PRODUCT OF AIR OXIDATION OF URIC ACID . AN INTERMEDIATE FORMED IN PRESENCE OF DIMETHYLAMINE

Uric and 1-methyluric acids were oxidized by air in 20% aqueous dimethylamine. The reaction is catalyzed by cupric ions or by manganese dioxide. Through nuclear magnetic resonance spectra theoxidation products have now been established as 2,5- dihydro -4-dimethylamino-2-oxo-5-ureido-1H-imidazole (IV) and 2,5-dihydro-4-dimethylamino-2-oxo-5-(3- methylureido)-1H-imidazole (V). The “isoallantoinanilide” of Frérejacque and Fosse (Frérejacque, M., and Fosse, R. 1931), Compt. Rend. 193, 860), prepared by oxidation of uric acid in aqueous potassium hydroxide in the presence of aniline, has proved to have a similar structure, rather than the symmetrical imidazolo[4,5-d]imidazole structure I previously proposed. It is apparent that the imidazole portions of uric acid and of 1-methyluric acid, respectively, remain unaffected during the formation of IV and V, in contrast to the oxidations to allantoin, in vivo or in vitro, which involve a symmetrical intermediate. © 1969, American Chemical Society. All rights reserved.