An Electrocatalytic System that Mimics the Catalytic Oxidation of Biogenic Mono- and Polyamines by Semicarbazide-sensitive Amine Oxidases (SSAOs)

Chemoselective oxidation of primary aliphatic biogenic mono- and polyamines into imines has been successfully achieved, under metal-free conditions, by using an electrocatalytic system that mimics the activity of semicarbazide-sensitive amine oxidase (SSAO) enzymes. Accordingly, high catalytic performance was observed with unbranched primary amines such as methylamine and aminoacetone, and with the primary amino groups of diamines and polyamines like putrescine and spermidine, all of them being reference substrates for SSAO enzymes. Furthermore, contrary to flavin-adenine dinucleotide (FAD)-dependent amine oxidase enzymes, no activity was found with secondary and tertiary amines. Finally, when compared with the direct electrochemical oxidation of primary aliphatic amines, which occurs at high anodic potential (Ean > + 1.5 V vs SCE) and led to unstable cation radicals that rapidly deprotonate and attach to the electrode surface (Pt, carbon), 1.0 V was gained using this electrocatalytic process (Ean = + 0.5 V vs SCE).