2-(2,4-Dichloro­phen­oxy)-1-(1H-pyrazol-1-yl)ethanone

Aisha Karamat; M Nawaz Tahir; Misbahul Ain Khan; Abdul Qayyum Ather

doi:10.1107/S1600536810035087

. 2010 Sep 4;66(Pt 10):o2476. doi: 10.1107/S1600536810035087

2-(2,4-Dichlorophenoxy)-1-(1H-pyrazol-1-yl)ethanone

Aisha Karamat ^a, M Nawaz Tahir ^b,^*, Misbahul Ain Khan ^a, Abdul Qayyum Ather ^c,^d

PMCID: PMC2983423 PMID: 21587477

Abstract

In the title compound, C₁₁H₈Cl₂N₂O₂, the 2,4-dichlorophenoxy and 1H-pyrazole groups are almost planar [r.m.s. deviations of 0.0157 and 0.0008 Å, respectively] and are oriented at a dihedral angle of 64.17 (5)° with respect to one another. In the crystal, the molecules are stabilized in the form of dimers due to inversion-related C—H⋯O hydrogen bonds, with R ₂ ²(10) ring motifs.

Related literature

Aryloxyacetic acid and its various derivatives are used as herbicides and pesticides, see: Crafts (1957 ▶). For our work on the synthesis of heterocyclic compounds, see: Khan et al. (2009 ▶). For a related structure, see: Wang et al. (2009 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₁H₈Cl₂N₂O₂
M _r = 271.09
Triclinic,
a = 4.2030 (1) Å
b = 10.3074 (3) Å
c = 13.4966 (4) Å
α = 87.510 (2)°
β = 83.774 (1)°
γ = 88.335 (1)°
V = 580.53 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.55 mm⁻¹
T = 296 K
0.30 × 0.22 × 0.18 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.982, T _max = 0.988
10353 measured reflections
2861 independent reflections
2232 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.093
S = 1.04
2861 reflections
154 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810035087/si2292sup1.cif

e-66-o2476-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810035087/si2292Isup2.hkl

e-66-o2476-Isup2.hkl^{(137.5KB, 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
C11—H11⋯O2ⁱ	0.93	2.42	3.339 (2)	170

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge the provision of funds for the purchase of diffractometer and encouragement by Dr Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha, Pakistan.

supplementary crystallographic information

Comment

Aryloxyacetic acid and its various derivatives are used as herbicides and pesticides (Crafts, 1957). During our research on the synthesis of heterocyclic compounds in our laboratories (Khan et al., 2009), we have isolated the title compound (I, Fig. 1).

The crystal structure of 5-(2,4-dichlorophenoxymethyl)-1,3,4-thiadiazol-2-amine has been published (Wang et al., 2009) which is related to the title compound.

In the title compound, 2,4-dichlorophenoxy group A (O1/C1—C6/CL1/CL2) and 1H-pyrazole group B (N1/N2/C9–C11) are planar with r. m. s. deviations of 0.0157 and 0.0008 Å, respectively. The dihedral angle between A/B is 64.17 (5)°. The central group C (C7/C8/O2) is of course planar. The dihedral angle between A/C and B/C is 69.23 (8) and 5.07 (25)°, respectively. The molecules are stabilized in the form of dimers (Table 1, Fig. 2) due to inversion related C—H···O type of H-bondings with R₂²(10) ring motifs (Bernstein et al., 1995).

Experimental

A mixture of 2,4-dichlorophenoxyacetic acid (0.5 g; 2.25 mmole) and 1 ml of thionyl chloride was heated under reflux for 1 h. Then an excess of pyrazole (0.5 g) in 5 ml of chloroform was added to the refluxing mixture and heated for a further period of 1.5 h. The solvents were removed and the residue dissolved in chloroform and washed with saturated sodium bicarbonate, dried and let crystallize to give pale brown prisms of (I).

Yield, 84%.