The chemistry of nitroso-compounds. Part VI. Direct and indirect transnitrosation reactions of N-nitrosodiphenylamine

Abstract

Transfer of the nitroso-function from N-nitrosodiphenylamine to N-methylaniline, sodium azide, and other nucleophilic species is reported for acidic 50% aqueous ethanol at 25 °C. Neutral N-nitrosodiphenylamine is unreactive and protonation is required to initiate these reactions. Transfer to N-methylaniline is not catalysed by added Cl^–, which suggests that the nitroso-group is transferred without the intermediacy of nitrous acid (direct transnitrosation). Transfer to sodium azide under similar conditions does proceed via nitrous acid. For other nucleophiles, however, both direct and indirect transnitrosation reactions may compete. Reaction rates are independent of these nucleophilic species when their concentration is high. Solvent isotope effects for reaction under these circumstances are negligible which suggests that an intramolecular rearrangement of the conjugate acid rather than protonation of the N-nitrosodiphenylamine is rate-limiting.