The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 08, 1997
Filed:
May. 01, 1995
Kureha Chemical Industry Co., Ltd., Tokyo, JP;
Abstract
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.