Study on the reaction of isatin with phosphorus pentasulfide

Abstract

Reaction of isatin with phosphorus pentasulfied gave an unexpected product. By this reaction, oxindole was obtained from isatin in one step. General procedure was the reaction of isatin with phosphorus pentasulfide in pyridine solvent and followed by aqueous work-up. Oxindole was also obtained by the reaction of isatin3-anilide with hydrogen sulfide. Isatin-3-anilide was prepared by the reaction of isatin with aniline in the ethanol solvent containing a drop of acetic acid. Hydrogen sulfide which was produced by treatment of ferrous sulfide with dilute sulfuric acid, was bubbled to ethanol solution of isatin-3-anilide. These compound were identified by $^1$H NMR, IR, and GC/MS.