Skip to main content
PMC home page
Acta Crystallographica Section E: Structure Reports Online logoLink to Acta Crystallographica Section E: Structure Reports Online
. 2010 Mar 27;66(Pt 4):o946. doi: 10.1107/S160053681001038X

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

Y Ouzidan a, S Obbade b, F Capet c, El Mokhtar Essassi d, Seik Weng Ng e,*
PMCID: PMC2983780  PMID: 21580750

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 ▶); Benham et al. (1995 ▶); Cundy et al. (1997 ▶); Kale et al. (2009 ▶); Walsh et al. (1994 ▶); Zaki & Proença (2007 ▶).graphic file with name e-66-0o946-scheme1.jpg

Experimental

Crystal data

  • C19H14BrN3

  • M r = 364.24

  • Monoclinic, Inline graphic

  • 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 ▶) 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 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

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

e-66-0o946-sup1.cif (17.8KB, cif)

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

e-66-0o946-Isup2.hkl (226KB, 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.

Fig. 1.

Open in a new tab

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

Crystal data

C19H14BrN3 F(000) = 736
Mr = 364.24 Dx = 1.530 Mg m−3
Monoclinic, P21/c Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc Cell parameters from 9876 reflections
a = 8.6613 (6) Å θ = 2.4–27.2°
b = 19.7631 (13) Å µ = 2.60 mm−1
c = 9.3683 (6) Å T = 293 K
β = 99.647 (3)° Prism, brown
V = 1580.93 (18) Å3 0.28 × 0.24 × 0.20 mm
Z = 4
Open in a new tab

Data collection

Bruker X8 APEXII diffractometer 4613 independent reflections
Radiation source: fine-focus sealed tube 3492 reflections with I > 2σ(I)
graphite Rint = 0.035
φ and ω scans θmax = 30.1°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) h = −12→11
Tmin = 0.529, Tmax = 0.624 k = −27→27
57936 measured reflections l = −13→13
Open in a new tab

Refinement

Refinement on F2 Primary atom site location: structure-invariant direct methods
Least-squares matrix: full Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.032 Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.098 H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.0518P)2 + 0.5269P] where P = (Fo2 + 2Fc2)/3
4613 reflections (Δ/σ)max = 0.001
208 parameters Δρmax = 0.63 e Å−3
0 restraints Δρmin = −0.50 e Å−3
Open in a new tab

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

x y z Uiso*/Ueq
Br1 0.10158 (3) 0.475089 (12) 0.85824 (2) 0.06483 (10)
N1 0.29485 (16) 0.43405 (7) 0.49901 (15) 0.0385 (3)
N2 0.26154 (17) 0.60722 (7) 0.40338 (16) 0.0424 (3)
N3 0.35446 (17) 0.50867 (7) 0.31224 (15) 0.0387 (3)
C1 0.1792 (2) 0.48667 (9) 0.68312 (19) 0.0454 (4)
C2 0.1807 (2) 0.55060 (9) 0.62007 (19) 0.0458 (4)
H2 0.1429 0.5886 0.6616 0.055*
C3 0.2408 (2) 0.55460 (8) 0.49376 (18) 0.0392 (3)
C4 0.29944 (19) 0.49489 (8) 0.43321 (17) 0.0367 (3)
C5 0.2352 (2) 0.43003 (9) 0.62362 (18) 0.0437 (4)
H5 0.2322 0.3884 0.6694 0.052*
C6 0.32810 (19) 0.57716 (8) 0.30027 (17) 0.0379 (3)
C7 0.37246 (19) 0.61435 (8) 0.17772 (18) 0.0390 (3)
C8 0.3423 (2) 0.68335 (9) 0.1595 (2) 0.0459 (4)
H8 0.2938 0.7067 0.2261 0.055*
C9 0.3845 (2) 0.71728 (10) 0.0425 (2) 0.0547 (5)
H9 0.3644 0.7634 0.0310 0.066*
C10 0.4557 (3) 0.68322 (11) −0.0569 (2) 0.0574 (5)
H10 0.4829 0.7062 −0.1357 0.069*
C11 0.4869 (3) 0.61517 (11) −0.0399 (2) 0.0624 (5)
H11 0.5353 0.5922 −0.1069 0.075*
C12 0.4459 (3) 0.58097 (10) 0.0773 (2) 0.0538 (5)
H12 0.4679 0.5350 0.0888 0.065*
C13 0.3544 (2) 0.37271 (8) 0.43491 (19) 0.0427 (3)
H13A 0.4041 0.3433 0.5121 0.051*
H13B 0.4331 0.3859 0.3778 0.051*
C14 0.22599 (19) 0.33413 (8) 0.34017 (17) 0.0380 (3)
C15 0.1392 (2) 0.36407 (9) 0.21824 (19) 0.0481 (4)
H15 0.1605 0.4084 0.1945 0.058*
C16 0.0214 (3) 0.32854 (11) 0.1321 (2) 0.0574 (5)
H16 −0.0379 0.3494 0.0522 0.069*
C17 −0.0082 (3) 0.26217 (11) 0.1643 (2) 0.0585 (5)
H17 −0.0859 0.2380 0.1050 0.070*
C18 0.0769 (3) 0.23206 (10) 0.2833 (3) 0.0598 (5)
H18 0.0570 0.1873 0.3047 0.072*
C19 0.1930 (2) 0.26789 (9) 0.3728 (2) 0.0517 (4)
H19 0.2487 0.2473 0.4548 0.062*
Open in a new tab

Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23
Br1 0.08695 (19) 0.06436 (15) 0.05128 (13) 0.00593 (10) 0.03507 (11) 0.00630 (9)
N1 0.0419 (7) 0.0355 (6) 0.0382 (7) 0.0001 (5) 0.0074 (5) 0.0003 (5)
N2 0.0515 (8) 0.0338 (6) 0.0437 (7) −0.0007 (6) 0.0131 (6) −0.0028 (5)
N3 0.0443 (7) 0.0337 (6) 0.0394 (7) −0.0009 (5) 0.0104 (5) −0.0012 (5)
C1 0.0501 (10) 0.0498 (10) 0.0386 (8) −0.0024 (7) 0.0140 (7) 0.0004 (7)
C2 0.0535 (10) 0.0417 (9) 0.0444 (9) −0.0007 (7) 0.0147 (7) −0.0056 (7)
C3 0.0431 (8) 0.0349 (7) 0.0402 (8) −0.0015 (6) 0.0088 (6) −0.0046 (6)
C4 0.0390 (8) 0.0345 (7) 0.0366 (7) −0.0020 (6) 0.0061 (6) −0.0035 (6)
C5 0.0485 (9) 0.0430 (8) 0.0403 (8) −0.0019 (7) 0.0094 (7) 0.0036 (7)
C6 0.0407 (8) 0.0345 (7) 0.0385 (7) −0.0028 (6) 0.0068 (6) −0.0023 (6)
C7 0.0420 (8) 0.0353 (7) 0.0395 (7) −0.0036 (6) 0.0064 (6) −0.0004 (6)
C8 0.0471 (9) 0.0360 (8) 0.0553 (10) −0.0020 (7) 0.0105 (8) −0.0007 (7)
C9 0.0567 (11) 0.0391 (9) 0.0678 (12) −0.0031 (8) 0.0092 (9) 0.0118 (8)
C10 0.0647 (12) 0.0560 (11) 0.0530 (10) −0.0070 (9) 0.0141 (9) 0.0153 (9)
C11 0.0851 (15) 0.0567 (12) 0.0516 (10) 0.0037 (11) 0.0298 (10) 0.0062 (9)
C12 0.0782 (13) 0.0393 (9) 0.0486 (10) 0.0062 (9) 0.0240 (9) 0.0040 (7)
C13 0.0430 (9) 0.0371 (8) 0.0483 (9) 0.0064 (7) 0.0091 (7) 0.0015 (7)
C14 0.0419 (8) 0.0331 (7) 0.0416 (8) 0.0029 (6) 0.0147 (6) −0.0002 (6)
C15 0.0608 (11) 0.0390 (8) 0.0446 (9) −0.0013 (8) 0.0092 (8) 0.0021 (7)
C16 0.0660 (12) 0.0574 (11) 0.0462 (10) −0.0037 (9) 0.0015 (9) −0.0030 (8)
C17 0.0603 (12) 0.0584 (12) 0.0587 (11) −0.0140 (9) 0.0152 (9) −0.0156 (9)
C18 0.0683 (13) 0.0396 (9) 0.0754 (14) −0.0103 (9) 0.0233 (11) −0.0022 (9)
C19 0.0583 (11) 0.0388 (9) 0.0593 (11) 0.0013 (8) 0.0139 (9) 0.0088 (8)
Open in a new tab

