organic compounds
6-Bromo-2-(4-chlorophenyl)-3-methyl-3H-imidazo[4,5-b]pyridine
aLaboratoire de Chimie Organique Appliquée, Université Sidi Mohamed Ben Abdallah, Faculté des Sciences et Techniques, Route d'Iimmouzzer, BP 2202, Fez, Morocco, bDepartment of Chemistry, Tulane University, New Orleans, LA 70118, USA, cLaboratoire de Chimie Organique Hétérocyclique, Pôle de Compétences Pharmacochimie, Mohammed V University in Rabat, BP 1014, Avenue Ibn Batouta, Rabat, Morocco, and dLaboratoire d'Ingénierie des Matériaux et d'Environnement: Modélisation et Application (LIMEMA), Ibn Tofail University, Kénitra, Morocco
*Correspondence e-mail: youssef_kandri_rodi@yahoo.fr
In the title compound, C13H9BrClN3, the imidazopyridine fused-ring system is almost planar, with r.m.s. deviation of 0.006 (19) Å, and makes a dihedral angle of 29.32 (8)° with the mean plane of the 4-chlorophenyl group. In the crystal, C—H⋯N hydrogen bonds link the molecules into chains propagating in the [100] direction. Weak intermolecular π–π interactions between the five- and six-membered rings of the 3H-imidazo[4,5-b]pyridine moieties of neighbouring molecules [centroid–centroid distance = 3.8648 (12) Å] further consolidate the packing into layers parallel to the ab plane.
CCDC reference: 1478609
Structure description
Imidazopyridine derivatives are a very important class of nitrogen-containing fused et al. 2007; Katritzky et al. 2003), as well as anti-viral, anti-bacterial, anti-microbial and anti-cytokinin activity. Some of them can be used to treat peptic ulcers, diabetes and mental illness (Scribner et al. 2007, Liang et al. 2007). Hence, the synthesis of imidazo[4,5-b]pyridine derivatives is currently of great interest. Many synthetic strategies have been developed to obtain a variety of substituted structures of this class. The most popular synthetic approach generally involves the cyclocondensation of 2,3-pyridinediamine with carboxylic acid derivatives or with (Dubey et al. 2004). In this work we report the synthesis of 6-bromo-2-(4-chlorophenyl)-3-methyl-3H-imidazo[4,5-b]pyridine according to the method employed for 4-benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine (Ouzidan et al. 2010).
Many imidazopyridines have a significant inhibitory effect on many target enzymes (PalmerIn the title compound (Fig. 1), the imidazopyridine fused ring system is quasiplanar, with a maximum deviation of 0.006 (19) Å, and forms a dihedral angle of 29.32 (8)° with the mean plane of the 4-chlorophenyl group. In the crystal, C—H⋯N hydrogen bonds (Table 1) link the molecules into chains propagating in [100]. The chains are further linked by π–π interactions between the five- and six-membered rings of the 3H-imidazo[4,5-b]pyridine moieties of neighbouring molecules [centroid–centroid distance = 3.8648 (12) Å], forming layers parallel to the ab plane (Figs. 2 and 3).
Synthesis and crystallization
