4-Benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine

Ouzidan, Y.; Obbade, S.; Capet, F.; Essassi, E.M.; Ng, S.W.

doi:10.1107/S160053681001038X

4-Benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine

Y. Ouzidan, S. Obbade, F. Capet, E. M. Essassi and S. W. Ng

The imidazopyridine fused ring in the title compound, C₁₉H₁₄BrN₃, is almost coplanar with the phenyl ring at the 2-position of the five-membered ring [dihedral angle = 2.4 (1). The crystal structure features short Br

Br contacts [3.562 (1) Å].

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S160053681001038X/pk2232sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S160053681001038X/pk2232Isup2.hkl Contains datablock I

CCDC reference: 774360

checkCIF report

Key indicators

Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.003 Å
R factor = 0.032
wR factor = 0.098
Data-to-parameter ratio = 22.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br1    ..  Br1     ..       3.56 Ang.
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         29

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

Imidazo[4,5-b]pyridines are a class of sedative drugs exemplified by Zolpidem, Alpidem, Saripidem and Necopidem. There is intense interest in designing new synthetic routes; for example, an eco-friendly synthesis by oxidation in aqueous medium has been claimed (Kale et al., 2009). Other methods require more than one step (Aridoss et al., 2006; Benham et al., 1995; Cundy et al., 1997; Walsh et al., 1994; Zaki & Proença, 2007).

We have been able to react 6-bromo-2-phenyl-1H-imidazo[4,5-b]pyridine with benzyl chloride in the presence of a catalytic quantity of tetra-n-butylammonium bromide under mild conditions to furnish the title compound (Scheme I, Fig. 1). The imidazopyridine fused-ring in C₁₉H₁₄BrN₃ is co-planar with the phenyl ring at the 2-position [dihedral angle 2.4 (1) °]. In the five-membered imidazo portion, the carbon–nitrogen bond whose carbon atom is also connected to the pyridine nitrogen atom is predominantly a double bond [1.329 (2) Å], whereas the carbon–nitrogen bond whose atom is connected to the pyridine carbon atom is predominantly a single bond [1.372 (2) Å].

Related literature top

For the synthesis of imidazo[4,5-b]pyridines, see: Aridoss et al. (2006); Benham et al. (1995); Cundy et al. (1997); Kale et al. (2009); Walsh et al. (1994); Zaki & Proença (2007).

Experimental top

To a solution of the 6-bromo-2-phenyl-1H-imidazo[4,5-b]pyridine (0.30 g, 1.09 mmol), potassium carbonate (0.20 g, 1.42 mmol) and tetra-n-butylammonium bromide (0.04 g (0,1 mmol) in DMF (15 ml) was added benzyl chloride (0.15 ml, 1.31 mmol). Stirring was continued at room temperature for 12 hours. The salt was removed by filtration and the filtrate concentrated under reduced pressure. The residue was separated by chromatography on a column of silica gel with ethyl acetate/hexane (1/1) as eluent. Brown crystals were isolated when the solvent was allowed to evaporate.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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).

Figures top

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of C₁₉H₁₄BrN₃ at the 50% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius.

4-Benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine top

Crystal data top

C₁₉H₁₄BrN₃	F(000) = 736
M_r = 364.24	D_x = 1.530 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9876 reflections
a = 8.6613 (6) Å	θ = 2.4–27.2°
b = 19.7631 (13) Å	µ = 2.60 mm⁻¹
c = 9.3683 (6) Å	T = 293 K
β = 99.647 (3)°	Prism, brown
V = 1580.93 (18) Å³	0.28 × 0.24 × 0.20 mm
Z = 4

Data collection top

Bruker X8 APEXII diffractometer	4613 independent reflections
Radiation source: fine-focus sealed tube	3492 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.035
ϕ and ω scans	θ_max = 30.1°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→11
T_min = 0.529, T_max = 0.624	k = −27→27
57936 measured reflections	l = −13→13

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.098	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.0518P)² + 0.5269P] where P = (F_o² + 2F_c²)/3
4613 reflections	(Δ/σ)_max = 0.001
208 parameters	Δρ_max = 0.63 e Å⁻³
0 restraints	Δρ_min = −0.51 e Å⁻³

Crystal data top

C₁₉H₁₄BrN₃	V = 1580.93 (18) Å³
M_r = 364.24	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.6613 (6) Å	µ = 2.60 mm⁻¹
b = 19.7631 (13) Å	T = 293 K
c = 9.3683 (6) Å	0.28 × 0.24 × 0.20 mm
β = 99.647 (3)°

