Crystal structure of (E)-3-(3,4-dimethoxyphenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one

The molecular structure of the title compound, C21H18O4, consists of a 3,4-dimethoxyphenyl ring and a naphthalene ring system linked via a prop-2-en-1-one spacer. The molecule is almost planar, with a dihedral angle between the benzene ring and the naphthalene ring system of 2.68 (12)°. There is an intramolecular O—H⋯O hydrogen bond involving the adjacent hydroxy and carbonyl groups. The molecule has an E conformation about the C=C bond and the carbonyl group is syn with respect to the C=C bond. In the crystal, molecules are linked by bifurcated C—H⋯(O,O) hydrogen bonds, enclosing an R 2 1(6) ring motif, and by a further C—H⋯O hydrogen bond, forming undulating sheets extending in b- and c-axis directions. There are π–π interactions between the sheets, involving inversion-related naphthalene and benzene rings [intercentroid distance = 3.7452 (17) Å], forming a three-dimensional structure.


S2. Refinement
Crystal data, data collection and structure refinement details are summarized in

S3. Comment
Chalcones are 1,3-diphenyl-2-propene-1-ones, in which two aromatic rings are linked by a three carbon α,β-unsaturated carbonyl system.These are abundant in edible plants and are considered to be precursors of flavonoids and isoflavonoids (Rahman et al., 2007). The presence of the enone functionality in the chalcone moiety confers biological activity upon it, such as antiinflammatory (Sashidhara et al., 2011), antifungal (Go et al., 2005) antioxidant (Mukherjee et al., 2001), antimalarial (Liu et al., 2003) antituberculosis (Sivakumar et al., 2007), analgesic (Viana et al., 2003], and antitumor (Ducki et al., 1998) activities. As part of our attempts to investigate the substituent effects of chalcones on molecular structures and hence activities, the title compound was synthesized and its crystal structure was determined.
The molecular structure of the title compound is shown in Fig. 1. The bond distances and angles are similar to those reported for a similar structure (Ahn et al., 2013). The molecule is almost planar with a dihedral angle between the benzene and naphthalene rings of 2.65 (1) Table 1).
There are π-π interactions between the sheets, involving inversion related naphthalene and benzene rings, resulting in a three-dimensional structure [Cg2···Cg3 i = 3.7452 (17)  The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
A view along the c axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1 for details). where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.29 e Å −3 Δρ min = −0.29 e Å −3 Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.212 (16) Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.