3-(4-Chlorophenylsulfonyl)-2-methylnaphtho[1,2-b]furan

The title compound, C19H13ClO3S, was prepared by the oxidation of 3-(4-chlorophenylsulfanyl)-2-methylnaphtho[1,2-b]furan with 3-chloroperoxybenzoic acid. The 4-chlorophenyl ring makes a dihedral angle of 68.59 (5)° with the plane of the naphthofuran fragment. The crystal structure is stabilized by π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.635 (3) Å], and by C—H⋯π interactions between a methyl H atom and the furan ring of an adjacent molecule. In addition, the crystal structure exhibits intermolecular C—H⋯O interactions.

The title compound, C 19 H 13 ClO 3 S, was prepared by the oxidation of 3-(4-chlorophenylsulfanyl)-2-methylnaphtho[1,2b]furan with 3-chloroperoxybenzoic acid. The 4-chlorophenyl ring makes a dihedral angle of 68.59 (5) with the plane of the naphthofuran fragment. The crystal structure is stabilized by interactions between the benzene rings of neighbouring molecules [centroid-centroid distance = 3.635 (3) Å ], and by C-HÁ Á Á interactions between a methyl H atom and the furan ring of an adjacent molecule. In addition, the crystal structure exhibits intermolecular C-HÁ Á ÁO interactions.
The naphthofuran unit is essentially planar, with a mean deviation of 0.007 Å from the least-squares plane defined by the thirteen constituent atoms. The 4-chlorophenyl ring (C13-C18) makes a dihedral angle of 68.59 (5)° with the plane of the naphthofuran fragment. The crystal packing (Fig. 2) is stabilized by aromatic π-π stacking interactions between the benzene rings from the adjacent molecules. The Cg1···Cg2 iii distance is 3.635 (3) Å (Cg1 and Cg2 are the centroids of the C5-C10 benzene ring and the C2/C3/C4/C5/C10/C11 benzene ring, respectively, symmetry code as in Fig. 2). The molecular packing is further stabilized by C-H···π interactions between a methyl H atom and the furan ring of the naphthofuran unit, with a C19-H19A···Cg3 i separation of 2.89 Å ( Fig. 2 and Table 1; Cg3 is the centroid of the O1/C12/C1/C2/C11 furan ring; symmetry code as in Fig. 2). Additionally, intermolecular C-H···O interactions in the structure were observed ( Fig.   2 and Table 1; symmetry code as in Fig. 2) Experimental 3-Chloroperoxybenzoic acid (77%, 336 mg, 1.5 mmol) was added in small portions to a stirred solution of 3-(4-chlorophenylsulfanyl)-2-methylnaphtho[1,2-b]furan (227 mg, 0.7 mmol) in dichloromethane (30 ml) at 273 K. After being stirred at room temperature for 4 h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography

Refinement
All H atoms were geometrically positioned and refined using a riding model, with C-H = 0.95 Å for aromatic H atoms and 0.98 Å for methyl H atoms, respectively, and with U iso (H) = 1.2U eq (C) for aromatic and U iso (H) = 1.5U eq (C) for methyl H atoms.

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.