PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2010 July 1; 66(Pt 7): o1723.
Published online 2010 June 23. doi:  10.1107/S1600536810022993
PMCID: PMC3006940

2-(6-Bromo-3-pyrid­yl)-8-methyl­imidazo[1,2-a]pyrazine

Abstract

The structure of the title compound, C12H9BrN4, prepared by the reaction of 2-bromo-1-(6-bromo-3-pyrid­yl)ethanone with 2-amino-3-methyl­pyrazine indicates that the compound with the bromo­pyridyl substituent at position 2 of the imidazopyrazine fused-ring system represents the major product of this reaction. The plane of the pyridine ring forms a dihedral angle of 16.2 (2)° with the essentially planar (r.m.s. deviation = 0.006 Å) imidazopyrazine system. In the crystal, mol­ecules are linked by weak C—H(...)N inter­actions.

Related literature

For the structure of the related imidazo(1,2-a)pyrazine deivative, see: Lumma & Springer (1981 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o1723-scheme1.jpg

Experimental

Crystal data

  • C12H9BrN4
  • M r = 289.14
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1723-efi1.jpg
  • a = 3.9007 (14) Å
  • b = 13.545 (5) Å
  • c = 20.673 (8) Å
  • β = 93.059 (5)°
  • V = 1090.7 (7) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 3.75 mm−1
  • T = 100 K
  • 0.27 × 0.11 × 0.05 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2001 [triangle]) T min = 0.431, T max = 0.835
  • 19939 measured reflections
  • 2668 independent reflections
  • 1887 reflections with I > 2σ(I)
  • R int = 0.085

Refinement

  • R[F 2 > 2σ(F 2)] = 0.057
  • wR(F 2) = 0.154
  • S = 1.05
  • 2668 reflections
  • 155 parameters
  • H-atom parameters constrained
  • Δρmax = 1.23 e Å−3
  • Δρmin = −1.30 e Å−3

Data collection: APEX2 (Bruker, 2007 [triangle]); cell refinement: SAINT (Bruker, 2007 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810022993/hb5478sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810022993/hb5478Isup2.hkl

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

supplementary crystallographic information

Comment

The reaction of 2-bromo-1-(6-bromo3-pyridyl)ethanone with 2-amino-3-methylpyrazine may potentially produce either 2- or 3-(6-bromo3-pyridyl)-8-methylimidazo[1,2-a]pyrazine. The present study shows that the compound with bromopyridyl substituent in position 2 of imidazopyrazine represents the major product of this reaction (Fig. 1).

The plane of the pyridine ring N1, C1—C5 forms the dihedral angle of 16.2 (2)° with the essentially planar imidazopyrazine system N2, N3, N4, C6—C11. Strange though it may seem, only one purely organic structure with non-protontated non-fused imidazo(1,2 - a)pyrazine system with only carbon substituents has been published heretofore (Lumma & Springer, 1981). The geometry of the bicyclic fragment in this structure is in good agreement with that of the title compound.

Experimental

A mixture of 2-bromo-1-(6-bromo-3-pyridyl)-ethanone (2.70 g, 9.68 mmol), 2-amino-3-methylpyrazine (1.06 g, 9.68 mmol), and sodium bicarbonate (1.22 g, 14.5 mmol) in 40 ml of 2-propanol was heated at 80°C overnight. After cooling down to rt, the reaction mixture was concentrated to dryness. The resulting residue was partitioned between ethyl acetate (100 ml) and water (100 ml). The organic phase was washed with brine (1 × 100 ml), dried over sodium sulfate, concentrated to dryness, and purified by column chromatography with 0 --> 5% MeOH/EA to afford the desired product as a solid (1.25 g, 44.7% yield).

Colourless needles of (I) were grown by slow evaporation of an ethanol/dichloroethane solution.

Refinement

All H atoms were placed in geometrically calculated positions (C—H 0.95 Å for aromatic and 0.98 Å for methyl H atoms, respectively) and included in the refinement in riding motion approximation. The Uiso(H) were set to 1.2Ueq of the carrying atom (1.5Ueq for methyl H atoms). The maximum residual density peak 1.23 e/Å3 is located at a distance of 0.99 Å from the Br1 atom; the deepest hole -1.30 e/Å3 is at a distance of 0.78 Å from the Br1 atom.

