Abstract: The redox reactions of 4-substituted piperidinc nitroxidcs with hydroxylamine (NH₂OH) in mcthanol over a wide range of pHvalues were investigated. It was found that the nitroxides were rapidly reduced to the corresponding hydroxylamine hydrochlorides in acidic medium, while hydroxylamine was oxidized to nitrous oxide. Futhcrmore, the reaction also took place slowly in alkaline media, but the piperidinc hydroxylamincs formed arc unstable under alkaline conditions and readily oxidized by oxygen in the air to regenerate the nitroxidc radicals. In order to examine this reaction, an alternative route to prepare the piperidine hydroxylamines was carried out via the reactions of the nitroxides with vitamin C.