4-(4-Cyano-2-fluorophenoxy)phenyl 4-methylbenzenesulfonate

The title compound, C20H14FNO4S, was synthesized from hydroquinone, p-toluenesulfonyl chloride and 3,4-difluorobenzonitrile. A folded conformation is adopted by the crystal structure. Intermolecular C—H⋯N hydrogen bonds form dimers arranged around inversion centers.

The title compound, C 20 H 14 FNO 4 S, was synthesized from hydroquinone, p-toluenesulfonyl chloride and 3,4-difluorobenzonitrile. A folded conformation is adopted by the crystal structure. Intermolecular C-HÁ Á ÁN hydrogen bonds form dimers arranged around inversion centers.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DN2473).
In the crystal structure, the molecules are linked to form pseudo dimers by inter molecular C-H···N hydrogen bonds generating a graph set motif R 2 2 (10) ( Table 1, Fig.2) (Etter, 1990, Bernstein et al., 1995. In addition, the structure is stabilized by weak C-H···O and van der Waal's interactions.

Experimental
A DMSO (10 ml) solution of hydroquinone and p-toluenesulfonyl chloride in the presence of KOH as base was stirred at room temperature for 48 h. Then the mixture was heated to 70°C and 3,4-difluorobenzonitrile was added dropwise. Finally the mixture was washed with water (20 ml) and extracted with ethyl acetate (three times). The organic solvent was removed under reduced pressure and the product was purified by silica gel chromatography (pentane: ethyl acetate mixtures). Suitable crystals were obtained by slow evaporation of ethanol at room temperature.

Refinement
All H atoms were placed in calculated positions with C-H = 0.93-0.98 Å, and were included in the refinement in the riding model with U iso (H) = 1.2U eq of the carrier atoms.  Refinement. Refinement using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).