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20 g of methyl 3-aminopyridine-2-carboxylate are suspended in 120 ml of water in a flask. After addition of 100 ml of sulfuric acid (2 mol/l), the mixture is cooled to 0° C., 6.73 ml of bromine are added dropwise, and the mixture is stirred at 25° C. until the acid has reacted completely (HPLC check, about 24 hours). A precipitate precipitates out of the reaction solution. This is filtered off, dissolved in EA, washed with sodium thiosulfate solution, the organic phase is dried and purified by means of column chromatography (gradient heptane: EA 5-100% in 30 min.), giving 15 g of methyl 3-amino-6-bromo-pyridine-2-carboxylate as red-brown solid (yield 50%, content 98%); MS-FAB (M+H+)=232.9; Rf (polar method): 1.518 min.

1. customhas reacted completely (HPLC check, about 24 hours)
2. customA precipitate precipitates out of the reaction solution
3. filtrationThis is filtered off
4. dissolutiondissolved in EA
5. washwashed with sodium thiosulfate solution
6. customthe organic phase is dried
7. custompurified by means of column chromatography (gradient heptane: EA 5-100% in 30 min.)