5-Cyclopentyl-2-(4-methylphenyl)-3-methylsulfinyl-1-benzofuran

In the title compound, C21H22O2S, the cyclopentyl ring adopts an envelope conformation with the flap atom connected to the benzofuran residue. The benzofuran unit is essentially planar, with a mean deviation from the least-squares plane defined by the nine constituent ring atoms of 0.008 (2) Å. In the crystal, molecules are linked via pairs of C—H⋯π interactions, forming inversion dimers. In the ring of the 4-methylphenyl group, four C atoms and their attached H atoms are disordered over two sets of sites, with site-ccupancy factors of 0.899 (5) and 0.10.

In the title compound, C 21 H 22 O 2 S, the cyclopentyl ring adopts an envelope conformation with the flap atom connected to the benzofuran residue. The benzofuran unit is essentially planar, with a mean deviation from the least-squares plane defined by the nine constituent ring atoms of 0.008 (2) Å . In the crystal, molecules are linked via pairs of C-HÁ Á Á interactions, forming inversion dimers. In the ring of the 4-methylphenyl group, four C atoms and their attached H atoms are disordered over two sets of sites, with site-ccupancy factors of 0.899 (5) and 0.10.   Table 1 Hydrogen-bond geometry (Å , ).

Related literature
Cg is the centroid of the C2-C7 benzene ring.
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.008 (2) Å from the least-squares plane defined by the nine constituent atoms. The cyclopentyl ring has an envelope conformation. In the phenyl ring of the 4-methylphenyl group, the four C atoms (C15/C16/C18/C19) are disordered over two positions with site-ccupancy factors, from refinement of of 0.899 (5) (part A) and 0.101 (5) (part B). In the crystal structure, molecules are connected via pairs of weak C-H···π interactions ( Fig. 2 & Table 1, Cg is the centroid of the C2-C7 benzene ring), forming inversion dimers.
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, 1:1 v/v) to afford the title compound as a colorless solid [yield 71%, m.p. 424-425 K; Rf = 0.65 (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 acetone at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å for aryl,1.00 Å for methine, 0.99 Å for methylene and 0.98 Å for methyl H atoms, respectively.U iso (H) = 1.2U eq (C) for aryl, methine and methylene, and 1.5U eq (C) for methyl H atoms. The positions of methyl hydrogens were optimized rotationally. In the phenyl ring of the 4-methylphenyl group, the C15/C16/C18/C19 atoms are disordered over two positions with site occupancy factors, from refinement of of 0.899 (5) (part A) and 0.101 (5) (part B). The distance of equivalent C-C pairs were restrained to 0.002 Å using the SHELXL-97 command SADI, and C14 and C17 set, was refined using EXYZ,and C14-C19 set was refined using EADP.    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.86 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.