4-[5-(4-Benzoyloxyphenyl)-1,2,4-oxadiazol-3-yl]phenyl benzoate

In the title compound, C28H18N2O5, the dihedral angle between the terminal benzoate rings is 20.67 (12)°. The central oxadiazole ring is almost coplanar with its two benzene ring substituents, making dihedral angles of 4.80 (16) and 5.82 (16)°. In the crystal, pairs of C—H⋯O hydrogen bonds form inversion dimers with R 2 2(40) ring motifs. The structure also features C—H⋯O, C—H⋯π and π–π interactions [centroid–centroid separation = 3.695 (4) Å].


Related literature
For the use of oxadiazole derivatives as antimicrobial agents, see: Dhol et al. (2005) and for a related structure, see: Emmerling et al. (2006). For hydrogen-bond motifs, see: Bernstein et al. (1995).

D-HÁ
Experimental 4-[(E)-(hydroxyimino)methyl] phenyl benzoate (4.8 mmole) was dissolved in chloroform, N-chlorosuccinimide (5.2 mmole) was added followed by slow addition of sodium carbonate (8.8 mmole) at room temperature. Then, the resulting reaction mixture was stirred for up to 18 h. After completion of reaction (monitored by TLC), the reaction mixture was diluted with water (50 ml). The aqueous layer was extracted with ethyl acetate (3*20 ml), the combined ethyl acetate layer was washed with brine solution (2*25 ml). Then, the organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford the crude product, which was further purified by column chromatography over silica gel (60-120 mesh) using hexane:ethyl acetate mixture in an 8:2 ratio as eluent. The pure compound was crystallized from ethyl acetate and hexane, to give white single crystals.

Refinement
All hydrogen atoms were located geometrically with C-H = 0.93-0.97) Å and allowed to ride on their parent atoms with U iso (H) = 1.2U eq (aromatic C) or 1.5U iso (methyl C).

Figure 1
ORTEP diagram of the title molecule with 50% probability ellipsoids.

Figure 2
Packing diagram of molecule, viewed along the crystallographic b axis. Dotted lines represent intermolecular hydrogen bonds.

4-[5-(4-Benzoyloxyphenyl)-1,2,4-oxadiazol-3-yl]phenyl benzoate
Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.