Methyl 5-methyl-1-(1H-pyrazol-3-yl)-1H-1,2,3-triazole-4-carboxylate

The asymmetric unit of the title compound, C8H9N5O2, contains two independent molecules (A and B) in which the dihedral angles between the triazole and pyrazole rings are 4.80 (14) and 8.45 (16)°. In the crystal, molecules are linked by N—H⋯N hydrogen bonds into supramolecular independent A and B chains propagating along the b-axis direction. The crystal structure also features π–π stacking between the aromatic rings of adjacent chains, the centroid–centroid separations being 3.8001 (15), 3.8078 (17), 3.8190 (14) and 3.8421 (15) Å.

The asymmetric unit of the title compound, C 8 H 9 N 5 O 2 , contains two independent molecules (A and B) in which the dihedral angles between the triazole and pyrazole rings are 4.80 (14) and 8.45 (16) . In the crystal, molecules are linked by N-HÁ Á ÁN hydrogen bonds into supramolecular independent A and B chains propagating along the b-axis direction. The crystal structure also featuresstacking between the aromatic rings of adjacent chains, the centroid-centroid separations being 3.8001 (15), 3.8078 (17), 3.8190 (14) and 3.8421 (15) Å .

Comment
1,2,3-Triazole and its derivatives had attracted considerable attention for the past few decades due to their chemotherapeutical value. Many 1,2,3-triazoles are found to be potent antimicrobial and antiviral agents. Some of them have exhibited antiproliferative and anticancer activities (Danoun et al., 1998). Some 1,2,3-triazoles are used as DNA cleaving agents (Manfredini et al., 2000) and potassium channel activators. Prompted by the chemotherapeutic importance of 1,2,3-triazoles and its derivatives, we have synthesized the title compound and report its crystal structure herein.
The title compound, contains two crystallographically independent molecules and bond lengths and angles are in the normal range (Fig. 1). The dihedral angle between the triazole and pyrazole rings is 4.80 (14)° and 8.45 (16)° respectively.
The crystal structure is stabilized by N-H···N hydrogen bonds linking molecules into one-dimensional chains running parallel to the b axis (Fig. 2). The structure is further stabilized by π···π stacking interactions, with centroid-to-centroid separations of 3.8001 (15)-3.8421 (15) Å.

Refinement
H-atoms were placed in calculated positions and refined constrained to ride on their parent atoms, with C-H = 0.93-0.96 Å and N-H = 0.86 Å, U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C,N) for the others.  The molecular structure of the title compound with displacement ellipsoids drawn at the 30% probability level.

Figure 2
View of the one-dimensional chains of the title compound extending along the b axis. All the hydrogen atoms except those involved in hydrogen bonding have been omitted for clarity. Hydrogen bonds are shown as dashed lines. Methyl 5-methyl-1-(1H-pyrazol-3-yl)-1H-1,2,3-triazole-4-carboxylate  Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.