2-Azido-1-(4-nitrophenyl)ethanone

In the title compound, C8H6N4O3, the ketone [C—C(=O)—C] and nitro groups are tilted with respect to the benzene ring by 18.92 (6) and 24.11 (15)°, respectively. In the crystal, molecules are linked into interwoven chains running parallel to the [100] direction by C—H⋯N hydrogen bonds and weak π–π stacking interactions, with centroid–centroid separations of 3.897 (3) Å.

In the title compound, C 8 H 6 N 4 O 3 , the ketone [C-C( O)-C] and nitro groups are tilted with respect to the benzene ring by 18.92 (6) and 24.11 (15) , respectively. In the crystal, molecules are linked into interwoven chains running parallel to the [100] direction by C-HÁ Á ÁN hydrogen bonds and weak stacking interactions, with centroid-centroid separations of 3.897 (3) Å .
The structure of the title compound ( Fig. 1) is similar to that of our recently published compound 2-azido-1-(4-fluorophenyl)ethanone (Yousuf et al., 2012) with the difference that the fluorophenyl ring is replaced by a nitrobenzene ring.
Experimental 1-(4-Nitrophenyl)ethanone (6.05 mmoL, 1.0 eq.) was dissolved in acetonitrile (18 ml) in a round bottom flask. To the stirred mixture, p-toluene sulphonic acid (9.08 mmoL, 1.5 eq.) and N-bromosuccinimide (8.48 mmol, 1.4 eq.) were added, and then heated to reflux for 1 to 1.5 h until TLC analysis showed no starting material present in the mixture. The reaction mixture was cooled to room temperature, sodium azide (18.16 mmoL, 3.0 eq.) was added and further stirred for 2 to 3 hrs followed by the addition of the ice cooled water to quench the reaction. The reaction mixture was extracted with diethyl ether (2 × 25 ml) and the combined organic layer was dried over anhydrous Na 2 SO 4 , filtered and concentrated in vacuum to get the crude product. The crude product was purified by flash silica gel chromatography (EtOAc/hexane 1/9-3/7 v/v) to afford the title compound in 70% yield. Recrystallization from ethanol afforded crystals suitable for single-crystal X-ray studies. All chemicals were purchased from Sigma-Aldrich.

Refinement
Methylene and aromatic H atoms were positioned geometrically with C-H = 0.93-0.97 Å, and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C). 765 Friedel pairs were not merged.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.