4-Benzyl-6-bromo-2-(4-chloro­phen­yl)-4H-imidazo[4,5-b]pyridine

Bourichi, S.; Kandri Rodi, Y.; Jasinski, J.P.; Kaur, M.; Ouzidan, Y.; Essassi, E.M.

doi:10.1107/S2414314617008999

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 6| June 2017| x170899

https://doi.org/10.1107/S2414314617008999

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4-Benzyl-6-bromo-2-(4-chlorophenyl)-4H-imidazo[4,5-b]pyridine

Selma Bourichi,^a ^* Youssef Kandri Rodi,^a Jerry P. Jasinski,^b Manpreet Kaur,^b Younes Ouzidan ^a and El Mokhtar Essassi ^c

^aLaboratoire de Chimie Organique Appliquée, Faculté des Sciences et Techniques, Université Sidi Mohammed Ben Abdellah, Fès, Morocco, ^bDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA, and ^cLaboratoire de Chimie Organique Hétérocyclique URAC 21, Pôle de Compétence Pharmacochimie, Av. Ibn Battouta, BP 1014, Faculté des Sciences, Université Mohammed V, Rabat, Morocco
^*Correspondence e-mail: bourichiselma@hotmail.com

Edited by L. Van Meervelt, Katholieke Universiteit Leuven, Belgium (Received 13 June 2017; accepted 16 June 2017; online 20 June 2017)

In the title compound, C₁₉H₁₃BrClN₃, the chlorophenyl ring occupies an equatorial position with respect to the mean plane of the imidazopyridine unit, while the other phenyl ring is twisted by 4.1 (2)° with respect to the mean plane of the imidazopyridine unit. In the crystal, pairwise C—H⋯Br interactions link the molecules into dimers, forming an R₂²(16) ring motif. In addition, weak π–π stacking interactions stabilize the crystal packing.

Keywords: crystal structure; imidazo[4,5-b]pyridine; hydrogen bonding.

CCDC reference: 1556392

Structure description

Imidazopyridine derivatives display anticancer (Lukasik et al., 2012 ), tuberculostatic (Bukowski & Janowiec, 1989 ) and antimitotic activities (Aridoss et al., 2006 ). This study is a continuation of our work (Bourichi et al., 2016 ; Ouzidan et al., 2010 ) on the syntheses and structures of new imidazopyridine derivatives.

The title compound, C₁₉H₁₃BrClN₃, crystallizes with one molecule in the asymmetric unit (Fig. 1). The imidazo[4,5-b]pyridine unit is essentially planar (r.m.s. deviation = 0.010 Å). The chlorophenyl ring occupies an equatorial position with respect to the mean plane of the imidazopyridine unit, with a dihedral angle of 4.1 (2)°. The other phenyl ring is twisted with respect to the mean plane of the imidazopyridine unit by 72.2 (3)°.

Figure 1
The structure of the title compound, showing the atom-numbering scheme and 30% probability displacement ellipsoids for the non-H atoms.

In the crystal, pairwise C19—H19⋯Br1 interactions link the molecules into inversion dimers, forming an R₂²(16) ring motif (Table 1 and Fig. 2). In addition, weak π–π stacking interactions stabilize the crystal packing [Cg1⋯Cg2ⁱ = 3.858 (2) Å; symmetry code: (i) −x + 1, −y + 1, −z + 1; Cg1 is the centroid of ring N2/C4/C6/N3/C5 and Cg2 of ring N1/C1/C2/C3/C4/C6].

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C19—H19⋯Br1ⁱ	0.93	2.54	3.202 (3)	128
Symmetry code: (i) -x+1, -y, -z+1.

Figure 2
The molecular packing of the title compound, viewed along the a axis. Dashed lines indicate weak C—H⋯Br intermolecular interactions linking the moleclues into dimers. H atoms not involved in the packing have been omitted for clarity.

Synthesis and crystallization

A mixture of 0.2 g (0.65 mmol) of 6-bromo-2-(4-chlorophenyl)-3H-imidazo[4,5-b]pyridine, dissolved in 25 ml of DMF, and 0.13 g (0.92 mmol) of potassium carbonate was stirred magnetically for 5 min and then 0.032 g (0.1 mmol) of tetra-n-butylammonium bromide (TBAB) and 0.094 g (0.78 mmol) of benzyl bromide were added. Stirring was continued at room temperature for 24 h. After removing the salts by filtration, the DMF was evaporated under reduced pressure and the residue obtained was dissolved in dichloromethane. The remaining salts were extracted with distilled water and the resulting mixture was chromatographed on a silica-gel column (eluent: ethyl acetate–hexane, 1:3 v/v). Yellow crystals were isolated when the solvent was allowed to evaporate (yield 65%; m.p. 464–465 K).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were placed in calculated positions and refined using the riding model, with C—H bond lengths of 0.93 (CH) or 0.97 Å (CH₂). Isotropic displacement parameters for these atoms were set at 1.2 times U_eq of the parent atom.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₉H₁₃BrClN₃
M_r	398.68
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	293
a, b, c (Å)	8.7749 (7), 9.9403 (7), 10.4475 (8)
α, β, γ (°)	76.030 (6), 66.511 (7), 85.843 (6)
V (Å³)	810.76 (12)
Z	2
Radiation type	Cu Kα
μ (mm⁻¹)	5.00
Crystal size (mm)	0.14 × 0.12 × 0.06

