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Acta Crystallogr Sect E Struct Rep Online. 2010 April 1; 66(Pt 4): o946.
Published online 2010 March 27. doi:  10.1107/S160053681001038X
PMCID: PMC2983780

4-Benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine

Abstract

The imidazopyridine fused ring in the title compound, C19H14BrN3, is almost coplanar with the phenyl ring at the 2-position of the five-membered ring [dihedral angle = 2.4 (1). The crystal structure features short Br(...)Br contacts [3.562 (1) Å].

Related literature

For the synthesis of imidazo[4,5-b]pyridines, see: Aridoss et al. (2006 [triangle]); Benham et al. (1995 [triangle]); Cundy et al. (1997 [triangle]); Kale et al. (2009 [triangle]); Walsh et al. (1994 [triangle]); Zaki & Proença (2007 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-0o946-scheme1.jpg

Experimental

Crystal data

  • C19H14BrN3
  • M r = 364.24
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o946-efi1.jpg
  • a = 8.6613 (6) Å
  • b = 19.7631 (13) Å
  • c = 9.3683 (6) Å
  • β = 99.647 (3)°
  • V = 1580.93 (18) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 2.60 mm−1
  • T = 293 K
  • 0.28 × 0.24 × 0.20 mm

Data collection

  • Bruker X8 APEXII diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.529, T max = 0.624
  • 57936 measured reflections
  • 4613 independent reflections
  • 3492 reflections with I > 2σ(I)
  • R int = 0.035

Refinement

  • R[F 2 > 2σ(F 2)] = 0.032
  • wR(F 2) = 0.098
  • S = 1.00
  • 4613 reflections
  • 208 parameters
  • H-atom parameters constrained
  • Δρmax = 0.63 e Å−3
  • Δρmin = −0.51 e Å−3

Data collection: APEX2 (Bruker, 2008 [triangle]); cell refinement: SAINT (Bruker, 2008 [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: X-SEED (Barbour, 2001 [triangle]); software used to prepare material for publication: publCIF (Westrip, 2010 [triangle]).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681001038X/pk2232sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681001038X/pk2232Isup2.hkl

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

Acknowledgments

We thank Université Sidi Mohammed Ben Abdallah, Université Mohammed V-Agdal and the University of Malaya for supporting this study.

supplementary crystallographic information

Comment

Imidazo[4,5-b]pyridines are a class of sedative drugs exemplified by Zolpidem, Alpidem, Saripidem and Necopidem. There is intense interest in designing new synthetic routes; for example, an eco-friendly synthesis by oxidation in aqueous medium has been claimed (Kale et al., 2009). Other methods require more than one step (Aridoss et al., 2006; Benham et al., 1995; Cundy et al., 1997; Walsh et al., 1994; Zaki & Proença, 2007).

We have been able to react 6-bromo-2-phenyl-1H-imidazo[4,5-b]pyridine with benzyl chloride in the presence of a catalytic quantity of tetra-n-butylammonium bromide under mild conditions to furnish the title compound (Scheme I, Fig. 1). The imidazopyridine fused-ring in C19H14BrN3 is co-planar with the phenyl ring at the 2-position [dihedral angle 2.4 (1) °]. In the five-membered imidazo portion, the carbon–nitrogen bond whose carbon atom is also connected to the pyridine nitrogen atom is predominantly a double bond [1.329 (2) Å], whereas the carbon–nitrogen bond whose atom is connected to the pyridine carbon atom is predominantly a single bond [1.372 (2) Å].

Experimental

To a solution of the 6-bromo-2-phenyl-1H-imidazo[4,5-b]pyridine (0.30 g, 1.09 mmol), potassium carbonate (0.20 g, 1.42 mmol) and tetra-n-butylammonium bromide (0.04 g (0,1 mmol) in DMF (15 ml) was added benzyl chloride (0.15 ml, 1.31 mmol). Stirring was continued at room temperature for 12 hours. The salt was removed by filtration and the filtrate concentrated under reduced pressure. The residue was separated by chromatography on a column of silica gel with ethyl acetate/hexane (1/1) as eluent. Brown crystals were isolated when the solvent was allowed to evaporate.

Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.93–0.97 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U(C).

