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

In the mol­ecule of the title compound, C₁₅H₁₂BrN₃·H₂O, the phenyl ring is coplanar with the imidazopyridine ring system [dihedral angle = 0.4 (1)°]. The water mol­ecule is disordered over two positions with occupancies of 0.58 (1) and 0.42 (1), and it is linked to the main mol­ecule via an O—H...N hydrogen bond.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• Disorder in solvent or counterion
• R factor = 0.027
• wR factor = 0.078
• Data-to-parameter ratio = 15.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          2
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         14
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              H2 O
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          5

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          6
PLAT154_ALERT_1_G The su's on the Cell Angles are Equal  (x 10000)        100 Deg.
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K
PLAT302_ALERT_4_G Note: Anion/Solvent Disorder ...................      50.00 Perc.

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

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

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S1. Comment

The imidazo[4,5-b]pyridine unit is an important heterocyclic nucleus found in a large number of molecules in medicinal chemistry. Heterocycles derived from such compounds posess useful medicinal properties. Owing to their importance, strategies have been developed for their synthesis. The most popular synthetic approach involves the cyclocondensation of 2,3-pyridinediamine with carboxylic acid derivatives or on condensation with aldehydes. An earlier study reported the crystal structure of 4-benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine (Ouzidan et al., 2010), which was synthesized by using a much more convenient route. The synthesis is extended to the title compound (Scheme I and Fig. 1).

The imidazopyridine ring system is coplanar with the phenyl ring at the 2-position of the five-membered ring [dihedral angle = 0.4 (1) °].

Related literature

For a related structure, see: Ouzidan et al. (2010).

S2. Experimental

To a solution 6-bromo-2-phenyl-1H-imidazo[4,5-b]pyridine (0.3 g, 1.09 mmol), was added a DMF (15 ml) solution of potassium carbonate (0.2 g, 1.42 mmol), tetra-n-butylammonium bromide (0.04 g, 0.1 mmol) and allyl bromide (0.11 ml, 1.31 mmol). Stirring was continued at room temperature for 12 h. The mixture was filtered and the solvent removed under reduced pressure. The residue was separated by chromatography on a column of silica gel with ethyl acetate-hexane (2:3) as eluent. Yellow crystals were isolated when the solvent was allowed to evaporate.

S3. Refinement

Carbon-bound H-atoms were placed in calculated positions (C–H = 0.93–0.97 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U_eq(C). The water molecule is disordered over two positions in a 58 (1):42 (1) ratio. The H atoms were located in a difference Fourier map and were refined with distance restraints of O–H = 0.84 (1) Å and H···H 1.37 (1) Å; their U_iso values were tied to those of the oxygen atoms by a factor of 1.5.

Computing details

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

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of the molecule of C15H12BrN3^.H2O at the 50% probability level. H atoms are shown as spheres of arbitrary radii. The disorder in the water molecule is shown.

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

Crystal data

C15H12BrN3·H2O	Z = 2
Mr = 332.20	F(000) = 336
Triclinic, P1	Dx = 1.594 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.4363 (1) Å	Cell parameters from 7204 reflections
b = 9.4238 (1) Å	θ = 2.3–27.2°
c = 11.0829 (2) Å	µ = 2.97 mm^−1
α = 68.076 (1)°	T = 293 K
β = 74.637 (1)°	Prism, yellow
γ = 79.736 (1)°	0.20 × 0.20 × 0.15 mm
V = 692.02 (2) Å^3

Data collection

Bruker X8 APEXII area-detector diffractometer	3158 independent reflections
Radiation source: fine-focus sealed tube	2791 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
φ and ω scans	θmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.588, Tmax = 0.664	k = −12→12
14314 measured reflections	l = −13→14

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.078	H atoms treated by a mixture of independent and constrained refinement
S = 0.98	w = 1/[σ^2(Fo^2) + (0.0529P)^2 + 0.1091P] where P = (Fo^2 + 2Fc^2)/3
3158 reflections	(Δ/σ)max = 0.001
203 parameters	Δρmax = 0.25 e Å^−3
6 restraints	Δρmin = −0.39 e Å^−3

