(E)-3-(2,4-Dimethoxyphenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one

The title compound, C19H20O5, is approximately planar; the dihedral angle between the benzene rings is 3.82 (8)°, and the central propenone C(=O)—C=C plane makes dihedral angles of 1.95 (10) and 3.17 (11)° with the two benzene rings. In the crystal structure, intra- and intermolecular C—H⋯O hydrogen bonds are observed.


Comment
Chalcones have the common skeleton of 1,3-diaryl-2-propen-1-ones and belong to the flavonoid family. Chalcones distribute widespread in fruits, vegetables and so on. Like as other flavonoids, chalcones have been reported to possess widerange biological activities, including antimicrobial, antitumor, anti-inflammatory, antifungal, antioxidant activities and so on (Nowakowska, 2007;Liu et al., 2008;Wu et al., 2010). Moreover, Chalcones belong to nature products and have low toxicity. Owing to its varied pharmacological activities and low toxicity, it has attracted more and more scientists attention and therefore several strategies have been developed to synthesize them (Nowakowska, 2007;Selvakumar et al., 2007;Wu, Chen et al., 2009;Wu, Qiu et al., 2009;Wu, Zhang et al., 2009).
In our effort to develop Chalcones activity, we have synthesized the title chalcone. In order to get detailed information such as the geometrical features and the underlying interaction of the crystal structure, an X-ray study of the title compound was carried out.
Two rings of molecule is approximately planar and the dihedral angle between the two rings is 3.82 (4)°. The average value of exocyclic bond angles [120.8 (5)°] and the bond distances [1.384 (2) Å] in the phenyl rings agree well with the normal values reported in the literature for some analogous structures (Peng et al., 2010;Wu, Chen et al., 2009;Wu, Qiu et al., 2009;Wu, Zhang et al., 2009;Huang et al., 2010;Yathirajan et al., 2006).

Experimental
The title compound was synthesized by Claisene-Schmidt condensation between 2,4-dimethoxybenzaldehyde and 1-(3,4dimethoxyphenyl)ethanone. 2,4-Dimethoxybenzaldehyde (1 mmol) and 1-(3,4-dimethoxyphenyl)ethanone (1 mmol) were dissolved in ethanol (15 ml). The mixture were controlled at 279 K and then 5 drops NaOH (20%) was added. The reaction was monitored by thin-layer chromatography. 15 ml H 2 O was added after 10 h and the yellow solid precipitated was washed with water and cold ethanol. It was then dried and purified by column chromatography on silica gel. Single crystals of the title compound were grown in a CH 2 Cl 2 /CH 3 CH 2 OH mixture (1:1) solution at 279 K.

Refinement
All H atoms were positioned geometrically and allowed to ride on their parent atoms at distances of 0.93 or 0.96 Å, with isotropic displacement parameters 1.2 or 1.5 times U eq of the parent atom.