Reaction of 1, 2-Epithioalkanes with Acid Anhydrides

Abstract

The reaction of 1, 2-epithiodecane with acetic anhydride in the presence of pyridine, triethylamine, and tributylamine gave S-(2-acetoxydecyl) thioacetate (1), 2-(acetylthio)decyl acetate (2), and S-[2-(acetylthio)decyl] thioacetate (3). Formation of bis(acetylthio)-compounds such as (3) had not been reported in the reaction of epithio-compounds with acetic anhydride. The ratio of the yields of (1), (2), and (3) was changed with reaction temperature, reaction time, amount of pyridine, and molar ratio of 1, 2-epithiodecane and acetic anhydride, but was independent of kinds of amines.The reaction of 1, 2-epithiooctane, 1, 2-epithiododecane, and 1, 2-epithiotetradecane with acetic anhydride in the presence of pyridine gave similar results described above. Higher selectivity to form the compound corresponding to (2) was observed in the reaction of 1, 2-epithiodecane with butyric and isobutyric anhydrides than with acetic anhydride.The reaction is presumed to be attack of carbonium ions of epithio-compounds activated by pyridine to acid anhydrides.