6-Chloro-2-phenyl-3-(2-phenyl­ethyn­yl)quinoxaline

Xi-Lin Ouyang; Miao Ouyang; Shi-Wen Huang

doi:10.1107/S1600536812020776

. 2012 May 16;68(Pt 6):o1741. doi: 10.1107/S1600536812020776

6-Chloro-2-phenyl-3-(2-phenylethynyl)quinoxaline

Xi-Lin Ouyang ^a, Miao Ouyang ^b, Shi-Wen Huang ^a,^*

PMCID: PMC3379328 PMID: 22719526

Abstract

In the title compound, C₂₂H₁₃ClN₂, the quinoxaline ring system is close to planar [maximum deviation = 0.061 (2) Å]. The phenyl ring at the 2-position and the phenyl ring of the phenylethynyl substituent make dihedral angles of 49.32 (7) and 11.99 (7) °, respectively, with the quinoxaline mean plane. The two phenyl rings are inclined to one another by 61.27 (9)°. In the crystal, molecules are linked by C—H⋯π and π–π interactions [centroid–centroid distances = 3.6210 (12) and 3.8091 (12) Å].

Related literature

For the biological activity of quinoxaline derivatives, see: Rodrigo et al. (2002 ▶); Watkins et al. (2009 ▶); Sashidhara et al. (2009 ▶). For the crystal structures of quinoxaline derivatives, see: Hegedus et al. (2003 ▶); Naraso et al. (2006 ▶); Hassan et al. (2010 ▶); Ammermann et al. (2008 ▶); Daouda et al. (2011 ▶); Ramli et al. (2012 ▶).

Experimental

Crystal data

C₂₂H₁₃ClN₂
M _r = 340.79
Triclinic,
a = 8.8652 (13) Å
b = 9.8591 (8) Å
c = 10.9740 (17) Å
α = 73.032 (15)°
β = 81.036 (17)°
γ = 64.374 (13)°
V = 826.68 (19) Å³
Z = 2
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 223 K
0.70 × 0.45 × 0.20 mm

Data collection

Rigaku Saturn diffractometer
Absorption correction: multi-scan (REQAB; Jacobson, 1998 ▶) T _min = 0.649, T _max = 0.954
7504 measured reflections
3714 independent reflections
2855 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.128
S = 1.07
3714 reflections
227 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.37 e Å⁻³

Data collection: CrystalClear (Rigaku, 2002 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalStructure (Rigaku, 2002 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812020776/su2414sup1.cif

e-68-o1741-sup1.cif^{(18.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812020776/su2414Isup2.hkl

e-68-o1741-Isup2.hkl^{(182.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812020776/su2414Isup3.cml

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

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

Cg2 is the centroid of the C17–C22 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C14—H14⋯Cg2ⁱ	0.94	3.00	3.845 (2)	151

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was funded by the Project of the Education Department of Guangxi Province (No. 201106LX593) and the Youth Foundation of Hechi University (No. 2011B-N004).

supplementary crystallographic information

Comment

The design of small molecular weight compounds has aroused much interest in the past decades due to the advances in targeted therapeutics coupled with novel techniques in target identification. It is well know that quinoxalines have broad applications in the fields of medicine and pharmaceuticals. It has been shown that many quinoxaline derivatives exhibit good biological activities, such as antituberculous activities (Rodrigo et al., 2002), antioxidative properties (Watkins et al., 2009), and antidyslipidemic (Sashidhara et al., 2009). Recently, a large number of crystal structures of quinoxaline derivatives have been reported (Hegedus et al., 2003; Naraso et al., 2006; Hassan et al., 2010; Ammermann et al., 2008; Daouda et al., 2011; Ramli et al., 2012).

In the title compound (Fig. 1) the phenyl ring of the phenylethynyl substituent is twisted by 11.99 (7)° out of the mean plane of the quinoxaline fused-ring system [planar to within 0.061 (2) Å]. The phenyl ring of the substituent at the 2-position, C7, makes dihedral angles of 49.32 (7)° and 61.27 (9)°, respectively, with the quinoxaline mean plane and the phenylethynyl phenyl ring.

In the crystal (Fig. 2), molecules are linked by C—H···π interactions involving the phenylethynyl phenyl ring (Table 1), and by π–π interactions involving inversion related quinoxaline rings and the phenylethynyl phenyl ring [Cg1···Cg1ⁱ 3.6210 (12) Å, interplanar spacing of 3.3635 (7) Å, slippage of 1.341 Å; Cg1···Cg2ⁱⁱ 3.8091 (12) Å; Cg1 is the centroid of the C1-C6 ring; Cg2 is the centroid of the C17-C22 ring; symmetry codes: (i) -x, -y+1, -z+2; (ii) -x+1, -y, -z+2].

Footnote to Table 1: Cg2 is the centroid of the C17-C22 ring.

Experimental

4-Chloro-1,2-diaminobenzene (2.5 mmol), CuCl (0.1 mmol), chlorobenzene (3 ml) and phenylethynylene(1 mmol) were added to a sealed tube and heated to 343 K by stirring. After the completion of the reaction (as monitored by TLC), the inorganic material salt was filtered and the reaction mixture was extracted with EtOAc. The mixture was separated after washed by saturated NaCl solution, then the oily layer was dried by anhydrous sodium sulfate and the solvent was removed under reduced pressure. The crude product obtained was purified by column chromatography (eluent: 50:1 Petroleum ether–EtOAc) to give the title compound. Block-like yellow crystals were obtained by slow evaporation of the solvents.