Investigation of the impurities found in methamphetamine synthesised from pseudoephedrine by reduction with hydriodic acid and red phosphorus.

The synthesis of methamphetamine from pseudoephedrine via the reduction with hydriodic acid and red phosphorus was studied and the impurities which were generated, along with the methamphetamine, were investigated. Some of the impurities found have been reported previously, while the diastereoisomers of N-methyl-N-(alpha- methylphenethyl)amino-1-phenyl-2-propanone and the cis-cinnamoyl derivative of methamphetamine are reported here for the first time. Further work on the sequence of reactions occurring in this reduction is also reported.