Enzymes in polymer synthesis: Horseradish peroxidase-catalyzed oxidative polymerization of phenols bearing nitron groups in p-position and their photochemical behavior

The horseradish peroxidase (HRP)-catalyzed polymerization of 4-hydroxy-benzaldehyde-methylnitron (3) led to the formation of corresponding soluble polyphenols (4). The polymers were synthesized in water/1,4-dioxane and in water/acetone mixtures. The molecular weight (M w) was found to be in the region of 9000 g/mol according to SEC measurements. From ESI-TOF spectra the existence of oligomers up to hexamers was established. By this way the polymeric nitron was directly synthesized for the first time via radical intermediates. Upon UV-treatment, the polymer became less polar and changed its solubility due to the formation of three-membered oxaziridine rings from the 1,3-dipolaric nitron functions.