Synthesis of 2-hydroxy-3-nitro-6-methylpyridine: 2-amino-3-nitro-6-methylpyridine (10 g, 0.065 mol) was added to 100 mL of water, and concentrated sulfuric acid (12 mL) was added slowly under stirring and cooled to 0 °C in an ice bath. Sodium nitrite (6.9 g, 0.098 mol) was added in batches, and the reaction temperature was maintained at 0 °C for 4 h, followed by a 12 h standing time. A large amount of yellow precipitate precipitated during the reaction, the precipitate was collected by filtration under reduced pressure and dried under vacuum to give 7.7 g of yellow target product in 77% yield. The melting point of the product was 216.5-218.5 °C (water).
