Synthesis of 1-chloro-1-[15N]nitrosocyclohexane, an electrophilic aminating reagent

We have prepared 1-chloro-1-[15N]nitrosocyclohexane, an electrophillic aminating reagent useful for the stereoselective synthesis of α-[15N]amino acids. Treatment of potassium [15N]nitrate with Pbo gave potassium [15N]nitrite, which was converted into the intermediate hydroxylamine disulfonate by treatment with sodium bisulfite and sulfur dioxide. Addition of an excess of cylohexanone followed by heating gave a mixture of the cyclohexanone [15N]oxime and unreacted cyclohexanone which was removed in vacuuo. The resulting [15N]oxime was then converted to 1-chloro-1-[15N]nitrosocyclohexane in essentially quantitative yield by treatment with chlorine gas. (Author)