3-(2,4-Dichlorophenyl)-5-phenyl-1,2,4-oxadiazole

In the title compound, C14H8Cl2N2O, the dihedral angles between the plane of the oxadiazole ring and those of the benzene rings are 2.3 (1) and 9.5 (1)°. In the crystal, molecules are linked into chains along the c axis by C—H⋯Cl interactions. These chains are stacked along the a axis.

In the title compound, C 14 H 8 Cl 2 N 2 O, the dihedral angles between the plane of the oxadiazole ring and those of the benzene rings are 2.3 (1) and 9.5 (1) . In the crystal, molecules are linked into chains along the c axis by C-HÁ Á ÁCl interactions. These chains are stacked along the a axis.

Comment
Heterocyclic compounds are becoming increasingly important in recent years due to their pharmacological activities . Nitrogen-and oxygen-containing five/six membered heterocyclic compounds are of enormous significance in the field of medicinal chemistry (Chandrakantha et al., 2010). Oxadiazoles play a very vital role in the preparation of various biologically active drugs with anti-inflammatory (Andersen et al., 1994), anti-cancer (Showell et al., 1991), anti-HIV (Watjen et al., 1989), anti-diabetic and anti-microbial (Swain et al., 1991) activities. The results of biological studies showed that oxadiazole derivatives also possess maximum anti-inflammatory, analgesic and minimum ulcerogenic and lipid per-oxidation (Clitherow et al., 1996) properties.
The C-H···Cl (Table 1) interactions link the molecules into infinite chains along the c-axis and these chains are stacked along the a-axis.

Refinement
All H atoms were located in a difference Fourier map and refined freely. Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
supplementary materials sup-3 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.