Geometric parameters (Å, °)

Br1—C1 1.8882 (18) C9—H9 0.9300
N1—C4 1.355 (2) C10—C11 1.376 (3)
N1—C5 1.356 (2) C10—H10 0.9300
N1—C13 1.483 (2) C11—C12 1.385 (3)
N2—C6 1.344 (2) C11—H11 0.9300
N2—C3 1.372 (2) C12—H12 0.9300
N3—C4 1.329 (2) C13—C14 1.508 (2)
N3—C6 1.374 (2) C13—H13A 0.9700
C1—C5 1.375 (3) C13—H13B 0.9700
C1—C2 1.396 (3) C14—C19 1.385 (2)
C2—C3 1.373 (2) C14—C15 1.390 (2)
C2—H2 0.9300 C15—C16 1.382 (3)
C3—C4 1.438 (2) C15—H15 0.9300
C5—H5 0.9300 C16—C17 1.379 (3)
C6—C7 1.468 (2) C16—H16 0.9300
C7—C12 1.388 (3) C17—C18 1.366 (3)
C7—C8 1.394 (2) C17—H17 0.9300
C8—C9 1.385 (3) C18—C19 1.390 (3)
C8—H8 0.9300 C18—H18 0.9300
C9—C10 1.376 (3) C19—H19 0.9300
C4—N1—C5 119.22 (14) C11—C10—H10 120.0
C4—N1—C13 120.17 (14) C9—C10—H10 120.0
C5—N1—C13 120.61 (14) C10—C11—C12 119.8 (2)
C6—N2—C3 102.99 (13) C10—C11—H11 120.1
C4—N3—C6 101.13 (13) C12—C11—H11 120.1
C5—C1—C2 122.44 (16) C11—C12—C7 120.86 (18)
C5—C1—Br1 117.06 (13) C11—C12—H12 119.6
C2—C1—Br1 120.49 (14) C7—C12—H12 119.6
C3—C2—C1 116.66 (16) N1—C13—C14 112.30 (13)
C3—C2—H2 121.7 N1—C13—H13A 109.1
C1—C2—H2 121.7 C14—C13—H13A 109.1
N2—C3—C2 133.11 (16) N1—C13—H13B 109.1
N2—C3—C4 106.70 (14) C14—C13—H13B 109.1
C2—C3—C4 120.18 (16) H13A—C13—H13B 107.9
N3—C4—N1 127.72 (15) C19—C14—C15 118.70 (17)
N3—C4—C3 111.64 (14) C19—C14—C13 120.47 (16)
N1—C4—C3 120.64 (15) C15—C14—C13 120.82 (15)
N1—C5—C1 120.85 (16) C16—C15—C14 120.56 (17)
N1—C5—H5 119.6 C16—C15—H15 119.7
C1—C5—H5 119.6 C14—C15—H15 119.7
N2—C6—N3 117.54 (14) C17—C16—C15 120.1 (2)
N2—C6—C7 122.76 (14) C17—C16—H16 119.9
N3—C6—C7 119.70 (14) C15—C16—H16 119.9
C12—C7—C8 118.69 (17) C18—C17—C16 119.88 (19)
C12—C7—C6 120.15 (15) C18—C17—H17 120.1
C8—C7—C6 121.17 (16) C16—C17—H17 120.1
C9—C8—C7 120.11 (18) C17—C18—C19 120.47 (18)
C9—C8—H8 119.9 C17—C18—H18 119.8
C7—C8—H8 119.9 C19—C18—H18 119.8
C10—C9—C8 120.42 (18) C14—C19—C18 120.25 (18)
C10—C9—H9 119.8 C14—C19—H19 119.9
C8—C9—H9 119.8 C18—C19—H19 119.9
C11—C10—C9 120.08 (18)
C5—C1—C2—C3 0.3 (3) N2—C6—C7—C12 177.72 (18)
Br1—C1—C2—C3 179.25 (13) N3—C6—C7—C12 −2.4 (2)
C6—N2—C3—C2 179.20 (19) N2—C6—C7—C8 −2.2 (3)
C6—N2—C3—C4 −0.16 (17) N3—C6—C7—C8 177.69 (16)
C1—C2—C3—N2 −179.77 (18) C12—C7—C8—C9 0.4 (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—C10 0.2 (3)
C6—N3—C4—C3 −0.15 (18) C8—C9—C10—C11 −0.6 (3)
C5—N1—C4—N3 179.35 (16) C9—C10—C11—C12 0.2 (4)
C13—N1—C4—N3 −0.7 (3) C10—C11—C12—C7 0.5 (4)
C5—N1—C4—C3 −0.5 (2) C8—C7—C12—C11 −0.8 (3)
C13—N1—C4—C3 179.47 (15) C6—C7—C12—C11 179.25 (19)
N2—C3—C4—N3 0.21 (19) C4—N1—C13—C14 −94.67 (18)
C2—C3—C4—N3 −179.25 (16) C5—N1—C13—C14 85.26 (19)
N2—C3—C4—N1 −179.95 (15) N1—C13—C14—C19 −119.47 (17)
C2—C3—C4—N1 0.6 (2) N1—C13—C14—C15 60.9 (2)
C4—N1—C5—C1 0.3 (2) C19—C14—C15—C16 0.5 (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—C18 1.4 (3)
C3—N2—C6—N3 0.1 (2) C16—C17—C18—C19 0.2 (3)
C3—N2—C6—C7 180.00 (15) C15—C14—C19—C18 1.1 (3)
C4—N3—C6—N2 0.05 (19) C13—C14—C19—C18 −178.56 (17)
C4—N3—C6—C7 −179.88 (14) C17—C18—C19—C14 −1.5 (3)
Open in a new tab

