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

Abstract

The title compound, C₇H₆BrN₃O, was obtained from the reaction of 6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one with methyl iodide. All non-H atoms lie in a common plane [r.m.s deviation = 0.017 (1) Å]. The amino group is a hydrogen-bond donor to the carbonyl group of an inversion-related mol­ecule, the pair of hydrogen bonds giving rise to a hydrogen-bonded dimer.

Related literature

For the synthesis of the title compound, see: Grivas & Lindström (1995 ▶); Smolyar et al. (2007 ▶).

Experimental

Crystal data

• C₇H₆BrN₃O

• M _r = 228.06

• Triclinic,

• a = 4.4151 (1) Å

• b = 9.6004 (2) Å

• c = 10.5330 (3) Å

• α = 116.248 (1)°

• β = 93.074 (2)°

• γ = 91.687 (1)°

• V = 399.14 (2) ų

• Z = 2

• Mo Kα radiation

• μ = 5.10 mm⁻¹

• T = 293 K

• 0.36 × 0.17 × 0.10 mm

Data collection

• Bruker X8 APEXII diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.478, T _max = 0.630

• 4790 measured reflections

• 1401 independent reflections

• 1199 reflections with I > 2σ(I)

• R _int = 0.027

• Standard reflections: 0

Refinement

• R[F ² > 2σ(F ²)] = 0.030

• wR(F ²) = 0.077

• S = 1.05

• 1401 reflections

• 114 parameters

• 1 restraint

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.52 e Å⁻³

• Δρ_min = −0.32 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

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3⋯O1i	0.86 (1)	1.95 (1)	2.804 (3)	176 (4)

Symmetry code: (i) .

supplementary crystallographic information

Comment

6-Bromo-1H-imidazo[4,5-b]pyridine-2(3H)-one reacts with organic compounds to form pharmaceutical active compounds. It is easily methylated; in this study, it is methylated by methyl iodide under catalytic conditions. The mono N-methylated compound (Scheme I) is planar [r.m.s 0.017 (1) Å]. The amino group is hydrogen-bond donor to the carbonyl group of an inversion-related molecule to generate a hydrogen-bonded dimer (Fig. 1).

Experimental

6-Bromo-1H-imidazo[4,5-b]pyridine-2(3H)-thione (1 mmol), potassium carbonate (4 mmol), tetra-n-butylammonium bromide (0.1 mmol) and methyl iodide (2.5 mmol) in DMF (15 ml) were stirred for 48 hours. After completion of reaction (as monitored by TLC), the salt was filtered and the solvent removed under reduced pressure. The resulting residue was purified by column chromatography on silica gel using ethyl acetate/hexane (1/2) as eluent. Yellow crystals was isolated when the solvent was allowed to evaporate.

Refinement

Carbon-bound H atoms were placed in calculated positions (C—H = 0.93–0.96 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U(C). The amino H atom was located in a difference Fourier map, and was refined isotropically with a distance restraint of N—H = 0.86 (1) Å.

Figures

Fig. 1.

Anisotropic displacement ellipsoid plot (Barbour, 2001) of the title compound forming a centrosymmetric dimer at the 50% probability level; H atoms are drawn as spheres of arbitrary radii.

Crystal data

C7H6BrN3O	Z = 2
Mr = 228.06	F(000) = 224
Triclinic, P1	Dx = 1.898 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.4151 (1) Å	Cell parameters from 2054 reflections
b = 9.6004 (2) Å	θ = 2.4–24.1°
c = 10.5330 (3) Å	µ = 5.10 mm−1
α = 116.248 (1)°	T = 293 K
β = 93.074 (2)°	Prism, yellow
γ = 91.687 (1)°	0.36 × 0.17 × 0.10 mm
V = 399.14 (2) Å3

Data collection

Bruker X8 APEXII diffractometer	1401 independent reflections
Radiation source: fine-focus sealed tube	1199 reflections with I > 2σ(I)
graphite	Rint = 0.027
φ and ω scans	θmax = 24.9°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→4
Tmin = 0.478, Tmax = 0.630	k = −11→11
4790 measured reflections	l = −12→12

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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.077	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.0493P)2 + 0.0118P] where P = (Fo2 + 2Fc2)/3
1401 reflections	(Δ/σ)max = 0.001
114 parameters	Δρmax = 0.52 e Å−3
1 restraint	Δρmin = −0.32 e Å−3

