2-(2-Chloropyridin-3-yl)-N-ethyl-4-methyl-1,3-oxazole-5-carboxamide

In the title compound, C12H12ClN3O2, the dihedral angle between the aromatic rings is 8.42 (10)°. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, generating C(4) chains propagating in [001].

In the title compound, C 12 H 12 ClN 3 O 2 , the dihedral angle between the aromatic rings is 8.42 (10) . In the crystal, molecules are linked by N-HÁ Á ÁO hydrogen bonds, generating C(4) chains propagating in [001].

Related literature
For background to derivatives of oxazolyl carboxylic acids, see: Takechi et al. (2000); Lechel et al. (2009 Table 1 Hydrogen-bond geometry (Å , ).  et al., 2000;Lechel et al., 2009). We report the crystal structure of the title compound (I) to determine the structure of the main product in the preparation of derivatives ofoxazolyl carboxylic acid. The molecular structure of (I) (Fig. 1) contains no crystallographically imposed symmetry. The pyridine and oxazole rings in each of the ligands are not coplanar, the dihedral angle formed by the least-squares planes of the benzene and pyrazole rings being equal to 8.8°. Analysis of the crystal packing of (I) shows the existence of N3-H3···O2 interactions, as shown in Fig. 2.
The reaction mixture was reacted for 2 h. After separation through silica gel column chromatography (fluent: ethyl acetate/ petroleum ether=1/5), The title compound was gained as a yellow solid (0.42 g, 58%).

Refinement
Although all H atoms were visible in difference maps, they were finally placed in geometrically calculated positions, with C-Hdistances in the range 0.93-0.97Å and N-H distances of 0.86 Å, andincluded in the final refinement in the riding model approximation,with U iso (H) = 1.2U eq (C, N) and U iso (H) = 1.5U eq (C).
Figures Fig. 1. The molecular structure of (I), with atom labels and 30% probability displacement ellipsoids.

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 > 2sigma(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.