N-(5-Amino-1H-1,2,4-triazol-3-yl)pyridine-2-carboxamide

The title compound, C8H8N6O, was obtained by the reaction of 3,5-diamino-1,2,4-triazole with ethyl 2-picolinate in a glass oven. The dihedral angles formed between the plane of the amide group and the pyridine and triazole rings are 11.8 (3) and 5.8 (3)°, respectively. In the crystal, an extensive system of classical N—H⋯N and N—H⋯O hydrogen bonds generate an infinite three-dimensional network.


N-(5-Amino-1H-1,2,4-triazol-3-yl)pyridine-2-carboxamide
Javier Hernández-Gil, Sacramento Ferrer, Rafael Ballesteros and Alfonso Castiñeiras Comment A significantly large variety of 1,2,4-triazole-based compounds have been prepared to serve as ligands with the aim of obtaining discrete polynuclear metal complexes or polymeric coordination networks, owing to the ability of the 1,2,4triazole ring to bridge metal ions through different coordination ways (Aromí et al., 2011;Olguín et al., 2012). Usually the 1,2,4-triazole-based family of ligands are classified in three categories (Aromí et al., 2011): (a) those containing an unique coordinative ring, (b) those possessing two or more coordinative rings linked by a spacer, and (c) the mixed ligands, which present two or more functional groups. Most of the 3,5-disubstituted derivatives can be included in the last category (Allouch et al., 2008;Ouakkaf et al., 2011).
The obtained H 2 V species is an attractive ligand since it presents 5 to 7 donor atoms (depending on the degree of deprotonation) but also the possibility of forming different chelating rings when coordinated to metals. Besides, in metal complexes the pyridyl ring often rotates around the single C-C bond leading to different binding conformations (Ouakkaf et al., 2011). This enlarges its capability to produce novel metal-organic structures.
As shown in Figure 1, the NH hydrogen is trans to the C=O group, as is observed for all N monosustituted amides.
Molecular dimensions, such as the C=O bond length of 1.227 (3) Å and the central C-N-C amide angle of 127.40 (17)°, may be considered normal.

Experimental
An evaporating flask containing 3,5-diamino-1,2,4-triazole (41.4 mmol, 4.10 g) and ethyl 2-picolinate (6.3 ml, 7 g, 46.3 mmol) was connected to a glass oven and the reaction temperature was slowly raised to 210 °C. The mixture was stirred (rotated) for 4 h. At this point, a vacuum pump was connected during 60 minutes to remove the excess of ethyl 2picolinate. Afterwards, the reaction was cooled down to room temperature and the mixture solidified. The crude product sup-2 Acta Cryst. (2013). E69, o227-o228 was washed with ethanol and acetone and then recrystallized from methanol to give analytically pure crystals.

Refinement
All H atoms were positioned geometrically and were treated as riding on their parent atoms, with C-H distances of 0.93 Å and N-H distances of 0.86 Å with U iso (H) = 1.2U eq (C/N). In the absence of significant anomalous dispersion, Friedel pairs were merged.

N-(5-Amino-1H-1,2,4-triazol-3-yl)pyridine-2-carboxamide
Crystal data 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.