[Br:1][C:2]1[CH:3]=[C:4]2[N:10]=[CH:9][NH:8][C:5]2=[N:6][CH:7]=1.[H-].[Na+].Cl[CH2:14][C:15]1[CH:25]=[CH:24][C:18]2[N:19]=[C:20]([S:22][CH3:23])[O:21][C:17]=2[CH:16]=1.O>CN(C=O)C>[Br:1][C:2]1[CH:3]=[C:4]2[N:10]=[CH:9][N:8]([CH2:14][C:15]3[CH:25]=[CH:24][C:18]4[N:19]=[C:20]([S:22][CH3:23])[O:21][C:17]=4[CH:16]=3)[C:5]2=[N:6][CH:7]=1
To a stirred solution of 6-bromo-3H-imidazo[4,5-b]pyridine (506 mg, 2.55 mmol) from Step 1 of this Example in anhydrous DMF (10 mL) at 0° C. was added in one portion sodium hydride (60% dispersion in mineral oil, 107 mg, 2.68 mmol), and the mixture was stirred at 0° C. for 30 min. To the reaction mixture was added a solution of 6-(chloromethyl)-2-(methylthio)benzo[d]oxazole (600 mg, 2.81 mmol) from Step 3 of Example 56 in DMF (2 mL). The mixture was allowed to warm to rt, then stirred for a further 15 h. To the reaction mixture was added water and the mixture was extracted with EtOAc. The organic layer was separated and the aq layer extracted with additional EtOAc. The combined organic layers were washed with water then brine. The organic layer was separated, dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography eluting with 100% DCM, followed by 1% MeOH in DCM to afford 6-((6-bromo-3H-imidazo[4,5-b]pyridin-3-yl)methyl)-2-(methylthio)benzo[d]oxazole (460 mg, 48%) as a white solid. The regiochemistry of the alkylation was determined by 2-dimensional nuclear Overhauser effect (NOE) experiment. 1H NMR (300 MHz, DMSO-d6) δ 8.70 (s, 1H), 8.48 (d, J=1.9 Hz, 1H), 8.40 (d, J=1.9 Hz, 1H), 7.68 (s, 1H), 7.58 (d, J=8.1 Hz, 1H), 7.34 (d, J=8.1 Hz, 1H), 5.59 (s, 2H), 2.73 (s, 3H). LCMS (ESI) m/z 375 and 377 (M+H)+.
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