Acta Cryst. (2008). E64, o1060 [ doi:10.1107/S1600536808013391 ]
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.
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.
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.
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).
![[Figure 1]](./hk2459fig1thm.gif)
| 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]](./hk2459fig2thm.gif)
| Fig. 2. A partial packing diagram of (I). Hydrogen bonds are shown as dashed lines. |
| C6H6BrNO | F000 = 368 |
| Mr = 188.03 | Dx = 1.899 Mg m−3 |
| Monoclinic, P21/n | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2yn | Cell parameters from 25 reflections |
| a = 7.3060 (15) Å | θ = 10–13º |
| b = 11.351 (2) Å | µ = 6.16 mm−1 |
| c = 8.4950 (17) Å | T = 294 (2) K |
| β = 111.01 (3)º | Block, colorless |
| V = 657.7 (3) Å3 | 0.10 × 0.05 × 0.05 mm |
| Z = 4 |
| Enraf–Nonius CAD-4 diffractometer | Rint = 0.036 |
| Radiation source: fine-focus sealed tube | θmax = 25.2º |
| Monochromator: graphite | θmin = 3.1º |
| T = 294(2) K | h = −8→8 |
| ω/2θ scans | k = 0→13 |
| Absorption correction: ψ scan (North et al., 1968) | l = 0→10 |
| Tmin = 0.578, Tmax = 0.748 | 3 standard reflections |
| 1275 measured reflections | every 120 min |
| 1180 independent reflections | intensity decay: none |
| 747 reflections with I > 2σ(I) |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.063 | H-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 reflections | Δρmax = 0.87 e Å−3 |
| 76 parameters | Δρmin = −0.69 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C6H6BrNO | V = 657.7 (3) Å3 |
| Mr = 188.03 | Z = 4 |
| Monoclinic, P21/n | Mo Kα |
| a = 7.3060 (15) Å | µ = 6.16 mm−1 |
| b = 11.351 (2) Å | T = 294 (2) K |
| c = 8.4950 (17) Å | 0.10 × 0.05 × 0.05 mm |
| β = 111.01 (3)º |
| 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 = 0.748 | 3 standard reflections |
| 1275 measured reflections | every 120 min |
| 1180 independent reflections | intensity decay: none |
| R[F2 > 2σ(F2)] = 0.063 | 76 parameters |
| wR(F2) = 0.162 | H-atom parameters constrained |
| S = 1.05 | Δρmax = 0.87 e Å−3 |
| 1180 reflections | Δρmin = −0.69 e Å−3 |
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. |
| x | y | z | Uiso*/Ueq | ||
| Br | 0.17025 (14) | 0.74086 (7) | 0.64566 (12) | 0.0448 (4) | |
| N | 0.6201 (9) | 0.9804 (5) | 0.7872 (8) | 0.0290 (15) | |
| O | 0.6767 (10) | 1.0662 (5) | 0.8994 (8) | 0.0506 (18) | |
| C1 | 0.4547 (13) | 0.9187 (7) | 0.7722 (10) | 0.038 (2) | |
| H1A | 0.3842 | 0.9381 | 0.8405 | 0.046* | |
| C2 | 0.3901 (11) | 0.8283 (6) | 0.6579 (10) | 0.0289 (18) | |
| C3 | 0.4939 (15) | 0.7989 (8) | 0.5576 (12) | 0.045 (2) | |
| H3A | 0.4523 | 0.7389 | 0.4781 | 0.053* | |
| C4 | 0.6635 (12) | 0.8623 (7) | 0.5795 (11) | 0.038 (2) | |
