Coupled and decoupled processes in the autoxidation of partially reduced pteridines and flavins

Organic hydroperoxide formation has to be regarded as the primary process in the autoxidation of partially reduced pteridines and flavins, to be distinguished from secondary oxidations and H 2 O 2 ‐production. Material balances between oxidized products, O 2 ‐uptake and H 2 O 2 ‐formation have been determined under varying experimental conditions and found to be in agreement with a general formula based on the new theory. Spontaneous oxidation of a blocked dihydroalloxazine afforded a tetrahydroquinoxaline‐2‐spiro‐5′‐hydantoin as the ring‐contraction product of the transient hydroperoxide, confirming the structure previously proposed by us.