Electrochemical Reduction of 4-aminopyrimidine in Aqueous Media

The redox and associated chemical behavior of 4aminopyrimidine (4AP) and its reduction products in buffered aqueous media have been examined by a variety of electrochemical techniques. In acidic medium (pH O-2), 4AP undergoes a two-step reduction: pH-dependent wave I corresponds to a threeelectron (3~) process; wave II, which corresponds to a le transfer, is accompanied by catalytic hydrogen discharge. Between pH 2and 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 electrochemkally 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 QAP is accompanied by isomerization, ring opening and/or deamination of the primary reduction products and of the resulting secondary chemical products.