FORFARANDE FOR FRAMSTELLNING AV 4,5-DIKLORO-2-FENYL-3(2H)-PYRIDAZINON UTGAENDE FRAN 5-KLORO-4-AMINO-2-FENYL-3(2H)-PYRIDAZINON

摘要

In a process for obtaining 4,5-dichloro-2-phenyl-3(2H)-pyridazinone from 5-chloro-4-amino-2-phenyl-3(2H)-pyridazinone the 5-chloro-4-amino-2-phenyl-3(2H)-pyridazinone is diazotized in a first stage in accordance with the following reaction: (1) the compound (I) being obtained by dilution with water and filtration. In a second stage of the process the compound (I) is reacted with thionyl chloride in accordance with the following reaction: (2) the 4,5-dichloro-2-phenyl-3(2H)-pyridazinone being obtained by dilution with water and filtration.