The benzene rings are inclined to one another by 13.89 (9) . The prop-2-en-1-one group is twisted slightly, the O C-C ar -C ar (ar = aromatic) and C C-C O torsion angles being À10.4 (3) and À7.4 (3) , respectively. In the crystal, molecules are linked by O-HÁ Á ÁO hydrogen bonds, forming chains along [100]. These chains are further linked by O-HÁ Á ÁO hydrogen bonds, forming corrugated sheets lying parallel to (010). There are C-HÁ Á Á interactions present within the sheets.

Comment
Chalcones are known as the precursors of all flavonoid type natural products in biosynthesis (Marais et al., 2005). They are a major class of natural products with widespread distribution in fruits, vegetables, spices, tea and soy based food stuff and have been the subjects of interest for their significant pharmacological activities (Di Carlo et al., 1999). Many chalcones have been described for their high anti-malarial activity, probably as a result of addition of nucleophilic species to the double bond of the enone (Troeberg et al., 2000). A review of anti-infective and anti-inflammatory chalcones and recent advances in therapeutic chalcones have been reported (Ni et al., 2004). To understand the three dimensional features of this class of compounds, we report herein on the crystal structure of the title compound.
In the crystal, molecules are linked by O-H···O hydrogen bonds forming chains propagating along the a axis (Table 1 and Fig. 2). These chains are linked by further O-H···O hydrogen bonds forming corrugated sheets lying parallel to (010). Within the sheets there are C-H···π interactions present (Table 1). In total each molecule is linked to four neighbours by O-H···O hydrogen bonds (Table 1 and Fig. 2). Atom O4 acts as a bifurcated donor forming intra-and inter-molecular O-H···O hydrogen bonds (Table 1 and Fig. 2).

Experimental
The title compound was synthesized by a published procedure using the acid catalyzed Claisen-Schmidt reaction

Refinement
The OH H atoms were located from difference Fourier maps and refined with U iso (H)= 1.5U eq (O). The C-bound H atoms were positioned geometrically and treated as riding atoms: C-H distance of 0.93 -0.96 Å with U iso (H)= 1.5U eq (Cmethyl) and = 1.2U eq (C) for other H atom. The molecular structure of the title molecule, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
A view along the x axis of the crystal packing of the title compound. Hydrogen bonds are shown as dashed lines (see Table 1 for details).  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.004 Δρ max = 0.18 e Å −3 Δρ min = −0.20 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0024 (6) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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 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.