Reactions of nitrosamines with nucleophiles in acid solution

The kinetics of denitrosation of N-alkyl (and aryl) N-nitrosoaniline derivatives in ethanolic HCl have been studied. In contrast with the results for the corresponding reactions in water, there is no catalysis by added nucleophiles and the solvent isotope effect is 3.8. Similar results were obtained for reactions in water at high nucleophile concentrations and also for N-methyl-N-nitrosourea in water in the absence of added nucleophiles. All the results are consistent with a change in rate-determining step which can be brought about in three independent ways. This also explains the absence of nucleophilic catalysis for N-nitrosation of amides. Results are presented for the nitrosation of N-methyl urea.