Electrochemical oxidative selective halogenation of pyrazolones for the synthesis of 4-halopyrazolones

Abstract

An efficient and environmentally friendly electrochemical oxidative selective halogenation of pyrazolones has been developed under conditions free of metals, external oxidants, and external supporting electrolytes. The reaction demonstrates good functional group tolerance and maintains high efficiency in large-scale synthesis, yielding moderate to excellent yields of the desired 4-halopyrazolones. This method provides a green and convenient route for the direct installation of a halogen moiety into bioactive pyrazolone derivatives, which can be utilized in a myriad of applications.