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Br1	0.78351 (3)	0.73753 (2)	0.425170 (19)	0.05007 (9)
O1	1.1389 (9)	0.1942 (6)	0.8855 (4)	0.0635 (16)	0.582 (14)
H11	1.028 (3)	0.229 (7)	0.903 (7)	0.095*	0.582 (14)
H12	1.208 (6)	0.237 (6)	0.908 (6)	0.095*	0.582 (14)
O1'	1.0501 (14)	0.1260 (12)	0.8987 (6)	0.081 (3)	0.418 (14)
H13	1.089 (17)	0.191 (10)	0.917 (11)	0.122*	0.418 (14)
H14	1.001 (16)	0.059 (9)	0.969 (6)	0.122*	0.418 (14)
N1	0.61186 (19)	0.78390 (15)	0.79149 (15)	0.0323 (3)
N2	0.66816 (19)	0.61173 (15)	1.00435 (15)	0.0347 (3)
N3	0.82874 (19)	0.41411 (16)	0.93153 (16)	0.0358 (3)
C1	0.6432 (2)	0.80592 (19)	0.66074 (18)	0.0350 (3)
H1	0.5976	0.8977	0.6035	0.042*
C2	0.7415 (2)	0.6947 (2)	0.61055 (19)	0.0368 (4)
C3	0.8123 (2)	0.55420 (19)	0.69201 (19)	0.0371 (4)
H3	0.8780	0.4791	0.6576	0.044*
C4	0.7798 (2)	0.53257 (18)	0.82533 (18)	0.0331 (3)
C5	0.6797 (2)	0.65118 (18)	0.87503 (17)	0.0313 (3)
C6	0.5091 (2)	0.90590 (19)	0.84527 (19)	0.0381 (4)
H6A	0.4210	0.9672	0.7908	0.046*
H6B	0.4386	0.8587	0.9352	0.046*
C7	0.6408 (3)	1.0068 (2)	0.8464 (2)	0.0481 (5)
H7	0.7367	0.9607	0.8917	0.058*
C8	0.6310 (5)	1.1541 (3)	0.7888 (3)	0.0711 (7)
H8A	0.5368	1.2037	0.7427	0.085*
H8B	0.7180	1.2105	0.7933	0.085*
C9	0.7604 (2)	0.46733 (18)	1.03315 (18)	0.0339 (3)
C10	0.7799 (2)	0.37743 (19)	1.17031 (18)	0.0354 (4)
C11	0.7034 (3)	0.4364 (2)	1.2724 (2)	0.0422 (4)
H11A	0.6407	0.5342	1.2535	0.051*
C12	0.7194 (3)	0.3511 (3)	1.4024 (2)	0.0498 (5)
H12A	0.6678	0.3919	1.4699	0.060*
C13	0.8118 (3)	0.2058 (3)	1.4313 (2)	0.0522 (5)
H13A	0.8219	0.1481	1.5184	0.063*
C14	0.8890 (3)	0.1467 (2)	1.3309 (2)	0.0509 (5)
H14A	0.9520	0.0490	1.3505	0.061*
