Patent · US Expired

Method for producing 4-amino-5-chloro-1-phenyl pyridazinone-(6)

US6538135B1 · kind B1 · utility

0Cited by

2References

5Claims

0Family size

Assignee

BASF SE

Inventors

Hans Rupert Merkle · Ludwigshafen, DE
Klaus Herbig · Schifferstadt, DE
Erich Fretschner · Neckarsteinach, DE
Helmut Fröhlich · Dinslaken, DE

Key dates

Filing date	Sep 28, 2001
Grant date	Mar 25, 2003
Priority date	—
Expiry date	Sep 28, 2021

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07D237/22
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.