Adrenalin oxidation revisited. New products beyond the adrenochrome stage

In neutral aq. buffer adrenochrome, the first isolable intermediate in the oxidn. of adrenalin, undergoes rearrangement to give, besides adrenolutin, a yellow compd. which was assigned the dimeric structure I. Under anaerobic conditions, compd. I is the major reaction product (∼60%). In the presence of air a more complex pattern of products is formed including, besides I the hitherto unknown 5,6-dihydroxy-1-methyl-2,3-indoledione and the 4,4'-dimer II