(E)-4-Bromo-N′-(4-hydroxy-3-methoxybenzylidene)benzohydrazide monohydrate

In the title compound, C15H13BrN2O3·H2O, the dihedral angle between the two benzene rings is 13.92 (6)°. The methoxy group of the 4-hydroxy-3-methoxyphenyl is almost coplanar with its bound benzene ring, as seen by the Cmethyl—O—C—C torsion angle of −0.35 (16)°. In the crystal, molecules are linked into a three-dimensional network by N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds and also weak C—H⋯O interactions. A short C⋯O contact of 3.0191 (15) Å is also present.

In the title compound, C 15 H 13 BrN 2 O 3 ÁH 2 O, the dihedral angle between the two benzene rings is 13.92 (6) . The methoxy group of the 4-hydroxy-3-methoxyphenyl is almost coplanar with its bound benzene ring, as seen by the C methyl -O-C-C torsion angle of À0.35 (16) . In the crystal, molecules are linked into a three-dimensional network by N-HÁ Á ÁO, O-HÁ Á ÁN and O-HÁ Á ÁO hydrogen bonds and also weak C-HÁ Á ÁO interactions. A short CÁ Á ÁO contact of 3.0191 (15) Å is also present.
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009  As part of our study on bioactivity of hydrazone and benzohydrazide derivatives, the title compound is one of the several benzohydrazide derivatives which were synthesized and tested for biological activity. It have been known that some benzohydrazides possess various biological properties, such as antibacterial and antifungal (Loncle et al., 2004), and antiproliferative (Raj et al., 2007) activities. We have previously reported some crystal structures of this category of compounds Horkaew et al., 2011;Promdet et al., 2011). The title compound (I) was synthesized in order to study the effect of functional groups and their positions on their bioactivities by comparing with the closely related structures in our research project. (I) was screened for antibacterial and antioxidant activities. Our biological testing found that (I) exhibits potent antioxidant activity whereas inactive against the tested bacteria strains which are
Bond distances are in normal ranges (Allen et al., 1987) and are comparable with the related structures Horkaew et al., 2011;Promdet et al., 2011).

Experimental
The title compound (I) was prepared by dissolving 4-bromobenzohydrazide (2 mmol, 0.43 g) in ethanol (15 ml reaction. The mixture was refluxed for around 5 hr and the white solid of the product that appeared was collected by filtration, washed with ethanol and dried in air. Colorless block-shaped single crystals of the title compound suitable for X-ray structure determination were recrystallized from methanol by slow evaporation of the solvent at room temperature after several days, Mp. 513 K (decomposed).

Refinement
All H atoms were positioned geometrically and allowed to ride on their parent atoms, with d(N-H) = 0. 86 Å, d(O-H) = 0.80 Å for hydroxy and 0.78 and 0.82 Å for water, d(C-H) = 0.95 Å for aromatic and CH and 0.98 Å for CH 3 atoms. The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups.

Figure 1
The molecular structure of the title compound, showing 55% probability displacement ellipsoids and the atom-numbering scheme.  The crystal packing of the title compound viewed approximately along the a axis, showing 3D network. Hydrogen bonds were drawn as dashed lines.  (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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Br1