Reactions of Nitrosoureas and Related Compounds in Dilute Aqueous Acid: Transnitrosation to Piperidine and Sulfamic Acid

Article abstract of DOI:10.1021/jo00330a016

The transnitrosation reactions of four classes of nitrosamides in dilute aqueous acid were studied.Trialkyl nitrosoureas and nitrosoguanidines were found to react very rapidly in transnitrosations to piperidine, giving high yields (70-90percent) of nitrosopiperidine at pH 1.7 (perchloric acid) or pH 3.3 (formate buffer).Methylnitrosourea reacted more slowly than either the trialkylnitrosoureas or the nitrosoguanidines and gave moderate yields (48percent) of nitrosopiperidine at pH 1.7 and low yields (6percent) at pH 3.3.Nitrosourethanes gave high yields at pH 1.7 and moderate yields at pH 3.3.Denitrosation rates (transnitrosation to a nitrite trap) are given for a series of monoalkyl- and trialkylnitrosoureas.An increase in the size of the alkyl group at N₁ decreased the rate of denitrosation.The kinetics of nucleophile-catalyzed transnitrosation from trialkylnitrosoureas to piperidine at pH 1.7 for a series of four trialkylnitrosoureas have been studied.Both the denitrosation of the donor and the nitrosation of the recipient were studied with respect to thiocyanate ion concentration.The denitrosation step was affected only at high , while the nitrosation step showed a first-order dependence on thiocyanate at most concentrations, with a "leveling off" effect observed at high .The denitrosation step does not exhibit a true dependence on thiocyanate concentration but merely reflects the rapid rate of the nitrosation of the recipient piperidine at high as a consequence of mass action.The behavior of nitrosoureas in transnitrosation reactions is compared with that of alicyclic nitrosamines.The latter differ from nitrosoureas in that they react more slowly, require a nucleophilic cataly sis at the denitrosation step, and do not always nitrosate strongly basic amines.