3-(4-Chloro­phen­yl)-1-phenyl-1H-pyrazole-4-carbaldehyde

Hoong-Kun Fun; Suhana Arshad; Shridhar Malladi; R Selvam; Arun M Isloor

doi:10.1107/S1600536811023713

. 2011 Jun 25;67(Pt 7):o1783–o1784. doi: 10.1107/S1600536811023713

3-(4-Chlorophenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde

Hoong-Kun Fun ^a,^*,^‡, Suhana Arshad ^a, Shridhar Malladi ^b, R Selvam ^b, Arun M Isloor ^b

PMCID: PMC3151838 PMID: 21837157

Abstract

In the title compound, C₁₆H₁₁ClN₂O, the chloro-substituted phenyl ring is disordered over two positions with refined site occupancies of 0.503 (2) and 0.497 (2). The dihedral angle between the pyrazole and phenyl rings is 7.93 (7)°. The pyrazole ring also forms dihedral angles of 24.43 (9)° and 28.67 (9)° with the disordered chloro-substituted benzene ring. In the crystal, molecules are linked by intermolecular C—H⋯O hydrogen bonds, generating R ₂ ¹(7) and R ₂ ²(10) ring motifs. π–π interactions between the pyrazole and phenyl rings [centroid–centroid distance = 3.758 (1) Å] further stabilize the crystal structure.

Related literature

For related pharmacological literature, see: Karci & Karci (2008 ▶); Isloor et al. (2000 ▶); Kalluraya et al. (2004 ▶); Isloor et al. (2009 ▶); Comber et al. (1992 ▶). For the experimental preparation, see: Vora et al. (2009 ▶). For reference bond-length data, see: Allen et al. (1987 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₆H₁₁ClN₂O
M _r = 282.72
Monoclinic,
a = 16.0429 (4) Å
b = 4.8585 (1) Å
c = 16.7960 (4) Å
β = 96.581 (1)°
V = 1300.53 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.29 mm⁻¹
T = 100 K
0.55 × 0.16 × 0.08 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.858, T _max = 0.979
26528 measured reflections
3859 independent reflections
3302 reflections with I > 2σ(I)
R _int = 0.057

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.098
S = 1.03
3859 reflections
218 parameters
H-atom parameters constrained
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.35 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/S1600536811023713/wn2437sup1.cif

e-67-o1783-sup1.cif^{(21.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811023713/wn2437Isup2.hkl

e-67-o1783-Isup2.hkl^{(189.2KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811023713/wn2437Isup3.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
C1—H1A⋯O1ⁱ	0.95	2.42	3.3545 (18)	167
C7—H7A⋯O1ⁱ	0.95	2.33	3.2684 (16)	169

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank Universiti Sains Malaysia (USM) for the Research University Grant (1001/PFIZIK/811160). SA thanks the Malaysian Government and USM for the award of a research scholarship. AMI thanks the Department of Atomic Energy, Board for Research in Nuclear Sciences, Government of India for a Young Scientist award.

supplementary crystallographic information

Comment

Heterocyclic compounds have been gaining more importance in recent years due to their pharmacological activities. Nitrogen-, sulfur-, oxygen-containing five- or six-membered heterocyclic compounds are of enormous significance in the field of drug discovery process. Pyrazoles are important compounds that have many derivatives with a wide range of interesting properties, such as antipyretic, hypoglycemic, sedative-hypnotic (Karci & Karci, 2008), analgesic (Isloor et al., 2000), anti-inflammatory (Kalluraya et al., 2004) and antimicrobial activities (Isloor et al., 2009). Much attention was paid to pyrazole as a potential antimicrobial agent after the discovery of the natural pyrazole C-glycoside and pyrazofurin which demonstrated a broad spectrum of antimicrobial activity (Comber et al., 1992).

The molecular structure is shown in Fig 1. The chloro-substituted phenyl ring (C10–C15) is disordered over two positions with refined site occupancies of 0.503 (2) and 0.497 (2). The dihedral angle between the pyrazole ring (N1/N2/C7–C9) and the phenyl ring (C1–C6) is 7.93 (7)°. The pyrazole ring also forms dihedral angles of 24.43 (9)° and 28.67 (9)° with the disordered chloro-substituted phenyl rings (C10–C15) and (C10–C11X–C12X–C13–C14X–C15X), respectively. The bond lengths (Allen et al., 1987) and angles are within normal ranges.

In the crystal packing (Fig. 2), the intermolecular C1—H1A···O1 and C7—H7A···O1 hydrogen bonds (Table 1) link the molecules to form dimers, generating R¹₂(7) and R²₂(10) ring motifs (Bernstein et al., 1995). π–π interactions between the pyrazole and phenyl rings further stabilize the crystal structure; [Cg1···Cg2 = 3.7579 (8) Å, where Cg1 and Cg2 are the centroids of the rings N1/N2/C7–C9 and C1–C6, respectively; symmetry code: x, y - 1, z].

Experimental

Phosphoryl chloride (5 ml) was added dropwise to cold N,N- dimethylformamide (DMF) (15 ml) with continuous stirring at 273–278 K for about 30 min. 4-Chloroacetophenone phenylhydrazone (3.66 g, 15 mmol) was separately dissolved in 5 ml of DMF and was added dropwise to the former cold mixture with continuous stirring at 273–278 K for an hour. The resulting mixture was further stirred at 323–333 K for 5–6 h and cooled to room temperature. The crude product was poured into crushed ice, resulting in a white precipitate. The precipitate was filtered, washed with water and recrystallized from ethanol. Yield: 3.7 g, 87.4%. M.p.: 413–415 K (Vora et al., 2009).