2-Phenyl-5-(trifluoro­meth­yl)pyrazol-3(2H)-one

Hugo Gallardo; Edivandro Girotto; Adailton J Bortoluzzi; Geovana G Terra

doi:10.1107/S1600536809029419

. 2009 Jul 29;65(Pt 8):o2040–o2041. doi: 10.1107/S1600536809029419

2-Phenyl-5-(trifluoromethyl)pyrazol-3(2H)-one

Hugo Gallardo ^a,^*, Edivandro Girotto ^a, Adailton J Bortoluzzi ^a, Geovana G Terra ^a

PMCID: PMC2977152 PMID: 21583705

Abstract

The title compound, C₁₀H₇F₃N₂O, is an analogue of pyrazolone derivatives with potential analgesic and anti-inflammatory properties. Its molecular structure consists of phenyl and pyrazol-3(2H)-one units with a dihedral angle between the mean planes of the rings of 33.0 (1)°. The crystal structure is stabilized by an intermolecular hydrogen bond between the N—H group and the carbonyl O atom of the pyrazol-3(2H)-one ring which links the molecules into supramolecular C(5) chains along [001] and by weak π–π stacking interactions between the phenyl rings [centroid-centroid distance = 3.881 (2) Å]. The F atoms are disordered over two positions with refined site occupancies of 0.768(11) and 0.232(11).

Related literature

For the analgesic properties of pyrazolones, see: Mehlisch (1983 ▶); Schnitzer (2003 ▶). For the biological activity of some pyrazolone derivatives, see: Pavlov et al. (1998 ▶). For the pharmacological properties of pyrazolone deriavtives, see: Kees et al. (1996 ▶). For related structures, see: Belmar et al. (2006a ▶,b ▶); Pérez et al. (2005 ▶). For metal complexes, see: Hyun-Shin et al. (2008 ▶); Gallardo et al. (2004 ▶); Meyer et al. (1998 ▶). For the synthesis of pyrazolones, see: Nakagawa et al. (2006 ▶); Belmar et al. (2001 ▶); Bartulín et al. (1994 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₀H₇F₃N₂O
M _r = 228.18
Monoclinic,
a = 5.8409 (5) Å
b = 15.2454 (14) Å
c = 11.2291 (17) Å
β = 92.403 (9)°
V = 999.0 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.14 mm⁻¹
T = 293 K
0.46 × 0.40 × 0.20 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: none
2262 measured reflections
2157 independent reflections
1141 reflections with I > 2σ(I)
R _int = 0.024
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F ² > 2σ(F ²)] = 0.060
wR(F ²) = 0.188
S = 1.03
2157 reflections
173 parameters
81 restraints
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: SET4 in CAD-4 Software; data reduction: HELENA (Spek, 1996 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809029419/bx2225sup1.cif

e-65-o2040-sup1.cif^{(16.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809029419/bx2225Isup2.hkl

e-65-o2040-Isup2.hkl^{(103.9KB, 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
N2—H2⋯O1ⁱ	0.88	1.89	2.667 (3)	146

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), the Fundação de Apoio à Pesquisa Científica e Tecnológica do Estado de Santa Catarina (FAPESC), the Instituto Nacional de Ciência e Tecnologia (INCT-cat) and the Financiadora de Estudos e Projetos (FINEP) for financial assistance.

supplementary crystallographic information

Comment

The pyrazolone analgesics (such as phenylbutazone) have effects similar to those of aspirin. They were commonly used to treat rheumatoid arthritis and has been the focus of medicinal chemists for over last 100 years because of the outstanding pharmacological properties shown by several of its derivatives (Kees et al., 1996). The interest in such compounds, pyrazolone derivative, arises from the fact that the incorporation of heteroatoms can result an ancillary ligand to study their photoactive lanthanide complexes. These compounds possess several sites for substitution, allowing for a systematic analysis of their effects on the photo optical properties. Particulary the luminescence properties of the Eu and Tb complexes.

The molecular structure of (I) consists of a phenyl group bonded to 2-N of the dihydropyrazole heterocyclic ring (Fig. 1). These rings are twisted with respect to each other and the dihedral angle between the mean plane is 33.0 (1)°.The molecules are linked into chains by one intermolecular N—H···O hydrogen bond. Atoms N2 in the molecules at (x,y,z) acts as hydrogen bonds donor vía atom H2 to atoms O1 at (-x, 3/2+y, -1-z) so generating by translation one C(5) chains running parallel to [001] direction (Bernstein et al., 1995), (Fig. 2, Table 1) and the crystal structure is reinforced by a weak face-to-face π-π stacking interactions between phenyl rings with the centroid-centroid distance of 3.881 (2) Å.