7-[4-(4-Fluorophenyl)-2-methylsulfanyl-1H-imidazol-5-yl]tetrazolo[1,5-a]pyridine

The crystal structure of the title compound, C15H11FN6S, forms a three-dimensional network stabilized by π–π interactions between the imidazole core and the tetrazole ring of the tetrazolopyridineunit; the centroid–centroid distance is 3.627 (1) Å. The crystal structure also displays bifurcated N—H⋯(N,N) hydrogen bonding and C—H⋯F interactions. The former involve the NH H atom of the imidazole core and the tetrazolopyridine N atoms, while the latter involve a methyl H atom, of the methylsulfanyl group, and the 4-fluorophenyl F atom. In the molecule, the imidazole ring makes dihedral angles of 40.45 (9) and 17.09 (8)°, respectively, with the 4-fluorophenyl ring and the tetrazolopyridine ring mean plane.

The crystal structure of the title compound, C 15 H 11 FN 6 S, forms a three-dimensional network stabilized byinteractions between the imidazole core and the tetrazole ring of the tetrazolopyridineunit; the centroid-centroid distance is 3.627 (1) Å . The crystal structure also displays bifurcated N-HÁ Á Á(N,N) hydrogen bonding and C-HÁ Á ÁF interactions. The former involve the NH H atom of the imidazole core and the tetrazolopyridine N atoms, while the latter involve a methyl H atom, of the methylsulfanyl group, and the 4-fluorophenyl F atom. In the molecule, the imidazole ring makes dihedral angles of 40.45 (9) and 17.09 (8) , respectively, with the 4fluorophenyl ring and the tetrazolopyridine ring mean plane.

Comment
Pyridylimidazoles like SB203580 are well known p38 MAP kinase inhibitors (Peifer et al., 2006). The function of the pyridine moiety is to accept a hydrogen bond from the backbone of Met109 in the Hinge region. In the course of our studies we have tried to modify this acceptor system by using the title tetrazolopyridine (Capelli et al., 2008).
The molecular structure of the title compound is given in Fig. 1, and the geometrical parameters are available in the Supplementary information and the archived CIF. The imidazole ring mean plane makes dihedral angles of 40.45 (9)° and 17.09 (8)° with the 4-fluorophenyl ring and the tetrazolopyridine ring mean plane, respectively.
The crystal structure displays asymmetric bifurcated N-H···N hydrogen bonds involving the tetrazolopyridine N-atoms and the NH H-atom of the the imidazole core (Table 1). There is also a C-H···F interaction involving the methylsulfanyl group and the 4-fluorophenyl F-atom (Table 1). The crystal structure of the title compound forms a three dimensional network stabilized by π-π interactions between the imidazole core and the tetrazole moiety of the tetrazolopyridine group; the centroid···centroid distance is 3.627 (1) Å (Table 1).

Experimental
A mixture of 300 mg 2-fluoro-4-[4-(4-fluorophenyl)-2-(methylthio)-1H-imidazol-5-yl]pyridine (Laufer & Liedtke, 2006) in anhydrous DMF with 100 mg sodium azide was heated at 353 K for 12 h. The solvent was then removed under reduced pressure and the residue was diluted with ethylacetate. The organic phase was washed with water and concentrated under reduced pressure. The residue was purified by flash chromatography with ethyl acetate/hexane (1/1) to yield 153 mg (47%) of the title compound. Crystals suitable for X-ray analysis were obtained by crystallization from methanol.