Footnotes

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

References

  1. Aridoss, G., Balasubramanian, S., Parthiban, P. & Kabilan, S. (2006). Eur. J. Med. Chem. 41, 268–275. [DOI] [PubMed]
  2. Barbour, L. J. (2001). J. Supramol. Chem.1, 189–191.
  3. Benham, C. D., Blackburn, T. P., Johns, A., Kotecha, N. R., Martin, R. T., Thomas, D. R., Thompson, M. & Ward, R. W. (1995). Bioorg. Med. Chem. Lett.5, 2455–2460.
  4. Bruker (2008). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  5. Cundy, D. J., Holan, G., Otaegui, M. & Simpson, G. W. (1997). Bioorg. Med. Chem. Lett.7, 669–674.
  6. Kale, R. P., Shaikh, M. U., Jadhav, G. R. & Gill, C. H. (2009). Tetrahedron Lett.50, 1780–1782.
  7. Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  8. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [DOI] [PubMed]
  9. Walsh, T. F., Fitch, K. J., MacCoss, M., Chang, R. S. L., Kivlighn, S. D., Lotti, V. J., Siegl, P. K. S., Patchett, A. & Greenlee, W. J. (1994). Bioorg. Med. Chem. Lett. 4, 219–222.
  10. Westrip, S. P. (2010). publCIF In preparation.
  11. Zaki, M. E. A. & Proença, M. F. (2007). Tetrahedron, 63, 3745–3753.

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

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

e-66-0o946-sup1.cif (17.8KB, cif)

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

e-66-0o946-Isup2.hkl (226KB, hkl)

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

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

RESOURCES