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Acta Crystallogr Sect E Struct Rep Online. 2008 June 1; 64(Pt 6): o1060.
Published online 2008 May 10. doi:  10.1107/S1600536808013391
PMCID: PMC2961373

5-Bromo-2-methyl­pyridine N-oxide

Abstract

In the mol­ecule of the title compound, C6H6BrNO, the methyl C and oxide O atoms lie in the pyridine ring plane, while the Br atom is displaced by 0.103 (3) Å. In the crystal structure, inter­molecular C—H(...)O hydrogen bonds link the mol­ecules into centrosymmetric dimers.

Related literature

For related literature, see: Ochiai (1953 [triangle]).

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Object name is e-64-o1060-scheme1.jpg

Experimental

Crystal data

  • C6H6BrNO
  • M r = 188.03
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1060-efi1.jpg
  • a = 7.3060 (15) Å
  • b = 11.351 (2) Å
  • c = 8.4950 (17) Å
  • β = 111.01 (3)°
  • V = 657.7 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 6.16 mm−1
  • T = 294 (2) K
  • 0.10 × 0.05 × 0.05 mm

Data collection

  • Enraf–Nonius CAD-4 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.578, T max = 0.748
  • 1275 measured reflections
  • 1180 independent reflections
  • 747 reflections with I > 2σ(I)
  • R int = 0.036
  • 3 standard reflections frequency: 120 min intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.063
  • wR(F 2) = 0.162
  • S = 1.05
  • 1180 reflections
  • 76 parameters
  • H-atom parameters constrained
  • Δρmax = 0.87 e Å−3
  • Δρmin = −0.69 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1989 [triangle]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2003 [triangle]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808013391/hk2459sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808013391/hk2459Isup2.hkl

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

Acknowledgments

The authors thank the Center of Testing and Analysis, Nanjing University, for support.

supplementary crystallographic information

Comment

Some derivatives of pyridine are important chemical materials. We report herein the crystal structure of the title compound, (I).

In the molecule of (I), (Fig. 1), ring A (N/C1-C5) is, of course, planar. Br atom is at a distance of -0.103 (3) Å to the plane of ring A, while atoms O and C6 lie in the ring plane.

In the crystal structure, intermolecular C-H···O hydrogen bonds (Table 1) link the molecules into centrosymmetric dimers (Fig. 2), in which they may be effective in the stabilization of the structure.

Experimental

For the preparation of the title compound, 5-bromo-2-methylpyridine (80 g, 462 mmol) was suspended in glacial acetic acid (300 ml), aqueous hydrogen peroxide (35%) was added and the mixture was heated in a water-bath at 343-353 K. After 3 h a further hydrogen peroxide solution (35 ml) was added and the mixture was maintained an additional 9 h at the same temperature. The mixture was concentrated to about 100 ml, diluted with water (100 ml), and then again concentrated in vacuum as far as possible upon cooling to room temperature, a precipitate formed, which was collected by filtration, and then washed with cold ethanol (2 × 50 ml) to afford the ethyl ester as a white solid (yield; 83 g, 95%) (Ochiai, 1953). Crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of a methanol solution.

Refinement

H atoms were positioned geometrically, with C-H = 0.93 and 0.96 Å for aromatic 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 aromatic H atoms.

Figures

Fig. 1.
The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
A partial packing diagram of (I). Hydrogen bonds are shown as dashed lines.

Crystal data

C6H6BrNOF000 = 368
Mr = 188.03Dx = 1.899 Mg m3
Monoclinic, P21/nMo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 25 reflections
a = 7.3060 (15) Åθ = 10–13º
b = 11.351 (2) ŵ = 6.16 mm1
c = 8.4950 (17) ÅT = 294 (2) K
β = 111.01 (3)ºBlock, colorless
V = 657.7 (3) Å30.10 × 0.05 × 0.05 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometerRint = 0.036
Radiation source: fine-focus sealed tubeθmax = 25.2º
Monochromator: graphiteθmin = 3.1º
T = 294(2) Kh = −8→8
ω/2θ scansk = 0→13
Absorption correction: ψ scan(North et al., 1968)l = 0→10
Tmin = 0.578, Tmax = 0.7483 standard reflections
1275 measured reflections every 120 min
1180 independent reflections intensity decay: none
747 reflections with I > 2σ(I)

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.063H-atom parameters constrained
wR(F2) = 0.162  w = 1/[σ2(Fo2) + (0.08P)2 + P] where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
1180 reflectionsΔρmax = 0.87 e Å3
76 parametersΔρmin = −0.69 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none

