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Acta Crystallogr Sect E Struct Rep Online. 2008 November 1; 64(Pt 11): o2234.
Published online 2008 October 31. doi:  10.1107/S1600536808033989
PMCID: PMC2959506

1-Ethyl-3-methyl­quinoxalin-2(1H)-one

Abstract

The asymmetric unit of the title compound, C11H12N2O, contains two independent mol­ecules. In the crystal structure, inter­molecular C—H(...)O hydrogen bonds link the mol­ecules. There are π–π contacts between the quinoxaline rings [centroid–centroid distances = 3.446 (2), 3.665 (2), 3.645 (3) and 3.815 (3) Å]. There also exist C—H(...)π contacts between the methyl groups and the quinoxaline rings.

Related literature

For general background, see: Amin (2003 [triangle]); Boutti & Lecolier (1975 [triangle]); Milos & John (1981 [triangle]); Rose et al. (1990 [triangle]); Salman et al. (2007 [triangle]); Kotharkar & Shinde (2006 [triangle]); Vishnu et al. (2006 [triangle]). For related literature, see: Nikolaenko & Munro (2004 [triangle]). For bond-length data, see: Allen et al. (1987 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o2234-scheme1.jpg

Experimental

Crystal data

  • C11H12N2O
  • M r = 188.23
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o2234-efi1.jpg
  • a = 7.4101 (6) Å
  • b = 9.1405 (8) Å
  • c = 14.2960 (12) Å
  • α = 84.976 (7)°
  • β = 78.717 (7)°
  • γ = 88.137 (7)°
  • V = 945.82 (14) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 180 K
  • 0.18 × 0.13 × 0.07 mm

Data collection

  • Oxford Diffraction Xcalibur diffractometer
  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 [triangle]) T min = 0.988, T max = 0.991
  • 7441 measured reflections
  • 3865 independent reflections
  • 2874 reflections with I > 2σ(I)
  • R int = 0.021

Refinement

  • R[F 2 > 2σ(F 2)] = 0.039
  • wR(F 2) = 0.111
  • S = 1.06
  • 3865 reflections
  • 257 parameters
  • H-atom parameters constrained
  • Δρmax = 0.17 e Å−3
  • Δρmin = −0.25 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2007 [triangle]); cell refinement: CrysAlis RED (Oxford Diffraction, 2007 [triangle]); data reduction: CrysAlis RED; program(s) used to solve structure: SIR92 (Altomare et al., 1994 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]) and PLATON (Spek, 2003 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]) and PLATON.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808033989/hk2546sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808033989/hk2546Isup2.hkl

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

supplementary crystallographic information

Comment

The quinoxaline derivatives have great importance in scientific research for their biological properties. It is well known that quinoxaline have antibacterial (Kotharkar & Shinde, 2006; Salman et al., 2007) and antifungal (Vishnu et al., 2006) activities. They are also used for colorimetry metal detection (Amin, 2003) and as oil stabilizant (Boutti & Lecolier, 1975). Likewise several patents describe them as hair azo dyes (Rose et al., 1990) and pigments (Milos & John, 1981). We report herein, the synthesis and crystal structure of the title compound.

The asymmetric unit of the title compound (Fig. 1), contains two independent molecules. The bond lengths (Allen et al., 1987) and angles are within normal ranges. The intramolecular C—H···O hydrogen bond (Table 1) links the molecules.

In the crystal structure, intra- and intermolecular C-H···O hydrogen bonds (Table 1) link the molecules (Fig. 2), in which they may be effective in the stabilization of the structure. The π—π contacts between the quinoxaline rings, Cg1···Cg1i, Cg1···Cg3ii, Cg2···Cg2iii and Cg2···Cg4iv [symmetry codes: (i) 1 - x, 1 - y, 1 - z; (ii) -x, 1 - y, 1 - z; (iii) -x, -y, -z; (iv) 1 - x, -y, -z, where Cg1, Cg2, Cg3 and Cg4 are the centroids of the rings A (N1/N2/C1-C3/C8), B (N3/N4/C12-C14/C19), C (C3-C8) and D (C14-C19), respectively] may further stabilize the structure, with centroid-centroid distances of 3.446 (2), 3.665 (2), 3.645 (3) and 3.815 (3) Å, respectively. There also exist C—H···π contacts (Table 1) between the methyl groups and rings C and D.

Experimental

To a solution of 3-methylquinoxalin-2(1H)-one (Nikolaenko & Munro, 2004) (1 g, 6.22 mmol) in dimethylformamide (20 ml), was added ethylbromide (0.67 ml, 6.22 mmol), K2CO3 (1 g, 7.46 mmol) and a catalytic quantity of tetrabutylammoniumbromide. The mixture was stirred at room temperature for 24 h. The solution was filtered to remove the salts. The solvent was removed under reduced pressure. The residue was crystallized in ethanol to afford the title compound as yellow crystals.

