Laccase-Catalysed Homocoupling of Primary Aromatic Amines towards the Biosynthesis of Dyes

摘要: Coloured disubstituted benzoquinonimine trimeric structures are obtained as main reaction products of the oxidation p-electron donor pri- mary aromatic amines using two different laccases, CotA-laccase from Baccilus subtilus and TvL Trametes versicolor. These orange-red to purple products, presenting high molar extinction coeffi- cients, presumably result oxidative homocou- pling reactions, through formation NC bonds at positions 2 5, laccase oxidised inter- mediate showed in proposed path- way. The product 1,4-phenylenediamine is shown be trimer known Bandrowskis base which has an established role hair fur dyeing. Our results also show that occurrence and/or rates strongly dependent on presence releasing substituents ring independent properties enzyme used. Overall our data con- tribute for (i) understanding key features reactivity with p-substituted (ii) establishing enzymatic processes lead syn- thesis coloured bio-products under mild condi- tions potential impact cosmetic dye industries.