N-p-Tolyl-1,3-selenazolo[5,4-b]pyridin-2-amine

In the title compound, C13H11N3Se, the dihedral angle between the mean plane of the fused selenoazolopyridine ring system and the p-toluidine ring is 14.260 (5)°. In the crystal, molecules are linked by N—H⋯N hydrogen bonds, forming zigzag chains extending along the b-axis direction.

In the title compound, C 13 H 11 N 3 Se, the dihedral angle between the mean plane of the fused selenoazolopyridine ring system and the p-toluidine ring is 14.260 (5) . In the crystal, molecules are linked by N-HÁ Á ÁN hydrogen bonds, forming zigzag chains extending along the b-axis direction.   Table 1 Hydrogen-bond geometry (Å , ).

Comment
Since the discovery of the importance of Se as a microelement in bacteria and animals, and the function of the selenoenzyme glutathione peroxidase (GPx) as an antioxidant, the interest in organoselenium compounds has increased significantly (Garud et al., 2007;Ling et al., 2010;Plamen et al., 2004Plamen et al., , 2010. The design and synthesis of organoselenium compounds, especially Se-containing heterocycles, are our current interest. The title molecule, C 13 H 11 N 3 Se, (Fig. 1) is built up from two fused rings, viz. the selenazolo and pyridine rings, linked to a p-toluidine group.
The dihedral angle between these two ring systems is 14.260 (5)°. In the crystal, the molecules are linked by intermolecular N-H···N hydrogen bonds (Table 1), giving one-dimensional zigzag chains extending along b.

Experimental
To a stirred solution of N-p-tolylformamide (10 mmol) in toluene (100 ml) in an ice bath, Et 3 N (4.0 g, 40 mmol) and Se black powder were added. Phosgene (8 g of a 20% solution in toluene) was then added slowly over 30 min. giving an exothermic reaction. After complete addition, the suspension was heated under reflux for 10 h (TLC control). The mixture was filtered and washed with several portions of toluene, and the filtrate was then concentrated, affording the raw isoselenocyanatobenzene. This was added to a stirred solution of 2-chloropyridin-3-amine (1.28 g, 10 mmol) in 2propanol at room temperature, and the mixture was heated to reflux for 6 h. After filtration, the precipitate was collected as a yellow solid. The impure product was dissolved in CCl 2 H 2 at room temperature. Yellow crystals suitable for X-ray analysis (80.2% yield) grew over a period of one week when the solution was exposed to the air.

Refinement
Hydrogen atoms were placed at calculated positions [N-H = 0.88 Å, C-H(aromatic) = 0.95 Å, C-H(methyl) = 0.98 Å] and treated as riding, with U iso (H) = 1.2U eq (N and aromatic C) and U iso (H) = 1.5U eq (methyl C). A check using  The molecular structure of the title compound showing the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. 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.