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:
Mar. 16, 2004
Filed:
Jun. 26, 2002
DSM Fine Chemicals Austria Nfg GmbH & Co KG, Linz, AT;
Abstract
The invention relates to a method for producing 2-oxindoles from the corresponding isatines of formula (I), wherein R can be H, CH , phenyl or benzyl and R can be H, C -C -alkyl, C -C -alkoxy, phenyl phenoxy, halogen, amino, nitro or hydroxy. Said isatines are converted by means of hydrazine hydrate in a polar solvent at a temperature of 15 to 185° C. to form a corresponding isatine hydrazone which directly undergoes further reaction to form the corresponding 2-oxindole of formula (II) by adding diazabicyclooctane and/or diazabicycloundecane and/or ethyldiisopropylamine as a catalyst in temperatures of 100 to 185° C., whereby the produced reaction water is distilled off. According to formula (II), R and R have the aforementioned definitions. The 2-oxindole is isolated from the reaction mixture by distilling off the solvent and by means of crystallisation.