Ethyl 1-(2-bromo­eth­yl)-3-(4-meth­oxy­phen­yl)-1H-pyrazole-5-carboxyl­ate

Ling Yin; Yi Wang; Ying-Ying Wang; Jian-Wu Wang

doi:10.1107/S1600536812032370

. 2012 Jul 21;68(Pt 8):o2513. doi: 10.1107/S1600536812032370

Ethyl 1-(2-bromoethyl)-3-(4-methoxyphenyl)-1H-pyrazole-5-carboxylate

Ling Yin ^a,^*, Yi Wang ^b, Ying-Ying Wang ^a, Jian-Wu Wang ^b

PMCID: PMC3414964 PMID: 22904951

Abstract

In the title compound, C₁₅H₁₇BrN₂O₃, the dihedral angle between the benzene and pyrazole rings is 5.63 (2)°. The crystal packing is stabilized by weak π–π stacking interactions [centroid–centroid distance = 3.927 (5) Å] and intermolecular C—H⋯O and C—H⋯Br hydrogen bonds.

Related literature

For the biological activity of pyrazole compounds, see: Nagwa et al. (2012 ▶); Fahmy et al. (2012 ▶); Wang et al. (2011 ▶). For related structures, see: Dong et al. (2007 ▶); Hao et al. (2012 ▶).

Experimental

Crystal data

C₁₅H₁₇BrN₂O₃
M _r = 353.22
Monoclinic,
a = 24.691 (7) Å
b = 6.7678 (17) Å
c = 17.884 (5) Å
β = 97.184 (5)°
V = 2965.1 (13) Å³
Z = 8
Mo Kα radiation
μ = 2.78 mm⁻¹
T = 113 K
0.20 × 0.18 × 0.14 mm

Data collection

Rigaku Saturn CCD area-detector diffractometer
Absorption correction: multi-scan (CrystalClear-SM Expert; Rigaku/MSC, 2009 ▶) T _min = 0.606, T _max = 0.697
13190 measured reflections
3501 independent reflections
2684 reflections with I > 2σ(I)
R _int = 0.033

Refinement

R[F ² > 2σ(F ²)] = 0.026
wR(F ²) = 0.062
S = 1.02
3501 reflections
192 parameters
H-atom parameters constrained
Δρ_max = 0.61 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Data collection: CrystalClear-SM Expert (Rigaku/MSC, 2009 ▶); cell refinement: CrystalClear-SM Expert; data reduction: CrystalClear-SM Expert; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812032370/rz2789sup1.cif

e-68-o2513-sup1.cif^{(18.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812032370/rz2789Isup2.hkl

e-68-o2513-Isup2.hkl^{(171.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812032370/rz2789Isup3.cml

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
C7—H7⋯Br1ⁱ	0.95	2.93	3.6791 (18)	137
C15—H15B⋯O1ⁱⁱ	0.99	2.56	3.288 (2)	130

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

Acknowledgments

The authors thank the Jining University Foundation (No. 2012YYJJ07) for financial support of this work.

supplementary crystallographic information

Comment

Pyrazole compounds are associated with a wide spectrum of biological activities (Nagwa et al., 2012; Fahmy et al., 2012). The title compound is a key intermediate during the synthesis of our own Lp-PLA₂ inhibitors (Wang et al., 2011).

In title compound (Fig. 1) the dihedral angle between the benzene ring (C2—C7) and the pyrazole ring (N1/N2/C8—C10) is 5.63 (2) °. All bond lengths and angles are normal and in a good agreement with those reported previously for related compounds (Dong et al., 2007; Hao et al., 2012). The crystal packing is stabilized by weak π–π stacking interactions [Cg1···Cg2ⁱ = 3.697 (9) Å, Cg1 and Cg2 are the centroids of the benzene and pyrazole ring, respectively; symmetry code: (i) -x, 2-y, 1-z] and weak intermolecular C—H···O and C—H···Br hydrogen interactions (Table 1).

Experimental

A mixture of of ethyl 3-(4-methoxyphenyl)-1H-pyrazole-5-carboxylate (2.46 g, 10 mmol), 1,2-dibromoethane (3.76 g, 20 mmol), K₂CO₃ (5.53 g, 40 mmol) in dried acetonitrile (30 ml) was refluxed overnight. On cooling, the reaction mixture was filtered and poured into 200 ml of brine. The resulting mixture was extracted with dichloromethane (3 × 50 ml), and the combined extracts were washed with saturated brine, dried over Na₂SO₄ and evaporated on a rotary evaporator to afford the crude product as brown solid, which was purified by column chromatography to yield the pure product as colourless crystals (yield 88%). Single crystals suitable for single-crystal X-ray diffraction were obtained by slow evaporation at room temperature of a solution of the title compound in dichloromethane/hexane (1:5 v/v). M.p.: 361–363 K.