organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

3-Allyl-6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one

aLaboratoire de Chimie Organique Appliquée, Université Sidi Mohamed Ben Abdallah, Faculté des Sciences et Techniques, Route d'Immouzzer, BP 2202 Fès, Morocco, bDepartamento de Quimica Inorganica & Organica, ESTCE, Universitat Jaume I, E-12080 Castellon, Spain, cInstitut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany, and dLaboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Université Mohammed V-Agdal, Avenue Ibn Battouta, BP 1014, Rabat, Morocco
*Correspondence e-mail: s_dahmani12@yahoo.fr

(Received 22 June 2011; accepted 25 June 2011; online 9 July 2011)

In the mol­ecule of the title compound, C9H8BrN3O, the fused-ring system is almost planar, the largest deviation from the mean plane being 0.008 (3) Å. The plane through the atoms forming the allyl group is roughly perpendicular to the imidazo[4,5-b]pyridin-2-one system, as indicated by the dihedral angle between them of 70.28 (11)°. In the crystal, each mol­ecule is linked to its symmetry equivalent about the center of inversion by a pair of strong N—H⋯O hydrogen bond, forming inversion dimers.

Related literature

For background to the biological activity of imidazopyridines, see: Chen & Dost (1992[Chen, S. T. & Dost, G. (1992). (Merck) US Patent 5 132 216.]); Cappelli et al. (2006[Cappelli, A., Mohr, G. P., Giuliani, G., Galeazzi, S., Anzini, M., Mennuni, L., Ferrari, F., Macoves, F., Krienrath, E. M., Langer, T., Valoti, M., Giorgi, G. & Vomero, S. (2006). J. Med. Chem. 49, 6451-6464.]); Weier et al. (1993[Weier, R. M., Khanna, I. K., Stealey, M. A. & Julien, J. (1993). US Patent 5 262 426.], 1994[Weier, R. M., Khanna, I. K., Lentz, K., Stealey, M. A. & Julien, J. (1994). (Searle) US Patent 5 359 073.]); Kulkarni & Newman (2007[Kulkarni, S. S. & Newman, A. H. (2007). Bioorg. Med. Chem. Lett. 17, 2987-2991.]). For background to their pharmacological activity, see: Bavetsias et al. (2007[Bavetsias, V., Sun, C., Bouloc, N., Reynisson, J., Workman, P., Linardopoulos, S. & McDonald, E. (2007). Bioorg. Med. Chem. 17, 6567-6571.], 2010[Bavetsias, V., Large, J. M., Sun, C., Bouloc, N., Kosmopoulou, M., Matteucci, M., Wilsher, N. E., Martins, V., Reynisson, J., Atrash, B., Faisal, A., Urban, F., Valenti, M. & Brandon, A. H. (2010). J. Med. Chem. 53, 5213-5228.]).

[Scheme 1]

Experimental

Crystal data
  • C9H8BrN3O

  • Mr = 254.09

  • Triclinic, [P \overline 1]

  • a = 4.5138 (5) Å

  • b = 9.7750 (9) Å

  • c = 11.5717 (11) Å

  • α = 78.748 (2)°

  • β = 82.526 (3)°

  • γ = 86.038 (2)°

  • V = 496.00 (9) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 4.11 mm−1

  • T = 571 K

  • 0.60 × 0.19 × 0.04 mm

Data collection
  • Bruker CCD three-circle diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.192, Tmax = 0.850

  • 3086 measured reflections

  • 2019 independent reflections

  • 1683 reflections with I > 2σ(I)

  • Rint = 0.026

Refinement
  • R[F2 > 2σ(F2)] = 0.046

  • wR(F2) = 0.127

  • S = 1.09

  • 2019 reflections

  • 127 parameters

  • H-atom parameters constrained

  • Δρmax = 0.89 e Å−3

  • Δρmin = −0.82 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O1i 0.86 1.95 2.798 (4) 168
Symmetry code: (i) -x, -y+1, -z+2.

Data collection: SMART (Bruker, 1997[Bruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 1997[Bruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Imidazopyridine molecules are important pharmacophores, which have proven to be useful for a number of biologically relevant targets. The compounds derived from the imidazopyridine system have recently been evaluated as antagonists of various biological receptors, including angiotensin-II (Chen & Dost 1992; Cappelli et al., 2006), platelet activating factor (Weier et al., (1993, 1994), and metabotropic glutamate subtype V (Kulkarni & Newman, 2007). Recently, a series of imidazo[4,5-b] pyridine derivatives as orally bioavailable Aurora A inhibitors with excellent potencies were reported (Bavetsias et al., 2007, 2010). Hence, the synthesis of imidazo [4,5-b]pyridine derivatives is currently of great interest. Despite the importance of these intermediates, the methodology available for the synthesis was generally target-specific and restrictive in its scope.

Here, we wish to report a novel route leading to 3-allyl-6-bromo-1,3-dihydro- imidazo[4,5-b]pyridin-2-one. We have checked the action of allyllbromide towards 6-bromo-1,3-dihydro-imidazo[4,5 - b-]pyridin-2- one using K2CO3 as a base (scheme 1).

The two fused five and six-membered rings building the molecule are nearly planar with the maximum deviation of 0.008 (3)Å from C1 (Fig. 1). The dihedral angle between the imidazo[4,5-b]pyridin-2-one system and the plane through the atoms forming the allyl group is about 70.28 (11)°. The allyl group is nearly perpendicular to the imidazo[4,5-b]pyridin-2-one system and the torsion angle N2–C7–C8–C9 is in the range of -131.6 (5)°. In the crystal, each molecule is linked to its symmetry equivalent about an inversion center by a strong N—H···O hydrogen bond to form a pseudo dimers as shown in Fig.2 and Table 1.

Related literature top

For background to the biological activity of imidazopyridines, see: Chen & Dost (1992); Cappelli et al. (2006); Weier et al. (1993, 1994); Kulkarni & Newman (2007). For background to their pharmacological activity, see: Bavetsias et al. (2007, 2010).

Experimental top

To a stirred solution of 6-bromo-1,3-dihydro-imidazo[4,5 - b-]pyridin-2-one (0.2 g; 93.4 mmol), K2CO3 (0.38 g; 2.8 mmol), and tetra n-butyl ammonium bromide (0.03 g; 9.34 10–5 mol)in DMF, allyllbromide (0.097 ml; 1.12 mmol) was added dropwise. Later the mixture was heated under reflux for 24 h. After completion of reaction (monitored by TLC), the salt was filtered and the solvent was removed under reduced pressure. The resulting residue was purified by column chromatography on silica gel using (ethylacetate/hexane) (1/1) as eluent. The crystals were obtained by dissolving 80 mg of product in 4 mL of methanol at about 353 K, followed by a slow evaporation of the solvent.

Refinement top

H atoms were located in a difference map and treated as riding with C—H = 0.93 Å, 0.97, Å, and 0.86 Å for aromatic, methylene and –NH * respectively. All H atoms had Uiso(H) = 1.2 Ueq (aromatic, methylene, –NH).

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. : Plot of the molecules of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small circles.
[Figure 2] Fig. 2. Partial plot showing N–H···O hydrogen bonds (dashed lines) between two symmetrical molecules (pseudo-dimer).
3-Allyl-6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one top
Crystal data top
C9H8BrN3OZ = 2
Mr = 254.09F(000) = 252
Triclinic, P1Dx = 1.701 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 4.5138 (5) ÅCell parameters from 2019 reflections
b = 9.7750 (9) Åθ = 1.8–26.4°
c = 11.5717 (11) ŵ = 4.11 mm1
α = 78.748 (2)°T = 571 K
β = 82.526 (3)°Fiber, colourless
γ = 86.038 (2)°0.60 × 0.19 × 0.04 mm
V = 496.00 (9) Å3
Data collection top
Bruker CCD three-circle
diffractometer
2019 independent reflections
Radiation source: fine-focus sealed tube1683 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
ω scansθmax = 26.4°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 55
Tmin = 0.192, Tmax = 0.850k = 1211
3086 measured reflectionsl = 1214
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)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.127H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0649P)2 + 0.1269P]
where P = (Fo2 + 2Fc2)/3
2019 reflections(Δ/σ)max < 0.001
127 parametersΔρmax = 0.89 e Å3
0 restraintsΔρmin = 0.82 e Å3
Crystal data top
C9H8BrN3Oγ = 86.038 (2)°
Mr = 254.09V = 496.00 (9) Å3
Triclinic, P1Z = 2
a = 4.5138 (5) ÅMo Kα radiation
b = 9.7750 (9) ŵ = 4.11 mm1
c = 11.5717 (11) ÅT = 571 K
α = 78.748 (2)°0.60 × 0.19 × 0.04 mm
β = 82.526 (3)°
Data collection top
Bruker CCD three-circle
diffractometer
2019 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1683 reflections with I > 2σ(I)
Tmin = 0.192, Tmax = 0.850Rint = 0.026
3086 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0460 restraints
wR(F2) = 0.127H-atom parameters constrained
S = 1.09Δρmax = 0.89 e Å3
2019 reflectionsΔρmin = 0.82 e Å3
127 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 > 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) top
xyzUiso*/Ueq
Br10.99854 (9)0.03225 (4)0.83292 (4)0.0624 (2)
N10.3023 (6)0.4132 (3)0.9218 (3)0.0429 (6)
H10.17810.38230.98270.052*
C10.3081 (8)0.5487 (4)0.8627 (3)0.0438 (7)
O10.1416 (6)0.6472 (3)0.8854 (2)0.0545 (6)
N20.5408 (7)0.5549 (3)0.7722 (3)0.0463 (7)
C20.6765 (8)0.4238 (4)0.7739 (3)0.0448 (8)
N30.9047 (7)0.3902 (3)0.7003 (3)0.0536 (7)
C30.9924 (8)0.2536 (4)0.7221 (4)0.0537 (9)
H31.15270.22270.67330.064*
C40.8551 (8)0.1578 (4)0.8137 (3)0.0474 (8)
C50.6169 (8)0.1954 (3)0.8914 (3)0.0446 (7)
H50.52600.13160.95410.054*
C60.5261 (7)0.3327 (3)0.8692 (3)0.0400 (7)
C70.6297 (9)0.6836 (4)0.6904 (4)0.0577 (10)
H7A0.84500.67930.66980.069*
H7B0.57860.76220.73020.069*
C80.4822 (12)0.7071 (5)0.5791 (4)0.0727 (13)
H80.48560.63300.53930.087*
C90.3510 (13)0.8229 (7)0.5349 (5)0.0923 (17)
H9A0.34350.89910.57250.111*
H9B0.26370.83040.46530.111*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0653 (3)0.0414 (3)0.0810 (4)0.01520 (18)0.0026 (2)0.0228 (2)
N10.0438 (15)0.0317 (14)0.0475 (15)0.0066 (11)0.0071 (11)0.0044 (11)
C10.0459 (18)0.0326 (17)0.0504 (19)0.0017 (14)0.0002 (14)0.0063 (14)
O10.0569 (15)0.0348 (13)0.0660 (16)0.0104 (11)0.0037 (12)0.0068 (11)
N20.0450 (15)0.0336 (14)0.0549 (17)0.0030 (12)0.0027 (13)0.0028 (12)
C20.0404 (17)0.0413 (18)0.0519 (19)0.0003 (14)0.0030 (14)0.0091 (15)
N30.0468 (16)0.0506 (18)0.0585 (18)0.0027 (13)0.0070 (13)0.0084 (14)
C30.0443 (19)0.056 (2)0.060 (2)0.0073 (16)0.0025 (16)0.0189 (18)
C40.0459 (18)0.0427 (18)0.056 (2)0.0057 (14)0.0047 (15)0.0181 (15)
C50.0457 (18)0.0352 (17)0.0512 (19)0.0023 (14)0.0001 (14)0.0089 (14)
C60.0383 (16)0.0344 (16)0.0464 (18)0.0013 (13)0.0010 (13)0.0095 (13)
C70.051 (2)0.042 (2)0.072 (2)0.0067 (16)0.0028 (18)0.0043 (17)
C80.101 (4)0.058 (3)0.051 (2)0.010 (2)0.009 (2)0.000 (2)
C90.094 (4)0.102 (5)0.068 (3)0.005 (3)0.007 (3)0.014 (3)
Geometric parameters (Å, º) top
Br1—C41.905 (4)C3—H30.9300
N1—C11.367 (4)C4—C51.387 (5)
N1—C61.388 (4)C5—C61.361 (5)
N1—H10.8600C5—H50.9300
C1—O11.228 (4)C7—C81.498 (7)
C1—N21.379 (5)C7—H7A0.9700
N2—C21.380 (5)C7—H7B0.9700
N2—C71.465 (5)C8—C91.286 (8)
C2—N31.315 (5)C8—H80.9300
C2—C61.406 (5)C9—H9A0.9300
N3—C31.351 (5)C9—H9B0.9300
C3—C41.381 (6)
C1—N1—C6110.1 (3)C6—C5—C4115.0 (3)
C1—N1—H1124.9C6—C5—H5122.5
C6—N1—H1124.9C4—C5—H5122.5
O1—C1—N1127.3 (3)C5—C6—N1134.3 (3)
O1—C1—N2126.0 (3)C5—C6—C2119.5 (3)
N1—C1—N2106.8 (3)N1—C6—C2106.3 (3)
C1—N2—C2109.5 (3)N2—C7—C8112.6 (3)
C1—N2—C7124.0 (3)N2—C7—H7A109.1
C2—N2—C7126.4 (3)C8—C7—H7A109.1
N3—C2—N2126.4 (3)N2—C7—H7B109.1
N3—C2—C6126.3 (3)C8—C7—H7B109.1
N2—C2—C6107.3 (3)H7A—C7—H7B107.8
C2—N3—C3114.0 (3)C9—C8—C7124.4 (5)
N3—C3—C4123.0 (3)C9—C8—H8117.8
N3—C3—H3118.5C7—C8—H8117.8
C4—C3—H3118.5C8—C9—H9A120.0
C3—C4—C5122.2 (3)C8—C9—H9B120.0
C3—C4—Br1118.6 (3)H9A—C9—H9B120.0
C5—C4—Br1119.2 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.861.952.798 (4)168
Symmetry code: (i) x, y+1, z+2.

Experimental details

Crystal data
Chemical formulaC9H8BrN3O
Mr254.09
Crystal system, space groupTriclinic, P1
Temperature (K)571
a, b, c (Å)4.5138 (5), 9.7750 (9), 11.5717 (11)
α, β, γ (°)78.748 (2), 82.526 (3), 86.038 (2)
V3)496.00 (9)
Z2
Radiation typeMo Kα
µ (mm1)4.11
Crystal size (mm)0.60 × 0.19 × 0.04
Data collection
DiffractometerBruker CCD three-circle
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.192, 0.850
No. of measured, independent and
observed [I > 2σ(I)] reflections
3086, 2019, 1683
Rint0.026
(sin θ/λ)max1)0.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.127, 1.09
No. of reflections2019
No. of parameters127
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.89, 0.82

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.861.952.798 (4)168
Symmetry code: (i) x, y+1, z+2.
 

References

First citationBavetsias, V., Large, J. M., Sun, C., Bouloc, N., Kosmopoulou, M., Matteucci, M., Wilsher, N. E., Martins, V., Reynisson, J., Atrash, B., Faisal, A., Urban, F., Valenti, M. & Brandon, A. H. (2010). J. Med. Chem. 53, 5213–5228.  Web of Science CrossRef CAS PubMed
First citationBavetsias, V., Sun, C., Bouloc, N., Reynisson, J., Workman, P., Linardopoulos, S. & McDonald, E. (2007). Bioorg. Med. Chem. 17, 6567–6571.  Web of Science CrossRef CAS
First citationBruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationCappelli, A., Mohr, G. P., Giuliani, G., Galeazzi, S., Anzini, M., Mennuni, L., Ferrari, F., Macoves, F., Krienrath, E. M., Langer, T., Valoti, M., Giorgi, G. & Vomero, S. (2006). J. Med. Chem. 49, 6451–6464.  Web of Science CSD CrossRef PubMed CAS
First citationChen, S. T. & Dost, G. (1992). (Merck) US Patent 5 132 216.
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals
First citationKulkarni, S. S. & Newman, A. H. (2007). Bioorg. Med. Chem. Lett. 17, 2987–2991.  Web of Science CrossRef PubMed CAS
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationWeier, R. M., Khanna, I. K., Lentz, K., Stealey, M. A. & Julien, J. (1994). (Searle) US Patent 5 359 073.
First citationWeier, R. M., Khanna, I. K., Stealey, M. A. & Julien, J. (1993). US Patent 5 262 426.

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ISSN: 2056-9890
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