| H4A | 0.7354 | 0.8418 | 0.5127 | 0.045* | |
| C5 | 0.7341 (13) | 0.9535 (7) | 0.6929 (10) | 0.036 (2) | |
| C6 | 0.9107 (13) | 1.0232 (8) | 0.7239 (12) | 0.047 | |
| H6A | 0.9754 | 0.9981 | 0.6493 | 0.071* | |
| H6B | 0.9971 | 1.0126 | 0.8387 | 0.071* | |
| H6C | 0.8761 | 1.1050 | 0.7043 | 0.071* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Br | 0.0512 (6) | 0.0387 (6) | 0.0354 (6) | −0.0061 (5) | 0.0045 (4) | 0.0010 (5) |
| N | 0.035 (4) | 0.022 (3) | 0.022 (4) | 0.009 (3) | 0.000 (3) | −0.006 (3) |
| O | 0.072 (5) | 0.042 (4) | 0.032 (4) | −0.021 (3) | 0.011 (4) | −0.016 (3) |
| C1 | 0.050 (6) | 0.030 (4) | 0.027 (5) | −0.004 (4) | 0.004 (4) | −0.002 (4) |
| C2 | 0.032 (4) | 0.020 (4) | 0.025 (4) | 0.006 (3) | −0.002 (4) | 0.006 (3) |
| C3 | 0.050 (6) | 0.035 (5) | 0.036 (5) | 0.003 (5) | 0.001 (5) | −0.014 (4) |
| C4 | 0.038 (5) | 0.037 (5) | 0.034 (5) | 0.013 (4) | 0.009 (4) | −0.008 (4) |
| C5 | 0.051 (5) | 0.025 (4) | 0.021 (5) | 0.011 (4) | 0.000 (4) | 0.003 (4) |
| C6 | 0.047 | 0.047 | 0.047 | 0.000 | 0.017 | 0.000 |
| Br—C2 | 1.859 (8) | C3—H3A | 0.9300 |
| N—O | 1.322 (8) | C4—C5 | 1.382 (12) |
| N—C1 | 1.362 (10) | C4—H4A | 0.9300 |
| N—C5 | 1.381 (10) | C5—C6 | 1.455 (12) |
| C1—C2 | 1.375 (11) | C6—H6A | 0.9600 |
| C1—H1A | 0.9300 | C6—H6B | 0.9600 |
| C2—C3 | 1.369 (12) | C6—H6C | 0.9600 |
| C3—C4 | 1.387 (12) | ||
| O—N—C1 | 118.9 (7) | C5—C4—C3 | 125.0 (8) |
| O—N—C5 | 118.9 (7) | C5—C4—H4A | 117.5 |
| C1—N—C5 | 122.1 (7) | C3—C4—H4A | 117.5 |
| N—C1—C2 | 121.2 (8) | N—C5—C4 | 114.7 (8) |
| N—C1—H1A | 119.4 | N—C5—C6 | 117.1 (7) |
| C2—C1—H1A | 119.4 | C4—C5—C6 | 128.2 (8) |
| C3—C2—C1 | 119.7 (8) | C5—C6—H6A | 109.5 |
| C3—C2—Br | 119.7 (6) | C5—C6—H6B | 109.5 |
| C1—C2—Br | 120.6 (6) | H6A—C6—H6B | 109.5 |
| C2—C3—C4 | 117.3 (8) | C5—C6—H6C | 109.5 |
| C2—C3—H3A | 121.4 | H6A—C6—H6C | 109.5 |
| C4—C3—H3A | 121.4 | H6B—C6—H6C | 109.5 |
| O—N—C1—C2 | −179.7 (7) | O—N—C5—C4 | 179.7 (7) |
| C5—N—C1—C2 | −1.9 (12) | C1—N—C5—C4 | 2.0 (11) |
| N—C1—C2—C3 | 0.3 (12) | O—N—C5—C6 | −0.3 (11) |
| N—C1—C2—Br | 177.3 (6) | C1—N—C5—C6 | −178.1 (7) |
| C1—C2—C3—C4 | 1.0 (13) | C3—C4—C5—N | −0.5 (13) |
| Br—C2—C3—C4 | −176.0 (6) | C3—C4—C5—C6 | 179.5 (9) |
| C2—C3—C4—C5 | −0.9 (14) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C1—H1A···Oi | 0.93 | 2.41 | 3.264 (11) | 153 |
| Symmetry codes: (i) −x+1, −y+2, −z+2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C1—H1A···Oi | 0.93 | 2.41 | 3.264 (11) | 153 |
| Symmetry codes: (i) −x+1, −y+2, −z+2. |
The authors thank the Center of Testing and Analysis, Nanjing University, for support.
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.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.
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.