Figures

Fig. 1.
Molecular structure of the title compound, showing 50% probability displacement ellipsoids. H atoms are drawn as circles of arbitrary small radius.

Crystal data

C12H9BrN4F(000) = 576
Mr = 289.14Dx = 1.761 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 6098 reflections
a = 3.9007 (14) Åθ = 3.3–27.2°
b = 13.545 (5) ŵ = 3.75 mm1
c = 20.673 (8) ÅT = 100 K
β = 93.059 (5)°Needle, colorless
V = 1090.7 (7) Å30.27 × 0.11 × 0.05 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer2668 independent reflections
Radiation source: fine-focus sealed tube1887 reflections with I > 2σ(I)
graphiteRint = 0.085
[var phi] and ω scansθmax = 28.7°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)h = −5→5
Tmin = 0.431, Tmax = 0.835k = −17→17
19939 measured reflectionsl = −27→26

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)] = 0.057Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.154H-atom parameters constrained
S = 1.05w = 1/[σ2(Fo2) + (0.0701P)2 + 3.9758P] where P = (Fo2 + 2Fc2)/3
2668 reflections(Δ/σ)max = 0.001
155 parametersΔρmax = 1.23 e Å3
0 restraintsΔρmin = −1.30 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
Br10.27478 (13)0.63452 (4)1.03763 (3)0.0279 (2)
N10.5377 (11)0.8165 (3)1.0087 (2)0.0247 (9)
N21.0290 (10)0.9281 (3)0.8097 (2)0.0195 (8)
N31.0640 (10)1.0898 (3)0.83304 (19)0.0193 (8)
N41.4045 (11)1.1347 (3)0.7232 (2)0.0221 (9)
C10.4653 (12)0.7301 (4)0.9823 (2)0.0215 (10)
C20.5223 (13)0.7047 (4)0.9189 (2)0.0241 (11)
H20.46870.64070.90260.029*
C30.6590 (12)0.7755 (4)0.8807 (2)0.0214 (10)
H30.70110.76110.83690.026*
C40.7370 (12)0.8692 (3)0.9062 (2)0.0190 (10)
C50.6736 (12)0.8850 (4)0.9704 (2)0.0220 (10)
H50.72900.94780.98870.026*
C60.8818 (12)0.9470 (3)0.8672 (2)0.0185 (10)
C70.8997 (12)1.0472 (3)0.8822 (2)0.0207 (10)
H70.81501.07900.91910.025*
C81.1395 (12)1.0161 (3)0.7898 (2)0.0174 (9)
C91.3167 (12)1.0417 (4)0.7337 (2)0.0207 (10)
C101.3238 (13)1.2048 (4)0.7677 (3)0.0256 (11)
H101.38971.27100.75980.031*
C111.1591 (13)1.1865 (3)0.8214 (3)0.0224 (10)
H111.10881.23800.85070.027*
C121.4005 (13)0.9642 (4)0.6864 (2)0.0241 (11)
H12A1.51530.99440.65030.036*
H12B1.18870.93190.67000.036*
H12C1.55300.91520.70770.036*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.0245 (3)0.0267 (3)0.0331 (3)−0.0011 (2)0.0081 (2)0.0102 (2)
N10.027 (2)0.024 (2)0.023 (2)0.0019 (18)0.0048 (17)0.0007 (18)
N20.018 (2)0.0173 (19)0.024 (2)0.0029 (16)0.0018 (16)−0.0005 (16)
N30.018 (2)0.016 (2)0.025 (2)0.0009 (16)0.0031 (16)0.0015 (16)
N40.021 (2)0.018 (2)0.027 (2)−0.0009 (17)0.0047 (16)0.0024 (17)
C10.017 (2)0.023 (2)0.025 (2)0.0025 (19)0.0039 (18)0.008 (2)
C20.024 (3)0.019 (2)0.029 (3)−0.001 (2)0.005 (2)−0.002 (2)
C30.019 (2)0.022 (2)0.023 (2)−0.0002 (19)0.0032 (19)−0.001 (2)
C40.017 (2)0.020 (2)0.020 (2)0.0028 (19)0.0033 (17)0.0016 (19)
C50.023 (2)0.022 (2)0.022 (2)0.0055 (19)−0.0005 (19)−0.0042 (19)
C60.015 (2)0.020 (2)0.021 (2)0.0061 (18)0.0003 (18)0.0002 (19)
C70.025 (3)0.016 (2)0.022 (2)0.0009 (19)0.0065 (19)−0.0035 (19)
C80.016 (2)0.015 (2)0.021 (2)0.0013 (17)0.0026 (18)0.0006 (18)
C90.017 (2)0.019 (2)0.026 (2)0.0029 (19)0.0026 (19)0.003 (2)
C100.027 (3)0.019 (2)0.031 (3)−0.001 (2)0.001 (2)0.001 (2)
C110.020 (2)0.013 (2)0.034 (3)0.0008 (18)0.002 (2)−0.003 (2)
C120.024 (3)0.027 (3)0.021 (2)0.002 (2)0.0069 (19)0.000 (2)

