Indirect Electrochemical Oxidation of Amines using Triazolinediones as an Environmentally Friendly Method

Organic electrosynthesis is one of the promising methodologies by having importantcriteria which is needed if society is to develop environmentally compatible processes. Eliminatingtoxic or hazardous oxidizing or reducing reagents, economical energy consumption, and in situproduction of unstable and dangerous reagents are some advantages of this strategy.Electrosynthesis covers at least nine priciples of twelve green chemistry principles. Amongelectrochemical procedure "indirect electrolysis" provides an important option to create catalyticsynthetic processes with decreased energy consumption and chemical waste. The catalyst isregenerated at the electrode and only small quantities of the redox reagent are used.Electrochemical oxidation of amines has a great attention due to industrial importance. Aminesparticipate in many important biological and chemical reactions and hence are of interest in thefood, corrosion, agrochemicals, pharmaceutical, and other industries. Herein we introducetriazolinediones as perfect mediatior for efficient amine oxidation. The oxidized form of ۴-phenylurazole (۴-phenyl triazolinediones) is highly unstable and ring cleavage occurs due to the۲simultaneous presence of both carbonyl and azo moieties. Instability is more critical by thepresence of electron-withdrawing group in the structure. However, the results revealtriazolinediones promote a wide range of amine oxidations despite high instability due to fastchemical kinetic of oxidative ring cleavage. The results of current work indicate thatelectrochemical oxidation of urazole in the presence of amine is not a simple electrocatalyticreaction (EC' (E: electron transfer, C': catalytic chemical reaction)). The voltammogram featuresshow that reaction proceeds via both EC' and ECE pathways. However, the reactions are stronglyinfluenced by media and reaction conditions. In this study, the effect of different parameters suchas pH, concentration ratio of amine to urazole, substitute effect of triazolinedione and amine havebeen studied. Moreover, the effects of electronic and structure nature of amines were evaluated foraromatic, aliphatic and benzylic amines.