Ethyl 1-cyclo­hexyl-5-(4-meth­oxy­phen­yl)-1H-pyrazole-4-carboxyl­ate

Hoong-Kun Fun; Ching Kheng Quah; B Chandrakantha; A M Isloor; Prakash Shetty

doi:10.1107/S1600536811049282

. 2011 Nov 30;67(Pt 12):o3460–o3461. doi: 10.1107/S1600536811049282

Ethyl 1-cyclohexyl-5-(4-methoxyphenyl)-1H-pyrazole-4-carboxylate

Hoong-Kun Fun ^a,^*,^‡, Ching Kheng Quah ^a,^§, B Chandrakantha ^b, A M Isloor ^c, Prakash Shetty ^d

PMCID: PMC3239089 PMID: 22199937

Abstract

In the title compound, C₁₉H₂₄N₂O₃, the benzene ring forms a dihedral angle of 65.34 (7)° with the pyrazole ring. The cyclohexane ring adopts a chair conformation. In the crystal, molecules are linked into a inversion dimers by pairs of C—H⋯O hydrogen bonds, generating R ₂ ²(22) ring motifs.

Related literature

For general background to pyrazole derivatives, see: Dhanya et al. (2009 ▶); Hall et al. (2008 ▶); Isloor et al. (2000 ▶, 2009 ▶); Ragavan et al. (2010 ▶); Premsai Rai et al. (2009 ▶). For bond-length data, see: Allen et al. (1987 ▶). For related structures, see: Fun et al. (2010a ▶,b ▶, 2011 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For ring conformations, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₉H₂₄N₂O₃
M _r = 328.40
Triclinic,
a = 6.8959 (7) Å
b = 11.0858 (7) Å
c = 12.0142 (12) Å
α = 100.690 (2)°
β = 93.107 (1)°
γ = 95.354 (1)°
V = 896.16 (14) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.40 × 0.31 × 0.15 mm

Data collection

Bruker SMART APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.968, T _max = 0.988
18767 measured reflections
5159 independent reflections
3928 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.164
S = 1.05
5159 reflections
219 parameters
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811049282/is5014sup1.cif

e-67-o3460-sup1.cif^{(20.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811049282/is5014Isup2.hkl

e-67-o3460-Isup2.hkl^{(252.6KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811049282/is5014Isup3.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
C16—H16A⋯O2ⁱ	0.96	2.44	3.358 (2)	159

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Symmetry code: (i) Inline graphic .

Acknowledgments

HKF and CKQ thank Universiti Sains Malysia for the Research University Grant (No. 1001/PFIZIK/811160). AMI thanks the Board for Research in Nuclear Sciences, Department of Atomic Energy, Government of India, for the Young Scientist award.

supplementary crystallographic information

Comment

Pyrazoles and their derivatives play an important role in medicinal chemistry (Dhanya et al., 2009). Several derivatives of pyrazole are of pharmaceutical interest due to their analgesic action. Pyrazole molecules also exhibit anticancer (Hall et al., 2008), anti-inflammatory, antidepressant, anticonvulsant and anti-HIV properties (Isloor et al., 2000, 2009). During the past years, considerable evidence has been accumulated to demonstrate the efficacy of pyrazole derivatives. The incorporation of aryl system into the pyrazole ring enhances the biological activities to a great extent (Ragavan et al., 2010). Presence of different substituents, both on the pyrazole ring and on the phenyl ring, can severely modify the biological properties of such molecules (Premsai Rai et al., 2009). Keeping in view of the importance of the pyrazole derivatives, we hereby report the crystal structure of the title compound.

The molecular structure is shown in Fig. 1. The benzene ring (C10–C15) forms a dihedral angle of 65.34 (7)° with the pyrazole ring (N1/N2/C1–C3). Bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to related structures (Fun et al., 2010a,b, 2011). The cyclohexane ring (C4–C9) adopts a chair conformation with puckering parameters (Cremer & Pople, 1975) Q = 0.5694 (17) Å, Θ = 177.82 (16)° and φ = 182 (5)°.

In the crystal (Fig. 2), molecules are linked into an inversion dimer by a pair of intermolecular C16—H16A···O2 hydrogen bonds (Table 1), generating an R²₂(22) ring motif (Bernstein et al., 1995).

Experimental

A mixture of ethyl 4-methoxy benzoyl acetate (2.0 g, 0.0090 mol) and N,N-dimethylformamide dimethyl acetal (20 ml) was heated to reflux for 18 h. The excess of acetal was distilled off under reduced pressure and the residue was purified by column chromatography using 60-120 silica gel mesh size with chloroform and methanol as an eluent to give yellow liquid (2.0 g, 95 %). A mixture of ethyl-3-(dimethylamino)-2-(4-methoxyphenylcarbonyl)prop-2-enoate (2.0 g, 0.0088 mol) and cyclohexyl hydrazine (1.1 g, 0.0096 mol) in absolute ethanol (20 ml) was refluxed for 2 h. On cooling, the separated colorless needle-shaped crystals of title compound were collected by filtration. Compound was recrystallized from ethanol (yield 2.5 g, 89%; m.p. 413-418 K).