Hydrolysis and Fe2+-induced Reduction of N-Aryl -O-pivaloylhydroxylamines: Aqueous Solution Chemistry of Model Carcinogens.

Article abstract of DOI:10.1021/jo00255a018

The N-aryl-O-pivaloylhydroxylamines, 1a-d, which serve as models for the carcinogenic metabolites of aromatic amines, decompose in aqueous media by heterolysis of the N-O bond.Substituent effects on rates of reaction and products of the decomposition of 1a-c are entirely consistent with the intermediacy of a singlet nitrenium ion.The least reactive compound in the series N-(4-nitrophenyl)-O-pivaloylhydroxylamine (1d) yields 4-nitroaniline (2d) as its major decomposition product.This material may be formed through H radical abstraction by a triplet ion, but a nitrene reaction appears to be more likely.In the presence of Fe²⁺ 1a-d undergo rapid reduction to the corresponding anilines 2a-d.This reaction requires complexation of the ester with Fe²⁺ and proceeds with heterolysis of the N-O bond since nearly quantitative yields of pivalic acid are isolated.The radical cations 25a-d appear to be the most likely precursors to the reduction products.