Activation and transfer of oxygen. V. Spontaneous oxidation of 1,3,10‐trimethyl‐5,10‐dihydroalloxazine in acidic media in connection with its hydroxylating ability

On autoxidation several dihydroalloxazines show a strong hydroxylating ability without addition of metal compounds. The assumption in the literature that N1 ‐alkylated dihydroalloxazines (I) cannot activate oxygen was proved to be wrong. The material balance was studied both in the absence and in the presence of phenylalanine as a substrate. Both autoxidation and hydroxylation to tyrosines were in agreement with calculations based on a theory which has already been put forward. Hydroxylation of organic compounds may be inhibited by some inorganic anions. An explanation is given for the inhibition occurring in hydrochloric acid.