[Br:1]Br.[Cl:3][C:4]1[CH:5]=[CH:6][C:7]([O:10][CH3:11])=[N:8][CH:9]=1.C([O-])(=O)C.[Na+].C(OCC)C>C(O)(=O)C.O>[Br:1][C:6]1[C:7]([O:10][CH3:11])=[N:8][CH:9]=[C:4]([Cl:3])[CH:5]=1A solution of bromine (1.5 mL, 29.28 mmol) in glacial acetic acid (7 mL) was slowly added to a mixture of 5-chloro-2-methoxypyridine (2.1 g, 14.63 mmol) and sodium acetate (1.2 g, 14.63 mmol) in glacial acetic acid (7 mL) and the resulting mixture was stirred at 80° C. for 6 hours. The reaction was allowed to cool down to ambient temperature and then diethyl ether and water were added. The organic layer was separated, washed with a 1N aqueous solution of sodium hydroxide and a 4% aqueous solution of sodium bisulphite, dried over magnesium sulphate and the solvent removed under reduced pressure. The residue was purified by flash chromatography (100% hexanes) to give the title compound (2.1 g, 64%) as a white solid.
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