(E)-1-{4-[Bis(4-methoxyphenyl)methyl]piperazin-1-yl}-3-(4-ethoxy-3-methoxyphenyl)prop-2-en-1-one

In the molecule of the title compound, C31H36N2O5, the piperazine ring displays a chair conformation. The dihedral angle between the benzene rings of the bis(4-methoxyphenyl)methyl group is 83.42 (15)°. In the crystal, centrosymmetrically related molecules are linked through pairs of C—H⋯O hydrogen bonds into dimers, generating an R 2 2(10) ring motif. The dimers are further connected into chains parallel to [2-10] by C—H⋯O hydrogen bonds involving the methoxy groups.


Comment
As a continuation of our study on the characterization of cinnamic acid derivatives (Teng et al., 2011;Zhong & Wu, 2012), we present here the crystal structure title compound (I).

Experimental
The synthesis follows the method of Wu et al. (2008). The title compound was prepared by stirring a mixture of (E)-3-(4ethoxy-3-methoxyphenyl) acrylic acid (0.889 g; 4 mmol), thionyl chloride (2 ml) and dichloromethane (30 ml) for 6 h at room temperature. The solvent was removed under reduced pressure. The residue was dissolved in acetone (15 ml) and reacted with 1-(bis(4-methoxyphenyl)methyl)iperazine (1.874 g; 6 mmol) in the presence of triethylamine (5 ml) for 12 h at room temperature. The resultant mixture was cooled. The solid obtained was filtered and was recrystallized from ethanol. The colourless single crystals of the title compound used for X-ray diffraction studies were grown by slow evaporation at room temperature of an ethanol:ethyl acetate:chloroform (3:1:1 v/i>v/i>v) solution.

Refinement
All hydrogen atoms were positioned geometrically with C-H distances ranging from 0.93 Å to 0.98 Å and refined as riding on their parent atoms, with U iso (H) = 1.2 or 1.5U eq (C).  The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level.

Figure 2
Packing diagram of the title compound, with intermolecular C-H···O hydrogen bonds drawn as dashed lines.

(E)-1-{4-[Bis(4-methoxyphenyl)methyl]piperazin-1-yl}-3-(4-ethoxy-3-methoxyphenyl)prop-2-en-1-one
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.