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

	x	y	z	Uiso*/Ueq
Br1	0.91934 (8)	0.96903 (4)	0.29671 (4)	0.04832 (17)
O1	0.0726 (5)	0.3085 (3)	0.3562 (3)	0.0478 (6)
N1	0.7410 (6)	0.4941 (3)	0.1298 (3)	0.0393 (6)
N2	0.4091 (6)	0.3574 (3)	0.2169 (3)	0.0368 (6)
N3	0.2638 (6)	0.5575 (3)	0.4045 (3)	0.0373 (6)
H3	0.165 (7)	0.603 (4)	0.478 (2)	0.052 (11)*
C1	0.8436 (8)	0.6389 (4)	0.1562 (3)	0.0395 (8)
H1	0.9737	0.6506	0.0946	0.047*
C2	0.7621 (7)	0.7715 (4)	0.2724 (3)	0.0362 (7)
C3	0.5682 (7)	0.7635 (3)	0.3680 (3)	0.0357 (7)
H3A	0.5157	0.8517	0.4462	0.043*
C4	0.4584 (7)	0.6171 (4)	0.3399 (3)	0.0332 (7)
C5	0.5521 (7)	0.4890 (4)	0.2200 (3)	0.0326 (7)
C6	0.2306 (7)	0.3988 (4)	0.3293 (3)	0.0359 (7)
C7	0.4409 (9)	0.1982 (4)	0.1123 (4)	0.0532 (10)
H7A	0.6141	0.1577	0.1406	0.080*
H7B	0.4681	0.1960	0.0216	0.080*
H7C	0.2613	0.1357	0.1055	0.080*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0551 (3)	0.0388 (2)	0.0537 (3)	−0.00649 (16)	0.00846 (17)	0.02302 (18)
O1	0.0560 (15)	0.0356 (12)	0.0502 (14)	−0.0057 (11)	0.0173 (12)	0.0168 (11)
N1	0.0399 (15)	0.0385 (15)	0.0382 (15)	0.0040 (12)	0.0119 (12)	0.0146 (13)
N2	0.0420 (15)	0.0298 (13)	0.0356 (14)	0.0018 (11)	0.0087 (12)	0.0112 (11)
N3	0.0406 (16)	0.0336 (14)	0.0361 (15)	0.0011 (12)	0.0140 (13)	0.0131 (12)
C1	0.0404 (18)	0.0410 (18)	0.0380 (18)	0.0024 (14)	0.0119 (15)	0.0175 (16)
C2	0.0372 (17)	0.0328 (16)	0.0416 (19)	−0.0016 (13)	0.0022 (15)	0.0194 (15)
C3	0.0367 (17)	0.0305 (16)	0.0381 (17)	0.0040 (13)	0.0074 (14)	0.0131 (14)
C4	0.0294 (16)	0.0336 (16)	0.0353 (17)	0.0032 (13)	0.0029 (13)	0.0139 (14)
C5	0.0305 (16)	0.0308 (15)	0.0344 (16)	0.0030 (13)	0.0015 (13)	0.0126 (13)
C6	0.0349 (17)	0.0367 (17)	0.0357 (17)	0.0011 (14)	0.0064 (14)	0.0155 (14)
C7	0.067 (3)	0.0341 (18)	0.049 (2)	0.0033 (17)	0.0166 (19)	0.0079 (16)

Geometric parameters (Å, °)

Br1—C2	1.902 (3)	C1—C2	1.394 (5)
O1—C6	1.233 (4)	C1—H1	0.9300
N1—C5	1.313 (4)	C2—C3	1.382 (4)
N1—C1	1.349 (4)	C3—C4	1.369 (4)
N2—C6	1.373 (4)	C3—H3A	0.9300
N2—C5	1.382 (4)	C4—C5	1.411 (4)
N2—C7	1.452 (4)	C7—H7A	0.9600
N3—C6	1.370 (4)	C7—H7B	0.9600
N3—C4	1.381 (4)	C7—H7C	0.9600
N3—H3	0.856 (10)
C5—N1—C1	114.5 (3)	C3—C4—N3	134.7 (3)
C6—N2—C5	109.8 (2)	C3—C4—C5	118.7 (3)
C6—N2—C7	124.2 (3)	N3—C4—C5	106.6 (3)
C5—N2—C7	126.1 (3)	N1—C5—N2	126.7 (3)
C6—N3—C4	110.0 (3)	N1—C5—C4	126.5 (3)
C6—N3—H3	119 (3)	N2—C5—C4	106.7 (3)
C4—N3—H3	131 (3)	O1—C6—N3	127.3 (3)
N1—C1—C2	122.5 (3)	O1—C6—N2	125.8 (3)
N1—C1—H1	118.7	N3—C6—N2	106.9 (3)
C2—C1—H1	118.7	N2—C7—H7A	109.5
C3—C2—C1	122.1 (3)	N2—C7—H7B	109.5
C3—C2—Br1	119.5 (2)	H7A—C7—H7B	109.5
C1—C2—Br1	118.4 (2)	N2—C7—H7C	109.5
C4—C3—C2	115.6 (3)	H7A—C7—H7C	109.5
C4—C3—H3A	122.2	H7B—C7—H7C	109.5
C2—C3—H3A	122.2
C5—N1—C1—C2	1.8 (5)	C6—N2—C5—C4	0.2 (3)
N1—C1—C2—C3	−0.5 (5)	C7—N2—C5—C4	−179.4 (3)
N1—C1—C2—Br1	−179.4 (2)	C3—C4—C5—N1	0.6 (5)
C1—C2—C3—C4	−0.9 (5)	N3—C4—C5—N1	−179.2 (3)
Br1—C2—C3—C4	178.0 (2)	C3—C4—C5—N2	−179.9 (3)
C2—C3—C4—N3	−179.4 (3)	N3—C4—C5—N2	0.3 (3)
C2—C3—C4—C5	0.8 (4)	C4—N3—C6—O1	−179.5 (3)
C6—N3—C4—C3	179.6 (3)	C4—N3—C6—N2	0.7 (4)
C6—N3—C4—C5	−0.6 (3)	C5—N2—C6—O1	179.7 (3)
C1—N1—C5—N2	178.8 (3)	C7—N2—C6—O1	−0.8 (5)
C1—N1—C5—C4	−1.9 (5)	C5—N2—C6—N3	−0.5 (3)
C6—N2—C5—N1	179.6 (3)	C7—N2—C6—N3	179.0 (3)
C7—N2—C5—N1	0.1 (5)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···O1i	0.86 (1)	1.95 (1)	2.804 (3)	176 (4)

Symmetry codes: (i) −x, −y+1, −z+1.