4-Difluoromethyl-1-(2,5-dimethoxyphenyl)-1 H -1,2,3-triazole

In the title compound, C11H11F2N3O2, the aryl and triazole rings are both planar, but at an angle of 45.27 (4)° to each other.

In the title compound, C 11 H 11 F 2 N 3 O 2 , the aryl and triazole rings are both planar, but at an angle of 45.27 (4) to each other.

Comment
Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a leading cause of mortality worldwide. The World Health Organization estimates that about one-third of the world's population harbours latent infection of TB. Among such infected individuals, approximately eight million develop active TB, and almost two million of these die from this disease each year. 95% of new TB cases occur in developing countries. The current human immunodeficiency virus (AIDS) pandemic and resistance to the currently available drugs are proving major obstacles to the control of tuberculosis (Tewari et al., 2004;World Health Organization, 2005;Tripathi et al., 2005).
Chemotherapy of TB started in the 1940s. Various drugs have been used against TB, including para-aminosalicylic acid, isoniazid, pyrazinamide, cycloserine, ethionamide, rifampicin and ethambutol. However, six decades have passed without any significant development of new chemical treatments of tuberculosis. TB really can be classed as a neglected disease.
In pursuit of new drugs for TB, we have synthesized a new series of 1-aryl-4-difluoromethyl-1,2,3-triazole derivatives and evaluated their inhibitory activities against M. tuberculosis. All derivatives exhibited tuberculosis inhibitory activity at high concentrations (MIC > 6.5 g ml À1 ); a full description of the biological tests will be reported elsewhere (Costa, Boechat, Rangel et al., 2006). The structure of the title compound, (I), which exhibited 74% of inhibition at a concentration of 80.0 mg ml À1 , is reported below.

Experimental
A solution of diazomalonaldehyde (5.0 mmol) in water (30 ml) was added dropwise to a stirred solution of 2,5-dimethoxyaniline hydrochloride (4.5 mmol) in water (5 ml). The reaction mixture was stirred for 24 h at room temperature; the solid was collected, washed with cold water and crystallized from aqueous ethanol.  (3) All H atoms were located in difference maps and then treated as riding atoms with C-H distances of 0.95 (aryl), 1.00 (methine), 1.01 (triazole) and 0.98 Å (methyl), and with U iso (H) values of 1.2U eq (aryl) or 1.5U eq (methyl); U iso values for the triazole and methine H atoms were freely refined.
We are indebted to the EPSRC for the use of both the Chemical Database Service at Daresbury, primarily for access to the Cambridge Structural Database (Fletcher et al., 1996), and the X-ray service at the University of Southampton for data collection. The molecular structure of the title compound, showing the atomlabelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as circles of arbitrary radii.

Figure 2
The unit-cell contents, showing the relative orientation of the triazole and aryl groups. Ellipsoids are represented as in Fig. 1 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.