Figures

Fig. 1.
Thermal ellipsoid plot (Barbour, 2001) of C19H14BrN3 at the 50% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius.

Crystal data

C19H14BrN3F(000) = 736
Mr = 364.24Dx = 1.530 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9876 reflections
a = 8.6613 (6) Åθ = 2.4–27.2°
b = 19.7631 (13) ŵ = 2.60 mm1
c = 9.3683 (6) ÅT = 293 K
β = 99.647 (3)°Prism, brown
V = 1580.93 (18) Å30.28 × 0.24 × 0.20 mm
Z = 4

Data collection

Bruker X8 APEXII diffractometer4613 independent reflections
Radiation source: fine-focus sealed tube3492 reflections with I > 2σ(I)
graphiteRint = 0.035
[var phi] and ω scansθmax = 30.1°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −12→11
Tmin = 0.529, Tmax = 0.624k = −27→27
57936 measured reflectionsl = −13→13

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)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.098H-atom parameters constrained
S = 1.00w = 1/[σ2(Fo2) + (0.0518P)2 + 0.5269P] where P = (Fo2 + 2Fc2)/3
4613 reflections(Δ/σ)max = 0.001
208 parametersΔρmax = 0.63 e Å3
0 restraintsΔρmin = −0.50 e Å3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
Br10.10158 (3)0.475089 (12)0.85824 (2)0.06483 (10)
N10.29485 (16)0.43405 (7)0.49901 (15)0.0385 (3)
N20.26154 (17)0.60722 (7)0.40338 (16)0.0424 (3)
N30.35446 (17)0.50867 (7)0.31224 (15)0.0387 (3)
C10.1792 (2)0.48667 (9)0.68312 (19)0.0454 (4)
C20.1807 (2)0.55060 (9)0.62007 (19)0.0458 (4)
H20.14290.58860.66160.055*
C30.2408 (2)0.55460 (8)0.49376 (18)0.0392 (3)
C40.29944 (19)0.49489 (8)0.43321 (17)0.0367 (3)
C50.2352 (2)0.43003 (9)0.62362 (18)0.0437 (4)
H50.23220.38840.66940.052*
C60.32810 (19)0.57716 (8)0.30027 (17)0.0379 (3)
C70.37246 (19)0.61435 (8)0.17772 (18)0.0390 (3)
C80.3423 (2)0.68335 (9)0.1595 (2)0.0459 (4)
H80.29380.70670.22610.055*
C90.3845 (2)0.71728 (10)0.0425 (2)0.0547 (5)
H90.36440.76340.03100.066*
C100.4557 (3)0.68322 (11)−0.0569 (2)0.0574 (5)
H100.48290.7062−0.13570.069*
C110.4869 (3)0.61517 (11)−0.0399 (2)0.0624 (5)
H110.53530.5922−0.10690.075*
C120.4459 (3)0.58097 (10)0.0773 (2)0.0538 (5)
H120.46790.53500.08880.065*