Data collection top

Bruker X8 APEXII diffractometer	4613 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	3492 reflections with I > 2σ(I)
T_min = 0.529, T_max = 0.624	R_int = 0.035
57936 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	0 restraints
wR(F²) = 0.098	H-atom parameters constrained
S = 1.00	Δρ_max = 0.63 e Å⁻³
4613 reflections	Δρ_min = −0.51 e Å⁻³
208 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.10158 (3)	0.475089 (12)	0.85824 (2)	0.06483 (10)
N1	0.29485 (16)	0.43405 (7)	0.49901 (15)	0.0385 (3)
N2	0.26154 (17)	0.60722 (7)	0.40338 (16)	0.0424 (3)
N3	0.35446 (17)	0.50867 (7)	0.31224 (15)	0.0387 (3)
C1	0.1792 (2)	0.48667 (9)	0.68312 (19)	0.0454 (4)
C2	0.1807 (2)	0.55060 (9)	0.62007 (19)	0.0458 (4)
H2	0.1429	0.5886	0.6616	0.055*
C3	0.2408 (2)	0.55460 (8)	0.49376 (18)	0.0392 (3)
C4	0.29944 (19)	0.49489 (8)	0.43321 (17)	0.0367 (3)
C5	0.2352 (2)	0.43003 (9)	0.62362 (18)	0.0437 (4)
H5	0.2322	0.3884	0.6694	0.052*
C6	0.32810 (19)	0.57716 (8)	0.30027 (17)	0.0379 (3)
C7	0.37246 (19)	0.61435 (8)	0.17772 (18)	0.0390 (3)
C8	0.3423 (2)	0.68335 (9)	0.1595 (2)	0.0459 (4)
H8	0.2938	0.7067	0.2261	0.055*
C9	0.3845 (2)	0.71728 (10)	0.0425 (2)	0.0547 (5)
H9	0.3644	0.7634	0.0310	0.066*
C10	0.4557 (3)	0.68322 (11)	−0.0569 (2)	0.0574 (5)
H10	0.4829	0.7062	−0.1357	0.069*
C11	0.4869 (3)	0.61517 (11)	−0.0399 (2)	0.0624 (5)
H11	0.5353	0.5922	−0.1069	0.075*
C12	0.4459 (3)	0.58097 (10)	0.0773 (2)	0.0538 (5)
H12	0.4679	0.5350	0.0888	0.065*
C13	0.3544 (2)	0.37271 (8)	0.43491 (19)	0.0427 (3)
H13A	0.4041	0.3433	0.5121	0.051*
H13B	0.4331	0.3859	0.3778	0.051*
C14	0.22599 (19)	0.33413 (8)	0.34017 (17)	0.0380 (3)
C15	0.1392 (2)	0.36407 (9)	0.21824 (19)	0.0481 (4)
H15	0.1605	0.4084	0.1945	0.058*
C16	0.0214 (3)	0.32854 (11)	0.1321 (2)	0.0574 (5)
H16	−0.0379	0.3494	0.0522	0.069*
C17	−0.0082 (3)	0.26217 (11)	0.1643 (2)	0.0585 (5)
H17	−0.0859	0.2380	0.1050	0.070*
C18	0.0769 (3)	0.23206 (10)	0.2833 (3)	0.0598 (5)
H18	0.0570	0.1873	0.3047	0.072*
C19	0.1930 (2)	0.26789 (9)	0.3728 (2)	0.0517 (4)
H19	0.2487	0.2473	0.4548	0.062*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.08695 (19)	0.06436 (15)	0.05128 (13)	0.00593 (10)	0.03507 (11)	0.00630 (9)
N1	0.0419 (7)	0.0355 (6)	0.0382 (7)	0.0001 (5)	0.0074 (5)	0.0003 (5)
N2	0.0515 (8)	0.0338 (6)	0.0437 (7)	−0.0007 (6)	0.0131 (6)	−0.0028 (5)
N3	0.0443 (7)	0.0337 (6)	0.0394 (7)	−0.0009 (5)	0.0104 (5)	−0.0012 (5)
C1	0.0501 (10)	0.0498 (10)	0.0386 (8)	−0.0024 (7)	0.0140 (7)	0.0004 (7)
C2	0.0535 (10)	0.0417 (9)	0.0444 (9)	−0.0007 (7)	0.0147 (7)	−0.0056 (7)
C3	0.0431 (8)	0.0349 (7)	0.0402 (8)	−0.0015 (6)	0.0088 (6)	−0.0046 (6)
C4	0.0390 (8)	0.0345 (7)	0.0366 (7)	−0.0020 (6)	0.0061 (6)	−0.0035 (6)
C5	0.0485 (9)	0.0430 (8)	0.0403 (8)	−0.0019 (7)	0.0094 (7)	0.0036 (7)
C6	0.0407 (8)	0.0345 (7)	0.0385 (7)	−0.0028 (6)	0.0068 (6)	−0.0023 (6)
C7	0.0420 (8)	0.0353 (7)	0.0395 (7)	−0.0036 (6)	0.0064 (6)	−0.0004 (6)
C8	0.0471 (9)	0.0360 (8)	0.0553 (10)	−0.0020 (7)	0.0105 (8)	−0.0007 (7)
C9	0.0567 (11)	0.0391 (9)	0.0678 (12)	−0.0031 (8)	0.0092 (9)	0.0118 (8)
C10	0.0647 (12)	0.0560 (11)	0.0530 (10)	−0.0070 (9)	0.0141 (9)	0.0153 (9)
C11	0.0851 (15)	0.0567 (12)	0.0516 (10)	0.0037 (11)	0.0298 (10)	0.0062 (9)
C12	0.0782 (13)	0.0393 (9)	0.0486 (10)	0.0062 (9)	0.0240 (9)	0.0040 (7)
C13	0.0430 (9)	0.0371 (8)	0.0483 (9)	0.0064 (7)	0.0091 (7)	0.0015 (7)
C14	0.0419 (8)	0.0331 (7)	0.0416 (8)	0.0029 (6)	0.0147 (6)	−0.0002 (6)
C15	0.0608 (11)	0.0390 (8)	0.0446 (9)	−0.0013 (8)	0.0092 (8)	0.0021 (7)
C16	0.0660 (12)	0.0574 (11)	0.0462 (10)	−0.0037 (9)	0.0015 (9)	−0.0030 (8)
C17	0.0603 (12)	0.0584 (12)	0.0587 (11)	−0.0140 (9)	0.0152 (9)	−0.0156 (9)
C18	0.0683 (13)	0.0396 (9)	0.0754 (14)	−0.0103 (9)	0.0233 (11)	−0.0022 (9)
C19	0.0583 (11)	0.0388 (9)	0.0593 (11)	0.0013 (8)	0.0139 (9)	0.0088 (8)

