In a 500 mL autoclave, 49.8 g (0.25 mol) of 2,6-difluoro-3,5-dichloro-4-aminopyridine, 200 mL of ethanol, 5.61 g (0.55 mol) of triethylamine, and 10.0 g of 10% palladium carbon catalyst were added. The reaction system was maintained at 25 °C and a hydrogen pressure of 0.46 MPa was applied and the reaction lasted for 24 hours. Upon completion of the reaction, the system was cooled and the hydrogen pressure was slowly released. The catalyst was removed by diafiltration followed by distillation under reduced pressure to remove the solvent. The crude product was purified by column chromatography using petroleum ether/ethyl acetate (3:1 v/v) as eluent. The final product was 20.6 g of 2,6-difluoro-4-aminopyridine as a white solid, which was determined to be 99.7% pure by liquid chromatographic normalization in 63.5% yield.
