Further insight into the reaction of electrogenerated o-quinone with amino-alcohols and amines. Products and mechanism

Abstract

Using 2,3,4-trihydroxybenzophenone as the starting material, the reaction of the electrogenerated 3,4-quinone with amino-alcohols and amines HC(R¹,R²)–NH₂ is suggested to proceed via an ionic mechanism that would involve a C(3) aminated carbinolamine intermediate and would afford, after dehydration, a 3,4-iminoquinone species. The subsequent step would consist either of a transamination reaction, or of the formation of a spiro aminoketal species (when using amino-alcohols as the substrate), or of a redox cycling reaction allowing the isolation of 3,4-alkylaminophenol derivatives.