The a solution of 0.2 g (0.64 mmol) of 6-bromo-2-(4-chlorophenyl)-3H-imidazo[4,5-b]pyridine dissolved in 25 ml of DMF, was added potassium carbonate (K2CO3; 0.11 g, 0.84 mmol). The mixture was stirred magnetically for 5 minutes and then 0.02 g (0.07 mmol) of tetra-n-butylammonium bromide (TBAB) and 0.05 ml (0.77 mmol) of methyl iodide was added. Stirring was continued at room temperature for 6 h. After removing 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 is chromatographed on silica gel column (eluent: ethyl acetate/hexane,1:3). Yellow crystals were isolated when the solvent was allowed to evaporate, yield = 72%
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2Structural data
CCDC reference: 1478609
10.1107/S241431461600763X/bt4009sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S241431461600763X/bt4009Isup2.hkl
Supporting information file. DOI: 10.1107/S241431461600763X/bt4009Isup3.cml
The a solution of 0.2 g (0.64 mmol) of 6-bromo-2-(4-chlorophenyl)-3H-imidazo[4,5-b]pyridine dissolved in 25 ml of DMF, was added potassium carbonate (K2CO3; 0.11 g, 0.84 mmol). The mixture was stirred magnetically for 5 minutes and then 0.02 g (0.07 mmol) of tetra-n-butylammonium bromide (TBAB) and 0.05 ml (0.77 mmol) of methyl iodide was added. Stirring was continued at room temperature for 6 h. After removing 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 is chromatographed on silica gel column (eluent: ethyl acetate/hexane,1:3). Yellow crystals were isolated when the solvent was allowed to evaporate, yield = 72%
Imidazopyridine derivatives are a very important class of nitrogen-containing fused
Many imidazopyridines have a significant inhibitory effect on many target enzymes (Palmer et al. 2007; Katritzky et al. 2003), as well as anti-viral, anti-bacterial, anti-microbial and anti-cytokinin activity. Some of them can be used to treat peptic ulcers, diabetes and mental illness (Scribner et al. 2007, Liang et al. 2007). Hence, the synthesis of imidazo[4,5-b]pyridine derivatives is currently of great interest. Many synthetic strategies have been developed to obtain a variety of substituted structures of this class. The most popular synthetic approach generally involves the cyclocondensation of 2,3-pyridinediamine with carboxylic acid derivatives or with (Dubey et al. 2004). In this work we report the synthesis of 6-bromo-2-(4-chlorophenyl)-3-methyl-3H-imidazo[4,5-b]pyridine according to the method employed for 4-benzyl-6-bromo-2-phenyl-4H-imidazo[4,5-b]pyridine (Ouzidan et al. 2010).In the title compound (Fig. 1), the imidazopyridine fused ring system is quasiplanar, with a maximum deviation of 0.006 (19) Å, and forms a dihedral angle of 29.32 (8)° with the mean plane of the 4-chlorophenyl group. In the crystal, C—H···N hydrogen bonds (Table 1) link the molecules into chains propagating in [100]. The chains are further linked by π–π interactions between the five- and six-membered rings of the 3H-imidazo[4,5-b]pyridine moieties of neighbouring molecules [centroid–centroid distance = 3.8648 (12) Å], forming layers parallel to the ab plane (Figs. 2 and 3).
Data collection: APEX2 (Bruker, 2015); cell
SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).Fig. 1. The molecular structure of the title compound, showing the atom labels and 50% probability displacement ellipsoids for non-H atoms. | |
Fig. 2. The packing viewed down the b axis. C—H···N interactions are shown as dotted lines. | |
Fig. 3. The packing viewed down the a axis. C—H···N interactions are shown as dotted lines. |