Data collection
Diffractometer	Rigaku Oxford Diffraction
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015 $[Rigaku Oxford Diffraction (2015). CrysAlis PRO. Rigaku Americas, The Woodlands, Texas, USA.]$ )
T_min, T_max	0.393, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	5047, 3076, 2637
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.614

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.124, 1.04
No. of reflections	3076
No. of parameters	218
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.64, −0.60
Computer programs: CrysAlis PRO (Rigaku Oxford Diffraction, 2015 $[Rigaku Oxford Diffraction (2015). CrysAlis PRO. Rigaku Americas, The Woodlands, Texas, USA.]$ ), SHELXT2014 (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1556392

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314617008999/vm4023sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617008999/vm4023Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314617008999/vm4023Isup3.cdx

Supporting information file. DOI: https://doi.org/10.1107/S2414314617008999/vm4023Isup4.cml

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); cell refinement: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); data reduction: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

4-Benzyl-6-bromo-2-(4-chlorophenyl)-4H-imidazo[4,5-b]pyridine top

Crystal data top

C₁₉H₁₃BrClN₃	Z = 2
M_r = 398.68	F(000) = 400
Triclinic, P1	D_x = 1.633 Mg m⁻³
a = 8.7749 (7) Å	Cu Kα radiation, λ = 1.54184 Å
b = 9.9403 (7) Å	Cell parameters from 2096 reflections
c = 10.4475 (8) Å	θ = 4.6–71.2°
α = 76.030 (6)°	µ = 5.00 mm⁻¹
β = 66.511 (7)°	T = 293 K
γ = 85.843 (6)°	Irregular, yellow
V = 810.76 (12) Å³	0.14 × 0.12 × 0.06 mm

Data collection top

Rigaku Oxford Diffraction diffractometer	3076 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source	2637 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.037
Detector resolution: 16.0416 pixels mm^-1	θ_max = 71.3°, θ_min = 4.6°
ω scans	h = −6→10
Absorption correction: multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015)	k = −11→12
T_min = 0.393, T_max = 1.000	l = −12→12
5047 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.044	w = 1/[σ²(F_o²) + (0.0674P)² + 0.2037P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.124	(Δ/σ)_max = 0.001
S = 1.04	Δρ_max = 0.64 e Å⁻³
3076 reflections	Δρ_min = −0.60 e Å⁻³
218 parameters	Extinction correction: SHELXT2014 (Sheldrick, 2015a), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0012 (4)
Primary atom site location: dual

Special details top

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.

