4,6-Bis(4-fluoro­phen­yl)-2-phenyl-1H-indazol-3(2H)-one

R J Butcher; M Akkurt; S Samshuddin; B Narayana; H S Yathirajan

doi:10.1107/S1600536811016369

. 2011 May 7;67(Pt 6):o1346–o1347. doi: 10.1107/S1600536811016369

4,6-Bis(4-fluorophenyl)-2-phenyl-1H-indazol-3(2H)-one

R J Butcher ^a, M Akkurt ^b,^*, S Samshuddin ^c, B Narayana ^c, H S Yathirajan ^d

PMCID: PMC3120412 PMID: 21754741

Abstract

In the title compound, C₂₅H₁₆F₂N₂O, the pyrazole ring is almost planar (r.m.s. deviation = 0.028 Å) and makes a dihedral angle of 5.86 (11)° with the indazole benzene ring. The dihedral angle between the pyrazole ring and the unsubstituted phenyl ring is 28.19 (11)°. The dihedral angles between the unsubstituted phenyl and the two fluorophenyl groups are 57.69 (10) and 18.01 (10)°. In the crystal, molecules are linked by intermolecular N—H⋯O and C—H⋯F interactions, forming infinite chains along the b axis with graph-set motif R ₃ ²(19). The crystal structure is further consolidated by π–π stacking [centroid–centroid distances = 3.5916 (13) and 3.6890 (13) Å] and C—H⋯π interactions.

Related literature

For the pharmacological activity of indazole derivatives, see: Beylin et al. (1991 ▶); George et al. (1998 ▶); Jain et al. (1987 ▶); Palazzo et al. (1966 ▶); Popat et al. (2003 ▶); Roman (1990 ▶). For related structures, see: van der Helm et al. (1979 ▶); Fun et al. (2010 ▶). For hybridization and electron delocalization around N atoms, see: Susindran et al. (2010 ▶); Jin et al. (2004 ▶). For graph-set analysis, see: Etter (1990 ▶); Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₂₅H₁₆F₂N₂O
M _r = 398.40
Orthorhombic,
a = 15.2947 (4) Å
b = 11.6259 (2) Å
c = 20.9388 (5) Å
V = 3723.23 (15) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 123 K
0.49 × 0.38 × 0.23 mm

Data collection

Oxford Diffraction Xcalibur Ruby Gemini diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2007 ▶) T _min = 0.895, T _max = 0.977
19870 measured reflections
3827 independent reflections
3416 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.057
wR(F ²) = 0.135
S = 1.09
3827 reflections
275 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.65 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis RED (Oxford Diffraction, 2007 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811016369/qk2004sup1.cif

e-67-o1346-sup1.cif^{(29.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811016369/qk2004Isup2.hkl

e-67-o1346-Isup2.hkl^{(187.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811016369/qk2004Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg5 is the centroid of the C20–C25 phenyl ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—HN2⋯O1ⁱ	0.86 (2)	2.00 (2)	2.830 (2)	162 (2)
C6—H6⋯F1ⁱⁱ	0.93	2.49	3.362 (2)	156
C15—H15⋯Cg5ⁱⁱⁱ	0.93	2.85	3.656 (2)	145

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

Acknowledgments

SS and BN thank Mangalore University and the UGC SAP for financial assistance for the purchase of chemicals. HSY thanks the UOM for sabbatical leave.

supplementary crystallographic information

Comment

In last few decades, much attention has been paid to the synthesis of heterocycles containing 1,2-diazole systems like indazole mainly due to their broad spectrum of pharmacological properties. Indazole derivatives possess variety of pharmacological activities such as analgesic, anti inflammatory, antidepressant, antihypertensive, antiviral and anticancer activities (Jain et al., 1987; Palazzo et al., 1966; Popat et al., 2003; Beylin et al., 1991; George et al., 1998; Roman, 1990).

The crystal structure of indazole derivative, viz., 1,2,4,5-tetrahydro-7-methoxy-3H-benz[g]indazol-3-one monohydrate (van der Helm et al., 1979) has been reported. Also the crystal structure of methyl 4,6-bis(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate, the precursor of the title compound, has been reported (Fun et al., 2010). In view of the importance of indazole derivatives, the title compound (I) is synthesized and its crystal structure is reported here.

The pyrazole ring (N1/N2/C1/C2/C7) in (I), (Fig. 1), is almost planar with the largest deviations from the mean plane being 0.039 (2) Å for C7 and -0.035 (2) Å for N2. The sum of the surrounding angles around N1 in the pyrazole ring is 358.15 (15)°, in accordance with the sp² hybridization of the N1 atom (Susindran et al., 2010). The C1—N1 and C7—N2 bond lengths in the pyrazole ring are 1.390 (2) and 1.367 (3) Å, respectively. The values of these distances are shorter than the pertinent single bond length of 1.443 Å and are longer than the double bond length of 1.269 Å (Jin et al., 2004). This case indicates electron delocalization.

The dihedral angle between the pyrazole ring and the indazole benzene ring in (I), (Fig. 1), is 5.86 (11)°. The dihedral angle between the two fluorophenyl groups is 42.56 (11)°, and the dihedral angle between the five-membered pyrazole ring and the unsubstituted phenyl ring is 28.19 (11)°. The unsubstituted phenyl ring and the two fluorophenyl groups make dihedral angles of 57.69 (10) and 18.01 (10)°, respectively, with each other.

In the crystal structure, molecules are linked by intermolecular N—H···O and C—H···F interactions, forming R²₃(19) graph-set motifs (Etter, 1990; Bernstein et al., 1995) along the b axis of the unit cell (Table 1, Fig. 2). In addition, the crystal structure is consolidated by C—H···π and π-π stacking [Cg1···Cg3(3/2 - x, 1/2 + y, z) = 3.5916 (13) Å and Cg3···Cg3(1 - x, y, 1/2 - z) = 3.6890 (13) Å; Cg1 and Cg3 are the centroids of the N1/N2/C1/C2/C7 pyrazole ring and C8—C13 benzene ring, respectively] interactions.

Experimental

A mixture of methyl 4,6-bis(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate (3.42 g, 0.01 mol) and phenyl hydrazine (1.08 g, 0.01 mol) in 50 ml e thanol containing 1 ml glacial acetic acid was refluxed for 10 h. The reaction mixture was cooled and poured into 50 ml ice-cold water. The precipitate was collected by filtration and purified by recrystallization from ethanol. Yellow prisms of (I) were grown from DMF by slow evaporation (m.p.: > 523 K, yield: 58%).