(E)-N′-[(2-Hydroxy-1-naphthalen-1-yl)methylidene]-3-methylbenzohydrazide

In the title compound, C19H16N2O2, the benzene ring and naphthyl ring system are inclined at a dihedral angle of 16.1 (3)°. An intramolecular O—H⋯N hydrogen bond influences the molecular conformation. In the crystal, molecules are linked through N—H⋯O hydrogen bonds into chains running along the a axis.

In the title compound, C 19 H 16 N 2 O 2 , the benzene ring and naphthyl ring system are inclined at a dihedral angle of 16.1 (3) . An intramolecular O-HÁ Á ÁN hydrogen bond influences the molecular conformation. In the crystal, molecules are linked through N-HÁ Á ÁO hydrogen bonds into chains running along the a axis.   Table 1 Hydrogen-bond geometry (Å , ).  The molecular structure of the title compound is shown in Fig. 1. The benzene ring and the naphthyl ring system are inclined at a dihedral angle of 16.1 (3) °. The dihedral angle between the C1-C10 benzene ring and the C13-C18 naphthyl ring is 16.1 (3)°. All the bond lengths are comparable to those observed in related structures (Xu et al., 2009;Shafiq et al., 2009) and those we reported previously.

Related literature
In the crystal structure, molecules are linked through N-H···O hydrogen bonds, to form one-dimensional chains running along the a axis ( Fig. 2 and Table 1).

Experimental
The title compound was prepared by the condensation reaction of 2-hydroxy-1-naphthaldehyde (0.05 mol, 8.6 g) and 3methylbenzohydrazide (0.05 mol, 7.5 g) in anhydrous methanol (200 ml) at ambient temperature. Colourless block-shaped single crystals suitable for X-ray structural determination were obtained by slow evaporation of the solution for a period of a week.

Refinement
H2 was located from a difference Fourier map and refined isotropically, with the N-H distance restrained to 0.90 (1) Å.
The remaining H atoms were positioned geometrically and constrained to ride on their parent atoms, with C-H distances of 0.93-0.96 Å, O-H distance of 0.82 Å, and with U iso (H) = 1.2U eq (C) and 1.5U eq (O and C19). Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms are shown as spheres of arbitrary radius and the intramolecular hydrogen bond is drawn as a dashed line.

Special details
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 supplementary materials sup-3 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.