C15	0.8741 (3)	0.2306 (2)	1.2012 (2)	0.0436 (4)
H15	0.9269	0.1892	1.1342	0.052*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.06412 (15)	0.05036 (14)	0.03761 (13)	0.00253 (9)	−0.01310 (9)	−0.01926 (9)
O1	0.076 (3)	0.056 (2)	0.068 (2)	0.020 (2)	−0.0289 (19)	−0.0341 (17)
O1'	0.091 (5)	0.084 (5)	0.074 (3)	0.022 (4)	−0.021 (3)	−0.044 (3)
N1	0.0350 (7)	0.0260 (6)	0.0359 (8)	0.0023 (5)	−0.0108 (6)	−0.0108 (5)
N2	0.0360 (7)	0.0294 (7)	0.0370 (8)	0.0013 (5)	−0.0094 (6)	−0.0104 (6)
N3	0.0352 (7)	0.0288 (7)	0.0422 (8)	0.0013 (5)	−0.0112 (6)	−0.0107 (6)
C1	0.0373 (8)	0.0307 (8)	0.0371 (9)	0.0006 (6)	−0.0122 (7)	−0.0106 (7)
C2	0.0394 (8)	0.0368 (9)	0.0373 (9)	−0.0032 (7)	−0.0104 (7)	−0.0148 (7)
C3	0.0382 (8)	0.0321 (8)	0.0435 (10)	0.0008 (6)	−0.0084 (7)	−0.0181 (7)
C4	0.0307 (7)	0.0276 (7)	0.0418 (9)	0.0004 (6)	−0.0095 (7)	−0.0129 (7)
C5	0.0302 (7)	0.0274 (7)	0.0368 (9)	−0.0010 (6)	−0.0083 (6)	−0.0116 (6)
C6	0.0422 (9)	0.0305 (8)	0.0394 (9)	0.0086 (7)	−0.0097 (7)	−0.0143 (7)
C7	0.0513 (11)	0.0487 (11)	0.0530 (12)	0.0017 (8)	−0.0112 (9)	−0.0303 (9)
C8	0.101 (2)	0.0508 (13)	0.0645 (16)	−0.0212 (13)	−0.0088 (14)	−0.0227 (12)
C9	0.0293 (7)	0.0299 (8)	0.0402 (9)	−0.0027 (6)	−0.0087 (6)	−0.0085 (7)
C10	0.0318 (8)	0.0307 (8)	0.0407 (9)	−0.0048 (6)	−0.0107 (7)	−0.0058 (7)
C11	0.0443 (9)	0.0376 (9)	0.0419 (10)	−0.0011 (7)	−0.0118 (8)	−0.0101 (7)
C12	0.0521 (11)	0.0543 (12)	0.0419 (11)	−0.0061 (9)	−0.0123 (9)	−0.0132 (9)
C13	0.0524 (11)	0.0521 (12)	0.0427 (11)	−0.0107 (9)	−0.0178 (9)	0.0021 (9)
C14	0.0495 (11)	0.0370 (10)	0.0561 (13)	−0.0005 (8)	−0.0199 (9)	−0.0006 (9)
C15	0.0432 (9)	0.0348 (9)	0.0482 (11)	0.0000 (7)	−0.0120 (8)	−0.0093 (8)