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 > 2sigma(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
Br0.17025 (14)0.74086 (7)0.64566 (12)0.0448 (4)
N0.6201 (9)0.9804 (5)0.7872 (8)0.0290 (15)
O0.6767 (10)1.0662 (5)0.8994 (8)0.0506 (18)
C10.4547 (13)0.9187 (7)0.7722 (10)0.038 (2)
H1A0.38420.93810.84050.046*
C20.3901 (11)0.8283 (6)0.6579 (10)0.0289 (18)
C30.4939 (15)0.7989 (8)0.5576 (12)0.045 (2)
H3A0.45230.73890.47810.053*
C40.6635 (12)0.8623 (7)0.5795 (11)0.038 (2)
H4A0.73540.84180.51270.045*
C50.7341 (13)0.9535 (7)0.6929 (10)0.036 (2)
C60.9107 (13)1.0232 (8)0.7239 (12)0.047
H6A0.97540.99810.64930.071*
H6B0.99711.01260.83870.071*
H6C0.87611.10500.70430.071*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br0.0512 (6)0.0387 (6)0.0354 (6)−0.0061 (5)0.0045 (4)0.0010 (5)
N0.035 (4)0.022 (3)0.022 (4)0.009 (3)0.000 (3)−0.006 (3)
O0.072 (5)0.042 (4)0.032 (4)−0.021 (3)0.011 (4)−0.016 (3)
C10.050 (6)0.030 (4)0.027 (5)−0.004 (4)0.004 (4)−0.002 (4)
C20.032 (4)0.020 (4)0.025 (4)0.006 (3)−0.002 (4)0.006 (3)
C30.050 (6)0.035 (5)0.036 (5)0.003 (5)0.001 (5)−0.014 (4)
C40.038 (5)0.037 (5)0.034 (5)0.013 (4)0.009 (4)−0.008 (4)
C50.051 (5)0.025 (4)0.021 (5)0.011 (4)0.000 (4)0.003 (4)
C60.0470.0470.0470.0000.0170.000

Geometric parameters (Å, °)

Br—C21.859 (8)C3—H3A0.9300
N—O1.322 (8)C4—C51.382 (12)
N—C11.362 (10)C4—H4A0.9300
N—C51.381 (10)C5—C61.455 (12)
C1—C21.375 (11)C6—H6A0.9600
C1—H1A0.9300C6—H6B0.9600
C2—C31.369 (12)C6—H6C0.9600
C3—C41.387 (12)
O—N—C1118.9 (7)C5—C4—C3125.0 (8)
O—N—C5118.9 (7)C5—C4—H4A117.5
C1—N—C5122.1 (7)C3—C4—H4A117.5
N—C1—C2121.2 (8)N—C5—C4114.7 (8)
N—C1—H1A119.4N—C5—C6117.1 (7)
C2—C1—H1A119.4C4—C5—C6128.2 (8)
C3—C2—C1119.7 (8)C5—C6—H6A109.5
C3—C2—Br119.7 (6)C5—C6—H6B109.5
C1—C2—Br120.6 (6)H6A—C6—H6B109.5
C2—C3—C4117.3 (8)C5—C6—H6C109.5
C2—C3—H3A121.4H6A—C6—H6C109.5
C4—C3—H3A121.4H6B—C6—H6C109.5
O—N—C1—C2−179.7 (7)O—N—C5—C4179.7 (7)
C5—N—C1—C2−1.9 (12)C1—N—C5—C42.0 (11)
N—C1—C2—C30.3 (12)O—N—C5—C6−0.3 (11)
N—C1—C2—Br177.3 (6)C1—N—C5—C6−178.1 (7)
C1—C2—C3—C41.0 (13)C3—C4—C5—N−0.5 (13)
Br—C2—C3—C4−176.0 (6)C3—C4—C5—C6179.5 (9)
C2—C3—C4—C5−0.9 (14)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C1—H1A···Oi0.932.413.264 (11)153

Symmetry codes: (i) −x+1, −y+2, −z+2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HK2459).

References

  • Enraf–Nonius (1989). CAD-4 Software Enraf–Nonius, Delft, The Netherlands.
  • Harms, K. & Wocadlo, S. (1995). XCAD4 University of Marburg, Germany.
  • North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.
  • Ochiai, E. (1953). J. Org. Chem 18, 534–551.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2003). J. Appl. Cryst.36, 7–13.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography