Alcohol- and Amine-Tolerant Synthesis of Six-Membered Cyclic Quaternary Ammonium Salts by Using a Triazine-Based Reagent

Six-membered cyclic quaternary ammonium salts, which are widely used in materials for both science and industry, were synthesized by using the triazine-based reagent 2-chloro-4,6-dimethoxy-1,3,5-triazine. The combination of sodium tetrafluoroborate as an additive and acetonitrile as a solvent was shown to be effective in the prevention of side reactions. Significantly, this method is tolerant toward hydroxy and amino groups, which are labile under conventional reaction conditions for the synthesis of cyclic quaternary ammonium salts. Moreover, a sterically hindered piperidinium salt was successfully prepared.