Evidence for the involvement of iodoephedrine and iodopseudoephedrine in the Nagai and related reactions

Three synthetic methods commonly used for the synthesis of methamphetamine, the Nagai, Hypo, and Moscow methods, were investigated as to their reaction mechanisms. Evidence for the involvement of iodoephedrine and iodopseudoephedrine as intermediates in these reactions was obtained, which supports a long-held hypothesis as to the reaction mechanism. However, experiments carried out invite a re-evaluation as to the origin and fate of cis- and trans-1-phenyl-2,3-dimethylaziridine in these synthetic methods, especially in regard to their involvement in the production of phenyl-2-propanone.