Oxidation of N-nitrosodibenzylamine and related compounds by metalloporphyrin-catalysed model systems for the cytochrome P450 dependent mono-oxygenases

Abstract

N-Nitrosodibenzylamine has been oxidised to benzaldehyde and benzyl alcohol by iodosylbenzene, 3-chloroperoxybenzoic acid and t-butyl hydroperoxide catalysed by tetraphenylporphyrinato-iron(III)chloride or -manganese (III)chloride. The influence of reaction conditions on the product yields and distribution have been studied. Kinetic isotope effects have been measured with deuteriated N-nitrosodibenzylamines for inter- and intra-molecular competition for the oxidants. The evidence presented is in favour of the iodosylbenzene and t-butyl hydroperoxide oxidations being initiated by hydrogen-atom abstraction by the oxidant from the α-hydrogen of the benzyl group. However, oxidations by the peroxy acid systems may proceed by an initial electron transfer. The reactions of N-nitrosodimethylamine and N-nitrosopiperidine with the metalloporphyrin-catalysed systems show that these substrates are surprisingly unreactive towards oxidation.