Cinnamyl 8-methoxy-2-oxo-2H-chromene-3-carboxylate

In the crystal structure of the title compound, C20H16O5, the molecule assumes an E configuration with the benzene ring and chromenecarboxyl group located on opposite ends of the C=C double bond. The chromene ring system and benzene ring are oriented at a dihedral angle of 74.66 (12)°. Weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure.

In the crystal structure of the title compound, C 20 H 16 O 5 , the molecule assumes an E configuration with the benzene ring and chromenecarboxyl group located on opposite ends of the C C double bond. The chromene ring system and benzene ring are oriented at a dihedral angle of 74.66 (12) . Weak intermolecular C-HÁ Á ÁO hydrogen bonding is present in the crystal structure.
In the crystal structure, an intramolecular C-H···O hydrogen bond is observed and helps to stablize the conformation of the molecule.

Experimental
A solution of cinnamic alcohol (7.2 mmol) dissolved in dried methyl dichloride (DCM) (25 ml) was added dropwise to a solution of 2-oxo-2H-chromene-3-acyl chloride (7.2 mmol) dissolved in DCM (25 ml) and triethylamine (1 ml) at room temperature. The reaction mixture was stirred for 24 h, monitored by TLC. The reaction mixture was neutralized with 5% HCl and washed by saturated NaHCO 3 solution and brine, respectively. The organic phase is dried over Na 2 SO 4 and evaporated under the reduced pressure. The resulting residue was purified by column chromatography (EtOAc:petroleum ether) to give the purified compound.

Refinement
All H atoms were positioned geometrically and refined as riding with C-H = 0.93 (aromatic), 0.97 (methylene) and 0.96 Å (methyl), U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for the others.

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.
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 Rfactors(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.