Superoxide-Promoted Oxidation Reactions of Aniline and N-Methylaniline in Dimethyl Sulfoxide

Article abstract of DOI:10.1021/jo00205a028

The chemistry of superoxide was investigated in reference to its reactions with primary and secondary aromatic amines.Two aromatic amines (aniline and N-methylaniline) reacted extensively in aprotic solutions containing potassium superoxide.In the case of aniline, trans-azobenzene and 4-nitrodiphenylamine were the major products, with smaller amounts of 4-aminodiphenylamine, 4-nitrosodiphenylamine, and p-(phenylazo)diphenylamine also being produced.With N-methylaniline, both oxidation and demethylation occurred, leading to the isolation of N-phenylformamide, aniline,and smaller amounts of azobenzene and 4-nitrodiphenylamine.Both superoxide and hydrogen peroxide alone were unable to convert either 4-aminodiphenylamine to its nitro and nitroso derivatives or N-phenylformamide to aniline.Solutions containing potassium tert-butoxide in place of superoxide produced the same products and oxygen was required for the reaction.Taken together, these results indicated that primary and secondary reducing aromatic amines are readily ionized by superoxide in aprotic solutions and then oxidized in a process involving molecular oxygen, leading to products whose structures suggest that processes such as radical recombination, N-oxidation, and N-demethylation have taken place.