(E)-N′-(5-Bromo-2-methoxybenzylidene)isonicotinohydrazide

The asymmetric unit of the title compound, C14H12BrN3O2, contains two independent molecules in which the dihedral angles between the benzene ring and the pyridine ring are 24.4 (6) and 23.7 (6)°. The molecules exist in a trans configuration with respect to the central methylidene units. In the crystal, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains along the a axis.

The asymmetric unit of the title compound, C 14 H 12 BrN 3 O 2 , contains two independent molecules in which the dihedral angles between the benzene ring and the pyridine ring are 24.4 (6) and 23.7 (6) . The molecules exist in a trans configuration with respect to the central methylidene units. In the crystal, molecules are linked through intermolecular N-HÁ Á ÁO hydrogen bonds, forming chains along the a axis.

Experimental
Crystal data
Hydrazone compounds derived from the condensation of aldehydes with hydrazides have been demonstrated to possess excellent biological activities (Zhong et al., 2007;Raj et al., 2007;Jimenez-Pulido et al., 2008). Due to the easy synthesis of such compounds, a number of hydrazone compounds have been synthesized and structurally characterized (Yehye et al., 2008;Fun et al., 2008a,b;Yang et al., 2008;Ejsmont et al., 2008;Yang, 2006). Recently, we have reported a few such compounds (Ban, 2010;Ban & Li, 2008a,b;Li & Ban, 2009a,b). We report here the crystal structure of the title new compound.
The asymmetric unit of the title hydrazone compound, Fig. 1, contains two independent molecules. The dihedral angles between the benzene ring and the pyridine ring in each molecule are 24.4 (6) and 23.7 (6)°, respectively. The molecules exist in a trans configuration with respect to the central methylidene units. In the crystal structure, molecules are linked through intermolecular N-H···O hydrogen bonds (Table 1), forming chains along the a axis, Fig. 2.

Experimental
The title compound was prepared by refluxing 5-bromo-2-methoxybenzaldehyde (1.0 mol, 0.22 g) with isonicotinohydrazide (1.0 mol, 0.14 g) in methanol (100 ml). Excess methanol was removed from the mixture by distillation. The colourless solid product was filtered, and washed three times with methanol. Colourless block-shaped crystals of the title compound were obtained from a methanol solution of the compound by slow evaporation in air.

Refinement
Atoms H2 and H5 were located in a difference Fourier map and refined isotropically, with the N-H distances restrained to 0.90 (1) Å. The remaining H atoms were placed in calculated positions (C-H = 0.93-0.96 Å) and refined as riding with U iso (H) = 1.2U eq (C) and 1.5 U eq (C7 and C21). Fig. 1. The molecular structure of the title compound, showing 30% probability displacement ellipsoids for the non-hydrogen atoms. A hydrogen bond is shown as a dashed line.