反应详情

10 parts of the betaine of 1-methyl-3-hydroxy-4,5-dichloropyridazinium salt: ##STR81## is boiled in 100 parts of thionyl chloride for two hours with an addition of 1 part of dimethylformamide. 9.5 parts (72.7% of theory) of 1-methyl-3,4,5-trichloropyridazinium chloride is obtained; C5H4N2Cl4, washed with acetonitrile.