C130.3544 (2)0.37271 (8)0.43491 (19)0.0427 (3)
H13A0.40410.34330.51210.051*
H13B0.43310.38590.37780.051*
C140.22599 (19)0.33413 (8)0.34017 (17)0.0380 (3)
C150.1392 (2)0.36407 (9)0.21824 (19)0.0481 (4)
H150.16050.40840.19450.058*
C160.0214 (3)0.32854 (11)0.1321 (2)0.0574 (5)
H16−0.03790.34940.05220.069*
C17−0.0082 (3)0.26217 (11)0.1643 (2)0.0585 (5)
H17−0.08590.23800.10500.070*
C180.0769 (3)0.23206 (10)0.2833 (3)0.0598 (5)
H180.05700.18730.30470.072*
C190.1930 (2)0.26789 (9)0.3728 (2)0.0517 (4)
H190.24870.24730.45480.062*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.08695 (19)0.06436 (15)0.05128 (13)0.00593 (10)0.03507 (11)0.00630 (9)
N10.0419 (7)0.0355 (6)0.0382 (7)0.0001 (5)0.0074 (5)0.0003 (5)
N20.0515 (8)0.0338 (6)0.0437 (7)−0.0007 (6)0.0131 (6)−0.0028 (5)
N30.0443 (7)0.0337 (6)0.0394 (7)−0.0009 (5)0.0104 (5)−0.0012 (5)
C10.0501 (10)0.0498 (10)0.0386 (8)−0.0024 (7)0.0140 (7)0.0004 (7)
C20.0535 (10)0.0417 (9)0.0444 (9)−0.0007 (7)0.0147 (7)−0.0056 (7)
C30.0431 (8)0.0349 (7)0.0402 (8)−0.0015 (6)0.0088 (6)−0.0046 (6)
C40.0390 (8)0.0345 (7)0.0366 (7)−0.0020 (6)0.0061 (6)−0.0035 (6)
C50.0485 (9)0.0430 (8)0.0403 (8)−0.0019 (7)0.0094 (7)0.0036 (7)
C60.0407 (8)0.0345 (7)0.0385 (7)−0.0028 (6)0.0068 (6)−0.0023 (6)
C70.0420 (8)0.0353 (7)0.0395 (7)−0.0036 (6)0.0064 (6)−0.0004 (6)
C80.0471 (9)0.0360 (8)0.0553 (10)−0.0020 (7)0.0105 (8)−0.0007 (7)
C90.0567 (11)0.0391 (9)0.0678 (12)−0.0031 (8)0.0092 (9)0.0118 (8)
C100.0647 (12)0.0560 (11)0.0530 (10)−0.0070 (9)0.0141 (9)0.0153 (9)
C110.0851 (15)0.0567 (12)0.0516 (10)0.0037 (11)0.0298 (10)0.0062 (9)
C120.0782 (13)0.0393 (9)0.0486 (10)0.0062 (9)0.0240 (9)0.0040 (7)
C130.0430 (9)0.0371 (8)0.0483 (9)0.0064 (7)0.0091 (7)0.0015 (7)
C140.0419 (8)0.0331 (7)0.0416 (8)0.0029 (6)0.0147 (6)−0.0002 (6)
C150.0608 (11)0.0390 (8)0.0446 (9)−0.0013 (8)0.0092 (8)0.0021 (7)
C160.0660 (12)0.0574 (11)0.0462 (10)−0.0037 (9)0.0015 (9)−0.0030 (8)
C170.0603 (12)0.0584 (12)0.0587 (11)−0.0140 (9)0.0152 (9)−0.0156 (9)
C180.0683 (13)0.0396 (9)0.0754 (14)−0.0103 (9)0.0233 (11)−0.0022 (9)
C190.0583 (11)0.0388 (9)0.0593 (11)0.0013 (8)0.0139 (9)0.0088 (8)

