Thio carbamates and their derivatives

Abstract

A method is provided for preparing N-acylaminothiophenols, e.g., N-acetyl-para-aminothiophenol, or aminothiophenols, e.g., para-aminothiophenol, or N,S-diacylaminothiophenols, e.g., N,S-diacetyl-para-aminothiophenol, by reacting any of certain sulfur-containing ketones, viz., an S-(acylaryl) N,N-di(organo)thiocarbamate, e.g., S-(4'-acetophenyl)-N,N-dimethylthiocarbamate, an acylthiophenol acylate ester, e.g., 4-acetothiophenol acetate, or a free acylthiophenol, e.g., 4-acetothiophenol 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 an S-(N-acyl-aminoaryl) N,N-di(organo)thiocarbamate, e.g., S-(N-acetyl-para-aminophenyl) N,N-dimethylthiocarbamate, an N,S-diacylaminothiophenol, e.g., N,S-diacetyl-paraaminothiophenol, or an N-acyl aminothiophenol, e.g., N-acetyl-para-aminothiophenol, respectively. The S-(N-acyl-aminoaryl) N,N-di(organo)thiocarbamate may be hydrolyzed to the N-acyl aminothiophenol or aminothiophenol. The S-(acylaryl) N,N-di(organo)thiocarbamate may be produced by reacting a hydroxy aromatic ketone, e.g., 4-hydroxyacetophenone (4-HAP) with an N,N-di(organo)thiocarbamoyl halide, e.g., N,N-dimethylthiocarbamoyl chloride (DMTC) to form an O-(acylaryl) N,N-di(organo)thiocarbamate, e.g., O-(4'-acetophenyl) N,N-dimethylthiocarbamate, and pyrolytically rearranging the latter compound. The acylthiophenol may be produced by hydrolyzing the S-(acylaryl) N,N-di(organo)thiocarbamate.