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

Javier Hernández-Gil; Sacramento Ferrer; Rafael Ballesteros; Alfonso Castiñeiras

doi:10.1107/S1600536813000123

. 2013 Jan 12;69(Pt 2):o227–o228. doi: 10.1107/S1600536813000123

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

Javier Hernández-Gil ^a, Sacramento Ferrer ^a, Rafael Ballesteros ^b, Alfonso Castiñeiras ^c,^*

PMCID: PMC3569762 PMID: 23424508

Abstract

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.

Related literature

For background to triazole derivatives, see: Aromí et al. (2011 ▶); Olguín et al. (2012 ▶). For related triazole structures, see: Allouch et al. (2008 ▶); Ouakkaf et al. (2011 ▶). For structures of metal complexes with related triazoles, see: Ferrer et al. (2004 ▶, 2012 ▶). For the synthesis of triazoles, see: Chernyshev et al. (2005 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). graphic file with name e-69-0o227-scheme1.jpg

Experimental

Crystal data

C₈H₈N₆O
M _r = 204.20
Tetragonal,
a = 9.5480 (5) Å
c = 21.9570 (9) Å
V = 2001.69 (17) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 293 K
0.15 × 0.09 × 0.05 mm

Data collection

Nonius KappaCCD diffractometer
4484 measured reflections
1407 independent reflections
915 reflections with I > 2σ(I)
R _int = 0.048

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.107
S = 1.07
1407 reflections
137 parameters
H-atom parameters constrained
Δρ_max = 0.12 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶) and DIAMOND (Brandenburg & Putz, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Click here for additional data file.^{(20.5KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813000123/gk2547sup1.cif

e-69-0o227-sup1.cif^{(20.5KB, cif)}

Click here for additional data file.^{(69.6KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813000123/gk2547Isup2.hkl

e-69-0o227-Isup2.hkl^{(69.6KB, hkl)}

Click here for additional data file.^{(3.9KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813000123/gk2547Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N21—H21⋯N23ⁱ	0.86	2.02	2.788 (3)	149
N21—H21⋯O17ⁱ	0.86	2.41	3.061 (3)	133
N18—H18⋯N20ⁱⁱ	0.86	2.45	3.253 (3)	155
N22—H22A⋯O17ⁱ	0.86	2.08	2.860 (3)	150
N22—H22B⋯N20ⁱⁱⁱ	0.86	2.26	3.068 (3)	157

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

This work was supported by the Ministerio de Educación y Ciencia (MEC, Spain) (project CTQ2007–63690/BQU) and by the Ministerio de Ciencia e Innovación and FEDER-EC (project MAT2010–15594). JHG acknowledges a PhD grant (project CTQ2007–63690/BQU, MEC, Spain). Technical support (X-ray measurements at S.C.S.I.E., University of Valencia) from M. Liu-González is gratefully acknowledged.

supplementary crystallographic information

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 1,2,4-triazole 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).

Our group has been reporting on the synthesis and structure of some 3,5-disubstituted triazole-based ligands, i.e. 5-amino-3-pyridin-2-yl-1,2,4-triazole (Ferrer et al., 2004) and 3-acetylamino-5-amino-1,2,4-triazole (Ferrer et al., 2012). In those cases, single crystals of the ligands suitable for X-ray analysis were not obtained. Instead, crystal structures of some of their Cu^II complexes could be determined, thus confirming the structure of the triazole, either in neutral or in anionic form. In this work we describe a novel compound of this series, namely: 5-amino-3-picolinamido-1H-1,2,4-triazole or 5-amino-3-(pyridin-2-yl-acetamido)-1H-1,2,4-triazole (abbreviated as H₂V to account for the presence of two acidic H atoms), for which it has been possible to solve the crystal structure.

The obtained H₂V 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.

In the crystal packing, the triazole ligands are linked by pairs of weak N—H···N hydrogen bonds involving the H18 and N20 atoms, thus generating a characteristic R²₂(8) ring motif (Bernstein et al., 1995) (Fig. 2). Moreover, the molecules are also linked by N—H···N and N—H···O hydrogen bonds, forming fused non-centrosymmetric rings R²₂(7), R²₁(6) and R¹₂(6) and giving rise to one-dimensional tapes parallel to the [010] and [100] directions (Fig. 3). These tapes joined by the R₂²(8) motif of N-H···N hydrogen bonds form a three dimensional framework (Fig.4).

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 2-picolinate. Afterwards, the reaction was cooled down to room temperature and the mixture solidified. The crude product was washed with ethanol and acetone and then recrystallized from methanol to give analytically pure crystals.