Methamphetamine from Ephedrine: I. Chloroephedrines and Aziridines

Illicit methamphetamine clandestinely synthesized from ephedrine via reduction of chloroephedrine is discussed. The stereochemistry, mechanism, synthetic impurities, and analysis of clandestine methamphetamine samples is addressed. Stereochemical relation of (+)methamphetamine to its initial precursor (−)ephedrine or (+)pseudoephedrine is achieved by detection of (+)chloropseudoephedrine or cis-1,2-dimethyl-3-phenylaziridine, in the case of the first, and (-)chloroephedrine or trans-1,2-dimethyl-3-phenylaziridine in the case of the latter.