公开(公告)号：CZ20013470A3

公开(公告)日：2002-03-13

申请号：CZ20013470

申请日：2000-03-30

Applicant: BASF AG

Inventor： MEKLE HANS RUPERT ,  HERBIG KLAUS ,  FRETSCHNER ERICH ,  FROHLICH HELMUT

IPC: C07D237/22

Abstract: In a process for preparing 4-amino-5-chloro-1-phenylpyridazin-6-one by reacting 4,5-dichloro-1-phenylpyridazin-6-one with aqueous ammonia in the presence of a catalyst, the catalyst used is soluble in the aqueous alkaline reaction medium but is essentially insoluble in the reaction medium which has been acidified after removal of the 4-amino-5-chloro-1-phenylpyridazin-6-one.The process of the present invention makes it possible for the catalyst to be recovered and reused in a simple manner.