N′-[(E)-2,3-Dihydroxybenzylidene]-2-methoxybenzohydrazide

The title compound, C15H14N2O4 adopts an E conformation about the azomethine double bond. Intramolecular N—H⋯O and O—H⋯N hydrogen bonds generate S(6) rings and help to establish the molecular conformation. The dihedral angle between the benzene rings is 17.84 (10)°. In the crystal, molecules are linked by O—H⋯O and C—H⋯O hydrogen bonds into a two-dimensional network with a herring-bone pattern arranged parallel to the bc plane.


Yousuf Comment
Schiff bases represent an important group of organic compounds with a wide range of medicinal applications (Panneerselvam et al., 2009;Khan et al., 2009;Jarahpour et al., 2007). The title Schiff base was synthesize as a part of our ongoing resaerch to study different bioactive organic compounds.
The bond lengths and angle in the title compound ( Fig. 1) are similar to the corresponding bond lengths and bond angles reported in structurally realted Schiff bases Promdet et al., 2011). The E configuration of azomethine oelfinic bond is stabilized by two intramolecular N1-H1A···O2, O4-H4A···N2 hydrogen bonds. O3-H3A···O1 and C8 -H8A···O3 hydrogen bonds play important roles in stabilizing the crystal structure by forming a two-dimensionalnetwork arranged parallel to the bc plane in a zig zag fashion (Table 2 and Fig. 2).

Experimental
The title compound was synthesized by refluxing a mixture of 2-methoxybenzohydrazide (0.332 g, 2 mmol) and 2,3-dihydroxybenzaldehyde (0.276 g, 2 mmol) in methanol (40 ml) along with a catalytical amount of acetic acid for 3 hr. The progress of reaction was monitored by TLC. After completion of reaction, the solvent was evaporated under reduced vacuum to afford crude product which was recrystallized by dissolving in methanol at room temperature to obtain pure needles (0.458 g, 80% yield). All chemicals were purchased by sigma Aldrich Germany.

Refinement
H atoms on methyl and phenyl C-atoms were positioned geometrically with C-H = 0.96 and 0.93 Å, respectively, and constrained to ride on their parent atoms with U iso (H) = 1.5U eq (methyl) 1.2U eq (aryl). The H atoms on the nitrogen and oxygen atoms were located from difference Fourier maps and refined isotropically. A rotating group model was applied to the methyl groups.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1 0.14939 (10