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

	x	y	z	U_iso*/U_eq
Br1	0.20904 (4)	0.05758 (4)	0.60405 (4)	0.04964 (18)
Cl1	0.40328 (14)	1.29736 (10)	0.10620 (12)	0.0608 (3)
N1	0.5634 (3)	0.3647 (3)	0.3684 (3)	0.0384 (6)
N2	0.2447 (3)	0.6063 (3)	0.3757 (3)	0.0384 (6)
N3	0.5333 (3)	0.6100 (3)	0.2869 (3)	0.0391 (6)
C1	0.4801 (4)	0.2417 (3)	0.4415 (3)	0.0393 (7)
H1	0.5392	0.1616	0.4542	0.047*
C2	0.3102 (4)	0.2344 (3)	0.4964 (4)	0.0401 (7)
C3	0.2119 (4)	0.3497 (3)	0.4823 (4)	0.0393 (7)
H3	0.0964	0.3427	0.5206	0.047*
C4	0.2966 (4)	0.4739 (4)	0.4081 (3)	0.0373 (7)
C5	0.3881 (4)	0.6806 (3)	0.3058 (3)	0.0373 (7)
C6	0.4742 (4)	0.4804 (3)	0.3519 (3)	0.0357 (6)
C7	0.3929 (4)	0.8314 (4)	0.2557 (4)	0.0385 (7)
C8	0.2453 (4)	0.9043 (4)	0.2807 (4)	0.0486 (8)
H8	0.1438	0.8561	0.3283	0.058*
C9	0.2486 (5)	1.0471 (4)	0.2356 (4)	0.0511 (9)
H9	0.1500	1.0950	0.2533	0.061*
C10	0.3991 (5)	1.1173 (3)	0.1645 (4)	0.0425 (7)
C11	0.5467 (4)	1.0485 (4)	0.1389 (4)	0.0497 (9)
H11	0.6477	1.0977	0.0919	0.060*
C12	0.5431 (4)	0.9057 (4)	0.1838 (4)	0.0470 (8)
H12	0.6424	0.8588	0.1657	0.056*
C13	0.7474 (4)	0.3741 (4)	0.3102 (4)	0.0416 (7)
H13A	0.7865	0.3112	0.3768	0.050*
H13B	0.7822	0.4675	0.3013	0.050*
C14	0.8254 (3)	0.3382 (3)	0.1653 (4)	0.0362 (7)
C15	0.8029 (4)	0.4197 (4)	0.0478 (4)	0.0500 (8)
H15	0.7384	0.4981	0.0560	0.060*
C16	0.8781 (5)	0.3832 (6)	−0.0831 (4)	0.0649 (12)
H16	0.8628	0.4348	−0.1639	0.078*
C17	0.9753 (6)	0.2690 (6)	−0.0899 (5)	0.0676 (12)
H17	1.0290	0.2421	−0.1762	0.081*
C18	0.9923 (5)	0.1951 (5)	0.0320 (5)	0.0649 (12)
H18	1.0594	0.1181	0.0258	0.078*
C19	0.9186 (4)	0.2268 (3)	0.1588 (3)	0.0369 (7)
H19	0.9319	0.1732	0.2398	0.044*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0423 (2)	0.0371 (2)	0.0573 (3)	0.00609 (15)	−0.01030 (17)	−0.00689 (16)
Cl1	0.0740 (6)	0.0384 (5)	0.0712 (7)	0.0027 (4)	−0.0354 (5)	−0.0031 (4)
N1	0.0338 (13)	0.0426 (15)	0.0375 (14)	0.0121 (11)	−0.0121 (11)	−0.0132 (12)
N2	0.0331 (12)	0.0376 (14)	0.0392 (14)	0.0080 (11)	−0.0108 (11)	−0.0075 (11)
N3	0.0323 (13)	0.0410 (15)	0.0403 (15)	0.0071 (11)	−0.0104 (11)	−0.0111 (12)
C1	0.0416 (16)	0.0368 (16)	0.0355 (16)	0.0104 (13)	−0.0116 (14)	−0.0101 (13)
C2	0.0442 (17)	0.0325 (15)	0.0380 (17)	0.0062 (13)	−0.0114 (14)	−0.0078 (13)
C3	0.0321 (14)	0.0392 (17)	0.0393 (17)	0.0061 (12)	−0.0083 (13)	−0.0074 (13)
C4	0.0335 (15)	0.0411 (17)	0.0335 (16)	0.0107 (13)	−0.0097 (13)	−0.0109 (13)
C5	0.0354 (15)	0.0400 (17)	0.0349 (16)	0.0080 (13)	−0.0127 (13)	−0.0097 (13)
C6	0.0352 (15)	0.0372 (16)	0.0322 (15)	0.0109 (12)	−0.0107 (13)	−0.0113 (12)
C7	0.0367 (15)	0.0403 (17)	0.0389 (17)	0.0064 (13)	−0.0156 (13)	−0.0101 (13)
C8	0.0329 (15)	0.0441 (19)	0.059 (2)	0.0048 (14)	−0.0119 (15)	−0.0061 (16)
C9	0.0436 (18)	0.047 (2)	0.058 (2)	0.0119 (15)	−0.0194 (17)	−0.0081 (17)
C10	0.0523 (19)	0.0358 (17)	0.0424 (18)	0.0033 (14)	−0.0244 (16)	−0.0051 (14)
C11	0.0402 (17)	0.047 (2)	0.057 (2)	−0.0028 (15)	−0.0185 (16)	−0.0052 (17)
C12	0.0346 (16)	0.050 (2)	0.051 (2)	0.0062 (14)	−0.0153 (15)	−0.0060 (16)
C13	0.0309 (15)	0.052 (2)	0.0420 (18)	0.0125 (14)	−0.0123 (14)	−0.0186 (15)
C14	0.0241 (12)	0.0405 (17)	0.0393 (17)	0.0001 (12)	−0.0074 (12)	−0.0094 (13)
C15	0.0413 (17)	0.058 (2)	0.048 (2)	0.0093 (16)	−0.0183 (16)	−0.0084 (17)
C16	0.052 (2)	0.098 (3)	0.039 (2)	−0.002 (2)	−0.0152 (17)	−0.009 (2)
C17	0.056 (2)	0.090 (3)	0.045 (2)	−0.005 (2)	0.0007 (19)	−0.029 (2)
C18	0.052 (2)	0.065 (3)	0.064 (3)	0.013 (2)	−0.004 (2)	−0.025 (2)
C19	0.0307 (13)	0.0339 (15)	0.0349 (16)	0.0091 (12)	−0.0038 (12)	−0.0061 (12)

