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ISSN: 2056-9890

5-Bromo-2-methyl­pyridine N-oxide

aCollege of Science, Nanjing University of Technolgy, Xinmofan Road No. 5, Nanjing 210009, People's Republic of China, and bCollege of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China
*Correspondence e-mail: guocheng@njut.edu.cn

(Received 29 April 2008; accepted 6 May 2008; online 10 May 2008)

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[Ochiai, E. (1953). J. Org. Chem. 18, 534-551.]).

[Scheme 1]

Experimental

Crystal data
  • C6H6BrNO

  • Mr = 188.03

  • Monoclinic, P 21 /n

  • 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[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.578, Tmax = 0.748

  • 1275 measured reflections

  • 1180 independent reflections

  • 747 reflections with I > 2σ(I)

  • Rint = 0.036

  • 3 standard reflections frequency: 120 min intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.063

  • wR(F2) = 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

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C1—H1A⋯Oi 0.93 2.41 3.264 (11) 153
Symmetry code: (i) -x+1, -y+2, -z+2.

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Supporting information


Comment top

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.

Related literature top

For related literature, see: Ochiai (1953).

Experimental top

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 top

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.

Computing details top

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

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. A partial packing diagram of (I). Hydrogen bonds are shown as dashed lines.
5-Bromo-2-methylpyridine N-oxide top
Crystal data top
C6H6BrNOF(000) = 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 = 10–13°
b = 11.351 (2) ŵ = 6.16 mm1
c = 8.4950 (17) ÅT = 294 K
β = 111.01 (3)°Block, colorless
V = 657.7 (3) Å30.10 × 0.05 × 0.05 mm
Z = 4
Data collection top
Enraf–Nonius CAD-4
diffractometer
747 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.036
Graphite monochromatorθmax = 25.2°, θmin = 3.1°
ω/2θ scansh = 88
Absorption correction: ψ scan
(North et al., 1968)
k = 013
Tmin = 0.578, Tmax = 0.748l = 010
1275 measured reflections3 standard reflections every 120 min
1180 independent reflections intensity decay: none
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)] = 0.063Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.162H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.08P)2 + P]
where P = (Fo2 + 2Fc2)/3
1180 reflections(Δ/σ)max < 0.001
76 parametersΔρmax = 0.87 e Å3
0 restraintsΔρmin = 0.69 e Å3
Crystal data top
C6H6BrNOV = 657.7 (3) Å3
Mr = 188.03Z = 4
Monoclinic, P21/nMo Kα radiation
a = 7.3060 (15) ŵ = 6.16 mm1
b = 11.351 (2) ÅT = 294 K
c = 8.4950 (17) Å0.10 × 0.05 × 0.05 mm
β = 111.01 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
747 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.036
Tmin = 0.578, Tmax = 0.7483 standard reflections every 120 min
1275 measured reflections intensity decay: none
1180 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0630 restraints
wR(F2) = 0.162H-atom parameters constrained
S = 1.05Δρmax = 0.87 e Å3
1180 reflectionsΔρmin = 0.69 e Å3
76 parameters
Special details top

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) top
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) top
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, º) top
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—C2179.7 (7)O—N—C5—C4179.7 (7)
C5—N—C1—C21.9 (12)C1—N—C5—C42.0 (11)
N—C1—C2—C30.3 (12)O—N—C5—C60.3 (11)
N—C1—C2—Br177.3 (6)C1—N—C5—C6178.1 (7)
C1—C2—C3—C41.0 (13)C3—C4—C5—N0.5 (13)
Br—C2—C3—C4176.0 (6)C3—C4—C5—C6179.5 (9)
C2—C3—C4—C50.9 (14)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···Oi0.932.413.264 (11)153
Symmetry code: (i) x+1, y+2, z+2.

Experimental details

Crystal data
Chemical formulaC6H6BrNO
Mr188.03
Crystal system, space groupMonoclinic, P21/n
Temperature (K)294
a, b, c (Å)7.3060 (15), 11.351 (2), 8.4950 (17)
β (°) 111.01 (3)
V3)657.7 (3)
Z4
Radiation typeMo Kα
µ (mm1)6.16
Crystal size (mm)0.10 × 0.05 × 0.05
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.578, 0.748
No. of measured, independent and
observed [I > 2σ(I)] reflections
1275, 1180, 747
Rint0.036
(sin θ/λ)max1)0.598
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.063, 0.162, 1.05
No. of reflections1180
No. of parameters76
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.87, 0.69

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···Oi0.93002.41003.264 (11)153.00
Symmetry code: (i) x+1, y+2, z+2.
 

Acknowledgements

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

References

First citationEnraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science Google Scholar
First citationOchiai, E. (1953). J. Org. Chem. 18, 534–551.  CrossRef CAS Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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COMMUNICATIONS
ISSN: 2056-9890
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