1-Cyclo­hexyl-5-(4-meth­oxy­phen­yl)-1H-pyrazole-4-carb­oxy­lic acid

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

doi:10.1107/S1600536811050872

. 2011 Nov 30;67(Pt 12):o3513. doi: 10.1107/S1600536811050872

1-Cyclohexyl-5-(4-methoxyphenyl)-1H-pyrazole-4-carboxylic acid

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

PMCID: PMC3239134 PMID: 22199982

Abstract

In the title compound, C₁₇H₂₀N₂O₃, the methoxyphenyl unit is disordered over two sets of sites in a 0.715 (4):0.285 (4) ratio. The pyrazole ring forms dihedral angles of 55.88 (16) and 72.6 (4)° with the benzene rings of its major and minor components, respectively. The cyclohexane ring adopts a chair conformation and its C—N bond is in an equatorial orientation. In the crystal, molecules are linked into inversion dimers by pairs of O—H⋯O hydrogen bonds, generating R ₂ ²(8) loops.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For related structures and medicinal background to pyrazole derivatives, 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

C₁₇H₂₀N₂O₃
M _r = 300.35
Monoclinic,
a = 12.0722 (9) Å
b = 12.7180 (9) Å
c = 11.7739 (8) Å
β = 118.698 (1)°
V = 1585.6 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.39 × 0.20 × 0.15 mm

Data collection

Bruker SMART APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.967, T _max = 0.987
24474 measured reflections
4585 independent reflections
2766 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.056
wR(F ²) = 0.159
S = 1.03
4585 reflections
239 parameters
17 restraints
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.28 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/S1600536811050872/hb6534sup1.cif

e-67-o3513-sup1.cif^{(23KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811050872/hb6534Isup2.hkl

e-67-o3513-Isup2.hkl^{(224.6KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811050872/hb6534Isup3.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
O2—H1O2⋯O1ⁱ	0.91	1.73	2.640 (2)	174

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Symmetry code: (i) Inline graphic .

Acknowledgments

HKF and CKQ thank Universiti Sains Malaysia (USM) 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

As part of our ongoing structural studies of pyrazole derivatives (Fun et al., 2010a, 2010b), we now describe the synthesis and structure of the title compound, (I).

The molecular structure is shown in Fig. 1. The methoxy phenyl moiety (O3/C4-C9/C17) is disordered over two sets of sites with refined site occupancies of 0.715 (4): 0.285 (4). The pyrazole ring (N1/N2/C1-C3) forms dihedral angles of 55.88 (16) and 72.6 (4)° with the benzene rings (C4-C9) of major and minor components of the methoxy phenyl moiety, respectively. Bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to related structures (Fun et al., 2010a, 2010b, 2011). The cyclohexane ring (C10-C15) adopts a chair conformation with puckering parameters (Cremer & Pople, 1975) Q = 0.571 (2) Å, Θ = 1.0 (2)° and φ = 300 (19)°.

In the crystal (Fig. 2), molecules are linked into inversion dimers by pairs of O2–H1O2···O1 hydrogen bonds (Table 1), generating eight-membered R²₂(8) ring motifs (Bernstein et al., 1995).

Experimental

A mixture of ethyl-3-(dimethylamino)-2-(4-methoxy phenylcarbonyl) prop-2-enoate (2.0g, 0.0088 mol) and cyclohexyl hydrazine (1.0 g, 0.0096 mol) in absolute ethanol (20 ml) was refluxed for 2h. On cooling, the separated colorless needle-shaped crystals of 5-(4-methoxy phenyl)-1-phenyl-1H-pyrazole-4- carboxylic acid ethyl ester were collected by filtration (yield: 2.0 g, 86%, m.p.: 390-395K). To a stirred solution of ester (1.0 g, 0.0031 mol) in THF with water (1:1, 20 ml) was added lithium hydroxide (0.26 g, 0.0062 mol) and the mixture was stirred at RT for 6h. The reaction mixture was concentrated and acidified with 10% citric acid solution. The solid that separated out was filtered and dried under high vacuum to afford title compound as colorless crystalline solid. Compound was recrystallized from methanol to yield colourless needles (yield: 1.5 g, 83%, m.p. 413-418K).