Thiocarbamates and their derivatives

Abstract

A process is provided for preparing N-acyl-aminothiophenols, e.g., N-acetyl-para-aminothiophenol, or aminothiophenols, e.g., para-aminothiophenol, by reacting a hydroxy aromatic ketone, e.g., 4-hydroxyacetophenone (4-HAP), with hydroxylamine or a hydroxylamine salt, to form the oxime of the ketone, subjecting the oxime to a Beckmann rearrangement in the presence of a catalyst to form the N-acyl-hydroxy aromatic amine, e.g., N-acetyl-para-aminophenol (APAP), reacting the N-acyl-hydroxy aromatic amine with an N,N-di (organo) thiocarbamoyl halide, e.g., N,N-dimethylthiocarbamoyl chloride, to form an O-(N-acyl-aminoaryl)-N,N-di (organo) thiocarbamate, e.g., O-(N-acetyl-para-aminophenyl)-N,N-dimethylthiocarbamate, pyrolytically rearranging the O-(N-acyl-aminoaryl)-N,N-di (organo) thiocarbamate to form an S-(N-acyl-aminoaryl)-N,N-di (organo) thiocarbamate, e.g., S-(N-acetyl-para-aminophenyl)-N,N-dimethylthiocarbamate, and hydrolyzing the latter compound to obtain the N-acyl aminothiophenol or aminothiophenol. The N-acyl aminothiophenol may be reacted with an acylating agent to form the N,S-diacyl-aminothiophenol, e.g., N,S-diacetyl-p-aminothiophenol, or may be further hydrolyzed to the aminothiophenol, e.g., p-aminothiophenol.