(E)-4-Hydroxy-N′-(3-hydroxy-4-methoxybenzylidene)benzohydrazide

The molecule of the title benzohydrazide derivative, C15H14N2O4, exists in a trans conformation with respect to the C=N double bond and is twisted, the dihedral angle between the two benzene rings being 24.17 (6)°. The methoxy group is almost co-planar with respect to the attached benzene ring [Cm—O—C—C (m = methyl) = −1.45 (17)°]. In the crystal, the molecules are linked by N—H⋯O and O—H⋯O hydrogen bonds into sheets parallel to the bc plane. These sheets are further connected into a three-dimensional network by weak C—H⋯O and C—H⋯π interactions.

These interesting properties lead us to synthesize the title compound (I), which contains hydroxyl and methoxy substituents, in order to study and compare its biological properties with other related benzohydrazide derivatives. Herein the crystal structure of (I) is reported.
The molecule of the title benzohydrazide derivative ( In the crystal packing ( Fig. 2), the molecules are linked by N-H···O and O-H···O hydrogen bonds (Table 1) into sheets parallel to the bc plane and these sheets are further connected into three dimensional network. The crystal is stabilized N-H···O and O-H···O hydrogen bonds together with C-H···O weak interaction. C-H···π weak interaction (Table 1) was also observed.
The mixture was refluxed for around 5 hr. The solution was then cooled to room temperature. Colorless blocks of (I) were obtained after slow evaporation of the solvent at room temperature after several days, Mp. 516 K (decompose).

Refinement
All H atoms were positioned geometrically and allowed to ride on their parent atoms, with d (

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1 0.43925 (8