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:
Sep. 07, 1982
Filed:
Jul. 13, 1981
Antoine G Breda, Craponne, FR;
Jacques G Roussel, Bosc Roger en Roumois, FR;
P C U K Produits Chimiques Ugine Kuhlmann, Courbevoie, FR;
Abstract
The invention relates to the preparation of 1-phenyl-3-carbamoyl-5-pyrazolones of the formula: ##STR1## in which the two symbols R and R' may be the same or different and each represents a hydrogen atom, an alkyl radical or a substituted alkyl radical containing 1 to 4 carbon atoms. An aqueous paste of diethyl oxalacetate phenylhydrazone is heated at a temperature not greater than 85.degree. C. until the hydrazone is completely melted, and the aqueous phase is then removed and the remaining hydrazone is treated with 2 to 12 molar equivalents of a compound of the formula HNRR' at a temperature between 20.degree. and 100.degree. C. The formation of 1-phenyl-3-carboxy-5-pyrazolone is thus avoided.