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

The two fused five- and six-membered rings in the mol-ecule of the title compound, C(8)H(6)BrN(3)O(2), are approximately coplanar, the largest deviation from the mean plane being 0.011 (3) Å at the NH atom. The acetyl group is slightly twisted with respect to the imidazo[4,5-b]pyridine system, making a dihedral angle of 2.7 (2)°. In the crystal, adjacent mol-ecules are linked by inter-molecular N-H⋯N and C-H⋯O hydrogen bonds, forming infinite chains.

Related literature

For background information on the pharmacological activities of imidazo[4,5-b]pyridines, see: Kale et al. (2009 ▶); Silverman (2004 ▶); Cristalli et al. (1995 ▶); Cundy et al. (1997 ▶); Banie et al. (2007 ▶); Mader (2008 ▶); Janssens et al. (1985 ▶); Bavetsias et al. (2007 ▶); Coates et al. (1993 ▶).

Experimental

Crystal data

C8H6BrN3O2

M = 256.07

Triclinic,

a = 4.8302 (15) Å

b = 9.645 (3) Å

c = 9.809 (3) Å

α = 81.542 (7)°

β = 85.735 (7)°

γ = 89.676 (8)°

V = 450.8 (2) Å3

Z = 2

Mo Kα radiation

μ = 4.53 mm−1

T = 298 K

0.41 × 0.16 × 0.11 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T min = 0.423, T max = 0.607

2559 measured reflections

1685 independent reflections

1583 reflections with I > 2σ(I)

R int = 0.019

Refinement

R[F 2 > 2σ(F 2)] = 0.028

wR(F 2) = 0.074

S = 1.07

1685 reflections

128 parameters

H-atom parameters constrained

Δρmax = 0.43 e Å−3

Δρmin = −0.48 e Å−3

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶) and ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811017004/dn2682sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811017004/dn2682Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811017004/dn2682Isup3.cml

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

C8H6BrN3O2	Z = 2
Mr = 256.07	F(000) = 252
Triclinic, P1	Dx = 1.887 Mg m−3
Hall symbol: -P 1	Melting point: 507 K
a = 4.8302 (15) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.645 (3) Å	Cell parameters from 1685 reflections
c = 9.809 (3) Å	θ = 2.1–26.0°
α = 81.542 (7)°	µ = 4.53 mm−1
β = 85.735 (7)°	T = 298 K
γ = 89.676 (8)°	Fiber, colourless
V = 450.8 (2) Å3	0.41 × 0.16 × 0.11 mm

Bruker APEXII CCD diffractometer	1685 independent reflections
Radiation source: fine-focus sealed tube	1583 reflections with I > 2σ(I)
graphite	Rint = 0.019
φ and ω scans	θmax = 26.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −5→5
Tmin = 0.423, Tmax = 0.607	k = −11→11
2559 measured reflections	l = 0→12

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.074	H-atom parameters constrained
S = 1.07	w = 1/[σ2(Fo2) + (0.0374P)2 + 0.2048P] where P = (Fo2 + 2Fc2)/3
1685 reflections	(Δ/σ)max = 0.001
128 parameters	Δρmax = 0.43 e Å−3
0 restraints	Δρmin = −0.48 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2σ(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.

	x	y	z	Uiso*/Ueq
C1	−0.0666 (6)	0.9228 (3)	0.7492 (3)	0.0412 (6)
H1	−0.0912	0.9789	0.6654	0.049*
C2	0.1373 (5)	0.8216 (3)	0.7536 (2)	0.0371 (5)
C3	0.1881 (5)	0.7340 (3)	0.8759 (2)	0.0377 (5)
H3	0.3253	0.6658	0.8796	0.045*
C4	0.0199 (5)	0.7562 (3)	0.9904 (2)	0.0355 (5)
C5	−0.1838 (5)	0.8602 (3)	0.9766 (3)	0.0372 (5)
C6	−0.2202 (6)	0.7636 (3)	1.2009 (3)	0.0435 (6)
C7	0.1715 (7)	0.5870 (3)	1.1871 (3)	0.0466 (6)
C8	0.1168 (8)	0.5301 (3)	1.3357 (3)	0.0588 (8)
H8A	0.2348	0.4510	1.3590	0.088*
H8B	−0.0740	0.5012	1.3534	0.088*
H8C	0.1541	0.6013	1.3909	0.088*
N1	−0.2322 (5)	0.9436 (2)	0.8618 (2)	0.0426 (5)
N2	−0.3244 (5)	0.8613 (3)	1.1034 (2)	0.0435 (5)
H2	−0.4601	0.9164	1.1191	0.052*
N3	−0.0003 (5)	0.6957 (2)	1.1302 (2)	0.0395 (5)
O1	−0.2966 (5)	0.7398 (2)	1.3223 (2)	0.0595 (6)
O2	0.3528 (6)	0.5462 (3)	1.1138 (2)	0.0757 (8)
Br1	0.35286 (6)	0.80290 (3)	0.58804 (2)	0.04632 (13)

