Patent ID: 6469181
Filing Date: 2002-10-22
Classification: C07C,C07D

Abstract:
A process for preparing a 2-oxindole, a N-hydroxy-2-oxindole, or mixtures thereof, comprising:A) catalytically hydrogenating a 2-nitroarylmalonate diester to produce a 2-(N-hydroxyamino)arylmalonate diester, a 2-aminoarylmalonate diester, or mixtures thereof as a first reaction intermediate; B) cyclizing, by intramolecular aminolysis of one ester group, the first reaction intermediate to produce a N-hydroxy-2-oxindole-3-carboxylate ester, 2-oxindole-3-carboxylate ester, or mixtures thereof as a second reaction intermediate; and C) hydrolyzing and decarboxylating the remaining ester group of the second reaction intermediate to produce the N-hydroxy-2-oxindole, the 2-oxindole, or mixtures thereof; wherein the cyclization reaction and the hydrolysis and decarboxylation reaction are conducted in situ with the catalytic hydrogenation reaction without isolation of said reaction intermediates.