3-(4-Chlorophenylsulfinyl)-2,5,7-trimethyl-1-benzofuran

In the title compound, C17H15ClO2S, the O atom and the 4-chlorophenyl group of the 4-chlorophenylsulfinyl substituent are located on opposite sides of the plane through the benzofuran fragment; the 4-chlorophenyl ring is approximately perpendicular to this plane [dihedral angle = 87.12 (3)°]. In the crystal structure, molecules are linked through a weak intermolecular C—H⋯O hydrogen bond, and by weak C—S⋯π [3.394 (2) Å] and C—Cl⋯π [3.800 (2) Å] interactions.

In the title compound, C 17 H 15 ClO 2 S, the O atom and the 4-chlorophenyl group of the 4-chlorophenylsulfinyl substituent are located on opposite sides of the plane through the benzofuran fragment; the 4-chlorophenyl ring is approximately perpendicular to this plane [dihedral angle = 87.12 (3) ]. In the crystal structure, molecules are linked through a weak intermolecular C-HÁ Á ÁO hydrogen bond, and by weak C-SÁ Á Á [3.394 (2) Å ] and C-ClÁ Á Á [3.800 (2) Å ] interactions.
The benzofuran unit is essentially planar, with a mean deviation of 0.005 (1) Å from the least-squares plane defined by the nine constituent atoms. The 4-chlorophenyl ring is nearly perpendicular to the benzofuran plane with a dihedral angle of 87.12 (3)° and is tilted slightly towards it. The molecular packing ( Fig. 2) is stabilized by a weak intermolecular C-H···O hydrogen bond between the 4-chlorophenyl H atom and the oxygen of the S═O unit, with a C13-H13···O2 i ( Table 1). The crystal packing (Fig. 2) is further stabilized by a weak intermolecular C-S···π interaction between the sulfur and 4-chlorophenyl ring of an adjacent molecule, with a C1-S···Cg1 ii [3.394 (2) Å] (Cg1 is the centroid of the C12-C17 4-chlorophenyl ring), and by an intermolecular C-Cl···π interaction between the chlorine and the benzene ring of a neighbouring benzofuran system, with a C15-Cl···Cg2 iii [3.800 (2) Å] (Cg2 is the centroid of the C2-C7 benzene ring).

Experimental
77% 3-chloroperoxybenzoic acid (247 mg, 1.1 mmol) was added in small portions to a stirred solution of 3-(4-chlorophenylsulfanyl)-2,5,7-trimethyl-1-benzofuran (303 mg, 1.0 mmol) in dichloromethane (40 ml) at 273 K. After being stirred at room temperature for 4 h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (hexane-ethyl acetate, 1:1 v/v) to afford the title compound as a colourless solid [yield 79%, m.p. 419-420 K; R f = 0.69 (hexane-ethyl acetate, 1:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å for aryl and 0.96 Å for methyl H atoms. U iso (H) = 1.2U eq (C) for aryl and 1.5U eq (C) for methyl H atoms.
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as a small spheres of arbitrary radius.

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 > 2sigma(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 Cl 0.59001 (8)