5-Chloro-3-ethylsulfinyl-7-methyl-2-(4-methylphenyl)-1-benzofuran

In the title compound, C18H17ClO2S, the dihedral angle between the mean planes of the benzofuran ring system and the methylphenyl ring is 14.50 (4)°. The centroid–centroid distances between the benzene and the methylphenyl rings are 3.827 (2) and 3.741 (2) Å, while the centroid–centroid distance between the furan and methylphenyl rings is 3.843 (2) Å. These distances indicate π–π interactions; on the other hand, the interplanar angles between the benzene and methylphenyl rings, and between the furan and methylphenyl rings are 13.89 (4) and 15.53 (4)°, respectively. In the crystal, the molecules stack along the a-axis direction.

In the title compound, C 18 H 17 ClO 2 S, the dihedral angle between the mean planes of the benzofuran ring system and the methylphenyl ring is 14.50 (4) . The centroid-centroid distances between the benzene and the methylphenyl rings are 3.827 (2) and 3.741 (2) Å , while the centroid-centroid distance between the furan and methylphenyl rings is 3.843 (2) Å . These distances indicateinteractions; on the other hand, the interplanar angles between the benzene and methylphenyl rings, and between the furan and methylphenyl rings are 13.89 (4) and 15.53 (4) , respectively. In the crystal, the molecules stack along the a-axis direction.

Related literature
For background information about related compounds and their crystal structures, see Choi et al. (2010a,b). Forstacking in metal complexes with aromatic nitrogen ligands, see: Janiak (2000).
Supporting information for this paper is available from the IUCr electronic archives (Reference: FB2296).

Comment
As a part of our ongoing study of 5-chloro-3-ethylsulfinyl-7-methyl-1-benzofuran derivatives which contain 4-fluorophenyl and 4 iodophenyl substituents in the 2-position (Choi et al. (2010a,b) for the F and I-compound, respectively), we report the crystal structure of the title compound.
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with the mean deviation from the least-squares plane defined by the nine constituent atoms which equals to 0.016 (1) Å. The 4-methylphenyl ring is also essentially planar, with the mean deviation of 0.004 (1) Å from the least-squares plane defined by the six core-ring atoms. The dihedral angle between the benzofuran ring system and the core of the 4-methylphenyl rings is 14.50 (4)°.
The residue was purified by column chromatography (hexane-ethyl acetate, 1:1v/v) to afford the title compound as a colourless solid [yield 71%, m.p. 392-393 K; R f = 0.56 (hexane-ethyl acetate, 1:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of the 5% solution of the title compound in acetone at room temperature.
The average crystal size was approximately 1.1 × 1.3 × 0.8 mm. (The measured crystal was cut from a large one.) The crystals are soluble in polar solvents.

Refinement
All the hydrogen atoms were observed in the difference electron density map. However, they were situated into the idealized positions and refined using a riding-model approximation. The used constraints: C-H = 0.95 Å for aryl, 0.98 Å for methyl and for 0.99 Å for methylene H atoms. U iso (H) = 1.2U eq (C) for aryl and methylene, while 1.5U eq (C) for the supplementary materials methyl H atoms. The positions of methyl hydrogens were optimized using the SHELXL-97's command AFIX 137 (Sheldrick, 2008).

Figure 1
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.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.31 e Å −3 Δρ min = −0.29 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.006 (2) 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.