Geometric parameters (Å, º)

Br1—C2	1.8887 (19)	C6—C7	1.487 (3)
O1—H11	0.834 (10)	C6—H6A	0.97
O1—H12	0.838 (10)	C6—H6B	0.97
O1—H13	0.43 (12)	C7—C8	1.291 (3)
O1'—H11	0.97 (5)	C7—H7	0.93
O1'—H13	0.836 (10)	C8—H8A	0.93
O1'—H14	0.838 (10)	C8—H8B	0.93
N1—C1	1.346 (2)	C9—C10	1.470 (3)
N1—C5	1.354 (2)	C10—C11	1.389 (3)
N1—C6	1.489 (2)	C10—C15	1.396 (2)
N2—C5	1.322 (2)	C11—C12	1.388 (3)
N2—C9	1.372 (2)	C11—H11A	0.93
N3—C9	1.344 (2)	C12—C13	1.379 (3)
N3—C4	1.365 (2)	C12—H12A	0.93
C1—C2	1.375 (2)	C13—C14	1.374 (3)
C1—H1	0.93	C13—H13A	0.93
C2—C3	1.398 (2)	C14—C15	1.381 (3)
C3—C4	1.374 (3)	C14—H14A	0.93
C3—H3	0.93	C15—H15	0.93
C4—C5	1.433 (2)
H11—O1—H12	110.6 (18)	H6A—C6—H6B	108.0
H12—O1—H13	101 (6)	C8—C7—C6	124.3 (2)
H11—O1'—H14	114 (9)	C8—C7—H7	117.8
H13—O1'—H14	110.2 (19)	C6—C7—H7	117.8
C1—N1—C5	119.78 (14)	C7—C8—H8A	120.0
C1—N1—C6	120.89 (14)	C7—C8—H8B	120.0
C5—N1—C6	119.29 (14)	H8A—C8—H8B	120.0
C5—N2—C9	101.46 (14)	N3—C9—N2	117.02 (16)
C9—N3—C4	103.09 (13)	N3—C9—C10	122.81 (15)
N1—C1—C2	120.95 (16)	N2—C9—C10	120.17 (16)
N1—C1—H1	119.5	C11—C10—C15	118.49 (18)
C2—C1—H1	119.5	C11—C10—C9	120.61 (16)
C1—C2—C3	122.00 (17)	C15—C10—C9	120.90 (17)
C1—C2—Br1	117.99 (14)	C12—C11—C10	120.79 (18)
C3—C2—Br1	120.01 (13)	C12—C11—H11A	119.6
C4—C3—C2	116.73 (15)	C10—C11—H11A	119.6
C4—C3—H3	121.6	C13—C12—C11	120.0 (2)
C2—C3—H3	121.6	C13—C12—H12A	120.0
N3—C4—C3	132.84 (15)	C11—C12—H12A	120.0
N3—C4—C5	106.85 (15)	C14—C13—C12	119.7 (2)
C3—C4—C5	120.29 (15)	C14—C13—H13A	120.1
N2—C5—N1	128.19 (15)	C12—C13—H13A	120.1
N2—C5—C4	111.57 (14)	C13—C14—C15	120.79 (19)
N1—C5—C4	120.24 (16)	C13—C14—H14A	119.6
C7—C6—N1	110.95 (14)	C15—C14—H14A	119.6
C7—C6—H6A	109.4	C14—C15—C10	120.2 (2)
N1—C6—H6A	109.4	C14—C15—H15	119.9
C7—C6—H6B	109.4	C10—C15—H15	119.9
N1—C6—H6B	109.4
C5—N1—C1—C2	0.8 (2)	C1—N1—C6—C7	−91.40 (19)
C6—N1—C1—C2	178.59 (16)	C5—N1—C6—C7	86.45 (19)
N1—C1—C2—C3	0.4 (3)	N1—C6—C7—C8	124.1 (2)
N1—C1—C2—Br1	−178.60 (12)	C4—N3—C9—N2	0.46 (19)
C1—C2—C3—C4	−0.4 (3)	C4—N3—C9—C10	179.96 (15)
Br1—C2—C3—C4	178.57 (12)	C5—N2—C9—N3	0.11 (19)
C9—N3—C4—C3	177.66 (18)	C5—N2—C9—C10	−179.41 (14)
C9—N3—C4—C5	−0.79 (17)	N3—C9—C10—C11	−178.67 (16)
C2—C3—C4—N3	−178.94 (17)	N2—C9—C10—C11	0.8 (2)
C2—C3—C4—C5	−0.7 (2)	N3—C9—C10—C15	0.8 (2)
C9—N2—C5—N1	179.89 (16)	N2—C9—C10—C15	−179.71 (15)
C9—N2—C5—C4	−0.63 (17)	C15—C10—C11—C12	−0.3 (3)
C1—N1—C5—N2	177.63 (16)	C9—C10—C11—C12	179.18 (17)
C6—N1—C5—N2	−0.2 (3)	C10—C11—C12—C13	−0.1 (3)
C1—N1—C5—C4	−1.8 (2)	C11—C12—C13—C14	0.5 (3)
C6—N1—C5—C4	−179.69 (15)	C12—C13—C14—C15	−0.4 (3)
N3—C4—C5—N2	0.95 (19)	C13—C14—C15—C10	0.0 (3)
C3—C4—C5—N2	−177.74 (14)	C11—C10—C15—C14	0.4 (3)
N3—C4—C5—N1	−179.52 (14)	C9—C10—C15—C14	−179.12 (16)
C3—C4—C5—N1	1.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H11···N3	0.83 (1)	2.14 (3)	2.887 (4)	149 (5)
O1—H12···N2^i	0.84 (1)	2.41 (2)	3.229 (7)	165 (5)

Symmetry code: (i) −x+2, −y+1, −z+2.