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The title mol­ecule, C9H7ClN2, is essentially planar, except for two methyl H atoms. The dihedral angle between the benzene ring and the pyrazine ring is 0.48 (7)°. A weak C—H...π inter­action is found in the crystal structure and there are no classical hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807054475/at2458sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807054475/at2458Isup2.hkl
Contains datablock I

CCDC reference: 672810

Key indicators

  • Single-crystal X-ray study
  • T = 200 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.044
  • wR factor = 0.135
  • Data-to-parameter ratio = 24.0

checkCIF/PLATON results

No syntax errors found



Alert level C ABSTM02_ALERT_3_C The ratio of expected to reported Tmax/Tmin(RR') is < 0.90 Tmin and Tmax reported: 0.723 1.000 Tmin(prime) and Tmax expected: 0.807 0.914 RR(prime) = 0.819 Please check that your absorption correction is appropriate. PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large ............. 0.81 PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 0.91
Alert level G ABSTM02_ALERT_3_G When printed, the submitted absorption T values will be replaced by the scaled T values. Since the ratio of scaled T's is identical to the ratio of reported T values, the scaling does not imply a change to the absorption corrections used in the study. Ratio of Tmax expected/reported 0.914 Tmax scaled 0.914 Tmin scaled 0.661
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 3 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

Various quinoxaline derivatives have aroused considerable interest of chemistry due to their versatile practical applications as well as their wide range of biological properties. Literature survey reveals that a large number of quinoxaline derivatives have been shown to possess a variety of pharmacological properties like antibacterial, antifungal, antiturberculosis, analgesic and anti-inflammatory activities and hence it is found to be an important structural feature in some synthetic drugs (Craig & Akinpelu, 2005; Michaus & Belen, 2005; and Vyas et al. 2005). Certain quinoxaline derivatives have been reported to possess antiallergic properties. Some natural compounds (echinomicine, triostine) contains quinoxaline skeleton. Thus quinoxaline derivatives continue to attract much attention as potential biological interest.

In the title molecule, C9H7ClN2, (Fig.1), the quinoxaline unit is planar. The benzene ring makes a dihedral angle of 0.48 (7)° with the pyrazine ring. A weak C31—H31B···π interaction involving a methyl hydrogen and the benzene ring is found in the crystal structure and there are no classical hydrogen bonds.

Related literature top

For the uses of quinoxalines, see Craig & Akinpelu, 2005; Michaus & Belen, 2005; Vyas et al. 2005.

Experimental top

3-methylquinoxalin-2(1H)-one (5.0 g, 0.0312 mol) was added to cold phosphorus oxychloride (41.0 g, 0.26 mol) in portions to get a slurry. To the resulting slurry N,N-Dimethyl aniline (0.95 g, 0.0078 mol) was added drop wise below 288 K. The brick red mixture was refluxed (at approx. 378 K) for 15 min and the resulting dark brown clear solution was then cooled to ambient temperature. It was added to ice cold water (250 ml) and basified slowly under cooling with 40% aq. NaOH to pH 8. The brick red solid, thus separated was filtered, washed with water (2x50 ml) and dried to obtain crude 2-chloro-3-methylquinoxaline. The crude product was dissolved in hot hexane (75 ml), treated with activated charcoal and filtered. The filtrate on concentration to a small volume (5 ml) gave pure 2-chloro-3-methylquinoxaline, as brick red crystals, which was further recrystalized from acetone to get colourless crystals, 4.0 g (72%).

