Process for the manufacture of 2-phenyl-4,5-oxazoledione 4-phenylhydrazones
申请人:KUREHA CHEMICAL INDUSTRY CO., LTD.
公开号:EP0493124B1
公开(公告)日:1996-09-18
Process for the manufacture of triazolecarboxamide
申请人:KUREHA CHEMICAL INDUSTRY CO., LTD.
公开号:EP0618199B1
公开(公告)日:1997-08-13
US5434268A
申请人:——
公开号:US5434268A
公开(公告)日:1995-07-18
US5646291A
申请人:——
公开号:US5646291A
公开(公告)日:1997-07-08
Process for the manufacture of 2-phenyl-4,5-oxazoledione
申请人:Kureha Chemical Industry Co., Ltd.
公开号:US05646291A1
公开(公告)日:1997-07-08
A process for manufacturing derivatives of 2-phenyl-4,5-oxazoledione 4-phenylhyrazone is disclosed. The process comprises reacting a derivative of a benezenediazonium salt, a hippuric acid derivative, and acetic anhydride in the presence of a neutralizing agent to effect the cyclization reaction for the formation of the oxazolone ring and the succeeding diazo-coupling reaction. The process does not require the conventional separate, independent step for the preparation of a solution of a hippuric acid derivative and acetic anhydride, thus eliminating the quick heating and quenching procedures and further avoiding the loss of the hippuric acid derivative due to decomposition of the oxazolone derivative. There is thus obtained a high yield of the desired product in a short period of time.