1-(6-Chloro-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)-3-(2-chlorophenyl)urea

In the title compound, C14H11Cl2N5O, the plane of the 1H-imidazo[4,5-c]pyridine ring system [r.m.s. deviation = 0.087 (19) Å] makes a dihedral angle of 4.87 (10)° with the terminal phenyl ring. An intramolecular N—H⋯N hydrogen bond stabilizes the molecular conformation. In the crystal, N—H⋯O hydrogen bonds link the molecules into inversion dimers. These dimers are connected by π–π interactions between imidazole rings [shortest centroid–centroid distance = 3.4443 (14) Å].


Comment
The identification of chemotherapeutic targets could lead to new therapeutic approaches and may be a key for the discovery of really effective drugs. The imidazopyridine (Cappelli et al., 2006;Weier et al., 1994;Barraclough et al., 1990;Bavetsias et al., 2007) moieties are important pharmacophores, which have proven to be useful for a number of biologically relevant targets. The compounds derived from the imidazopyridine system have recently been evaluated as antagonists of various biological receptors, including angiotensin-II and platelet activating factor (Cooper et al., 1992).
An intramolecular N-H···N hydrogen bond stabilizes the molecular conformation. Intermolecular N-H···O hydrogen bonds link the molecules to centrosymmetric dimers. These dimers are further connected by intermolecular π-π interactions between imidazole rings [shortest centroid-centroid distance = 3.4443 (14) Å]. A view of the crystal packing is given in Figure 2.

Experimental
A mixture of 2,4,6-trichloropyridene, methylamine in ethanol was heated and filtered to get pure product. To this sulfuric acid and fuming nitric acid was added, then it was stirred and cooled. A solution of iron powder and ammonium chloride in methanol/water was added and heated. Then triethylorthoformate in ethanol was added and continued the heating.
Amination of reaction product was achieved by adding benzophenone imine, potassium carbonate, palladium complex, in dioxane, and then it was heated. The obtained product was dissolved in HCl, stirred, and concentrated in vacuo to give the product. A mixture of obtained product, sodium hydride, 6-chloro-1-methyl-1H-imidazol [4,5-c]pyridin-4-amine and carbonyl/sulfonyl chlorides in tetahydrofuran was stirred and concentrated in vacuo to give the expected products. After completion of each step of the reaction TLC was monitored. The compound is recrystallized by ethanol-chloroform mixture. Colourless needles of the title compound were grown from a mixed solution of Ethanol/Chloroform (V/V = 2/1) by slow evaporation at room temperature.

Refinement
All H atoms were positioned geometrically; N-H = 0.86 Å, C-H = 0.93 Å for aromatic H, and C-H = 0.96 Å for methyl H, and refined using a riding model with U iso (H) = 1.5U eq (C) for methyl H and U iso (H) = 1.2U eq (C) for all other H.

Computing details
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).  The packing of the title compound. Intermolecular hydrogen bonds are shown as dashed lines.  Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq  (17)