C13H9BrClN3 | Dx = 1.725 Mg m−3 |
Mr = 322.59 | Cu Kα radiation, λ = 1.54178 Å |
Orthorhombic, Pbca | Cell parameters from 9992 reflections |
a = 12.1163 (2) Å | θ = 4.2–72.4° |
b = 9.7911 (2) Å | µ = 6.35 mm−1 |
c = 20.9428 (4) Å | T = 150 K |
V = 2484.48 (8) Å3 | Thick plate, light yellow |
Z = 8 | 0.28 × 0.18 × 0.12 mm |
F(000) = 1280 |
Bruker D8 VENTURE PHOTON 100 CMOS diffractometer | 2433 independent reflections |
Radiation source: INCOATEC IµS micro–focus source | 2111 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.042 |
Detector resolution: 10.4167 pixels mm-1 | θmax = 72.5°, θmin = 4.2° |
ω scans | h = −14→12 |
Absorption correction: numerical (SADABS; Bruker, 2015) | k = −12→10 |
Tmin = 0.37, Tmax = 0.52 | l = −24→25 |
17929 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.026 | H-atom parameters constrained |
wR(F2) = 0.069 | w = 1/[σ2(Fo2) + (0.0357P)2 + 1.6642P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max = 0.002 |
2433 reflections | Δρmax = 0.38 e Å−3 |
165 parameters | Δρmin = −0.44 e Å−3 |
0 restraints | Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.00050 (5) |
C13H9BrClN3 | V = 2484.48 (8) Å3 |
Mr = 322.59 | Z = 8 |
Orthorhombic, Pbca | Cu Kα radiation |
a = 12.1163 (2) Å | µ = 6.35 mm−1 |
b = 9.7911 (2) Å | T = 150 K |
c = 20.9428 (4) Å | 0.28 × 0.18 × 0.12 mm |
Bruker D8 VENTURE PHOTON 100 CMOS diffractometer | 2433 independent reflections |
Absorption correction: numerical (SADABS; Bruker, 2015) | 2111 reflections with I > 2σ(I) |
Tmin = 0.37, Tmax = 0.52 | Rint = 0.042 |
17929 measured reflections |
R[F2 > 2σ(F2)] = 0.026 | 0 restraints |
wR(F2) = 0.069 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.38 e Å−3 |
2433 reflections | Δρmin = −0.44 e Å−3 |
165 parameters |
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. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. H-atoms were placed in calculated positions (C—H = 0.95 - 0.98 Å) and included as riding contributions with isotropic displacement parameters 1.2 - 1.5 times those of the attached carbon atoms. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.74454 (2) | 0.96264 (2) | 0.62272 (2) | 0.02958 (10) | |
Cl1 | 0.49454 (6) | 0.15942 (7) | 0.21428 (3) | 0.05102 (19) | |
N1 | 0.90119 (14) | 0.69452 (18) | 0.50012 (8) | 0.0259 (4) | |
N2 | 0.81367 (14) | 0.54647 (17) | 0.42228 (8) | 0.0233 (4) | |
N3 | 0.63564 (13) | 0.60528 (18) | 0.43957 (8) | 0.0255 (4) | |
C1 | 0.70284 (17) | 0.6795 (2) | 0.47964 (10) | 0.0235 (4) | |
C2 | 0.67830 (17) | 0.7774 (2) | 0.52549 (10) | 0.0244 (4) | |
H2 | 0.6049 | 0.8058 | 0.5342 | 0.029* | |
C3 | 0.76839 (16) | 0.8304 (2) | 0.55755 (10) | 0.0246 (4) | |
C4 | 0.87671 (17) | 0.7888 (2) | 0.54435 (10) | 0.0265 (4) | |
H4 | 0.9354 | 0.8293 | 0.5678 | 0.032* | |
C5 | 0.81385 (16) | 0.6445 (2) | 0.46971 (9) | 0.0232 (4) | |
C6 | 0.91170 (17) | 0.4733 (2) | 0.40010 (11) | 0.0283 (4) | |
H6A | 0.9390 | 0.5157 | 0.3608 | 0.042* | |
H6B | 0.8926 | 0.3777 | 0.3917 | 0.042* | |
H6C | 0.9691 | 0.4774 | 0.4330 | 0.042* | |
C7 | 0.70395 (17) | 0.5267 (2) | 0.40658 (10) | 0.0244 (4) | |
C8 | 0.66153 (17) | 0.4291 (2) | 0.35938 (10) | 0.0248 (4) | |
C9 | 0.71738 (19) | 0.3912 (2) | 0.30403 (11) | 0.0321 (5) | |
