1,3-Bis[(3-chloropyrazin-2-yl)oxy]benzene

The asymmetric unit of the title compound, C14H8Cl2N4O2, contains one half-molecule, the complete molecule being generated by the operation of a twofold rotation axis. The Cl atom deviates significantly from the plane of the pyrazine ring [0.0215 (4) Å]. The central benzene ring makes a dihedral angle of 72.82 (7)° with the plane of the pyrazine ring.

The asymmetric unit of the title compound, C 14 H 8 Cl 2 N 4 O 2 , contains one half-molecule, the complete molecule being generated by the operation of a twofold rotation axis. The Cl atom deviates significantly from the plane of the pyrazine ring [0.0215 (4) Å ]. The central benzene ring makes a dihedral angle of 72.82 (7) with the plane of the pyrazine ring.

1,3-Bis[(3-chloropyrazin-2-yl)oxy]benzene
Thothadri Srinivasan, Venkatesan Kalpana, Perumal Rajakumar and Devadasan Velmurugan Comment The pyrazine ring system is a useful structural element in medicinal chemistry and has found broad applications in drug development which can be used as antiproliferative agent (Dubinina et al., 2006), potent CXCR3 antagonists (Du et al., 2009), CB1 antagonists (Ellsworth et al., 2007), and c-Src inhibitory (Mukaiyama et al., 2007). On-going structural studies of heterocyclic N-containing derivatives (Nasir et al., 2010) are motivated by an investigation of their fluorescence properties (Kawai et al., 2001;Abdullah, 2005). In view of different applications of this class of compounds, we have undertaken the single crystal structure determination of the title compound.

Experimental
To a stirred solution of Cs 2 CO 3 /K 2 CO 3 (22 mmol) in CH 3 CN (50 mL), resorcinol (10 mmol) was added and stirred for 5 min. 2,3-dichloropyrazine (20 mmol) in CH 3 CN (100 mL) was added dropwise to the above reaction mixture and allowed for stirring at refluxing condition for 12 h. After the reaction was complete, the reaction mixture was allowed to attain room temperature and then evaporated to dryness. The residue obtained was extracted with CH 2 Cl 2 (3 x 100 mL), washed with water (3 x 100 mL), brine and then dried over Na 2 SO 4 . Evaporation of the organic layer gave a residue, which on purification using column chromatography with hexane/CHCl 3 (1:1) as an eluent gave the corresponding compound.
Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a solution of the title compound in hexane at room temperature.

Refinement
The hydrogen atoms were placed in calculated positions with C-H = 0.93 Å, refined in the riding model with fixed isotropic displacement parameters:U iso (H) = 1.2U eq (C).

Computing details
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae, et al.,2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009   The molecular structure of the title compound, showing displacement ellipsoids drawn at the 30% probability level. H atoms are presented as small spheres of arbitrary radius. The related atoms have the symmetry code: (a) -x, y, -z+1/2. 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.