Intramolecular Conversion of N-Nitroso Ketimines into Ketones and Nitrogen. 1,2,3-Oxadiazetines as Analogues of Dioxetanes

Article abstract of DOI:10.1021/jo00136a016

N-Nitrosobenzophenone imine and N-nitrosocamphorimine have been prepared by the nitrosation of the corresponding imines with nitrosyl chloride or dinitrogen tetraoxide.N-Nitrosobenzophenone imine decomposes by first-order kinetics to yield benzophenone and nitrogen; the activation parameters are ΔH₂₅(excit.) = 18.7 kcal/mol and ΔS₂₅(excit.) = -11 eu.The reaction is not affected appreciably by small amounts of water, and the use of H2(18)O has shown that the oxygen atom of the nitroso imine is retained in the benzophenone.The kinetic information, entropy ofactivation, and lack of water incorporation indicate that the ketone-forming reaction is an intramolecular one.A proposed intermediate in this decomposition bears a resemblance to the dioxetanes, which are known to yield excited states on decomposition.However, we were unable to detect excited states from the decomposition of either N-nitrosobenzophenone imine or the nitroso imine of N-methylacridone.