Refinement

H atoms were positioned geometrically, with C-H = 0.93, 0.97 and 0.96 Å for aromatic, methylene and methyl H, respectively, and constrained to ride on their parent atoms with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Figures

Fig. 1.
The molecular structure of the title molecule, with the atom-numbering scheme. Hydrogen bond is shown as dashed line.
Fig. 2.
A partial packing diagram. Hydrogen bonds are shown as dashed lines [symmetry code: (') -x, -y, -z].

Crystal data

C11H12N2OZ = 4
Mr = 188.23F(000) = 400
Triclinic, P1Dx = 1.322 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.4101 (6) ÅCell parameters from 4794 reflections
b = 9.1405 (8) Åθ = 2.8–31.9°
c = 14.2960 (12) ŵ = 0.09 mm1
α = 84.976 (7)°T = 180 K
β = 78.717 (7)°Block, colorless
γ = 88.137 (7)°0.18 × 0.13 × 0.07 mm
V = 945.82 (14) Å3

Data collection

Oxford Diffraction Xcalibur diffractometer3865 independent reflections
Radiation source: fine-focus sealed tube2874 reflections with I > 2σ(I)
graphiteRint = 0.021
[var phi] and ω scansθmax = 26.4°, θmin = 2.8°
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)h = −9→8
Tmin = 0.988, Tmax = 0.991k = −11→11
7441 measured reflectionsl = −14→17

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.111H-atom parameters constrained
S = 1.06w = 1/[σ2(Fo2) + (0.0636P)2 + 0.0861P] where P = (Fo2 + 2Fc2)/3
3865 reflections(Δ/σ)max < 0.001
257 parametersΔρmax = 0.17 e Å3
0 restraintsΔρmin = −0.25 e Å3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.
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)

