4-{(E)-[2-(Pyridin-3-ylcarbonyl)hydrazinylidene]methyl}phenyl acetate

The title compound, C15H13N3O3, exists in the E conformation with respect to the azomethane C=N double bond. The pyridyl and phenyl rings form dihedral angles of 35.67 (8) and 36.65 (7)°, respectively with the central C(=O)N2C unit. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds connect the molecules into chains along the b axis. Another C—H⋯O interaction connects molecules along the c-axis direction, forming layers.


Comment
Hydrazone derivatives show excellent spectrum of biological activities (Sreeja et al., 2004). The chemical and pharmacological properties of aroylhydrazones have been extensively investigated recently owing to their potential application as antineoplastic, antiviral and antiinflammatory agents (Rakha et al., 1996;Takahama, 1996).
The compound ( Fig. 1) crystallizes in the monoclinic space group P2 1 /n. This molecule adopts an E configuration with respect to the C7=N3 bond and it exists in the amido form with a C6=O1 bond length of 1.2277 (18) Å which is very close to the reported C=O bond length of a related structure (Reshma et al., 2012). The O1 and N2 atoms are in a Z configuration with respect to C6-N2 having a torsion angle of 9.9 (3)°. The central C(=O)N 2 C unit has dihedral angles of 35.67 (8) and 36.65 (7)°, respectively with the pyridyl and the phenyl rings.
There is a classical intermolecular N-H···O hydrogen bond interaction between the H atom attached at the N2 and O1 atom of neighbouring molecule with D···A distance of 2.9107 (18) Å and two C-H···O hydrogen bond interactions (Fig. 2) between the H atoms attached at the C7 & C15 and O1 & O3 atoms of neighbouring molecules with D···A distances of 3.251 (2) and 3.469 (4) Å, respectively. The classical hydrogen bond together with C-H···O interaction connect the molecules along b axis while the other C-H···O interaction chain the molecules along c axis in the crystal system. Four types of C-H···π interactions are also found in the molecular system ( Fig. 3) with H···Cg distances of 3.1267, 3.2825, 3.3911 and 3.1984 Å forming a three-dimensional-supramolecuar architecture together with the intermolecular hydrogen bonding interactions. Although there are very weak short ring interactions found in the crystal system, they are not significant to support the network since centroid-centroid distances are above 4 Å. Fig. 4 shows a packing diagram of the title compound viewed along the b axis.

Experimental
The title compound was prepared by adapting a reported procedure (Emmanuel et al., 2011). A solution of pyridine-3carbohydrazide (0.137 g, 1 mmol) in ethanol (10 ml) was mixed with a methanolic solution (10 ml) of 4-formylphenyl acetate (0.164 g, 1 mmol). The mixture was refluxed for 6 h after adding few drops of glacial acetic acid and then cooled to room temperature. The formed crystals were collected, washed with few drops of methanol and dried over P 4 O 10 in vacuo. Colorless block shaped crystals, suitable for SXRD studies, were obtained after slow evaporation of the solution in air for a few days.

Refinement
The atom H2′ was located from a difference Fourier map and N-H3′ distance was restrained to 0.

Figure 1
ORTEP view of the title compound drawn with 50% probability displacement ellipsoids for the non-H atoms.

Figure 4
Packing diagram of the compound along the b axis.

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.