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

Dahmani, S.; Kandri Rodi, Y.; Luis, S.V.; Bolte, M.; El Ammari, L.

doi:10.1107/S1600536811025037

organic compounds

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ISSN: 2056-9890

Volume 67| Part 8| August 2011| Page o1998

doi:10.1107/S1600536811025037

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

Siham Dahmani,^a ^* Youssef Kandri Rodi,^a Santiago V. Luis,^b Michael Bolte ^c and Lahcen El Ammari ^d

^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 ); 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

Crystal data

C₉H₈BrN₃O
M_r = 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 ) T_min = 0.192, T_max = 0.850
3086 measured reflections
2019 independent reflections
1683 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.046
wR(F²) = 0.127
S = 1.09
2019 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 0.89 e Å⁻³
Δρ_min = −0.82 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	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 ); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; 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 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811025037/sj5172sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811025037/sj5172Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811025037/sj5172Isup3.cml

checkCIF report

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.

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

	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.
	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

C₉H₈BrN₃O	Z = 2
M_r = 254.09	F(000) = 252
Triclinic, P1	D_x = 1.701 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.5138 (5) Å	Cell parameters from 2019 reflections
b = 9.7750 (9) Å	θ = 1.8–26.4°
c = 11.5717 (11) Å	µ = 4.11 mm⁻¹
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 tube	1683 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ω scans	θ_max = 26.4°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→5
T_min = 0.192, T_max = 0.850	k = −12→11
3086 measured reflections	l = −12→14

Refinement top

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.127	H-atom parameters constrained
S = 1.09	w = 1/[σ²(F_o²) + (0.0649P)² + 0.1269P] where P = (F_o² + 2F_c²)/3
2019 reflections	(Δ/σ)_max < 0.001
127 parameters	Δρ_max = 0.89 e Å⁻³
0 restraints	Δρ_min = −0.82 e Å⁻³

Crystal data top

C₉H₈BrN₃O	γ = 86.038 (2)°
M_r = 254.09	V = 496.00 (9) Å³
Triclinic, P1	Z = 2
a = 4.5138 (5) Å	Mo Kα radiation
b = 9.7750 (9) Å	µ = 4.11 mm⁻¹
c = 11.5717 (11) Å	T = 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)
T_min = 0.192, T_max = 0.850	R_int = 0.026
3086 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.046	0 restraints
wR(F²) = 0.127	H-atom parameters constrained
S = 1.09	Δρ_max = 0.89 e Å⁻³
2019 reflections	Δρ_min = −0.82 e Å⁻³
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

	x	y	z	U_iso*/U_eq
Br1	0.99854 (9)	−0.03225 (4)	0.83292 (4)	0.0624 (2)
N1	0.3023 (6)	0.4132 (3)	0.9218 (3)	0.0429 (6)
H1	0.1781	0.3823	0.9827	0.052*
C1	0.3081 (8)	0.5487 (4)	0.8627 (3)	0.0438 (7)
O1	0.1416 (6)	0.6472 (3)	0.8854 (2)	0.0545 (6)
N2	0.5408 (7)	0.5549 (3)	0.7722 (3)	0.0463 (7)
C2	0.6765 (8)	0.4238 (4)	0.7739 (3)	0.0448 (8)
N3	0.9047 (7)	0.3902 (3)	0.7003 (3)	0.0536 (7)
C3	0.9924 (8)	0.2536 (4)	0.7221 (4)	0.0537 (9)
H3	1.1527	0.2227	0.6733	0.064*
C4	0.8551 (8)	0.1578 (4)	0.8137 (3)	0.0474 (8)
C5	0.6169 (8)	0.1954 (3)	0.8914 (3)	0.0446 (7)
H5	0.5260	0.1316	0.9541	0.054*
C6	0.5261 (7)	0.3327 (3)	0.8692 (3)	0.0400 (7)
C7	0.6297 (9)	0.6836 (4)	0.6904 (4)	0.0577 (10)
H7A	0.8450	0.6793	0.6698	0.069*
H7B	0.5786	0.7622	0.7302	0.069*
C8	0.4822 (12)	0.7071 (5)	0.5791 (4)	0.0727 (13)
H8	0.4856	0.6330	0.5393	0.087*
C9	0.3510 (13)	0.8229 (7)	0.5349 (5)	0.0923 (17)
H9A	0.3435	0.8991	0.5725	0.111*
H9B	0.2637	0.8304	0.4653	0.111*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0653 (3)	0.0414 (3)	0.0810 (4)	0.01520 (18)	−0.0026 (2)	−0.0228 (2)
N1	0.0438 (15)	0.0317 (14)	0.0475 (15)	0.0066 (11)	0.0071 (11)	−0.0044 (11)
C1	0.0459 (18)	0.0326 (17)	0.0504 (19)	0.0017 (14)	−0.0002 (14)	−0.0063 (14)
O1	0.0569 (15)	0.0348 (13)	0.0660 (16)	0.0104 (11)	0.0037 (12)	−0.0068 (11)
N2	0.0450 (15)	0.0336 (14)	0.0549 (17)	0.0030 (12)	0.0027 (13)	−0.0028 (12)
C2	0.0404 (17)	0.0413 (18)	0.0519 (19)	0.0003 (14)	−0.0030 (14)	−0.0091 (15)
N3	0.0468 (16)	0.0506 (18)	0.0585 (18)	0.0027 (13)	0.0070 (13)	−0.0084 (14)
C3	0.0443 (19)	0.056 (2)	0.060 (2)	0.0073 (16)	0.0025 (16)	−0.0189 (18)
C4	0.0459 (18)	0.0427 (18)	0.056 (2)	0.0057 (14)	−0.0047 (15)	−0.0181 (15)
C5	0.0457 (18)	0.0352 (17)	0.0512 (19)	0.0023 (14)	−0.0001 (14)	−0.0089 (14)
C6	0.0383 (16)	0.0344 (16)	0.0464 (18)	0.0013 (13)	−0.0010 (13)	−0.0095 (13)
C7	0.051 (2)	0.042 (2)	0.072 (2)	−0.0067 (16)	0.0028 (18)	0.0043 (17)
C8	0.101 (4)	0.058 (3)	0.051 (2)	−0.010 (2)	0.009 (2)	0.000 (2)
C9	0.094 (4)	0.102 (5)	0.068 (3)	−0.005 (3)	−0.007 (3)	0.014 (3)