Refinement top

H atoms were positioned geometrically and allowed to ride on their parent atoms, with C—H = 0.95 or 0.98 Å and Uiso=1.2 or1.5 times Ueq(C).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell refinement: CrysAlis CCD (Oxford Diffraction, 2007); data reduction: CrysAlis RED (Oxford Diffraction, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atomic numbering and 50% probability displacement ellipsoids. H atoms are shown shown as small spheres of arbitrary radius.
2-Chloro-3-methylquinoxaline top
Crystal data top
C9H7ClN2Z = 2
Mr = 178.62F(000) = 184
Triclinic, P1Dx = 1.472 Mg m3
Hall symbol: -P 1Melting point: 352(1) K
a = 6.8876 (4) ÅMo Kα radiation, λ = 0.71073 Å
b = 7.4022 (4) ÅCell parameters from 3999 reflections
c = 9.4124 (5) Åθ = 4.7–32.3°
α = 70.654 (4)°µ = 0.41 mm1
β = 72.438 (5)°T = 200 K
γ = 65.019 (5)°Square-plate, pale-pink
V = 403.01 (4) Å30.51 × 0.49 × 0.22 mm
Data collection top
Oxford Diffraction Gemini
diffractometer
2645 independent reflections
Radiation source: fine-focus sealed tube2094 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
Detector resolution: 10.5081 pixels mm-1θmax = 32.4°, θmin = 4.7°
ϕ and ω scansh = 910
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2007)
k = 1011
Tmin = 0.723, Tmax = 1.000l = 814
5962 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.135H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0789P)2 + 0.0905P]
where P = (Fo2 + 2Fc2)/3
2645 reflections(Δ/σ)max < 0.001
110 parametersΔρmax = 0.51 e Å3
0 restraintsΔρmin = 0.31 e Å3
Crystal data top
C9H7ClN2γ = 65.019 (5)°
Mr = 178.62V = 403.01 (4) Å3
Triclinic, P1Z = 2
a = 6.8876 (4) ÅMo Kα radiation
b = 7.4022 (4) ŵ = 0.41 mm1
c = 9.4124 (5) ÅT = 200 K
α = 70.654 (4)°0.51 × 0.49 × 0.22 mm
β = 72.438 (5)°
Data collection top
Oxford Diffraction Gemini
diffractometer
2645 independent reflections
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2007)
2094 reflections with I > 2σ(I)
Tmin = 0.723, Tmax = 1.000Rint = 0.024
5962 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.135H-atom parameters constrained
S = 1.08Δρmax = 0.51 e Å3
2645 reflectionsΔρmin = 0.31 e Å3
110 parameters
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl20.00177 (6)0.70740 (7)0.80205 (4)0.0376 (1)
N10.21428 (18)0.72294 (18)0.52218 (14)0.0255 (3)
N40.14312 (18)0.76886 (17)0.40874 (13)0.0247 (3)
C20.0251 (2)0.7312 (2)0.60775 (15)0.0241 (3)
C30.1618 (2)0.7568 (2)0.55461 (15)0.0231 (3)
C4A0.0544 (2)0.7597 (2)0.31326 (15)0.0235 (3)
C50.0785 (2)0.7733 (2)0.15555 (16)0.0296 (4)
C60.2739 (3)0.7667 (3)0.05928 (17)0.0350 (5)
C70.4533 (3)0.7452 (3)0.11537 (18)0.0352 (4)
C80.4348 (2)0.7302 (2)0.26786 (18)0.0304 (4)
C8A0.2340 (2)0.7380 (2)0.36893 (15)0.0237 (3)
C310.3786 (2)0.7725 (2)0.66060 (17)0.0281 (4)
H50.040640.787010.116760.0355*
H60.289330.776650.046520.0420*
H70.587710.741150.046890.0422*
H80.556020.714780.305130.0364*
H31A0.479230.772230.606060.0422*
H31B0.358500.655280.749600.0422*
H31C0.439020.900070.695080.0422*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl20.0392 (2)0.0539 (3)0.0267 (2)0.0194 (2)0.0076 (1)0.0133 (2)
N10.0232 (5)0.0307 (6)0.0270 (5)0.0123 (4)0.0069 (4)0.0068 (4)
N40.0210 (5)0.0291 (6)0.0268 (5)0.0097 (4)0.0064 (4)0.0074 (4)
C20.0248 (6)0.0269 (6)0.0246 (6)0.0102 (5)0.0071 (5)0.0076 (5)
C30.0211 (5)0.0230 (6)0.0273 (6)0.0085 (4)0.0062 (4)0.0063 (5)
C4A0.0220 (5)0.0259 (6)0.0246 (6)0.0094 (5)0.0068 (4)0.0053 (5)
C50.0297 (6)0.0371 (8)0.0253 (6)0.0131 (6)0.0086 (5)0.0069 (5)
C60.0367 (8)0.0445 (9)0.0240 (7)0.0160 (7)0.0042 (5)0.0077 (6)
