3-(2,4-Dichlorophenyl)-2-oxo-1-oxaspiro[4.5]dec-3-en-4-yl 2-methylprop-2-enoate

In the title molecule, C19H18Cl2O4, the cyclohexane ring adopts a chair conformation. The furan ring is essentially planar and forms a dihedral angle of 82.1 (1)° with the benzene ring. In the crystal, weak C—H⋯O interactions are present.

In the title molecule, C 19 H 18 Cl 2 O 4 , the cyclohexane ring adopts a chair conformation. The furan ring is essentially planar and forms a dihedral angle of 82.1 (1) with the benzene ring. In the crystal, weak C-HÁ Á ÁO interactions are present.

Related literature
For the potential biological activity of the title compound and the crystal structures of related compounds, see: Bretschneider et al. (2003). For the synthesis, see: Lu et al. (2008).  Table 1 Hydrogen-bond geometry (Å , ). The title compound (I) was synthesized as a new compound with potential biological activity (Bretschneider et al., 2003).

Experimental
We report herein its crystal structure.

Experimental
The synthesis followed the prodedure of Lu et al. (2008). In a flask equipped with stirrer and reflux condenser, 3-(2,4-dichlorophenyl)-2-oxo-1-oxaspiro[4.5]dec-3-ene-4-ol 3.13 g (10.0 mmol), and triethylamine 5 ml was mixed in dichloromethane (30 ml), at 273-278K. The mixture was stirred, then methacryloyl chloride 1.25g (12.0 mmol) for was added dropwise for 1h, then the mixtures was left at room temperature for 3 h. The mixture was then washed with 1% HCl (60 ml) and water (60 ml), and the organic layer was dried over sodium sulfate. Excess dichloromethane was removed on a water vacuum pump to obtain an oily colorless product. The product was crystallized from methanol to afford the title compound 3.39 g (89% yield). Single crystals suitable for X-ray measurements were obtained from a solution of the title compound in acetone and methanol at room temperature.

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