xyzUiso*/Ueq
O10.46438 (13)0.21858 (11)0.37756 (7)0.0375 (3)
O20.28053 (14)0.17912 (12)−0.17004 (7)0.0438 (3)
N10.33532 (14)0.31106 (11)0.51763 (7)0.0244 (2)
N20.28293 (14)0.57622 (11)0.41274 (8)0.0279 (3)
N30.30886 (13)0.14773 (11)−0.01436 (7)0.0258 (2)
N40.19176 (14)−0.14053 (12)−0.01083 (8)0.0274 (3)
C10.39293 (17)0.32233 (14)0.42044 (9)0.0267 (3)
C20.36552 (17)0.46723 (14)0.37053 (9)0.0274 (3)
C30.21391 (16)0.55680 (13)0.51001 (9)0.0237 (3)
C40.11835 (18)0.67263 (14)0.55460 (10)0.0300 (3)
H40.10210.76010.51860.036*
C50.04770 (19)0.66048 (15)0.65059 (10)0.0342 (3)
H5−0.01610.73880.67990.041*
C60.07254 (19)0.52952 (16)0.70377 (10)0.0344 (3)
H60.02510.5210.76920.041*
C70.16544 (18)0.41247 (15)0.66197 (9)0.0296 (3)
H70.17950.32530.69870.036*
C80.23840 (16)0.42472 (13)0.56451 (9)0.0228 (3)
C90.37008 (19)0.16990 (14)0.56915 (10)0.0311 (3)
H9A0.38220.18640.63370.037*
H9B0.48520.12760.53730.037*
C100.2174 (2)0.06358 (15)0.57337 (11)0.0386 (3)
H10A0.10590.10050.61060.058*
H10B0.2494−0.02980.60250.058*
H10C0.19950.05220.50970.058*
C110.4365 (2)0.48358 (17)0.26554 (10)0.0396 (3)
H11A0.35030.44280.23320.059*
H11B0.55270.43260.2510.059*
H11C0.45250.58580.24460.059*
C120.26924 (17)0.09898 (15)−0.09593 (9)0.0287 (3)
C130.21489 (17)−0.05575 (15)−0.08903 (9)0.0279 (3)
C140.22409 (16)−0.08415 (13)0.07134 (9)0.0236 (3)
C150.19919 (18)−0.17617 (15)0.15556 (9)0.0306 (3)
H150.157−0.27090.15560.037*
C160.23571 (19)−0.12955 (17)0.23841 (10)0.0361 (3)
H160.2194−0.19210.29420.043*
C170.29710 (19)0.01175 (17)0.23769 (10)0.0358 (3)
H170.32230.0440.29360.043*
C180.32169 (17)0.10564 (15)0.15571 (10)0.0308 (3)
H180.36240.20060.15670.037*
C190.28562 (16)0.05865 (13)0.07122 (8)0.0232 (3)
C200.37012 (19)0.29997 (14)−0.01979 (11)0.0359 (3)
H20A0.4320.3291−0.08470.043*
H20B0.45770.30610.0220.043*
C210.2105 (2)0.40401 (17)0.00908 (14)0.0525 (4)
H21A0.12430.399−0.03260.079*
H21B0.25490.50240.00440.079*
H21C0.15080.37680.07390.079*
C220.1875 (2)−0.11426 (18)−0.17904 (10)0.0399 (4)
H22A0.1497−0.2146−0.1660.06*
H22B0.3009−0.109−0.22510.06*
H22C0.0943−0.0569−0.20420.06*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0409 (6)0.0364 (5)0.0342 (5)0.0068 (4)−0.0026 (4)−0.0111 (4)
O20.0460 (6)0.0514 (6)0.0287 (5)0.0052 (5)−0.0026 (4)0.0131 (5)
N10.0263 (5)0.0214 (5)0.0260 (6)0.0021 (4)−0.0066 (4)−0.0019 (4)
N20.0302 (6)0.0253 (6)0.0291 (6)−0.0059 (4)−0.0083 (5)0.0009 (4)
N30.0222 (5)0.0247 (5)0.0273 (6)0.0021 (4)0.0011 (4)0.0009 (4)
N40.0246 (6)0.0304 (6)0.0266 (6)0.0030 (4)−0.0023 (4)−0.0061 (5)
C10.0221 (6)0.0302 (7)0.0285 (7)−0.0015 (5)−0.0051 (5)−0.0058 (5)
C20.0257 (6)0.0310 (7)0.0263 (7)−0.0063 (5)−0.0065 (5)−0.0013 (5)
C30.0219 (6)0.0229 (6)0.0283 (6)−0.0039 (5)−0.0086 (5)−0.0024 (5)
C40.0321 (7)0.0212 (6)0.0396 (8)−0.0005 (5)−0.0136 (6)−0.0036 (5)
C50.0326 (7)0.0302 (7)0.0419 (8)0.0034 (6)−0.0077 (6)−0.0154 (6)
C60.0359 (8)0.0396 (8)0.0277 (7)−0.0012 (6)−0.0033 (6)−0.0094 (6)
C70.0331 (7)0.0295 (7)0.0265 (7)0.0001 (6)−0.0071 (5)−0.0006 (5)
C80.0212 (6)0.0223 (6)0.0268 (6)−0.0013 (5)−0.0075 (5)−0.0046 (5)
C90.0369 (8)0.0251 (7)0.0312 (7)0.0088 (6)−0.0081 (6)−0.0015 (5)
C100.0475 (9)0.0257 (7)0.0394 (8)0.0006 (6)−0.0026 (7)0.0013 (6)
C110.0436 (8)0.0447 (8)0.0284 (7)−0.0039 (7)−0.0023 (6)0.0003 (6)
C120.0216 (6)0.0377 (7)0.0234 (7)0.0069 (5)0.0010 (5)0.0014 (6)
C130.0202 (6)0.0381 (7)0.0242 (7)0.0066 (5)−0.0014 (5)−0.0060 (5)
C140.0193 (6)0.0268 (6)0.0235 (6)0.0041 (5)−0.0010 (5)−0.0041 (5)
C150.0295 (7)0.0287 (7)0.0301 (7)0.0041 (5)−0.0002 (5)0.0028 (5)
C160.0351 (8)0.0462 (9)0.0235 (7)0.0105 (6)−0.0019 (6)0.0039 (6)
C170.0319 (7)0.0518 (9)0.0251 (7)0.0110 (6)−0.0078 (5)−0.0102 (6)
C180.0263 (7)0.0332 (7)0.0341 (7)0.0034 (5)−0.0058 (5)−0.0117 (6)
C190.0171 (6)0.0265 (6)0.0238 (6)0.0054 (5)0.0001 (5)−0.0017 (5)
C200.0325 (7)0.0263 (7)0.0445 (8)−0.0010 (6)0.0015 (6)0.0022 (6)
C210.0460 (9)0.0285 (8)0.0800 (13)0.0068 (7)−0.0047 (8)−0.0070 (8)
C220.0340 (8)0.0588 (10)0.0284 (7)0.0060 (7)−0.0064 (6)−0.0136 (7)

Geometric parameters (Å, °)

