5-(4-Chloro­phen­yl)-1-(2,4-dichloro­phen­yl)-4-methyl-1H-pyrazole-3-carboxylic acid

Wei Wang; Zheng Fang

doi:10.1107/S1600536808038105

. 2008 Nov 22;64(Pt 12):o2413. doi: 10.1107/S1600536808038105

5-(4-Chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxylic acid

Wei Wang ^a, Zheng Fang ^a,^*

PMCID: PMC2960141 PMID: 21581382

Abstract

The asymmetric unit of the title compound, C₁₇H₁₁Cl₃N₂O₂, contains two independent molecules; the pyrazole rings are oriented with respect to the chlorophenyl and dichlorophenyl rings at dihedral angles of 43.00 (3) and 65.06 (4)°, respectively, in one molecule, and 51.17 (3) and 69.99 (3)°, respectively, in the other. Pairs of intermolecular O—H⋯O hydrogen bonds link the molecules into dimers. In the crystal structure, there are π–π contacts between the pyrazole rings and dichlorophenyl rings [centroid–centroid distances = 3.859 (3) and 3.835 (3) Å].

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For the chemical background, see: Tang et al. (2007 ▶).

Experimental

Crystal data

C₁₇H₁₁Cl₃N₂O₂
M _r = 381.63
Monoclinic,
a = 13.192 (3) Å
b = 8.8170 (18) Å
c = 30.012 (6) Å
β = 102.42 (3)°
V = 3409.1 (13) Å³
Z = 8
Mo Kα radiation
μ = 0.55 mm⁻¹
T = 294 (2) K
0.30 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.853, T _max = 0.947
6479 measured reflections
6190 independent reflections
2893 reflections with I > 2σ(I)
R _int = 0.038
3 standard reflections frequency: 120 min intensity decay: 1%

Refinement

R[F ² > 2σ(F ²)] = 0.072
wR(F ²) = 0.181
S = 0.99
6190 reflections
433 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808038105/hk2574sup1.cif

e-64-o2413-sup1.cif^{(27.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808038105/hk2574Isup2.hkl

e-64-o2413-Isup2.hkl^{(303KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯O4	0.85	1.74	2.564 (7)	163
O3—H3B⋯O1	0.85	1.89	2.723 (6)	165

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank the Center for Testing and Analysis, Nanjing University, for the support.

supplementary crystallographic information

Comment

Some derivatives of benzoic acid are important chemical materials. We report herein the crystal structure of the title compound.

The asymmetric unit of the title compound contains two crystallographically independent molecules (Fig. 1). The bond lengths (Allen et al., 1987) and angles are within normal ranges. Rings A (C1-C6), B (C7-C12), C (N1/N2/C13-C15) and D (C18-C23), E (C24-C29), F (N3/N4/C30-C32) are, of course, planar and they are oriented at dihedral angles of A/B = 58.42 (3)°, A/C = 65.06 (4), B/C = 43.00 (3)° and D/E = 57.07 (4)°, D/F = 69.99 (3)°, E/F = 51.17 (3)°. The intramolecuar O-H···O hydrogen bonds (Table 1) link the molecules (Fig. 1), in which they may be effective in the stabilization of the structure.

In the crystal structure, there are π-π contacts between the pyrazole rings and dichlorophenyl rings, Cg1—Cg2ⁱ and Cg3—Cg5ⁱⁱ [symmetry codes: (i) x + 1, y, z; (ii) 1 - x, y, 1/2 -z, where Cg1, Cg2, Cg3 and Cg5 are centroids of the rings C (N1/N2/C13-C15), F (N3/N4/C30-C32), A (C3-C8) and D (C18-C23), respectively] may stabilize the structure, with centroid-centroid distances of 3.859 (3) Å and 3.835 (3) Å, respectively. There also exist C—H···π contacts (Table 1) between the methyl groups and the chlorophenyl rings.

Experimental

For the preparation of the title compound, 2,4-dichlorophenylhydrazine hydrochloride (13.3 g) diluted in ethanol (20 ml) is added to ethyl 4-(4-chlorophenyl)-3-methyl-2,4-dioxobutanoate (17.6 g) diluted in toluene (50 ml) and the mixture is stirred for 18 h at room temperature. Without isolating the hydrazone, paratoluenesulfonic acid (0.56 g) is added, and the ternary azeotrope (water, ethanol, toluene) is distilled. Toluene reflux is continued for 1 h and the reaction mixture is cooled to room temperature. The insoluble material is filtered off. The solvents are removed under reduced pressure to give an oil. KOH (8.1 g) in pellets are added to a solution of the oil obtained in the previous step in MeOH (100 ml). The mixture is left for 1 h at room temperature and the solvents are decanted into water (200 ml) at 333 K. Hydrochloric acid is then added to the aqueous phase until pH = 1.5. The colorless crystals formed are filtered off, washed with water and dried under vaccum to give the expected product (yield; 9.9 g). Crystals suitable for X-ray analysis were obtained by slow evaporation of an acetic acid solution.