Hydrochloric Acid → 3,5-Dichloro-3-pyridylamine

참여 물질

반응 단계

To produce 2-amino-3,5-dichloropyridine, 30 parts of chlorine are introduced in the course of 30 minutes, with slight cooling, into a solution of 37.6 parts of 2-aminopyridine in 160 parts of concentrated hydrochloric acid. The temperature is then raised to 50° to 60° C. and a further 60 parts of chlorine are introduced during 6 hours. After completion of the chlorine addition, the solution is poured onto ice, and the chlorine still present is removed with sodium bisulphite. There is then added a solution of 95 parts of sodium hydroxide in 150 parts of water, whereupon 2-amino-3,5-dichloropyridine precipitates. It is filtered off, washed with ice-water and dried at room temperature in water-jet vacuum. There are obtained 58.5 parts (90% of theory) of 2-amino-3,5-dichloropyridine, m.p. 77°-79° C.

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