反应详情

温度

40 °C

A solution of hydroxylamine-O-sulfonic acid (73.4 g) in water (80 mL) and a separate solution of potassium carbonate (65.5 g) in water (80 mL) were added concurrently dropwise to a solution of pyridazine (40.0 g) in water (120 mL) at 50° C., maintaining a reaction mixture pH of 3.5-4.0. The reaction mixture was then heated at 40° C. for 2 hours to give a solution of N-aminopyridazinium sulfate, which was subsequently cooled to 20° C. and filtered. The filtrate was added dropwise to a solution of potassium hexafluorophosphate (91.9 g) in water (460 mL) at 50° C. The resulting suspension was slowly cooled to 5° C. over a 2 hour period, stirred for 30 minutes and the product isolated by filtration. The filtercake was washed portionwise with water (320 mL) and the product dried in vacuo at 40° C. to give the title compound as a white crystalline solid (69.9 g, 58%).