77992-44-0

2-Chloro-5-bromopyridine (64 g, 333 mmol) was suspended in hydrazine monohydrate (250 mL), and the mixture was heated at 70° C. for 72 hours. The reaction mixture was then diluted with water (750 mL), and the resulting precipitate was filtered off and azeotrope, firstly with toluene (*2) and then dichloromethane (*2), to afford 5-Bromo-2-hydrazinopyridine as a pale brown solid in 83percent yield, 52 g.