Electron-transfer initiated nucleophilic substitution of thiophenolate anion by 1-chloro-substituted 4-(thiazol-2-ylazo)naphthalenes

Abstract

In this work, the electrochemical transformation of 5-chloro-2-[(4-chloronaphthalen-1-yl)azo]thiazoles (A) into the corresponding radical anion A·− and its subsequent reaction with diphenyldisulfide (PhSSPh) was studied. It was found that the primarily generated azo anion radical A·− is able to initiate an electron transfer process which converts the disulfide into its thiolate anion PhS−. This anion was subsequently able to substitute the Cl- and H-groups by phenylmercapto moieties in the starting azo compound A. The structures of the phenylmercapto-substituted azo compounds thus generated were confirmed by thin-layer chromatography and mass spectrometry using independently prepared compounds as references. Keywords: Nucleophilic substitution, Spectroelectrochemistry, Radical anions, Disulfide splitting, Azo compounds