Geometric parameters (Å, º) top

Br1—C4	1.905 (4)	C3—H3	0.9300
N1—C1	1.367 (4)	C4—C5	1.387 (5)
N1—C6	1.388 (4)	C5—C6	1.361 (5)
N1—H1	0.8600	C5—H5	0.9300
C1—O1	1.228 (4)	C7—C8	1.498 (7)
C1—N2	1.379 (5)	C7—H7A	0.9700
N2—C2	1.380 (5)	C7—H7B	0.9700
N2—C7	1.465 (5)	C8—C9	1.286 (8)
C2—N3	1.315 (5)	C8—H8	0.9300
C2—C6	1.406 (5)	C9—H9A	0.9300
N3—C3	1.351 (5)	C9—H9B	0.9300
C3—C4	1.381 (6)

C1—N1—C6	110.1 (3)	C6—C5—C4	115.0 (3)
C1—N1—H1	124.9	C6—C5—H5	122.5
C6—N1—H1	124.9	C4—C5—H5	122.5
O1—C1—N1	127.3 (3)	C5—C6—N1	134.3 (3)
O1—C1—N2	126.0 (3)	C5—C6—C2	119.5 (3)
N1—C1—N2	106.8 (3)	N1—C6—C2	106.3 (3)
C1—N2—C2	109.5 (3)	N2—C7—C8	112.6 (3)
C1—N2—C7	124.0 (3)	N2—C7—H7A	109.1
C2—N2—C7	126.4 (3)	C8—C7—H7A	109.1
N3—C2—N2	126.4 (3)	N2—C7—H7B	109.1
N3—C2—C6	126.3 (3)	C8—C7—H7B	109.1
N2—C2—C6	107.3 (3)	H7A—C7—H7B	107.8
C2—N3—C3	114.0 (3)	C9—C8—C7	124.4 (5)
N3—C3—C4	123.0 (3)	C9—C8—H8	117.8
N3—C3—H3	118.5	C7—C8—H8	117.8
C4—C3—H3	118.5	C8—C9—H9A	120.0
C3—C4—C5	122.2 (3)	C8—C9—H9B	120.0
C3—C4—Br1	118.6 (3)	H9A—C9—H9B	120.0
C5—C4—Br1	119.2 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.86	1.95	2.798 (4)	168

Symmetry code: (i) −x, −y+1, −z+2.

Experimental details

Crystal data
Chemical formula	C₉H₈BrN₃O
M_r	254.09
Crystal system, space group	Triclinic, 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)
V (Å³)	496.00 (9)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	4.11
Crystal size (mm)	0.60 × 0.19 × 0.04

Data collection
Diffractometer	Bruker CCD three-circle diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.192, 0.850
No. of measured, independent and observed [I > 2σ(I)] reflections	3086, 2019, 1683
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.625

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.127, 1.09
No. of reflections	2019
No. of parameters	127
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	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···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.86	1.95	2.798 (4)	168

Symmetry code: (i) −x, −y+1, −z+2.

References

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CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 67| Part 8| August 2011| Page o1998

doi:10.1107/S1600536811025037

Open

access