5-Chloro-2,7-dimethyl-3-(3-methylphenylsulfonyl)-1-benzofuran

In the title compound, C17H15ClO3S, the dihedral angle between the mean planes of the benzofuran and 3-methylphenyl rings is 76.99 (4)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds into chains along the b-axis direction. These chains are linked by π–π interactions between the benzene and furan rings of neighbouring molecules [centroid–centroid distance = 3.976 (2) Å].


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Supporting information for this paper is available from the IUCr electronic archives (Reference: IM2452).

Comment
Many compounds involving a benzofuran moiety have attracted much attention due to their valuable pharmacological activities such as antifungal (Aslam et al., 2006), antitumor and antiviral (Galal et al., 2009) and antimicrobial (Khan et al., 2005) properties.
As a part of our ongoing study of 5-chloro-2,7-dimethyl-1-benzofuran derivatives containing cyclohexylsulfinyl (Choi et al., 2011) and 4-bromophenylsulfinyl (Choi et al., 2013) substituents in the 3-position, we report here on the crystal structure of the title compound.
In the title molecule ( Fig. 1), the benzofuran ring system is essentially planar, with a mean deviation of 0.007 (1) Å from the least-squares plane defined by the nine constituent atoms. The 3-methylphenyl ring also is essentially planar, with a mean deviation of 0.004 (1) Å from the least-squares plane defined by the six constituent atoms. The dihedral angle formed by the benzofuran ring system and the 3-methylphenyl ring is 76.99 (4)°. In the crystal structure (Fig. 2), molecules are linked by C-H···O hydrogen bonds (Table 1) into chains along the b-axis direction. These chains are further connected by π···π interactions between the benzene and furan rings of neighbouring molecules, with a Cg1···Cg2 iii distance of 3.976 (2) Å and an interplanar distance of 3.470 (2) Å resulting in a slippage of 1.941 (2) Å (Cg1 and Cg2 are the centroids of the C2-C7 benzene ring and the C1/C2/C7/O1/C8 furan ring, respectively).

Experimental
3-Chloroperoxybenzoic acid (77%, 448 mg, 2.0 mmol) was added in small portions to a stirred solution of 5-chloro-2,7dimethyl-3-(3-methylphenylsulfanyl)-1-benzofuran (272 mg, 0.9 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 8h, 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 (benzene) to afford the title compound as a colorless solid [yield 71%, m.p. 426-427 K; R f = 0.52 (benzene)]. 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 = 0.95 Å for aryl and 0.98 Å for methyl H atoms, respectively. U iso (H) = 1.2U eq (C) for aryl and 1.5U eq (C) for methyl H atoms. The positions of methyl hydrogens were optimized using the SHELXL-97's command AFIX 137 (Sheldrick, 2008).  The molecular structure of the title compound with the atom numbering scheme Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms are presented as small spheres of arbitrary radius.   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.32 e Å −3 Δρ min = −0.36 e Å −3 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.