Geometric parameters (Å, º) top

Br1—C2	1.902 (3)	C9—H9	0.9300
Cl1—C10	1.744 (3)	C9—C10	1.373 (5)
N1—C1	1.359 (4)	C10—C11	1.379 (5)
N1—C6	1.359 (4)	C11—H11	0.9300
N1—C13	1.482 (4)	C11—C12	1.382 (5)
N2—C4	1.370 (4)	C12—H12	0.9300
N2—C5	1.343 (4)	C13—H13A	0.9700
N3—C5	1.376 (4)	C13—H13B	0.9700
N3—C6	1.336 (4)	C13—C14	1.512 (4)
C1—H1	0.9300	C14—C15	1.376 (5)
C1—C2	1.367 (5)	C14—C19	1.326 (4)
C2—C3	1.399 (4)	C15—H15	0.9300
C3—H3	0.9300	C15—C16	1.387 (6)
C3—C4	1.375 (5)	C16—H16	0.9300
C4—C6	1.429 (4)	C16—C17	1.367 (7)
C5—C7	1.461 (5)	C17—H17	0.9300
C7—C8	1.398 (4)	C17—C18	1.367 (7)
C7—C12	1.390 (5)	C18—H18	0.9300
C8—H8	0.9300	C18—C19	1.328 (5)
C8—C9	1.382 (5)	C19—H19	0.9300

C1—N1—C13	121.2 (3)	C9—C10—C11	121.4 (3)
C6—N1—C1	118.5 (3)	C11—C10—Cl1	119.4 (3)
C6—N1—C13	120.3 (3)	C10—C11—H11	120.4
C5—N2—C4	103.0 (3)	C10—C11—C12	119.3 (3)
C6—N3—C5	100.9 (3)	C12—C11—H11	120.4
N1—C1—H1	119.6	C7—C12—H12	119.6
N1—C1—C2	120.7 (3)	C11—C12—C7	120.8 (3)
C2—C1—H1	119.6	C11—C12—H12	119.6
C1—C2—Br1	116.4 (3)	N1—C13—H13A	109.3
C1—C2—C3	123.3 (3)	N1—C13—H13B	109.3
C3—C2—Br1	120.2 (3)	N1—C13—C14	111.8 (3)
C2—C3—H3	122.1	H13A—C13—H13B	107.9
C4—C3—C2	115.8 (3)	C14—C13—H13A	109.3
C4—C3—H3	122.1	C14—C13—H13B	109.3
N2—C4—C3	132.5 (3)	C15—C14—C13	121.1 (3)
N2—C4—C6	107.1 (3)	C19—C14—C13	116.0 (3)
C3—C4—C6	120.4 (3)	C19—C14—C15	122.9 (3)
N2—C5—N3	117.5 (3)	C14—C15—H15	120.5
N2—C5—C7	122.3 (3)	C14—C15—C16	118.9 (4)
N3—C5—C7	120.2 (3)	C16—C15—H15	120.5
N1—C6—C4	121.3 (3)	C15—C16—H16	121.0
N3—C6—N1	127.2 (3)	C17—C16—C15	118.1 (4)
N3—C6—C4	111.5 (3)	C17—C16—H16	121.0
C8—C7—C5	120.4 (3)	C16—C17—H17	120.5
C12—C7—C5	121.1 (3)	C18—C17—C16	119.0 (4)
C12—C7—C8	118.5 (3)	C18—C17—H17	120.5
C7—C8—H8	119.6	C17—C18—H18	118.1
C9—C8—C7	120.8 (3)	C19—C18—C17	123.8 (4)
C9—C8—H8	119.6	C19—C18—H18	118.1
C8—C9—H9	120.4	C14—C19—C18	117.3 (4)
C10—C9—C8	119.2 (3)	C14—C19—H19	121.4
C10—C9—H9	120.4	C18—C19—H19	121.4
C9—C10—Cl1	119.2 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C19—H19···Br1ⁱ	0.93	2.54	3.202 (3)	128

Symmetry code: (i) −x+1, −y, −z+1.

Acknowledgements

JPJ acknowledges the NSF–MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.

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