5-(4-Chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde

In the title compound, C17H13ClN2O2, the phenyl and chlorobenzene rings are inclined to the central pyrazole ring at 40.84 (9) and 65.30 (9)°, respectively. In the crystal, pairs of C—H⋯π interactions link the molecules into inversion dimers and C—H⋯O hydrogen bonds link these dimers into columns extended in [010]. The crystal packing exhibits short intermolecular O⋯Cl contacts of 3.0913 (16) Å.

In the title compound, C 17 H 13 ClN 2 O 2 , the phenyl and chlorobenzene rings are inclined to the central pyrazole ring at 40.84 (9) and 65.30 (9) , respectively. In the crystal, pairs of C-HÁ Á Á interactions link the molecules into inversion dimers and C-HÁ Á ÁO hydrogen bonds link these dimers into columns extended in [010]. The crystal packing exhibits short intermolecular OÁ Á ÁCl contacts of 3.0913 (16) Å .

Comment
Aryloxy pyrazoles and their derivatives possess a significant pharmcological activities such as antimicrobial (Rai et al. 2008;Girisha et al., 2010), anti-inflammatory (Isloor et al., 2009) and analgesic activities (Shobhitha et al., 2013). The title compound can serve as an intermediate in the synthesis of various pyrazole derivatives with significant pharmacological activities (Isloor et al., 2010).
In the title compound ( Fig.1), all bond lengths and angles are normal and correspond well to those observed in the related compounds (Shahani, Fun, Ragavan et al., 2011;Shahani, Fun, Shetty et al., 2011;Prasath et al., 2011). The pyrazole ring makes dihedral angles of 65.30 (9)° with chlorobenzene ring and 40.84 (9)° with benzene ring. The dihedral angle between the chlorobenzene ring and benzene ring is 76.23 (9)°.

Experimental
The title compound was prepared by refluxing a mixture of 5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-carboxaldehyde (0.1 mol) and 4-chloro phenol (0.1 mol) in 10 ml of dimethyl sulfoxide. To this solution, 0.1 mol of potassium hydroxide was added. The reaction mixture was refluxed for 3 hrs and then it was cooled to room temperature and poured to crushed ice. The solid product that separated was filtered and dried. It was then recrystallized from ethanol. Crystals suitable for X-ray analysis were obtained from slow evaporation of ethanol.

Refinement
All the H atoms were fixed geometrically (C-H= 0.93-0.96 Å) and allowed to ride on their parent atoms with U iso (H) = 1.5U eq (C-methyl) and = 1.2U eq (C) for other H atoms.  The molecular structure of the title compound showing the atomic numbering and 50% probability displacement ellipsoids. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.25 e Å −3 Δρ min = −0.38 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), FC * =KFC[1+0.001XFC 2 Λ 3 /SIN(2Θ)] -1/4 Extinction coefficient: 0.0171 (10) Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.