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

Abstract

The reaction of propargyl bromide and 6-bromo-1,3-dihydro­imidazo[4,5-b]pyridin-2-one in refluxing dimethyl­formamide yields the title compound, C₁₂H₈BrN₃O, which features nitro­gen-bound propadienyl and propynyl substituents. The imidazolopyridine fused ring is planar (r.m.s. deviation = 0.012 Å); the propadienyl chain is coplanar with the fused ring as it is conjugated with it, whereas the propynyl chain is not as the nitro­gen-bound C atom is a methyl­ene linkage. The acetyl­enic H atom is hydrogen bonded to the carbonyl O atom of an adjacent mol­ecule, forming a helical chain runnning along the b axis.

Related literature

For the crystal structures of other imidazo[4,5-b]pyridin-2-ones, see: Kourafalos et al. (2002 ▶); Meanwell et al. (1995 ▶).

Experimental

Crystal data

• C₁₂H₈BrN₃O

• M _r = 290.12

• Monoclinic,

• a = 9.6369 (4) Å

• b = 9.3086 (4) Å

• c = 13.5481 (5) Å

• β = 99.123 (2)°

• V = 1199.97 (8) ų

• Z = 4

• Mo Kα radiation

• μ = 3.41 mm⁻¹

• T = 293 K

• 0.55 × 0.35 × 0.30 mm

Data collection

• Bruker X8 APEXII diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.256, T _max = 0.428

• 51411 measured reflections

• 3393 independent reflections

• 2577 reflections with I > 2σ(I)

• R _int = 0.040

Refinement

• R[F ² > 2σ(F ²)] = 0.031

• wR(F ²) = 0.087

• S = 1.02

• 3393 reflections

• 166 parameters

• 3 restraints

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

• Δρ_max = 0.49 e Å⁻³

• Δρ_min = −0.63 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
C12—H12⋯O1i	0.94 (1)	2.22 (1)	3.161 (3)	173 (2)

Symmetry code: (i) .

supplementary crystallographic information

Experimental

To a solution of 6-bromo-1,3-dihydro-imidazo[4,5-b]pyridin-2-one (1 mmol), potassium carbonate (4 mmol) and tetra-n-butylammonium bromide (0.1 mmol) in DMF (20 ml) was added propargyl bromide (2.5 mmol). The solution was refluxed for 48 hours. After completion of the reaction (as monitored byTLC), the salt was filtered and the solvent was removed under reduced pressure. The residue was purified by column chromatography on silica gel by using an ethyl acetate/hexane (1/1) mixture as eluent. Slow evaporation of the solvent furnished colorless crystals.

Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.93 to 0.97 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U(C). The terminal acetylenic and allenic H-atoms were located in a difference Fourier map, and were refined with a distance restraint of C–H 0.95±0.01 Å; their temperature factors were refined.

Figures

Fig. 1.

Thermal ellipsoid plot (Barbour, 2001) of C12H8BrN3O at the 50% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.

Crystal data

C12H8BrN3O	F(000) = 576
Mr = 290.12	Dx = 1.606 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 9975 reflections
a = 9.6369 (4) Å	θ = 2.4–25.6°
b = 9.3086 (4) Å	µ = 3.41 mm−1
c = 13.5481 (5) Å	T = 293 K
β = 99.123 (2)°	Irregular, colorless
V = 1199.97 (8) Å3	0.55 × 0.35 × 0.30 mm
Z = 4

Data collection

Bruker X8 APEXII diffractometer	3393 independent reflections
Radiation source: fine-focus sealed tube	2577 reflections with I > 2σ(I)
graphite	Rint = 0.040
φ and ω scans	θmax = 29.7°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −13→13
Tmin = 0.256, Tmax = 0.428	k = −12→12
51411 measured reflections	l = −18→18

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.087	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ2(Fo2) + (0.0413P)2 + 0.4635P] where P = (Fo2 + 2Fc2)/3
3393 reflections	(Δ/σ)max = 0.001
166 parameters	Δρmax = 0.49 e Å−3
3 restraints	Δρmin = −0.63 e Å−3

