The Cocaine Diastereoisomers

In the past, it has been argued in court, from a theoretical basis, that the techniques available to the forensic chemist would differentiate the “cocaines.” This work has moved that argument from the realm of the theoretical into that of experimental fact. The techniques of infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and mass spectrometry (MS) will unequivocally identify the racemic cocaine diastereoisomer. In addition, this work shows that the enantiomeric form of cocaine can be assigned by crystal tests, IR, and melting point techniques. The pure enantiomers of allococaine and pseudoallococaine were not isolated. This does not create a problem because the techniques of NMR and MS, as performed in this study, will not differentiate enantiomers. Therefore, the logical sequence of first identifying the diastereoisomer (via IR, MNR, or MS) and then determining the chirality by crystal tests, IR, melting points, or optical rotation measurements is valid.