1161847-36-4

1161847-35-3

1161847-36-4

Tert-butyl (6-chloroimidazo[1,2-b]pyridazin-8-yl)carbamate (1.59 g, 5.91 mmol) was used as a raw material and dissolved in a mixture of 30 mL of dichloromethane and 15 mL of trifluoroacetic acid. After the reaction was completed, the solution was concentrated to a yellow oil. Subsequently, 50 mL of saturated aqueous sodium bicarbonate solution was slowly added for treatment. Undissolved solids were separated by filtration through a Brinell funnel and rinsed with plenty of water. Finally, drying by vacuum aspiration gave 1.10 g (102% crude yield) of 6-chloroimidazo[1,2-b]pyridazin-8-amine as a yellow solid, which can be used without further purification.