Electrochemical reduction off 4-aminopyrimidine in aqueous media

Abstract

The redox and associated chemical behavior of 4-aminopyrimidine (4-AP) and its reduction products in buffered aqueous media have been examined by a variety of electrochemical techniques. In acidic medium (pH 0-2), 4-AP undergoes a two-step reduction: pH-dependent wave I corresponds to a three-electron (3e) process; wave II, which corresponds to a 1e transfer, is accompanied by catalytic hydrogen discharge. Between pH 2 and 7.5, only wave I is visible; its height diminishes above pH 4, becoming zero by pH 8. Macroscale electroreduction at potentials on the crests of waves I and II has been followed electrochemically and by ultraviolet spectrophotometry with isolation and identification of the wave I reduction products. The photochemical transformation of the reduction products on ultraviolet irradiation has been examined. The reduction of 4-AP is accompanied by isomerization, ring opening and/or deamination of the primary reduction products and of the resulting secondary chemical products.