3-Acetyl-5-phenyl-1-p-tolyl-1H-pyrazole-4-carbonitrile

In the title pyrazole derivative, C19H15N3O, the central pyrazole ring makes dihedral angles of 42.71 (9) and 61.34 (9)°, respectively, with the phenyl and p-tolyl rings. The dihedral angle between the phenyl and p-tolyl rings is 58.22 (9)°. The 3-acetyl-1H-pyrazole-4-carbonitrile unit is essentially planar, with an r.m.s. deviation of 0.0295 (1) Å for the ten non-H atoms.


Comment
During the course of our medicinal chemistry research on pyrazole derivatives (Abdel-Aziz et al., 2009, 2010Abdel-Wahab et al., 2009), we previously reported the crystal structure of 3-acetyl-1,5-diphenyl-1H-pyrazole-4-carbonitrile (I) (Abdel-Aziz et al., 2012). The title compound (II), was synthesized by retaining the core part but changing the phenyl group which was attached to N atom at position 1 of the pyrazole ring in compound (I) to the p-tolyl in order to investigate the influence of the substituents to their biological properties. Herein, the crystal structure of (II) was reported.
The molecule of (II), C 19 H 15 N 3 O, has the same butterfly-like structure as in (I) (Abdel-Aziz et al., 2012). However there are differences in the dihedral angles between the equivalent moieties and the crystal packing of (I) and (II). In (II), the pyrazole ring forms dihedral angles of 42.71 (9) and 61.34 (9)°, respectively, with the C5-C10 and C11-C16 benzene  et al., 1987) and are comparable to the closely related structure (Abdel-Aziz et al., 2012). The crystal packing of (II) is stabilized by van der Waals interactions. Even there is no hydrogen bonds, the crystal packing of (II) was shown in Fig. 2 for comparison with that of (I).

Experimental
The title compound was prepared according to the reported method (Dawood et al., 2003). Single crystals of the title compound suitable for X-ray structure determination were recrystallized from ethanol by the slow evaporation of the solvent at room temperature after several days.

Refinement
All H atoms were placed in calculated positions with C-H = 0.93 Å for aromatic and 0.96 Å for CH 3 atoms. The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups.

Figure 1
The structure of the title compound, showing 40% probability displacement ellipsoids and the atom-numbering scheme.

Figure 2
A packing diagram of the title compound viewed along the a axis. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.20 e Å −3 Δρ min = −0.14 e Å −3 Extinction correction: SHELXTL (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0113 (9) 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.