Geometric parameters (Å, °)

Br1—C11.8882 (18)C9—H90.9300
N1—C41.355 (2)C10—C111.376 (3)
N1—C51.356 (2)C10—H100.9300
N1—C131.483 (2)C11—C121.385 (3)
N2—C61.344 (2)C11—H110.9300
N2—C31.372 (2)C12—H120.9300
N3—C41.329 (2)C13—C141.508 (2)
N3—C61.374 (2)C13—H13A0.9700
C1—C51.375 (3)C13—H13B0.9700
C1—C21.396 (3)C14—C191.385 (2)
C2—C31.373 (2)C14—C151.390 (2)
C2—H20.9300C15—C161.382 (3)
C3—C41.438 (2)C15—H150.9300
C5—H50.9300C16—C171.379 (3)
C6—C71.468 (2)C16—H160.9300
C7—C121.388 (3)C17—C181.366 (3)
C7—C81.394 (2)C17—H170.9300
C8—C91.385 (3)C18—C191.390 (3)
C8—H80.9300C18—H180.9300
C9—C101.376 (3)C19—H190.9300
C4—N1—C5119.22 (14)C11—C10—H10120.0
C4—N1—C13120.17 (14)C9—C10—H10120.0
C5—N1—C13120.61 (14)C10—C11—C12119.8 (2)
C6—N2—C3102.99 (13)C10—C11—H11120.1
C4—N3—C6101.13 (13)C12—C11—H11120.1
C5—C1—C2122.44 (16)C11—C12—C7120.86 (18)
C5—C1—Br1117.06 (13)C11—C12—H12119.6
C2—C1—Br1120.49 (14)C7—C12—H12119.6
C3—C2—C1116.66 (16)N1—C13—C14112.30 (13)
C3—C2—H2121.7N1—C13—H13A109.1
C1—C2—H2121.7C14—C13—H13A109.1
N2—C3—C2133.11 (16)N1—C13—H13B109.1
N2—C3—C4106.70 (14)C14—C13—H13B109.1
C2—C3—C4120.18 (16)H13A—C13—H13B107.9
N3—C4—N1127.72 (15)C19—C14—C15118.70 (17)
N3—C4—C3111.64 (14)C19—C14—C13120.47 (16)
N1—C4—C3120.64 (15)C15—C14—C13120.82 (15)
N1—C5—C1120.85 (16)C16—C15—C14120.56 (17)
N1—C5—H5119.6C16—C15—H15119.7
C1—C5—H5119.6C14—C15—H15119.7
N2—C6—N3117.54 (14)C17—C16—C15120.1 (2)
N2—C6—C7122.76 (14)C17—C16—H16119.9
N3—C6—C7119.70 (14)C15—C16—H16119.9
C12—C7—C8118.69 (17)C18—C17—C16119.88 (19)
C12—C7—C6120.15 (15)C18—C17—H17120.1
C8—C7—C6121.17 (16)C16—C17—H17120.1
C9—C8—C7120.11 (18)C17—C18—C19120.47 (18)
C9—C8—H8119.9C17—C18—H18119.8
C7—C8—H8119.9C19—C18—H18119.8
C10—C9—C8120.42 (18)C14—C19—C18120.25 (18)
C10—C9—H9119.8C14—C19—H19119.9
C8—C9—H9119.8C18—C19—H19119.9
C11—C10—C9120.08 (18)
C5—C1—C2—C30.3 (3)N2—C6—C7—C12177.72 (18)
Br1—C1—C2—C3179.25 (13)N3—C6—C7—C12−2.4 (2)
C6—N2—C3—C2179.20 (19)N2—C6—C7—C8−2.2 (3)
C6—N2—C3—C4−0.16 (17)N3—C6—C7—C8177.69 (16)
C1—C2—C3—N2−179.77 (18)C12—C7—C8—C90.4 (3)
C1—C2—C3—C4−0.5 (3)C6—C7—C8—C9−179.61 (16)
C6—N3—C4—N1−179.97 (16)C7—C8—C9—C100.2 (3)
C6—N3—C4—C3−0.15 (18)C8—C9—C10—C11−0.6 (3)
C5—N1—C4—N3179.35 (16)C9—C10—C11—C120.2 (4)
C13—N1—C4—N3−0.7 (3)C10—C11—C12—C70.5 (4)
C5—N1—C4—C3−0.5 (2)C8—C7—C12—C11−0.8 (3)
C13—N1—C4—C3179.47 (15)C6—C7—C12—C11179.25 (19)
N2—C3—C4—N30.21 (19)C4—N1—C13—C14−94.67 (18)
C2—C3—C4—N3−179.25 (16)C5—N1—C13—C1485.26 (19)
N2—C3—C4—N1−179.95 (15)N1—C13—C14—C19−119.47 (17)
C2—C3—C4—N10.6 (2)N1—C13—C14—C1560.9 (2)
C4—N1—C5—C10.3 (2)C19—C14—C15—C160.5 (3)
C13—N1—C5—C1−179.68 (16)C13—C14—C15—C16−179.83 (17)
C2—C1—C5—N1−0.2 (3)C14—C15—C16—C17−1.8 (3)
Br1—C1—C5—N1−179.17 (13)C15—C16—C17—C181.4 (3)
C3—N2—C6—N30.1 (2)C16—C17—C18—C190.2 (3)
C3—N2—C6—C7180.00 (15)C15—C14—C19—C181.1 (3)
C4—N3—C6—N20.05 (19)C13—C14—C19—C18−178.56 (17)
C4—N3—C6—C7−179.88 (14)C17—C18—C19—C14−1.5 (3)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PK2232).

References

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  • Kale, R. P., Shaikh, M. U., Jadhav, G. R. & Gill, C. H. (2009). Tetrahedron Lett.50, 1780–1782.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
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