	U11	U22	U33	U12	U13	U23
C1	0.0412 (14)	0.0477 (14)	0.0338 (13)	0.0047 (11)	−0.0012 (10)	−0.0033 (10)
C2	0.0392 (14)	0.0439 (13)	0.0276 (11)	−0.0007 (10)	0.0057 (10)	−0.0072 (9)
C3	0.0387 (14)	0.0428 (12)	0.0310 (12)	0.0059 (10)	0.0035 (10)	−0.0064 (10)
C4	0.0369 (13)	0.0405 (12)	0.0283 (11)	0.0025 (10)	0.0032 (9)	−0.0050 (9)
C5	0.0330 (13)	0.0449 (13)	0.0341 (12)	0.0037 (10)	0.0031 (10)	−0.0100 (10)
C6	0.0405 (15)	0.0523 (15)	0.0366 (14)	0.0057 (11)	0.0085 (11)	−0.0088 (11)
C7	0.0598 (18)	0.0451 (14)	0.0325 (13)	0.0098 (12)	0.0069 (12)	−0.0034 (10)
C8	0.078 (2)	0.0572 (17)	0.0349 (15)	0.0131 (15)	0.0123 (14)	0.0039 (12)
N1	0.0397 (13)	0.0504 (12)	0.0371 (12)	0.0090 (10)	−0.0002 (9)	−0.0059 (9)
N2	0.0382 (12)	0.0550 (13)	0.0359 (12)	0.0105 (10)	0.0076 (9)	−0.0074 (9)
N3	0.0417 (12)	0.0461 (11)	0.0287 (10)	0.0075 (9)	0.0083 (8)	−0.0045 (8)
O1	0.0640 (14)	0.0745 (14)	0.0354 (11)	0.0152 (11)	0.0188 (9)	−0.0049 (9)
O2	0.0976 (19)	0.0822 (16)	0.0386 (11)	0.0532 (15)	0.0185 (11)	0.0060 (10)
Br1	0.0522 (2)	0.0565 (2)	0.02805 (16)	0.00477 (12)	0.00836 (11)	−0.00472 (11)

C1—N1	1.354 (3)	C6—O1	1.209 (3)
C1—C2	1.381 (4)	C6—N2	1.363 (4)
C1—H1	0.9300	C6—N3	1.433 (3)
C2—C3	1.398 (4)	C7—O2	1.193 (4)
C2—Br1	1.894 (2)	C7—N3	1.409 (4)
C3—C4	1.379 (3)	C7—C8	1.486 (4)
C3—H3	0.9300	C8—H8A	0.9600
C4—C5	1.401 (4)	C8—H8B	0.9600
C4—N3	1.406 (3)	C8—H8C	0.9600
C5—N1	1.319 (3)	N2—H2	0.8600
C5—N2	1.374 (3)
N1—C1—C2	122.6 (2)	N2—C6—N3	105.9 (2)
N1—C1—H1	118.7	O2—C7—N3	118.5 (2)
C2—C1—H1	118.7	O2—C7—C8	123.7 (3)
C1—C2—C3	122.0 (2)	N3—C7—C8	117.8 (2)
C1—C2—Br1	118.30 (19)	C7—C8—H8A	109.5
C3—C2—Br1	119.66 (19)	C7—C8—H8B	109.5
C4—C3—C2	115.1 (2)	H8A—C8—H8B	109.5
C4—C3—H3	122.5	C7—C8—H8C	109.5
C2—C3—H3	122.5	H8A—C8—H8C	109.5
C3—C4—C5	119.2 (2)	H8B—C8—H8C	109.5
C3—C4—N3	134.3 (2)	C5—N1—C1	115.0 (2)
C5—C4—N3	106.5 (2)	C6—N2—C5	110.9 (2)
N1—C5—N2	125.6 (2)	C6—N2—H2	124.6
N1—C5—C4	126.0 (2)	C5—N2—H2	124.6
N2—C5—C4	108.4 (2)	C4—N3—C7	124.2 (2)
O1—C6—N2	127.0 (3)	C4—N3—C6	108.4 (2)
O1—C6—N3	127.1 (3)	C7—N3—C6	127.4 (2)
N1—C1—C2—C3	−0.5 (5)	N1—C5—N2—C6	−178.9 (3)
N1—C1—C2—Br1	179.6 (2)	C4—C5—N2—C6	0.7 (3)
C1—C2—C3—C4	0.1 (4)	C3—C4—N3—C7	0.3 (5)
Br1—C2—C3—C4	−179.98 (19)	C5—C4—N3—C7	−179.4 (3)
C2—C3—C4—C5	0.5 (4)	C3—C4—N3—C6	−179.8 (3)
C2—C3—C4—N3	−179.2 (3)	C5—C4—N3—C6	0.5 (3)
C3—C4—C5—N1	−0.8 (4)	O2—C7—N3—C4	2.8 (5)
N3—C4—C5—N1	178.9 (3)	C8—C7—N3—C4	−177.5 (3)
C3—C4—C5—N2	179.5 (2)	O2—C7—N3—C6	−177.1 (3)
N3—C4—C5—N2	−0.7 (3)	C8—C7—N3—C6	2.6 (5)
N2—C5—N1—C1	−179.9 (3)	O1—C6—N3—C4	−179.6 (3)
C4—C5—N1—C1	0.5 (4)	N2—C6—N3—C4	0.0 (3)
C2—C1—N1—C5	0.2 (4)	O1—C6—N3—C7	0.3 (5)
O1—C6—N2—C5	179.1 (3)	N2—C6—N3—C7	179.8 (3)
N3—C6—N2—C5	−0.4 (3)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···N1i	0.86	2.02	2.877 (3)	175.
C3—H3···O2ii	0.93	2.56	3.481 (3)	172.

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯N1i	0.86	2.02	2.877 (3)	175
C3—H3⋯O2ii	0.93	2.56	3.481 (3)	172

Symmetry codes: (i) ; (ii) .