Geometric parameters (Å, °)

Br1—C11.905 (5)C3—H30.9500
N1—C11.316 (7)C4—C51.381 (7)
N1—C51.347 (7)C4—C61.458 (7)
N2—C81.340 (6)C5—H50.9500
N2—C61.371 (6)C6—C71.393 (7)
N3—C71.359 (6)C7—H70.9500
N3—C81.382 (6)C8—C91.424 (7)
N3—C111.386 (6)C9—C121.482 (7)
N4—C91.327 (6)C10—C111.335 (7)
N4—C101.371 (7)C10—H100.9500
C1—C21.384 (7)C11—H110.9500
C2—C31.369 (7)C12—H12A0.9800
C2—H20.9500C12—H12B0.9800
C3—C41.401 (7)C12—H12C0.9800
C1—N1—C5116.8 (4)C7—C6—C4126.6 (4)
C8—N2—C6104.9 (4)N3—C7—C6105.4 (4)
C7—N3—C8107.6 (4)N3—C7—H7127.3
C7—N3—C11132.2 (4)C6—C7—H7127.3
C8—N3—C11120.2 (4)N2—C8—N3111.1 (4)
C9—N4—C10118.5 (4)N2—C8—C9130.2 (4)
N1—C1—C2125.0 (5)N3—C8—C9118.7 (4)
N1—C1—Br1115.9 (4)N4—C9—C8120.4 (4)
C2—C1—Br1119.1 (4)N4—C9—C12119.8 (5)
C3—C2—C1117.3 (5)C8—C9—C12119.9 (4)
C3—C2—H2121.3C11—C10—N4124.6 (5)
C1—C2—H2121.3C11—C10—H10117.7
C2—C3—C4120.2 (5)N4—C10—H10117.7
C2—C3—H3119.9C10—C11—N3117.6 (5)
C4—C3—H3119.9C10—C11—H11121.2
C5—C4—C3117.0 (4)N3—C11—H11121.2
C5—C4—C6121.0 (4)C9—C12—H12A109.5
C3—C4—C6122.0 (4)C9—C12—H12B109.5
N1—C5—C4123.8 (5)H12A—C12—H12B109.5
N1—C5—H5118.1C9—C12—H12C109.5
C4—C5—H5118.1H12A—C12—H12C109.5
N2—C6—C7110.9 (4)H12B—C12—H12C109.5
N2—C6—C4122.4 (4)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7—H7···N1i0.952.523.438 (6)163
C10—H10···N2ii0.952.603.484 (7)156

Symmetry codes: (i) −x+1, −y+2, −z+2; (ii) −x+5/2, y+1/2, −z+3/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5478).

References

  • Bruker (2001). SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (2007). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Lumma, W. C. Jr & Springer, J. P. (1981). J. Org. Chem.46, 3735–3736.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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