Geometric parameters (Å, º) top

Br1—C1	1.8882 (18)	C9—H9	0.9300
N1—C4	1.355 (2)	C10—C11	1.376 (3)
N1—C5	1.356 (2)	C10—H10	0.9300
N1—C13	1.483 (2)	C11—C12	1.385 (3)
N2—C6	1.344 (2)	C11—H11	0.9300
N2—C3	1.372 (2)	C12—H12	0.9300
N3—C4	1.329 (2)	C13—C14	1.508 (2)
N3—C6	1.374 (2)	C13—H13A	0.9700
C1—C5	1.375 (3)	C13—H13B	0.9700
C1—C2	1.396 (3)	C14—C19	1.385 (2)
C2—C3	1.373 (2)	C14—C15	1.390 (2)
C2—H2	0.9300	C15—C16	1.382 (3)
C3—C4	1.438 (2)	C15—H15	0.9300
C5—H5	0.9300	C16—C17	1.379 (3)
C6—C7	1.468 (2)	C16—H16	0.9300
C7—C12	1.388 (3)	C17—C18	1.366 (3)
C7—C8	1.394 (2)	C17—H17	0.9300
C8—C9	1.385 (3)	C18—C19	1.390 (3)
C8—H8	0.9300	C18—H18	0.9300
C9—C10	1.376 (3)	C19—H19	0.9300

