FOERFARANDE Før audio FRAMSTAELLNING 4-CHLORO-5-AMINO-2-PHENYL-3 (2H) -pyridazinone UR 4,5-dichloro-2-PHENYL-3 (2H) -pyridazinone ammonia OCH

摘要

4-Chloro-5-amino-2-phenyl-3(2H)-pyridazinone is prepared from 4,5-dichloro-2-phenyl-3(2H)-pyridazinone and ammonia in high yield and substantially free from 4-amino-5-chloro- 2-phenyl-3(2 H)-pyridazinone in a method comprising reacting 4,5-dichloro-2-phenyl- 3(2H)-pyridazinone with aqueous ammonia in the presence of a catalyst (a phenolic compound) which is capable of selectively exchanging the 5-chlorine atom in 4,5-dichloro-2- phenyl-3(2H)-pyridazinone with a leaving group of such a nature that the resulting intermediate compound is capable of aklylating ammonia to 4-chloro-5-amino-2- phenyl-3(2H)-pyridazinone in high yield in the reaction medium, thereby regenerating the catalyst. The end product is isolated by filtration after the reaction and washed with water, and the mother liquor plus the wash water are used as reaction medium for the next batch.