C([O-])(=O)C.[Na+].[Cl:6][C:7]1[CH:8]=[CH:9][C:10]([O:13][CH3:14])=[N:11][CH:12]=1.[Br:15]Br>C(O)(=O)C>[Br:15][C:9]1[C:10]([O:13][CH3:14])=[N:11][CH:12]=[C:7]([Cl:6])[CH:8]=1To a stirred suspension of 2.5 g of anhydrous sodium acetate in 10 ml of acetic acid was added 4.3 g of 5-chloro-2-methoxypyridine followed by a solution of 3.1 ml of bromine in 10 ml of acetic acid. The mixture was warmed to 80° C. for 6 hours and then allowed to cool and stirred at 23° C. for 64 hours. It was then partitioned between ether and water and the resulting ether layer was washed with aqueous 1N sodium hydroxide solution and then with aqueous 5% sodium bisulfite solution, dried over potassium carbonate and concentrated at reduced pressure to leave a residual brown solid. This residue was bulb-to-bulb distilled with the material distilling at 140°-150° C. at 20 torr collected to give 3-bromo-5-chloro-2-methoxypyridine as a solid melting at about 45°-47.5° C.
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