C70.0286 (7)0.0442 (9)0.0308 (7)0.0163 (6)0.0007 (5)0.0077 (6)
C80.0229 (6)0.0355 (8)0.0345 (7)0.0132 (5)0.0044 (5)0.0078 (6)
C8A0.0215 (5)0.0263 (6)0.0259 (6)0.0099 (5)0.0068 (4)0.0057 (5)
C310.0213 (5)0.0339 (7)0.0298 (7)0.0105 (5)0.0013 (5)0.0107 (5)
Geometric parameters (Å, º) top
Cl2—C21.7420 (14)C6—C71.415 (3)
N1—C21.297 (2)C7—C81.373 (2)
N1—C8A1.3782 (18)C8—C8A1.413 (2)
N4—C31.3159 (17)C5—H50.9500
N4—C4A1.374 (2)C6—H60.9500
C2—C31.436 (2)C7—H70.9500
C3—C311.507 (2)C8—H80.9500
C4A—C51.4169 (19)C31—H31A0.9800
C4A—C8A1.414 (2)C31—H31B0.9800
C5—C61.368 (3)C31—H31C0.9800
Cl2···C4Ai3.6077 (15)C5···H31Bvi2.9300
Cl2···H5ii3.1100C6···H31Bvi2.9500
Cl2···H6ii3.0400C7···H31Bvi3.0800
Cl2···H31B2.8700C8···H31Ci2.8800
Cl2···H31C3.0800C31···H6iii3.0000
Cl2···H7iii3.0500H5···Cl2vii3.1100
N1···N42.820 (2)H6···Cl2vii3.0400
N4···N12.820 (2)H6···C31viii3.0000
N1···H31Aiv2.6600H7···Cl2viii3.0500
N4···H8v2.7500H8···N4iv2.7500
C3···C4Avi3.425 (2)H31A···N1v2.6600
C4A···Cl2i3.6077 (15)H31B···Cl22.8700
C4A···C3vi3.425 (2)H31B···C4Avi3.0300
C4A···C31vi3.581 (2)H31B···C5vi2.9300
C8A···C31vi3.564 (2)H31B···C6vi2.9500
C31···C4Avi3.581 (2)H31B···C7vi3.0800
C31···C8Avi3.564 (2)H31C···Cl23.0800
C4A···H31Bvi3.0300H31C···C8i2.8800
C2—N1—C8A116.20 (14)N1—C8A—C8119.77 (14)
C3—N4—C4A118.27 (13)C4A—C8A—C8120.11 (13)
Cl2—C2—N1116.17 (12)C4A—C5—H5120.00
Cl2—C2—C3118.67 (11)C6—C5—H5120.00
N1—C2—C3125.16 (13)C5—C6—H6120.00
N4—C3—C2118.88 (13)C7—C6—H6120.00
N4—C3—C31119.21 (14)C6—C7—H7120.00
C2—C3—C31121.91 (12)C8—C7—H7120.00
N4—C4A—C5119.38 (14)C7—C8—H8120.00
N4—C4A—C8A121.37 (12)C8A—C8—H8120.00
C5—C4A—C8A119.25 (13)C3—C31—H31A109.00
C4A—C5—C6119.78 (15)C3—C31—H31B109.00
C5—C6—C7120.82 (14)C3—C31—H31C109.00
C6—C7—C8120.58 (17)H31A—C31—H31B109.00
C7—C8—C8A119.46 (16)H31A—C31—H31C109.00
N1—C8A—C4A120.12 (13)H31B—C31—H31C109.00
C8A—N1—C2—Cl2178.86 (10)N4—C4A—C5—C6179.25 (15)
C8A—N1—C2—C30.8 (2)C8A—C4A—C5—C60.4 (2)
C2—N1—C8A—C4A0.4 (2)N4—C4A—C8A—N10.8 (2)
C2—N1—C8A—C8179.95 (12)N4—C4A—C8A—C8179.64 (13)
C4A—N4—C3—C21.05 (19)C5—C4A—C8A—N1179.50 (13)
C4A—N4—C3—C31178.28 (12)C5—C4A—C8A—C80.0 (2)
C3—N4—C4A—C5179.71 (13)C4A—C5—C6—C70.4 (3)
C3—N4—C4A—C8A0.0 (2)C5—C6—C7—C80.1 (3)
Cl2—C2—C3—N4178.05 (11)C6—C7—C8—C8A0.5 (3)
Cl2—C2—C3—C312.63 (18)C7—C8—C8A—N1179.97 (15)
N1—C2—C3—N41.6 (2)C7—C8—C8A—C4A0.4 (2)
N1—C2—C3—C31177.76 (13)
Symmetry codes: (i) x, y+2, z+1; (ii) x, y, z+1; (iii) x1, y, z+1; (iv) x+1, y, z; (v) x1, y, z; (vi) x, y+1, z+1; (vii) x, y, z1; (viii) x+1, y, z1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C31—H31B···Cgvi0.982.713.461 (2)133.00
Symmetry code: (vi) x, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC9H7ClN2
Mr178.62
Crystal system, space groupTriclinic, P1
Temperature (K)200
a, b, c (Å)6.8876 (4), 7.4022 (4), 9.4124 (5)
α, β, γ (°)70.654 (4), 72.438 (5), 65.019 (5)
V3)403.01 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.41
Crystal size (mm)0.51 × 0.49 × 0.22
Data collection
DiffractometerOxford Diffraction Gemini
diffractometer
Absorption correctionMulti-scan
(CrysAlis RED; Oxford Diffraction, 2007)
Tmin, Tmax0.723, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
5962, 2645, 2094
Rint0.024
(sin θ/λ)max1)0.753
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.135, 1.08
No. of reflections2645
No. of parameters110
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.51, 0.31

Computer programs: CrysAlis CCD (Oxford Diffraction, 2007), CrysAlis RED (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C31—H31B···Cgi0.982.713.461 (2)133.00
Symmetry code: (i) x, y+1, z+1.
 

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