Concentrated sulfuric acid (20 ml) was added dropwise to a methanolic solution (150 ml) of 6-aminopyridine-2-carboxylic acid (10 g). The mixture was refluxed for 16 hours. Most of the methanol was removed in vacuum. The residue was poured into ice water. The mixture was adjusted to pH with 6n sodium hydroxide solution
8-9 and then extracted with ethyl acetate. The organic phase was washed with brine, dried over sodium sulfate and filtered. The filtrate was concentrated to the title compound methyl 6-aminopyridinecarboxylate. Yield 7.5 g.
