112581-77-8

127566-18-1

112581-77-8

Example 4: 1.88 g of 6-chloro-3-imino-2,3-dihydropyridazine-2-acetic acid (purity: 99.5 wt%) was mixed with 7.52 g of monochlorobenzene and 0.79 g of pyridine. 3.84 g of phosphoryl chloride was slowly added dropwise to the mixture over a period of 3 minutes at an endothermic condition of 20 to 40 °C. Subsequently, the reaction system was heated to an endothermic temperature of 120 °C within 20 minutes and the reaction was continued at this temperature for 6 hours. Upon completion of the reaction, the mixture was cooled to give a reaction mixture containing 2,6-dichloroimidazo[1,2-b]pyridazine.The yield of 2,6-dichloroimidazo[1,2-b]pyridazine was 99%.