4-Butoxy-3-(2,4-dichlorophenyl)-1-oxaspiro[4.5]dec-3-en-2-one

In the title compound, C19H22Cl2O3, the cyclohexane ring adopts a chair conformation. The furan ring plane forms dihedral angles of 81.88 (2) and 50.19 (3)°, respectively, with the benzene ring and the plane formed by the butyl C atoms. The crystal structure is stabilized by weak intermolecular C—H⋯O hydrogen bonds.

In the title compound, C 19 H 22 Cl 2 O 3 , the cyclohexane ring adopts a chair conformation. The furan ring plane forms dihedral angles of 81.88 (2) and 50.19 (3) , respectively, with the benzene ring and the plane formed by the butyl C atoms. The crystal structure is stabilized by weak intermolecular C-HÁ Á ÁO hydrogen bonds.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH2747).

S1. Comment
The title compound (I) was prepared as part of a project in search for new compounds with biological activity (Thomas et al., 2003). We report here the crystal structure of (I).
Toluene (40 ml) was added after 0.5 h, the mixture was heated to dehydration to distill the toluene solvent. Then 1bromobutane 1.51 g (11.0 mmol) and N,N-dimethylformamide(DMF) solvent (20 ml) were added while maintaining the temperature at 373K for 4 h. Upon cooling at room temperature water (20 ml) was added. The mixture was extracted with CH 2 Cl 2 (15 ml) and the organic layer was washed with water and dried over sodium sulfate. The excess CH 2 Cl 2 was removed on a water vacuum pump to obtain the oily product which was crystallized from methanol to afford the title compound 2.95 g (80% yield) (Raeppel et al., 1998;Sarcevic et al., 1973). Single crystals suitable for X-ray diffraction were obtained by recrystallization of the title compound from a mixture of acetone and methanol at room temperature.

S3. Refinement
All C-bound H atoms were placed in calculated positions, with C-H = 0.93-0.97 Å, and included in the final cycles of refinement using a riding model, with U iso (H) = 1.2U eq (C) for the aryl and methylene H atoms and 1.5U eq (C) for the methyl H atoms.  The molecular structure of (I), with displacement ellipsoids drawn at the 40% probability level. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.60 e Å −3 Δρ min = −0.35 e Å −3 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.