3-(3,4-Dimethoxybenzyl)chroman-4-one

In the title compound, C18H18O4, the six-membered chroman-4-one ring adopts an envelope conformation with the C atom bonded to the bridging CH2 atom as the flap. The dihedral angle between the mean plane of the fused pyranone ring and the dimethoxy-substituted benzene ring is 89.72 (2)°. In the crystal, adjacent molecules are linked via C—H⋯π interactions.

In the title compound, C 18 H 18 O 4 , the six-membered chroman-4-one ring adopts an envelope conformation with the C atom bonded to the bridging CH 2 atom as the flap. The dihedral angle between the mean plane of the fused pyranone ring and the dimethoxy-substituted benzene ring is 89.72 (2) . In the crystal, adjacent molecules are linked via C-HÁ Á Á interactions.
supplementary materials Acta Cryst. (2013). E69, o241 [doi:10.1107/S1600536813000925]  No classical inter-or intra-molecular hydrogen bonds are observed. The packing of the title compound is stabilized into a three-dimensional network by C-H···π intermolecular interactions, which serve to link inversion-related sheets (Fig 2).

Experimental
2′-Hydroxydihydrochalcone (0.1 g) was dissolved in ethanol (10 ml) and refluxed with paraformaldehyde (0.022 g) and 50% aqueous diethylamine (0.2 ml) for 7 hrs. Ethanol was distilled off and the residue was taken up in ethyl acetate. The ethyl acetate layer washed with water then with dilute HCl and finally with water. Ethyl acetate was distilled off and the oily residue was column chromatographed over silica using pet ether (7): ethyl acetate(3) as eluent to get the 3-(3,4-dimethoxybenzyl)-2,3-dihydro-4H-chroman-4-one. Single crystals of the title compound were grown using methanol as solvent by slow evaporation technique and white needle-like crystals were harvested at room temperature. M.P. 397 K.

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 O1 0.29295 (5