Practical Method for the Synthesis of Mesoionic 1,3-Diaryltetrazolium Derivatives Bearing a Para-substituted Phenyl Group at the 1- or 3-Position from Anilines

A simple, economical, and safe method for the synthesis of mesoionic 1,3-diaryltetrazolium derivatives bearing a p-substituted phenyl group at the 1- or 3-position via thiosemicarbazides was established. Such compounds were directly obtained from the corresponding p-substituted anilines instead of aryl isothiocyanates and arylhydrazines. The newly synthesized mesoionic compounds were successfully converted into the corresponding nitrosotetrazolium salts, which were utilized as catalysts for oxidation of an aliphatic alcohol and analyzed by cyclic voltammetry to determine the correlation between the catalytic efficiencies and redox potentials. The proposed method can be widely applied and is valuable for investigating the substituent effects in mesoionic and related compounds.