3,5-Bis(4-fluoro­phen­yl)-1-(4-nitro­phen­yl)-4,5-dihydro-1H-pyrazole

Seranthimata Samshuddin; Badiadka Narayana; Hemmige S Yathirajan; Thomas Gerber; Eric Hosten; Richard Betz

doi:10.1107/S160053681204370X

. 2012 Oct 27;68(Pt 11):o3216–o3217. doi: 10.1107/S160053681204370X

3,5-Bis(4-fluorophenyl)-1-(4-nitrophenyl)-4,5-dihydro-1H-pyrazole

Seranthimata Samshuddin ^a, Badiadka Narayana ^a, Hemmige S Yathirajan ^b, Thomas Gerber ^c, Eric Hosten ^c, Richard Betz ^c,^*

PMCID: PMC3515302 PMID: 23284522

Abstract

In the title compound, C₂₁H₁₅F₂N₃O₂, a pyrazole derivative bearing three aromatic substituents, the central five-membered heterocyclic ring makes dihedral angles of 1.77 (14), 3.68 (13) and 72.15 (14)° with the three benzene rings. In the crystal, C—H⋯O and C—H⋯F interactions connect the molecules into double layers parallel to the bc plane.

Related literature

For general information about the pharmacological properties and medical applications of pyrazole derivatives, see: Kumar et al. (2009 ▶); Sarojini et al. (2010 ▶); Samshuddin et al. (2012 ▶). For the crystal structures of other pyrazole derivatives, see: Baktır et al. (2011 ▶); Jasinski et al. (2012 ▶). For the puckering analysis of cyclic motifs, see: Cremer & Pople (1975 ▶). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₂₁H₁₅F₂N₃O₂
M _r = 379.36
Monoclinic,
a = 13.2884 (13) Å
b = 12.7364 (10) Å
c = 11.4656 (9) Å
β = 115.324 (3)°
V = 1754.0 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 200 K
0.57 × 0.33 × 0.27 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.692, T _max = 0.971
15973 measured reflections
4301 independent reflections
3066 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.067
wR(F ²) = 0.221
S = 1.06
4301 reflections
253 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2010 ▶); 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 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(25.6KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681204370X/is5210sup1.cif

e-68-o3216-sup1.cif^{(25.6KB, cif)}

Click here for additional data file.^{(3KB, cdx)}

Supplementary material file. DOI: 10.1107/S160053681204370X/is5210Isup2.cdx

Click here for additional data file.^{(210.8KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681204370X/is5210Isup3.hkl

e-68-o3216-Isup3.hkl^{(210.8KB, hkl)}

Click here for additional data file.^{(6.9KB, cml)}

Supplementary material file. DOI: 10.1107/S160053681204370X/is5210Isup4.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
C12—H12⋯O2ⁱ	0.95	2.41	3.305 (3)	157
C16—H16⋯F2ⁱⁱ	0.95	2.55	3.427 (3)	154
C26—H26⋯F1ⁱⁱⁱ	0.95	2.56	3.494 (3)	169

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

Acknowledgments

BN thanks the UGC for financial assistance through a BSR one-time grant for the purchase of chemicals. SS thanks Mangalore University for the research facilities.

supplementary crystallographic information

Comment

Pyrazole derivatives are well known for their broad spectrum of pharmacological properties and have been found – among others – to exhibit antimicrobial, antioxidant, antiamoebic, anti-inflammatory, analgesic, antidepressant and anticancer activity (Kumar et al., 2009; Sarojini et al., 2010; Samshuddin et al., 2012). Because of these various interesting fields of application as well as their fairly assessable path of synthesis, the pyrazoline ring became a center of attraction for organic chemists. The crystal structures of some pyrazolines derived from 4,4'-difluoro chalcone have been reported (Baktır et al., 2011; Jasinski et al., 2012). Fuelled by our ongoing interest in pharmacological active compounds, the title compound was synthesized.

Three phenyl-derived substituents are bonded to a central 4,5-dihydro-1H-pyrazole moiety. The least-squares planes defined by the C11–C16, C31–C36 and C21–C26 benzene rings enclose dihedral angles of 1.77 (14), 3.68 (13) and 72.15 (14)°, respectively, with the least-squares plane defined by the intracyclic atoms of the central five-membered heterocycle with the largest angle formed by one of the two para-fluoro phenyl groups. A conformational analysis of the 4,5-dihydro-1H-pyrazole moiety is precluded due to its low puckering amplitude (Cremer & Pople, 1975). The nitro group is slightly tilted out of plane of the least-square plane defined by the carbon atoms of the aromatic moiety it is bonded to, the corresponding O2—N3—C34—C35 torsion angle being 17.0 (3)° (Fig. 1).

In the crystal, C—H···O and C—H···F contacts can be observed whose range falls by more than 0.1 Å below the sum of van-der-Waals radii of the atoms participating in them. These are exclusively supported by hydrogen atoms bonded to para-fluoro phenyl groups. Metrical parameters as well as information about the symmetry of these contacts are summarized in Table 1. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the C—H···O contacts is C(12) on the unary level, while the C—H···F contacts necessitate a C(11)C(11) descriptor on the same level. In total, the molecules are connected to double layers parallel to the bc plane. The shortest intercentroid distance between two aromatic systems was measured at 4.8923 (17) Å and is observed between the two different fluorinated phenyl groups in neighbouring molecules. Taking into account the centroid of the 4,5-dihydro-1H-pyrazole moiety as well, the shortest intercentroid distance is found at 3.5918 (15) Å between this pyrazole unit and the nitrated phenyl group (Fig. 2). The packing of the title compound in the crystal structure is shown in Figure 3.

Experimental

A mixture of 4,4'-difluoro chalcone (2.68 g, 0.01 mol) and 4-nitrophenyl hydrazine (1.53 g, 0.01 mol) was refluxed in glacial acetic acid (50 ml) for 6 h. The reaction mixture was cooled and pourred into ice-cold water (50 ml). The precipitate was collected by filtration and purified by recrystallization from ethanol (yield: 74%). Yellow blocks, suitable for the X-ray diffraction study, were grown from a DMF solution by slow evaporation at room temperature.