Crystal structure of 4-[(2E)-3-(4-methoxyphenyl)prop-2-enoyl]phenyl benzoate

In the title compound, C23H18O4, the methoxybenzene ring and attached C=C grouping are disordered over two sets of sites in a 0.823 (5):0.177 (5) ratio. The dihedral angles between the central benzene ring and the pendant phenyl and methoxybenzene ring (major orientation) are 51.21 (1) and 51.6 (1)°, respectively. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds generate R 2 2(28) loops.

considerable interest in the development of new therapeutic agents for various diseases and are generally believed to be non-toxic compounds since they are widely distributed in the human diet (Rackova et al.., 2005;Harborne et al., 2000).
This may be due to the presence of keto group and the associated steric forces. The prop-2-en-1-one group is twisted In the crystal, the symmetry related molecules linked by C-H···O type hydrogen bonds forming dimer R 2 2 (28), described by the graph set motif. These dimer units inturn linked by C-H···O type hydrogen bond results in a molecular chain running along [100] direction.

S2. Experimental
The chalcone derivative is prepared by two steps.
In a 250 mL round-bottomed flask 4-hydroxyacetophenone (0.05 mol) and 4-methoxybenzaldehyde (0.05 mol) were taken to which 120 mL of absolute alcohol was added and stirred at room temperature for a span of 5 minutes. Then 20 mL of 20% sodium hydroxide solution was added and the mixture was stirred for 2 h. The precipitate generated by adding sufficient amount of dilute hydrochloric acid was filtered, washed with water and dried. The crude product was recrystallized twice from absolute alcohol. % of yield: 90.
The second step involves esterification reaction: in a 250 mL round-bottomed flask the chalcone (0.02 mol) was taken in, to which 120 mL of ethyl methyl ketone was added and stirred at room temperature. After a span of 5 minutes, triethylamine (0.04 mol) was added and the mixture was stirred for 15 minutes. Then benzoylchloride (0.02 mol) was added and the reaction mixture was stirred at room temperature for about 2 h. A white precipitate of triethyl ammonium chloride was formed. It was filtered and the filterate was evaporated to get the crude product. The crude product was recrystallized twice from ethyl methyl ketone solution. % of yield: 95.

S3. Refinement
H atoms were positioned geometrically and treated as riding on their parent atoms, with C-H distance of 0.93-0.96 Å, with U iso (H)= 1.5 U eq (c-methyl) and U iso (H)= 1.2Ueq(C) for other H atom. The phenyl benzoate group of the molecule was refined using a disorder model, with relative occupancies of approximately 82.3% and 17.7%.

Figure 1
The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level.

Figure 2
The packing of the molecules in the crystal structure. The dashed lines indicate the hydrogen bonds. Experimental procedure.  (17) 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ.