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fj2630 scheme

Acta Cryst. (2013). E69, o962    [ doi:10.1107/S1600536813013780 ]

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

Y. Kandri Rodi, A. Haoudi, F. Capet, A. Mazzah, E. M. Essassi and L. El Ammari

Abstract top

The fused imidazole and pyridine rings in the title compound, C13H10BrN3O, are linked to a benzyl group. The fused ring system is essentially planar, the largest deviation from the mean plane being 0.006 (2) Å. The phenyl ring is not coplanar with the fused ring system, as indicated by the dihedral angle of 67.04 (12)°. In the crystal, molecules are linked by pairs of N-H...O hydrogen bonds, forming inversion dimers.

Comment top

The imidazopyridine moieties 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 et al., 1992; Cappelli et al., 2006), platelet activating factor (Weier et al., 1994), and metabotropic glutamate subtype V (Kulkarni et al., 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; Bavetsias et al., 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 their scope.

Here, we wish to report a novel route leading to 3-benzyl-6-bromo-1,3- dihydro-imidazo[4,5-b]pyridin-2-one. We have checked the action of benzyl chloride towards 6-bromo-1,3-dihydro-imidazo[4,5 - b-]pyridin-2- one using K2CO3 as base (schem1).

The molecule of title compound, 3-benzyl-6-bromo-1,3-dihydro-imidazo [4,5-b]pyridin-2-one, build up from two fused five- and six-membered rings liked to a benzyl cycle as shown in Fig. 1. The fused rings system (N1N2N3 C1 to C6) is essentially planar with the largest deviation from the mean plane being -0.006 (2) A° at C5 atom. The dihedral angle between the benzyl cycle and the fused imidazole and pyridine rings is of 67.04 (12) °. In the crystal, the molecules are linked by N3–H14···O1 hydrogen bond in the way to build dimers as shown in Fig. 2 and Table 2.

Related literature top

For the biological activity of imidazopyridine derivatives, see: Chen & Dost (1992); Cappelli et al. (2006); Weier et al. (1994); Kulkarni & Newman (2007); 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-butylammonium bromide (0.03 g; 9.34 10 -5 mol) in DMF, benzyl chloride (95 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 (ethyl acetate/hexane) (1/2) as eluent. The yield of the reaction is of 85%. Crystals were isolated after the solvent (hexane / acetate d'ethyle: 1/1) was allowed to evaporate.

Refinement top

All H atoms could be located in a difference Fourier map. However, they were placed in calculated positions with C—H = 0.93 Å (aromatic), N—H = 0.86 and C—H = 0.97 Å (methylene) and refined as riding on their parent atoms with Uiso(H) = 1.2 Ueq (C, N).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT-Plus (Bruker, 2009); data reduction: SAINT-Plus (Bruker, 2009); 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, 2012); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. : Molecular plot 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. : Intermolecular interactions in the title compound building a dimers. Hydrogen bonds are shown as dashed lines.
3-Benzyl-6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one top
Crystal data top
C13H10BrN3OZ = 2
Mr = 304.15F(000) = 304
Triclinic, P1Dx = 1.677 Mg m3
Hall symbol: -P 1Melting point: 358 K
a = 4.2399 (2) ÅMo Kα radiation, λ = 0.71073 Å
b = 10.4463 (4) ÅCell parameters from 2772 reflections
c = 14.5144 (6) Åθ = 1.5–27.5°
α = 107.611 (2)°µ = 3.40 mm1
β = 90.628 (3)°T = 296 K
γ = 99.784 (3)°Platelet, colourless
V = 602.49 (4) Å30.26 × 0.19 × 0.02 mm
Data collection top
Bruker APEXII CCD
diffractometer
2772 independent reflections
Radiation source: microfocus source2169 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
φ and ω scansθmax = 27.5°, θmin = 1.5°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 55
Tmin = 0.472, Tmax = 0.935k = 1313
13819 measured reflectionsl = 1818
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)] = 0.033Hydrogen site location: difference Fourier map
wR(F2) = 0.085H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0374P)2 + 0.3201P]
where P = (Fo2 + 2Fc2)/3
2772 reflections(Δ/σ)max < 0.001
163 parametersΔρmax = 0.56 e Å3
0 restraintsΔρmin = 0.55 e Å3
Crystal data top
C13H10BrN3Oγ = 99.784 (3)°
Mr = 304.15V = 602.49 (4) Å3
Triclinic, P1Z = 2
a = 4.2399 (2) ÅMo Kα radiation
b = 10.4463 (4) ŵ = 3.40 mm1
c = 14.5144 (6) ÅT = 296 K
α = 107.611 (2)°0.26 × 0.19 × 0.02 mm
β = 90.628 (3)°
Data collection top
Bruker APEXII CCD
diffractometer
2772 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
2169 reflections with I > 2σ(I)
Tmin = 0.472, Tmax = 0.935Rint = 0.026
13819 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.033H-atom parameters constrained
wR(F2) = 0.085Δρmax = 0.56 e Å3
S = 1.06Δρmin = 0.55 e Å3
2772 reflectionsAbsolute structure: ?
163 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
Br10.26054 (8)0.40434 (3)0.14153 (2)0.06526 (14)
C10.6829 (7)0.6528 (3)0.2362 (2)0.0522 (7)
H10.72690.60480.27790.063*
C20.4658 (7)0.5871 (3)0.15899 (19)0.0463 (6)
C30.3894 (6)0.6511 (3)0.09261 (18)0.0448 (6)
H30.24370.60730.03950.054*
C40.5450 (6)0.7837 (2)0.11128 (16)0.0373 (5)
C50.7610 (6)0.8423 (2)0.19198 (16)0.0379 (5)
C60.7491 (6)0.9986 (2)0.11485 (16)0.0387 (5)
C71.1131 (6)1.0750 (3)0.26618 (18)0.0433 (6)
H7A1.23621.13710.23630.052*
H7B1.26151.02890.28960.052*
C80.9545 (5)1.1565 (2)0.35104 (16)0.0381 (5)
C90.8773 (7)1.2797 (3)0.3530 (2)0.0503 (6)
H90.91881.31260.30080.060*
C100.7386 (8)1.3551 (3)0.4320 (2)0.0644 (8)
H100.68701.43850.43270.077*
C110.6766 (8)1.3071 (4)0.5096 (2)0.0647 (8)
H110.58651.35860.56320.078*
C120.7474 (8)1.1844 (4)0.5076 (2)0.0656 (8)
H120.70291.15130.55960.079*
C130.8849 (7)1.1088 (3)0.42872 (19)0.0536 (7)
H130.93131.02450.42780.064*
N10.8370 (6)0.7832 (2)0.25554 (15)0.0479 (5)
N20.8850 (5)0.9739 (2)0.19325 (14)0.0385 (4)
N30.5415 (5)0.8819 (2)0.06533 (14)0.0412 (5)
H140.42620.87120.01350.049*
O10.8058 (5)1.10622 (18)0.09525 (13)0.0507 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0925 (3)0.04191 (17)0.0673 (2)0.00734 (15)0.02819 (17)0.02745 (14)
C10.0752 (19)0.0483 (15)0.0458 (15)0.0241 (14)0.0182 (14)0.0259 (13)
C20.0615 (16)0.0352 (13)0.0453 (14)0.0094 (12)0.0203 (12)0.0159 (11)
C30.0572 (15)0.0369 (13)0.0378 (13)0.0036 (11)0.0109 (11)0.0103 (11)
C40.0468 (13)0.0346 (12)0.0323 (11)0.0084 (10)0.0083 (10)0.0121 (10)
C50.0437 (13)0.0369 (12)0.0352 (12)0.0119 (10)0.0100 (10)0.0113 (10)
C60.0460 (13)0.0358 (12)0.0345 (12)0.0060 (10)0.0040 (10)0.0119 (10)
C70.0357 (12)0.0496 (14)0.0428 (13)0.0047 (11)0.0023 (10)0.0134 (12)
C80.0321 (12)0.0419 (13)0.0355 (12)0.0009 (10)0.0081 (9)0.0094 (10)
C90.0581 (16)0.0427 (14)0.0511 (15)0.0044 (12)0.0053 (12)0.0185 (12)
C100.074 (2)0.0440 (16)0.074 (2)0.0150 (15)0.0095 (17)0.0142 (15)
C110.069 (2)0.065 (2)0.0518 (17)0.0155 (16)0.0109 (14)0.0036 (15)
C120.080 (2)0.079 (2)0.0422 (15)0.0184 (18)0.0089 (14)0.0238 (15)
C130.0682 (18)0.0556 (17)0.0426 (14)0.0191 (14)0.0021 (13)0.0194 (13)
N10.0618 (13)0.0493 (13)0.0397 (11)0.0181 (11)0.0045 (10)0.0199 (10)
N20.0435 (11)0.0369 (10)0.0337 (10)0.0055 (9)0.0001 (8)0.0099 (8)
N30.0544 (12)0.0349 (10)0.0324 (10)0.0006 (9)0.0056 (9)0.0125 (8)
O10.0670 (12)0.0366 (9)0.0466 (10)0.0043 (8)0.0091 (9)0.0177 (8)
Geometric parameters (Å, º) top
Br1—C21.898 (3)C7—C81.507 (3)
C1—N11.350 (4)C7—H7A0.9700
C1—C21.368 (4)C7—H7B0.9700
C1—H10.9300C8—C91.372 (4)
C2—C31.392 (4)C8—C131.380 (4)
C3—C41.373 (3)C9—C101.381 (4)
C3—H30.9300C9—H90.9300
C4—N31.385 (3)C10—C111.375 (5)
C4—C51.392 (3)C10—H100.9300
C5—N11.320 (3)C11—C121.357 (5)
C5—N21.380 (3)C11—H110.9300
C6—O11.227 (3)C12—C131.378 (4)
C6—N31.367 (3)C12—H120.9300
C6—N21.381 (3)C13—H130.9300
C7—N21.458 (3)N3—H140.8600
N1—C1—C2123.9 (2)C9—C8—C7120.9 (2)
N1—C1—H1118.1C13—C8—C7120.5 (2)
C2—C1—H1118.1C8—C9—C10120.6 (3)
C1—C2—C3121.7 (2)C8—C9—H9119.7
C1—C2—Br1119.55 (19)C10—C9—H9119.7
C3—C2—Br1118.8 (2)C11—C10—C9120.0 (3)
C4—C3—C2115.1 (2)C11—C10—H10120.0
C4—C3—H3122.5C9—C10—H10120.0
C2—C3—H3122.5C12—C11—C10119.8 (3)
C3—C4—N3133.9 (2)C12—C11—H11120.1
C3—C4—C5119.2 (2)C10—C11—H11120.1
N3—C4—C5106.8 (2)C11—C12—C13120.2 (3)
N1—C5—N2125.9 (2)C11—C12—H12119.9
N1—C5—C4126.6 (2)C13—C12—H12119.9
N2—C5—C4107.5 (2)C12—C13—C8120.7 (3)
O1—C6—N3127.5 (2)C12—C13—H13119.6
O1—C6—N2125.6 (2)C8—C13—H13119.6
N3—C6—N2107.0 (2)C5—N1—C1113.6 (2)
N2—C7—C8113.10 (19)C5—N2—C6109.01 (19)
N2—C7—H7A109.0C5—N2—C7126.9 (2)
C8—C7—H7A109.0C6—N2—C7124.1 (2)
N2—C7—H7B109.0C6—N3—C4109.67 (19)
C8—C7—H7B109.0C6—N3—H14125.2
H7A—C7—H7B107.8C4—N3—H14125.2
C9—C8—C13118.6 (2)
N1—C1—C2—C30.8 (4)C7—C8—C13—C12178.3 (3)
N1—C1—C2—Br1178.9 (2)N2—C5—N1—C1179.1 (2)
C1—C2—C3—C40.6 (4)C4—C5—N1—C10.3 (4)
Br1—C2—C3—C4179.11 (17)C2—C1—N1—C50.6 (4)
C2—C3—C4—N3179.7 (2)N1—C5—N2—C6179.6 (2)
C2—C3—C4—C50.3 (3)C4—C5—N2—C60.2 (2)
C3—C4—C5—N10.1 (4)N1—C5—N2—C72.6 (4)
N3—C4—C5—N1179.7 (2)C4—C5—N2—C7178.0 (2)
C3—C4—C5—N2179.3 (2)O1—C6—N2—C5179.4 (2)
N3—C4—C5—N20.3 (3)N3—C6—N2—C50.1 (3)
N2—C7—C8—C993.6 (3)O1—C6—N2—C71.5 (4)
N2—C7—C8—C1386.6 (3)N3—C6—N2—C7177.9 (2)
C13—C8—C9—C101.2 (4)C8—C7—N2—C586.5 (3)
C7—C8—C9—C10178.5 (3)C8—C7—N2—C691.0 (3)
C8—C9—C10—C110.0 (5)O1—C6—N3—C4179.6 (2)
C9—C10—C11—C121.1 (5)N2—C6—N3—C40.1 (3)
C10—C11—C12—C130.9 (5)C3—C4—N3—C6179.2 (3)
C11—C12—C13—C80.4 (5)C5—C4—N3—C60.3 (3)
C9—C8—C13—C121.4 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H14···O1i0.861.952.789 (3)166
Symmetry code: (i) x+1, y+2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H14···O1i0.861.952.789 (3)166
Symmetry code: (i) x+1, y+2, z.
Acknowledgements top

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

references
References top

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