C4—N1—C5	119.22 (14)	C11—C10—H10	120.0
C4—N1—C13	120.17 (14)	C9—C10—H10	120.0
C5—N1—C13	120.61 (14)	C10—C11—C12	119.8 (2)
C6—N2—C3	102.99 (13)	C10—C11—H11	120.1
C4—N3—C6	101.13 (13)	C12—C11—H11	120.1
C5—C1—C2	122.44 (16)	C11—C12—C7	120.86 (18)
C5—C1—Br1	117.06 (13)	C11—C12—H12	119.6
C2—C1—Br1	120.49 (14)	C7—C12—H12	119.6
C3—C2—C1	116.66 (16)	N1—C13—C14	112.30 (13)
C3—C2—H2	121.7	N1—C13—H13A	109.1
C1—C2—H2	121.7	C14—C13—H13A	109.1
N2—C3—C2	133.11 (16)	N1—C13—H13B	109.1
N2—C3—C4	106.70 (14)	C14—C13—H13B	109.1
C2—C3—C4	120.18 (16)	H13A—C13—H13B	107.9
N3—C4—N1	127.72 (15)	C19—C14—C15	118.70 (17)
N3—C4—C3	111.64 (14)	C19—C14—C13	120.47 (16)
N1—C4—C3	120.64 (15)	C15—C14—C13	120.82 (15)
N1—C5—C1	120.85 (16)	C16—C15—C14	120.56 (17)
N1—C5—H5	119.6	C16—C15—H15	119.7
C1—C5—H5	119.6	C14—C15—H15	119.7
N2—C6—N3	117.54 (14)	C17—C16—C15	120.1 (2)
N2—C6—C7	122.76 (14)	C17—C16—H16	119.9
N3—C6—C7	119.70 (14)	C15—C16—H16	119.9
C12—C7—C8	118.69 (17)	C18—C17—C16	119.88 (19)
C12—C7—C6	120.15 (15)	C18—C17—H17	120.1
C8—C7—C6	121.17 (16)	C16—C17—H17	120.1
C9—C8—C7	120.11 (18)	C17—C18—C19	120.47 (18)
C9—C8—H8	119.9	C17—C18—H18	119.8
C7—C8—H8	119.9	C19—C18—H18	119.8
C10—C9—C8	120.42 (18)	C14—C19—C18	120.25 (18)
C10—C9—H9	119.8	C14—C19—H19	119.9
C8—C9—H9	119.8	C18—C19—H19	119.9
C11—C10—C9	120.08 (18)

C5—C1—C2—C3	0.3 (3)	N2—C6—C7—C12	177.72 (18)
Br1—C1—C2—C3	179.25 (13)	N3—C6—C7—C12	−2.4 (2)
C6—N2—C3—C2	179.20 (19)	N2—C6—C7—C8	−2.2 (3)
C6—N2—C3—C4	−0.16 (17)	N3—C6—C7—C8	177.69 (16)
C1—C2—C3—N2	−179.77 (18)	C12—C7—C8—C9	0.4 (3)
C1—C2—C3—C4	−0.5 (3)	C6—C7—C8—C9	−179.61 (16)
C6—N3—C4—N1	−179.97 (16)	C7—C8—C9—C10	0.2 (3)
C6—N3—C4—C3	−0.15 (18)	C8—C9—C10—C11	−0.6 (3)
C5—N1—C4—N3	179.35 (16)	C9—C10—C11—C12	0.2 (4)
C13—N1—C4—N3	−0.7 (3)	C10—C11—C12—C7	0.5 (4)
C5—N1—C4—C3	−0.5 (2)	C8—C7—C12—C11	−0.8 (3)
C13—N1—C4—C3	179.47 (15)	C6—C7—C12—C11	179.25 (19)
N2—C3—C4—N3	0.21 (19)	C4—N1—C13—C14	−94.67 (18)
C2—C3—C4—N3	−179.25 (16)	C5—N1—C13—C14	85.26 (19)
N2—C3—C4—N1	−179.95 (15)	N1—C13—C14—C19	−119.47 (17)
C2—C3—C4—N1	0.6 (2)	N1—C13—C14—C15	60.9 (2)
C4—N1—C5—C1	0.3 (2)	C19—C14—C15—C16	0.5 (3)
C13—N1—C5—C1	−179.68 (16)	C13—C14—C15—C16	−179.83 (17)
C2—C1—C5—N1	−0.2 (3)	C14—C15—C16—C17	−1.8 (3)
Br1—C1—C5—N1	−179.17 (13)	C15—C16—C17—C18	1.4 (3)
C3—N2—C6—N3	0.1 (2)	C16—C17—C18—C19	0.2 (3)
C3—N2—C6—C7	180.00 (15)	C15—C14—C19—C18	1.1 (3)
C4—N3—C6—N2	0.05 (19)	C13—C14—C19—C18	−178.56 (17)
C4—N3—C6—C7	−179.88 (14)	C17—C18—C19—C14	−1.5 (3)

Experimental details

Crystal data
Chemical formula	C₁₉H₁₄BrN₃
M_r	364.24
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	8.6613 (6), 19.7631 (13), 9.3683 (6)
β (°)	99.647 (3)
V (Å³)	1580.93 (18)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.60
Crystal size (mm)	0.28 × 0.24 × 0.20

Data collection
Diffractometer	Bruker X8 APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.529, 0.624
No. of measured, independent and observed [I > 2σ(I)] reflections	57936, 4613, 3492
R_int	0.035
(sin θ/λ)_max (Å⁻¹)	0.705

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.098, 1.00
No. of reflections	4613
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.63, −0.51

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2010).

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