Synthesis of oxindoles from anilines and intermediates therein

Claim 1

A process for preparing 2-oxindoles which comprises a. reacting an N-haloaniline with a β-thio compound selected from the group consisting of a lower-alkyl β-thioalkanoate ester and a lower-alkyl β-thioalkanoyl acylamide in organic liquid diluent under substantially anhydrous conditions at a temperature of from about -78° C to about 10° C to form an azasulfonium salt; b. reacting the azasulfonium salt from step (a) with a substantially anhydrous base which will cause formation of an ylid intermediate to form an .[.ortho-[(thioalkyl) (alkylthiocarbonyl)methyl]-aniline,.]. .Iadd.ortho-[1-(thioalkyl) (lower-alkyloxycarbonyl)-methyl]-aniline, when the β-thio compound of step (a) is a lower-alkyl β-thioalkanoate ester, and an ortho [1-(thioalkyl) (lower-alkylaminocarbonyl) methyl]-aniline when the β-thio compound of step (a) is a lower-alkyl β-thioalkanoyl acylamide, .Iaddend. c. heating the ortho-substituted aniline from step (b) to from about 50° C to about 150° C or acidifying the substituted aniline from step (b) to form a 3-thioalkyl-2-oxindole, and d. desulfurizing the 3-thioalkyl-2-oxindole from step (c) to form the 2-oxindole.