N′-[(E)-1-(5-Bromo-2-hydroxyphenyl)ethylidene]-4-nitrobenzohydrazide

The title compound, C15H12BrN3O4, displays a trans conformation with respect to the C=N double bond. The central atoms around the C=N double bond are not coplanar, in contrast to the aromatic rings, which exhibit a dihedral angle of 1.80 (4)° between their mean planes. An intramolecular O—H⋯N hydrogen bond occurs. In the crystal, molecules are connected via intermolecular N—H⋯O hydrogen bonding into chains along the a axis.

The title compound, C 15 H 12 BrN 3 O 4 , displays a trans conformation with respect to the C N double bond. The central atoms around the C N double bond are not coplanar, in contrast to the aromatic rings, which exhibit a dihedral angle of 1.80 (4) between their mean planes. An intramolecular O-HÁ Á ÁN hydrogen bond occurs. In the crystal, molecules are connected via intermolecular N-HÁ Á ÁO hydrogen bonding into chains along the a axis.  Data collection: SMART (Bruker, 1996); cell refinement: SAINT (Bruker, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Comment
The chemistry of aroylhydrazones continues to attract much attention due to their coordination ability to metal ions (Zhang et al., 2011;Zheng et al., 2008;Ali et al., 2004) and their biological activity (Carcelli et al., 1995). As an extension of work on the structural characterization of aroylhydrazone derivatives, the title compound, C 15 H 12 N 3 O 4 Br, was synthesized and its crystal structure is reported here.
The title compound, C 15 H 12 N 3 O 4 Br, displays a trans conformation with respect to the C=N double bond (Fig. 1). The central atoms around the C=N double bond are not coplanar since the dihedral angle C7-N1-N2-C9 is 154.7 (5)° in contrast to the aromatic rings which exhibit a dihedral angle of 1.80 (4)° between their mean planes. In the crystal structure, one intramolecular O-H···N hydrogen bond occurs ( Table 1). The molecules are connected via intermolecular N-H···O into one-dimensional linear chains along the a axis (Table 1; Fig. 2).

Experimental
Ethyl 4-nitrobenzoate (9.76 g, 0.05 mol) was dissolved in ethanol (40 ml) at room temperature and heated at 363 K, followed by the addition of hydrazine hydrate (2.50 g, 0.05 mol). Subsequently, the mixture was refluxed for 10 h, and then cooled to room temperature. The crystals were precipitated and collected by filtration. The product was recrystallized from ethanol and dried under reduced pressure to give compound of 4-nitrobenzhydrazide. 4-Nitrobenzhydrazide (4.53 g, 0.025 mol) was dissolved in ethanol (20 ml) at room temperature and heated at 363 K, followed by the addition of 5-bromo-2-hydroxyphenyl ethyl ketone (5.38 g, 0.025 mol). Subsequently, the mixture was refluxed for 9 h, and then cooled to room temperature. The crystals were precipitated and collected by filtration. The product was recrystallized from ethanol and dried under reduced pressure to the title compound.

Refinement
All H atoms were positioned geometrically and treated as riding on their parent atoms, with C-H (methyl) = 0.96 Å, C-H (aromatic) = 0.93 Å, O-H = 0.82 Å, N-H = 0.86 Å and with U iso (H) = 1.5U eq (C methyl , O) and 1.2U eq (C aromatic , N). Fig. 1. The molecular structure of the title compound showing the atom-numbering scheme and displacement ellipsoids drawn at the 30% probability level. H atoms are presented as small spheres of arbitrary radius.