(E)-4-Amino-N′-(2-hydroxy-5-methylbenzylidene)benzohydrazide

The asymmetric unit of the title compound, C15H15N3O2, comprises two crystallographically independent molecules (A and B), each having an E conformation around the C=N bond. In each molecule, there is an intramolecular O—H⋯N hydrogen bond making an S(6) ring motif. The dihedral angles between the substituted phenyl rings are 17.49 (9) and 10.03 (9)°. In the crystal, N—H⋯O hydrogen bonds link neighbouring independent molecules into infinite chains, of the type –A–B–A–B–, along the a axis, enclosing R 2 1(7) ring motifs. The chains are linked by N—H⋯O hydrogen bonds and C—H⋯O interactions, leading to the formation of a three-dimensional network.

The asymmetric unit of the title compound, Fig. 1, comprises two crystallographically independent molecules (A and B) both with an E conformation around the C═N bond. The bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to those reported for related structures (Xu, 2012;Shi & Li, 2012;Bakir & Green, 2002;Kargar et al. (2012a,b). In each molecule there is an intramolecular O-H···N hydrogen bond making an S(6) ring motif.
In the crystal, N-H···O hydrogen bonds (Table 1 and Fig. 2) link neighbouring independent molecules into infinite chains, of the type -A-B-A-B-, along the a axis, enclosing R 1 2 (7) ring motifs (Bernstein et al., 1995). The chains are linked by N-H···O hydrogen bonds and C-H···O interactions leading to the formation of a three-dimensional network (Table 1).

Experimental
The title compound was synthesized by adding 1 mmol of methyl 4-aminobenzoate to a solution of 5-methylsalicylaldehyde (1 mmol) in methanol (30 ml). The mixture was refluxed with stirring for 30 min and after cooling to room temperature a light-yellow precipitate was filtered and washed with diethylether and dried in air. Yellow prismatic crystals of the title compound, suitable for X-ray structure analysis, were recrystallized from ethanol by slow evaporation of the solvents at room temperature over several days.

Refinement
The N-bound H-atoms were located in a difference Fourier map and were constrained to ride on their parent N atoms with U iso (H) = 1.2U eq (N). The OH and C-bound H atoms were included in calculated positions and treated as riding atoms: O-H = 0.82 Å, C-H = 0.93 and 0.96 Å for CH and CH 3 H atoms, respectively, with U iso (H) = k × U eq (O,C) where k = 1.5 for OH and CH 3 H atoms and = 1.2 for other H atoms.   Table 1 for details).

Figure 2
A view along the c axis of the crystal packing of the title compound. The N-H···O hydrogen bonds and the C-H···O interactions are shown as dashed lines (see Table 1 for details; Only the H atoms involved in these interactions are shown).