Aspects of the denitrosation of nitroso compounds in acidic solution

Abstract

The thesis seeks to provide a rationale for the behaviour of a wide range of N-nitroso compounds in acidic solution. The work is introduced by a review of the various mechanisms proposed to date. It is shown that the behaviour of the system towards certain catalytic agents is dictated by the relative rates of the protonation and denitrosation reactions. The effect of changing nitroso compound structure, changing nucleophile concentrations and changing solvents has been investigated and the results used to provide a common rationale for the denitrosation and N-nitrosation reactions.Supporting data is provided in the form of investigations of the denitrosations of N-methyl-N-nitrosoaniline, N-nitrosodiphenylamine, N-methyl-N-nitrosourea and a series of p-substituted N-methyl-N- nitrosoanilines. The N-nitrosation of N-methylurea is also examined. A comprehensive study of the action of sulphur containing nucleophiles such as the thioureas has led to the proposal of a reaction between N-methyl-N-nitrosoaniline and the naturally occurring nucleophiles, cysteine, S-methylcysteine, glutathione and methionine. The results maybe important in the elucidation of cancer mechanisms. Evidence is also provided for an interaction between N-methyl-N- nitrosoaniline and the ferrous ion.