H9 | 0.7905 | 0.4228 | 0.2969 | 0.039* | |
C10 | 0.6667 (2) | 0.3072 (2) | 0.25921 (12) | 0.0376 (5) | |
H10 | 0.7047 | 0.2815 | 0.2214 | 0.045* | |
C11 | 0.55998 (19) | 0.2614 (2) | 0.27032 (11) | 0.0335 (5) | |
C12 | 0.50354 (18) | 0.2972 (2) | 0.32544 (11) | 0.0293 (5) | |
H12 | 0.4307 | 0.2647 | 0.3326 | 0.035* | |
C13 | 0.55415 (17) | 0.3804 (2) | 0.36966 (10) | 0.0264 (4) | |
H13 | 0.5159 | 0.4051 | 0.4075 | 0.032* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02748 (16) | 0.02992 (15) | 0.03136 (15) | −0.00062 (8) | −0.00260 (8) | −0.00404 (9) |
Cl1 | 0.0467 (4) | 0.0564 (4) | 0.0499 (4) | −0.0141 (3) | −0.0010 (3) | −0.0251 (3) |
N1 | 0.0163 (8) | 0.0318 (9) | 0.0297 (9) | −0.0019 (6) | −0.0011 (7) | 0.0026 (7) |
N2 | 0.0162 (8) | 0.0270 (9) | 0.0268 (8) | 0.0017 (6) | −0.0011 (6) | 0.0019 (7) |
N3 | 0.0166 (8) | 0.0309 (9) | 0.0291 (9) | 0.0009 (7) | −0.0031 (7) | −0.0038 (7) |
C1 | 0.0176 (10) | 0.0262 (10) | 0.0268 (10) | −0.0005 (8) | −0.0020 (8) | 0.0022 (8) |
C2 | 0.0167 (10) | 0.0295 (11) | 0.0271 (10) | 0.0023 (8) | −0.0005 (8) | 0.0025 (8) |
C3 | 0.0218 (10) | 0.0257 (10) | 0.0262 (10) | −0.0002 (8) | −0.0013 (8) | 0.0028 (8) |
C4 | 0.0189 (10) | 0.0310 (11) | 0.0295 (10) | −0.0033 (8) | −0.0037 (8) | 0.0014 (8) |
C5 | 0.0183 (10) | 0.0254 (10) | 0.0260 (9) | 0.0015 (8) | −0.0013 (7) | 0.0048 (8) |
C6 | 0.0189 (10) | 0.0306 (11) | 0.0354 (11) | 0.0034 (8) | 0.0028 (8) | 0.0002 (9) |
C7 | 0.0168 (10) | 0.0283 (10) | 0.0280 (10) | −0.0009 (8) | −0.0022 (8) | 0.0027 (8) |
C8 | 0.0202 (10) | 0.0259 (10) | 0.0281 (10) | 0.0024 (8) | −0.0037 (8) | 0.0019 (8) |
C9 | 0.0248 (11) | 0.0366 (12) | 0.0350 (12) | −0.0018 (9) | 0.0006 (9) | −0.0042 (10) |
C10 | 0.0339 (13) | 0.0427 (13) | 0.0362 (12) | −0.0008 (10) | 0.0026 (10) | −0.0083 (10) |
C11 | 0.0338 (13) | 0.0290 (11) | 0.0376 (12) | −0.0023 (9) | −0.0040 (10) | −0.0074 (9) |
C12 | 0.0231 (11) | 0.0299 (11) | 0.0348 (11) | −0.0032 (8) | −0.0014 (9) | 0.0014 (9) |
C13 | 0.0237 (11) | 0.0275 (10) | 0.0281 (10) | 0.0004 (8) | −0.0009 (8) | 0.0031 (8) |
Br1—C3 | 1.903 (2) | C6—H6A | 0.9800 |
Cl1—C11 | 1.733 (2) | C6—H6B | 0.9800 |
N1—C5 | 1.329 (3) | C6—H6C | 0.9800 |
N1—C4 | 1.341 (3) | C7—C8 | 1.468 (3) |
N2—C5 | 1.381 (3) | C8—C9 | 1.393 (3) |
N2—C7 | 1.383 (3) | C8—C13 | 1.402 (3) |
N2—C6 | 1.463 (3) | C9—C10 | 1.391 (3) |
N3—C7 | 1.325 (3) | C9—H9 | 0.9500 |
N3—C1 | 1.377 (3) | C10—C11 | 1.388 (3) |
C1—C2 | 1.389 (3) | C10—H10 | 0.9500 |
C1—C5 | 1.404 (3) | C11—C12 | 1.387 (3) |
C2—C3 | 1.383 (3) | C12—C13 | 1.378 (3) |
C2—H2 | 0.9500 | C12—H12 | 0.9500 |
C3—C4 | 1.402 (3) | C13—H13 | 0.9500 |
C4—H4 | 0.9500 | ||
C5—N1—C4 | 114.13 (18) | H6A—C6—H6C | 109.5 |
C5—N2—C7 | 105.66 (16) | H6B—C6—H6C | 109.5 |
C5—N2—C6 | 124.56 (17) | N3—C7—N2 | 113.28 (18) |
C7—N2—C6 | 129.52 (18) | N3—C7—C8 | 120.71 (18) |
C7—N3—C1 | 104.77 (16) | N2—C7—C8 | 126.01 (19) |
N3—C1—C2 | 131.22 (19) | C9—C8—C13 | 119.2 (2) |
N3—C1—C5 | 110.34 (18) | C9—C8—C7 | 124.34 (19) |
C2—C1—C5 | 118.44 (19) | C13—C8—C7 | 116.28 (19) |
C3—C2—C1 | 115.20 (19) | C10—C9—C8 | 120.3 (2) |
C3—C2—H2 | 122.4 | C10—C9—H9 | 119.8 |
C1—C2—H2 | 122.4 | C8—C9—H9 | 119.8 |
C2—C3—C4 | 122.31 (19) | C11—C10—C9 | 119.3 (2) |