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

	x	y	z	Uiso*/Ueq
Br1	0.40648 (3)	0.39876 (3)	0.231050 (17)	0.06785 (11)
O1	0.49655 (17)	0.95432 (17)	0.64205 (11)	0.0577 (4)
N1	0.21863 (16)	0.64109 (19)	0.42594 (13)	0.0453 (4)
N2	0.54742 (15)	0.78896 (16)	0.52363 (11)	0.0395 (3)
N3	0.32605 (16)	0.81244 (17)	0.54674 (11)	0.0417 (3)
C1	0.2477 (2)	0.5495 (2)	0.35479 (15)	0.0490 (4)
H1	0.1744	0.4972	0.3188	0.059*
C2	0.3815 (2)	0.53039 (19)	0.33326 (13)	0.0435 (4)
C3	0.4981 (2)	0.60309 (19)	0.38454 (13)	0.0399 (4)
H3	0.5887	0.5895	0.3708	0.048*
C4	0.46792 (17)	0.69616 (18)	0.45684 (12)	0.0346 (3)
C5	0.32815 (18)	0.71031 (18)	0.47294 (12)	0.0365 (3)
C6	0.6938 (2)	0.8150 (2)	0.53701 (16)	0.0503 (5)
H6	0.7302	0.8828	0.5845	0.060*
C7	0.7806 (2)	0.7510 (2)	0.48776 (17)	0.0529 (5)
C8	0.8709 (3)	0.6872 (4)	0.4413 (2)	0.0750 (8)
H81	0.916 (3)	0.602 (2)	0.467 (3)	0.106 (12)*
H82	0.890 (3)	0.722 (3)	0.3788 (13)	0.089 (10)*
C9	0.4605 (2)	0.8628 (2)	0.57909 (14)	0.0416 (4)
C10	0.2020 (2)	0.8584 (2)	0.58740 (16)	0.0509 (5)
H10A	0.1252	0.8736	0.5328	0.061*
H10B	0.2218	0.9494	0.6217	0.061*
C11	0.1586 (2)	0.7538 (2)	0.65707 (15)	0.0521 (5)
C12	0.1208 (3)	0.6715 (3)	0.71186 (19)	0.0694 (7)
H12	0.093 (3)	0.601 (2)	0.7550 (18)	0.088 (11)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0918 (2)	0.05653 (15)	0.05116 (14)	0.01376 (12)	−0.00107 (12)	−0.01710 (9)
O1	0.0645 (9)	0.0499 (8)	0.0563 (9)	0.0031 (7)	0.0024 (7)	−0.0158 (7)
N1	0.0357 (8)	0.0481 (9)	0.0513 (9)	−0.0027 (7)	0.0046 (7)	0.0022 (7)
N2	0.0367 (7)	0.0396 (8)	0.0417 (7)	−0.0023 (6)	0.0050 (6)	−0.0021 (6)
N3	0.0417 (8)	0.0425 (8)	0.0431 (8)	0.0011 (6)	0.0133 (6)	−0.0014 (6)
C1	0.0469 (10)	0.0461 (10)	0.0504 (10)	−0.0050 (8)	−0.0035 (8)	−0.0017 (8)
C2	0.0555 (11)	0.0369 (9)	0.0362 (8)	0.0034 (8)	0.0016 (7)	−0.0014 (7)
C3	0.0408 (9)	0.0411 (9)	0.0385 (8)	0.0031 (7)	0.0085 (7)	0.0024 (7)
C4	0.0351 (8)	0.0350 (8)	0.0334 (7)	−0.0008 (6)	0.0051 (6)	0.0060 (6)
C5	0.0386 (8)	0.0350 (8)	0.0364 (8)	0.0006 (7)	0.0079 (6)	0.0057 (6)
C6	0.0381 (9)	0.0515 (11)	0.0592 (12)	−0.0078 (8)	0.0015 (8)	−0.0032 (9)
C7	0.0343 (9)	0.0597 (12)	0.0628 (12)	−0.0064 (9)	0.0017 (9)	0.0098 (10)
C8	0.0396 (11)	0.101 (2)	0.0867 (19)	0.0039 (13)	0.0176 (12)	0.0060 (17)
C9	0.0474 (10)	0.0370 (9)	0.0402 (9)	0.0029 (7)	0.0061 (7)	0.0014 (7)
C10	0.0512 (11)	0.0491 (11)	0.0570 (12)	0.0097 (9)	0.0224 (9)	0.0029 (9)
C11	0.0510 (11)	0.0614 (12)	0.0461 (10)	0.0007 (9)	0.0149 (8)	−0.0033 (9)
C12	0.0748 (16)	0.0808 (18)	0.0555 (13)	−0.0120 (14)	0.0197 (12)	0.0087 (12)

