40966-87-8

35570-68-4

40966-87-8

Example 2: Sodium hydroxide (355 g, 8.883 mol) and deionized water (3.5 L) were added to a 50 L single-necked round-bottomed flask equipped with a magnetic stirrer. After the sodium hydroxide was completely dissolved, 6-chloro-oxazolo[4,5-b]pyridin-2(3H)-one (3.14 g, 0.018 mol) was added to the reaction system and a reflux condenser was installed. The reaction mixture was heated to reflux for 10 hours. The completion of the reaction was confirmed by thin layer chromatography (TLC) and gas chromatography (GC) monitoring. The pH of the reaction mixture was adjusted to 8 with 12 mol/L hydrochloric acid solution, at which point a large amount of precipitate was generated. The reaction mixture was filtered and the filter cake was washed with deionized water (400 mL) and dried to give the target product 2-amino-3-hydroxy-5-chloropyridine (420 g, 98% yield), which was analyzed by GC to be 97.9% pure. The melting point of the product was measured to be 197°C~202°C (literature value: 198°C~201°C).