5-Chloro-2-methyl-3-(4-methylphenylsulfonyl)-1-benzofuran

The title compound, C16H13ClO3S, crystallized with two independent molecules in the asymmetric unit. The 4-methylphenyl rings make dihedral angles of 75.15 (4)° and 72.18 (4)° with the planes of the benzofuran ring systems in the two molecules. In the crystal, molecules are linked by weak C—H⋯O and C—H⋯π interactions, forming a three-dimensional network.

The title compound, C 16 H 13 ClO 3 S, crystallized with two independent molecules in the asymmetric unit. The 4-methylphenyl rings make dihedral angles of 75.15 (4) and 72.18 (4) with the planes of the benzofuran ring systems in the two molecules. In the crystal, molecules are linked by weak C-HÁ Á ÁO and C-HÁ Á Á interactions, forming a three-dimensional network.  Table 1 Hydrogen-bond geometry (Å , ).
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.006 (1) and 0.007 (1) Å, for A and B, respectively, from the least-squares plane defined by the nine constituent atoms. The dihedral angles between the 4-methylphenyl ring and the mean plane of the benzofuran ring system are 75.15 (4)° in molecule A and 72.18 (4)° in molecule B, respectively. In the crystal packing (Fig. 2), molecules are connected by weak C-H···O and C -H···π interactions (Table 1, Cg is the centroid of the C26-C31 4-methylphenyl ring), forming a three-dimensional network.
Experimental 3-Chloroperoxybenzoic acid (77%, 560 mg, 2.5 mmol) was added in small portions to a stirred solution of 5-chloro-2methyl-3-(4-methylphenylsulfanyl)-1-benzofuran (346 mg, 1.2 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 10h, 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, 4:1 v/v) to afford the title compound as a colorless solid [yield 68%, m.p. 461-462 K; R f = 0.64 (hexane-ethyl acetate, 4:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in benzene 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 0.98Å 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 rotationally.  The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A view of the C-H···O and C-H···π interactions (dotted lines) in the crystal structure of the title compound. H atoms non-participating in hydrogen-bonding were omitted for clarity. [Symmetry codes:  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.