Methyl 2-{1-[(Z)-3-methyl-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazol-4-ylidene]ethylamino}-3-phenylpropanoate

The molecule of the title compound, C22H23N3O3, exists in the enamine–keto form. A strong intramolecular N—H⋯O hydrogen bond occurs, generating an S(6) ring. The dihedral angle between the heterocycle and the adjacent phenyl ring is 3.75 (15)°.


Comment
The Schiff bases derived from 4-acyl-5-pyrazolones and their metal complexes have been studied widely for their high antibacterial activation [Li et al., 1997[Li et al., , 2004. Since amino acid esters also possess good antibacterial and biological activations (Xiong et al., 1993), several Structures of Schiff bases derived from 4-acyl-5-pyrazolones and amino acid esters and closely related to the title compound have been reported [Zhu et al., 2005;Zhang et al., 2010]. We report the the crystal structure of the title compound.
In the molecule of the title compound, (

Experimental
The title compound was synthesized by refluxing the mixture of HPMAP (15 m mol) and phenylalanine methyl ester (15m mol) in ethanol (100 ml) over a steam bath for about 4 h, then the solution was cooled down to room temperature. After four days, white block was obtained and dried in air. The product was recrystallized from ethanol which afforded colorless and acerate crystals suitable for X-ray analysis.

Refinement
In the absence of significant anomalous scattering effect, 1127 Friedel pairs were merged. All H atoms were geometrically positioned and refined using a riding model, with C-H = 0.93 Å for the aryl, 0.97 Å for methylene, 0.98 Å for methyne and 0.96 Å for the methyl H atoms. U iso (H)= 1.2 U eq (C) for aryl, methylene and methyne, and 1.5U eq (C) for methyl H atoms.
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius.

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.