Geometric parameters (Å, °)

Br1—C2	1.8928 (18)	C3—C4	1.373 (2)
O1—C9	1.216 (2)	C3—H3	0.9300
N1—C5	1.312 (2)	C4—C5	1.404 (2)
N1—C1	1.349 (3)	C6—C7	1.295 (3)
N2—C4	1.390 (2)	C6—H6	0.9300
N2—C9	1.393 (2)	C7—C8	1.296 (4)
N2—C6	1.414 (2)	C8—H81	0.95 (1)
N3—C5	1.382 (2)	C8—H82	0.95 (1)
N3—C9	1.382 (2)	C10—C11	1.463 (3)
N3—C10	1.458 (2)	C10—H10A	0.9700
C1—C2	1.378 (3)	C10—H10B	0.9700
C1—H1	0.9300	C11—C12	1.164 (3)
C2—C3	1.398 (3)	C12—H12	0.94 (1)
C5—N1—C1	114.50 (16)	N1—C5—C4	126.59 (17)
C4—N2—C9	109.96 (14)	N3—C5—C4	107.53 (15)
C4—N2—C6	128.72 (16)	C7—C6—N2	124.62 (19)
C9—N2—C6	121.29 (16)	C7—C6—H6	117.7
C5—N3—C9	110.03 (15)	N2—C6—H6	117.7
C5—N3—C10	125.63 (16)	C8—C7—C6	178.0 (3)
C9—N3—C10	124.33 (16)	C7—C8—H81	121 (2)
N1—C1—C2	122.72 (18)	C7—C8—H82	120.7 (19)
N1—C1—H1	118.6	H81—C8—H82	118 (3)
C2—C1—H1	118.6	O1—C9—N3	127.55 (18)
C1—C2—C3	122.49 (17)	O1—C9—N2	126.48 (18)
C1—C2—Br1	118.07 (14)	N3—C9—N2	105.97 (15)
C3—C2—Br1	119.43 (14)	N3—C10—C11	112.56 (17)
C4—C3—C2	114.56 (16)	N3—C10—H10A	109.1
C4—C3—H3	122.7	C11—C10—H10A	109.1
C2—C3—H3	122.7	N3—C10—H10B	109.1
C3—C4—N2	134.39 (16)	C11—C10—H10B	109.1
C3—C4—C5	119.12 (16)	H10A—C10—H10B	107.8
N2—C4—C5	106.49 (15)	C12—C11—C10	178.4 (3)
N1—C5—N3	125.87 (16)	C11—C12—H12	177.2 (19)
C5—N1—C1—C2	0.0 (3)	C3—C4—C5—N1	0.9 (3)
N1—C1—C2—C3	0.9 (3)	N2—C4—C5—N1	−179.58 (17)
N1—C1—C2—Br1	−179.76 (15)	C3—C4—C5—N3	−178.29 (15)
C1—C2—C3—C4	−0.8 (3)	N2—C4—C5—N3	1.26 (18)
Br1—C2—C3—C4	179.81 (12)	C4—N2—C6—C7	−1.4 (3)
C2—C3—C4—N2	−179.36 (18)	C9—N2—C6—C7	−179.6 (2)
C2—C3—C4—C5	0.0 (2)	C5—N3—C9—O1	178.90 (19)
C9—N2—C4—C3	178.04 (18)	C10—N3—C9—O1	−2.7 (3)
C6—N2—C4—C3	−0.3 (3)	C5—N3—C9—N2	−0.2 (2)
C9—N2—C4—C5	−1.41 (19)	C10—N3—C9—N2	178.17 (16)
C6—N2—C4—C5	−179.75 (17)	C4—N2—C9—O1	−178.10 (19)
C1—N1—C5—N3	178.16 (17)	C6—N2—C9—O1	0.4 (3)
C1—N1—C5—C4	−0.9 (3)	C4—N2—C9—N3	1.00 (19)
C9—N3—C5—N1	−179.84 (17)	C6—N2—C9—N3	179.49 (16)
C10—N3—C5—N1	1.8 (3)	C5—N3—C10—C11	76.4 (2)
C9—N3—C5—C4	−0.67 (19)	C9—N3—C10—C11	−101.7 (2)
C10—N3—C5—C4	−179.00 (16)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12···O1i	0.94 (1)	2.22 (1)	3.161 (3)	173 (2)

Symmetry codes: (i) −x+1/2, y−1/2, −z+3/2.