4-[(1-Hydroxy-2-naphthyl)methyleneamino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one

The title antipyrine derivative, C22H19N3O2, was synthesized by the reaction of 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one and 1-hydroxynaphthalene-2-carbaldehyde in methanol solution. As expected, the compound adopts a trans configuration about the central C=N bond. The N atom is involved in an intramolecular O—H⋯N bond which stabilizes the molecular configuration. In the crystal structure, adjacent molecules stack with no short contacts.

The title antipyrine derivative, C 22 H 19 N 3 O 2 , was synthesized by the reaction of 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one and 1-hydroxynaphthalene-2-carbaldehyde in methanol solution. As expected, the compound adopts a trans configuration about the central C N bond. The N atom is involved in an intramolecular O-HÁ Á ÁN bond which stabilizes the molecular configuration. In the crystal structure, adjacent molecules stack with no short contacts.
In the crystal structure, the molecules stack along the a axis with no short contacts except the O-H···N intramolecular hydrogen (Table 2 and Fig. 2).

Experimental
All the chemicals were obtained from commercial sources and used without purification. 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydropyrazole-3-one (0.5 mmol, 101.6 mg) and an equimolar quantity of 1-hydroxynaphthalene-2-carbaldehyde (0.5 mmol, 86.1 mg) were dissolved in methanol (100 ml). The mixture was stirred for 1 h at room temperature to give a clear yel- for methyl H atoms. Fig. 1. The molecular structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme. The O-H···O hydrogen bond is shown 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 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 Occ. (