C2—C3—Br1 | 118.93 (15) | C11—C10—H10 | 120.4 |
C4—C3—Br1 | 118.75 (15) | C9—C10—H10 | 120.4 |
N1—C4—C3 | 122.90 (19) | C12—C11—C10 | 121.1 (2) |
N1—C4—H4 | 118.6 | C12—C11—Cl1 | 118.94 (17) |
C3—C4—H4 | 118.6 | C10—C11—Cl1 | 119.92 (19) |
N1—C5—N2 | 127.03 (18) | C13—C12—C11 | 119.3 (2) |
N1—C5—C1 | 127.02 (19) | C13—C12—H12 | 120.3 |
N2—C5—C1 | 105.94 (17) | C11—C12—H12 | 120.3 |
N2—C6—H6A | 109.5 | C12—C13—C8 | 120.7 (2) |
N2—C6—H6B | 109.5 | C12—C13—H13 | 119.6 |
H6A—C6—H6B | 109.5 | C8—C13—H13 | 119.6 |
N2—C6—H6C | 109.5 | ||
C7—N3—C1—C2 | −179.5 (2) | C1—N3—C7—C8 | 178.44 (19) |
C7—N3—C1—C5 | 0.4 (2) | C5—N2—C7—N3 | 0.8 (2) |
N3—C1—C2—C3 | 179.4 (2) | C6—N2—C7—N3 | 175.10 (19) |
C5—C1—C2—C3 | −0.5 (3) | C5—N2—C7—C8 | −178.35 (19) |
C1—C2—C3—C4 | 0.4 (3) | C6—N2—C7—C8 | −4.1 (3) |
C1—C2—C3—Br1 | −178.73 (15) | N3—C7—C8—C9 | 148.4 (2) |
C5—N1—C4—C3 | 0.3 (3) | N2—C7—C8—C9 | −32.5 (3) |
C2—C3—C4—N1 | −0.4 (3) | N3—C7—C8—C13 | −26.8 (3) |
Br1—C3—C4—N1 | 178.78 (16) | N2—C7—C8—C13 | 152.37 (19) |
C4—N1—C5—N2 | −179.77 (19) | C13—C8—C9—C10 | 0.7 (3) |
C4—N1—C5—C1 | −0.4 (3) | C7—C8—C9—C10 | −174.3 (2) |
C7—N2—C5—N1 | 178.96 (19) | C8—C9—C10—C11 | −0.2 (4) |
C6—N2—C5—N1 | 4.3 (3) | C9—C10—C11—C12 | −0.4 (4) |
C7—N2—C5—C1 | −0.5 (2) | C9—C10—C11—Cl1 | 178.75 (19) |
C6—N2—C5—C1 | −175.13 (18) | C10—C11—C12—C13 | 0.4 (4) |
N3—C1—C5—N1 | −179.42 (19) | Cl1—C11—C12—C13 | −178.75 (17) |
C2—C1—C5—N1 | 0.5 (3) | C11—C12—C13—C8 | 0.1 (3) |
N3—C1—C5—N2 | 0.1 (2) | C9—C8—C13—C12 | −0.7 (3) |
C2—C1—C5—N2 | 179.97 (18) | C7—C8—C13—C12 | 174.72 (19) |
C1—N3—C7—N2 | −0.8 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···N3i | 0.95 | 2.51 | 3.321 (3) | 143 |
C2—H2···N1ii | 0.95 | 2.57 | 3.411 (3) | 148 |
Symmetry codes: (i) x+1/2, −y+3/2, −z+1; (ii) x−1/2, −y+3/2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···N3i | 0.95 | 2.51 | 3.321 (3) | 143 |
C2—H2···N1ii | 0.95 | 2.57 | 3.411 (3) | 148 |
Symmetry codes: (i) x+1/2, −y+3/2, −z+1; (ii) x−1/2, −y+3/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C13H9BrClN3 |
Mr | 322.59 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 150 |
a, b, c (Å) | 12.1163 (2), 9.7911 (2), 20.9428 (4) |
V (Å3) | 2484.48 (8) |
Z | 8 |
Radiation type | Cu Kα |
µ (mm−1) | 6.35 |
Crystal size (mm) | 0.28 × 0.18 × 0.12 |
Data collection | |
Diffractometer | Bruker D8 VENTURE PHOTON 100 CMOS |
Absorption correction | Numerical (SADABS; Bruker, 2015) |
Tmin, Tmax | 0.37, 0.52 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 17929, 2433, 2111 |
Rint | 0.042 |
(sin θ/λ)max (Å−1) | 0.619 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.026, 0.069, 1.03 |
No. of reflections | 2433 |
No. of parameters | 165 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.38, −0.44 |
Computer programs: APEX2 (Bruker, 2015), SAINT (Bruker, 2015), SAINT (Bruker, 2015), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b), PLATON (Spek, 2009), publCIF (Westrip, 2010).
Acknowledgements
The support of NSF–MRI Grant No. 1228232 for the purchase of the diffractometer and Tulane University for support of the Tulane Crystallography Laboratory are gratefully acknowledged.
References
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