N′-[(3-Methyl-2-thienyl)carbonyl]isonicotinohydrazide

In the title compound, C12H11N3O2S, the pyridine ring is inclined to the thiophene ring, forming a dihedral angle of 34.96 (7)°. The mean plane through the hydrazide unit forms dihedral angles of 21.57 (8) and 53.08 (8)°, respectively, with the pyridine and thiophene rings. The two O atoms are twisted away from each other, as indicated by the C—N—N—C torsion angle of −81.27 (15)°. In the crystal structure, molecules are linked into an extended three-dimensional network by intermolecular N—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds. The crystal structure also features a short S⋯O [3.2686 (10) Å] interaction and a weak intermolecular C—H⋯π interaction.


Comment
In the search of new compounds, isoniazid derivatives have been found to possess potential tuberculostatic activity (Janin, 2007;Maccari et al., 2005;Slayden et al., 2000). As a part of a current work on synthesis of such derivatives, in this paper we present the crystal structure of the title compound, (I) which was synthesized in our lab.

Experimental
Compound (I) was prepared following the procedure by literature (Besra et al., 1993). Dry dichloromethane (30 ml) and 4-dimethylaminopyridine (4-DMAP) (1.2 eq) was added to 3-methylthiophene-2-carbonyl chloride followed by isoniazid (1.1 eq). The reaction mixture was kept in an ice bath for 1 h and then left stirring under nitrogen atmosphere overnight at room temperature. Dichloromethane (20 ml) was added to the reaction mixture, which was then washed with water, and the organic layer dried over anhydrous sodium sulphate. The solvent was removed under reduced pressure to afford the crude product which was purified by column chromatography and recrystallized from ethanol to afford colorless single crystals.

Refinement
All the H atoms were placed in calculated positions, with N-H = 0.86 Å, U iso (H) = 1.2 U eq (N), C-H = 0.93 Å, U iso (H) = 1.2 U eq (C) for aromatic, and C-H = 0.96 Å, U iso (H) = 1.5 U eq (C) for methyl group. These H atoms were refined as riding on their parent atoms. A rotating group model was used for the methyl group.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.
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.