5-Bromo-2,4,6-trimethyl-3-(3-methylphenylsulfinyl)-1-benzofuran

In the title compound, C18H17BrO2S, the dihedral angle between the mean plane of the benzofuran ring system and the benzene ring is 68.58 (4)°. In the crystal, molecules are linked via pairs of C—H⋯O hydrogen bonds into inversion dimers. These dimers are linked by C—H⋯O hydrogen bonds and π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.783 (1) Å], forming a three-dimensional network. In addition, the stacked molecules exhibit inversion-related S⋯O contacts [3.153 (1) Å] involving the sulfinyl groups.

In the title compound, C 18 H 17 BrO 2 S, the dihedral angle between the mean plane of the benzofuran ring system and the benzene ring is 68.58 (4) . In the crystal, molecules are linked via pairs of C-HÁ Á ÁO hydrogen bonds into inversion dimers. These dimers are linked by C-HÁ Á ÁO hydrogen bonds andinteractions between the benzene rings of neighbouring molecules [centroid-centroid distance = 3.783 (1) Å ], forming a three-dimensional network. In addition, the stacked molecules exhibit inversion-related SÁ Á ÁO contacts [3.153 (1) Å ] involving the sulfinyl groups.
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.027 (1) Å from the least-squares plane defined by the nine constituent atoms. The 3-methylphenyl ring is essentially planar, with a mean deviation of 0.011 (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 68.58 (4)°.

Experimental
3-Chloroperoxybenzoic acid (77%, 269 mg, 1.2 mmol) was added in small portions to a stirred solution of 5bromo-2,4,6-trimethyl-3-(3-methylphenylsulfanyl)-1-benzofuran (397 mg, 1.1 mmol) in dichloromethane (35 mL) at 273 K. After being stirred at room temperature for 5h, 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, 2:1 v/v) to afford the title compound as a colorless solid [yield 72%, m.p. 469-470 K; R f = 0.52 (hexane-ethyl acetate, 2:1 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 = 0.95 Å for aryl and 0.95 Å for methyl H atoms. 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 molecule with the atom numbering scheme The displacement ellipsoids are drawn at the 50% probability level. The hydrogen atoms are presented as small spheres of arbitrary radius.  (iii) -x + 2, -y + 1, -z; (iv) -x + 1, -y + 1, -z + 1; (v) x + 1, y, z.] where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.36 e Å −3 Δρ min = −0.49 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq