(E)-3-(4-Methyl­phen­yl)-3-[3-(4-methyl­phen­yl)-1H-pyrazol-1-yl]-2-propenal

P Ramesh; A Subbiahpandi; Ramaiyan Manikannan; S Muthusubramanian; M N Ponnuswamy

doi:10.1107/S1600536808034697

. 2008 Oct 31;64(Pt 11):o2243. doi: 10.1107/S1600536808034697

(E)-3-(4-Methylphenyl)-3-[3-(4-methylphenyl)-1H-pyrazol-1-yl]-2-propenal

P Ramesh ^a, A Subbiahpandi ^a, Ramaiyan Manikannan ^b, S Muthusubramanian ^b, M N Ponnuswamy ^c,^*

PMCID: PMC2959754 PMID: 21581097

Abstract

In the title compound, C₂₀H₁₈N₂O, the pyrazole ring adopts a planar conformation. The C—N bond lengths in the pyrazole ring are shorter than a standard C—N single bond (1.443 Å), but longer than a standard double bond (1.269 Å), indicating electron delocalization. The propenal group assumes an extended conformation. Intermolecular C—H⋯O hydrogen bonds connect molecules into cyclic centrosymmetric R ₂ ²(26) dimers, which are cross-linked via C—H⋯π interactions.

Related literature

For the properties of pyrazole derivatives, see: Baraldi et al. (1998 ▶); Bruno et al. (1990 ▶); Chen & Li (1998 ▶); Cottineau et al. (2002 ▶); Londershausen (1996 ▶); Mishra et al. (1998 ▶); Smith et al. (2001 ▶). For related literature, see: Beddoes et al. (1986 ▶); Jin et al. (2004 ▶); Bernstein et al. (1995 ▶); Cordell (1981 ▶).

Experimental

Crystal data

C₂₀H₁₈N₂O
M _r = 302.36
Triclinic,
a = 10.0560 (9) Å
b = 10.0786 (8) Å
c = 10.3176 (9) Å
α = 62.040 (4)°
β = 79.356 (4)°
γ = 63.038 (4)°
V = 822.73 (12) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 (2) K
0.30 × 0.22 × 0.20 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ▶) T _min = 0.980, T _max = 0.985
14086 measured reflections
2887 independent reflections
2315 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.154
S = 1.03
2887 reflections
210 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808034697/gw2051sup1.cif

e-64-o2243-sup1.cif^{(19.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808034697/gw2051Isup2.hkl

e-64-o2243-Isup2.hkl^{(138.8KB, 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
C22—H22B⋯O1ⁱ	0.96	2.60	3.446 (3)	148
C9—H9⋯Cg1ⁱⁱ	0.93	2.80	3.690 (3)	161

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Symmetry codes: (i) Inline graphic ; (ii) . Cg1 is the centroid of the C16–C21 ring.

Acknowledgments

PR thanks Dr Babu Varghese, SAIF, IIT, Madras, India, for his help with the data collection.

supplementary crystallographic information

Comment

Some pyrazole derivatives are successfully tested for their antifungal (Chen & Li, 1998), antihistaminic (Mishra et al., 1998) and anti-inflammatory (Smith et al., 2001) properties. These derivatives also possess significant antiarrhythmic and sedative (Bruno et al., 1990), hypoglycemic (Cottineau et al., 2002), antiviral (Baraldi et al., 1998), and pesticidal (Londershausen,1996) activities.

The pyrazole ring adopts planar conformation. The sum of the angles at N1 of the pyrazole ring (360.0°) is in accordance with sp² hybridization (Beddoes et al., 1986). The C—N bond lengths in the pyrazole ring are 1.321 (2) and 1.360 (2) Å, which are shorter than a C—N single bond length of 1.443 Å, but longer than a double bond length of 1.269 Å, (Jin et al., 2004), indicating electron delocalization. The pyrazole ring A and methylphenyl ring C are near-coplanar with the inter-ring dihedral angle of 4.50 (13)°, whereas the pyrazole ring is twisted by an angle of 66.31 (12)° to the methylphenyl ring B. The propenal group assumes an extended conformation which is evidenced from the torsion angles [N1—C6—C14—C15]-169.74 (16) ° and [C5—N1—C6—C14]-160.85 (19)°. The crystal packing is stabilized by C—H···O and C—H-π interactions in addition to van der Waals forces. The molecules at (x, y, z) and (2 - x,-y,1 - z) are linked by C22—H22B···O1 hydrogen bonds into cyclic cenrosymmetric R₂²(26) dimers,

Experimental

The mixture of 1-(4-methylphenyl)-1-ethanone N-[(E)-1-phenylethylidene] hydrazone (0.003 mole) and 3 ml of dimethyl formamide kept in an ice bath at 0° C, phosphorus oxycholride (0.024 mole) was added dropwise for 5–10 minutes. The reaction mixture was then kept in a microwave oven at 600 W for 30–60 sec. The process of the reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into crushed ice and extracted with dichloromethane. The organic layer was dried with anhydrous sodium sulfate. The different compounds present in the mixture were separated by column chromatography using petroleum ether and ethyl acetate mixture as eluent. This isolated compound was recrystallized in dichloromethane to obtain (E)-3-(4-methylphenyl)-3-[3-(4-methylphenyl)-1H -pyrazol-1-yl]-2-propenal in 34% yield.