C1—O11.2238 (15)C12—O21.2245 (15)
C1—N11.3671 (16)C12—N31.3705 (17)
C1—C21.4759 (18)C12—C131.473 (2)
C2—N21.2854 (16)C13—N41.2891 (17)
C2—C111.4862 (18)C13—C221.4876 (19)
C3—N21.3825 (17)C14—N41.3882 (16)
C3—C41.3862 (17)C14—C151.3918 (18)
C3—C81.4049 (17)C14—C191.3963 (18)
C4—C51.366 (2)C15—C161.371 (2)
C4—H40.93C15—H150.93
C5—C61.388 (2)C16—C171.382 (2)
C5—H50.93C16—H160.93
C6—C71.3707 (19)C17—C181.3761 (19)
C6—H60.93C17—H170.93
C7—C81.3885 (18)C18—C191.3926 (18)
C7—H70.93C18—H180.93
C8—N11.3891 (15)C19—N31.3934 (16)
C9—N11.4696 (15)C20—N31.4687 (17)
C9—H9A0.97C20—H20A0.97
C9—H9B0.97C20—H20B0.97
C10—C91.5041 (19)C21—C201.509 (2)
C10—H10A0.96C21—H21A0.96
C10—H10B0.96C21—H21B0.96
C10—H10C0.96C21—H21C0.96
C11—H11A0.96C22—H22A0.96
C11—H11B0.96C22—H22B0.96
C11—H11C0.96C22—H22C0.96
O1—C1—N1121.88 (12)N4—C13—C22119.61 (13)
O1—C1—C2122.05 (12)C12—C13—C22116.56 (12)
N1—C1—C2116.07 (11)N4—C14—C15118.06 (12)
N2—C2—C1123.59 (11)N4—C14—C19122.33 (11)
N2—C2—C11119.68 (12)C15—C14—C19119.57 (12)
C1—C2—C11116.73 (12)C16—C15—C14121.14 (13)
N2—C3—C4118.34 (11)C16—C15—H15119.4
N2—C3—C8122.24 (11)C14—C15—H15119.4
C4—C3—C8119.42 (12)C15—C16—C17118.97 (13)
C5—C4—C3121.10 (12)C15—C16—H16120.5
C5—C4—H4119.5C17—C16—H16120.5
C3—C4—H4119.5C18—C17—C16121.23 (13)
C4—C5—C6119.04 (12)C18—C17—H17119.4
C4—C5—H5120.5C16—C17—H17119.4
C6—C5—H5120.5C17—C18—C19120.05 (13)
C7—C6—C5121.44 (13)C17—C18—H18120
C7—C6—H6119.3C19—C18—H18120
C5—C6—H6119.3C18—C19—N3122.96 (12)
C6—C7—C8119.68 (12)C18—C19—C14119.04 (12)
C6—C7—H7120.2N3—C19—C14118.00 (11)
C8—C7—H7120.2N3—C20—C21111.52 (11)
C7—C8—N1122.76 (11)N3—C20—H20A109.3
C7—C8—C3119.32 (11)C21—C20—H20A109.3
N1—C8—C3117.92 (11)N3—C20—H20B109.3
N1—C9—C10111.68 (11)C21—C20—H20B109.3
N1—C9—H9A109.3H20A—C20—H20B108
C10—C9—H9A109.3C20—C21—H21A109.5
N1—C9—H9B109.3C20—C21—H21B109.5
C10—C9—H9B109.3H21A—C21—H21B109.5
H9A—C9—H9B107.9C20—C21—H21C109.5
C9—C10—H10A109.5H21A—C21—H21C109.5
C9—C10—H10B109.5H21B—C21—H21C109.5
H10A—C10—H10B109.5C13—C22—H22A109.5
C9—C10—H10C109.5C13—C22—H22B109.5
H10A—C10—H10C109.5H22A—C22—H22B109.5
H10B—C10—H10C109.5C13—C22—H22C109.5
C2—C11—H11A109.5H22A—C22—H22C109.5
C2—C11—H11B109.5H22B—C22—H22C109.5
H11A—C11—H11B109.5C1—N1—C8121.35 (10)
C2—C11—H11C109.5C1—N1—C9116.87 (10)
H11A—C11—H11C109.5C8—N1—C9121.66 (10)
H11B—C11—H11C109.5C2—N2—C3118.47 (11)
O2—C12—N3121.81 (13)C12—N3—C19121.53 (11)
O2—C12—C13122.35 (13)C12—N3—C20117.23 (11)
N3—C12—C13115.83 (11)C19—N3—C20121.20 (11)
N4—C13—C12123.82 (12)C13—N4—C14118.27 (11)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7—H7···O2i0.932.433.291 (3)154
C17—H17···O10.932.463.301 (3)151
C11—H11B···Cg3ii0.963.343.893 (3)119
C22—H22C···Cg4iii0.962.713.516 (3)142

Symmetry codes: (i) x, y, z+1; (ii) −x+1, −y+1, −z+1; (iii) −x, −y, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HK2546).

References

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