1-[5-Methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl]ethanone

The asymmetric unit of the title compound, C11H10N4O3, contains two independent molecules in which the benzene rings make dihedral angles of 38.3 (2) and 87.1 (2)° with respect to the triazole rings. In the crystal, the molecules are linked by C—H⋯O hydrogen bonds, forming chains along [021]. Further, weak C—O⋯π [3.865 (5) Å, 83.8 (3)°] and N—O⋯π [3.275 (5) and 3.240 (6) Å, 141.8 (4) and 102.8 (3)°] interactions are observed.

The asymmetric unit of the title compound, C 11 H 10 N 4 O 3 , contains two independent molecules in which the benzene rings make dihedral angles of 38.3 (2) and 87.1 (2) with respect to the triazole rings. In the crystal, the molecules are linked by C-HÁ Á ÁO hydrogen bonds, forming chains along [021]. Further, weak C-OÁ Á Á   Table 1 Hydrogen-bond geometry (Å , ).

Comment
1,2,3-Triazoles are attractive constructs, because of their unique chemical properties and they find many applications in organic and medicinal chemistry (Nithinchandra et al., 2013). They are found to be potent antimicrobial (Sherement et al., 2004)and antiviral agents. Some of them have exhibited antiproliferative and anti-inflammatory property (Nithinchandra et al., 2012). Also, 1,2,3-triazoles are used as DNA cleaving agents (Manfredini et al., 2000) and potassium channel activators (Biagi et al., 2004).
The asymmetric unit of of the title compound consists of two molecules A and B (Fig. 1). They show conformational difference, as evident from dihedral angles. The dihedral angle between benzene ring and triazole moiety is 38.2 (3)° in A and 87.6 (4)° in B. The values of the bond lengths are similar to the reported literature (Allen et al., 1987).

Experimental
1-Azido-4-nitrobenzene (0.01 mol) was treated with acetyl acetone (0.01 mol) in methanol (10 ml) and the mixture was cooled to 0 °C. Sodium methoxide (0.01 mol) was added under inert atmosphere to the above mixture and stirred at ambient temperature for 8 h. Progress of the reaction was monitored by TLC (ethyl acetate/petroleum ether, 2:3, v/v).
After completion of the reaction, the mixture was poured onto ice cold water. The precipitated solid was filtered, washed with water and recrystallized from ethanol. Single crystals suitable for X-ray analysis were obtained from a 1:2 mixture of DMF and ethanol by slow evaporation.

Refinement
All the H atoms were fixed geometrically (C-H = 0.93-0.96 Å) and allowed to ride on their parent atoms with U iso (H) = 1.5U eq (C-methyl) and 1.2U eq (C) for other H atoms. The Flack parameter x refines to 0.2 (4) with unmerged data, and the absolute structure cannot be determined reliably. The final refinement was performed with the merged data.

Figure 1
Asymmetric unit of the title compound with 50% probability ellipsoids.

Figure 2
Packing diagram of the title compound, viewed along the b axis. Dotted lines indicate hydrogen bonds and short contacts involved. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.17 e Å −3 Δρ min = −0.17 e Å −3 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.