The general procedure for the synthesis of 6-fluoro-3,5-dichloro-4-amino-2-hydroxypyridine using 2,6-difluoro-3,5-dichloro-4-aminopyridine as starting material was as follows: accurately weighed 80 mmol of 2,6-difluoro-3,5-dichloro-4-amino-pyridine in a reaction flask, and 5,000 mL of N,N-dimethylacetamide (DMAC) was added to dissolve it completely. A 40 wt% aqueous sodium hydroxide solution was slowly added dropwise with continuous stirring. After the dropwise addition was completed, the reaction system was warmed up to 100 °C and the reaction was maintained at this temperature for 3 hours. After completion of the reaction, the mixture was cooled to room temperature and the target compound 6-fluoro-3,5-dichloro-4-amino-2-hydroxypyridine (Compound I) was isolated by suitable method in 94.5% yield.
