Prediction of designer drugs: Synthesis and spectroscopic analysis of synthetic cathinone analogs that may appear on the Swedish drug market

Andreas Carlsson, Veronica Sandgren, Stefan Svensson, Peter Konradsson, Simon Dunne, Martin Josefsson, Johan Dahlén

The use of hyphenated analytical techniques in forensic drug screening enables simultaneous identification of a wide range of different compounds. However, the appearance of drug seizures containing new substances, mainly new psychoactive substances (NPS), is steadily increasing. These new and other already known substances often possess structural similarities and consequently they exhibit spectral data with small differences. This situation has made the criteria that ensure indubitable identification of compounds increasingly important. In this work, six new synthetic cathinones that have not yet appeared in any Swedish drug seizures were synthesized. Their chemical structures were similar to those of already known cathinone analogues of which 42 were also included in the study. Hence, a total of 48 synthetic cathinones making up sets of homologous and regioisomeric compounds were used to challenge the capabilities of various analytical techniques commonly applied in forensic drug screening, i.e. GC-MS, GC-FTIR, NMR and LC-QTOF-MS. Special attention was paid to the capabilities of GC-MS and GC-FTIR to distinguish between the synthetic cathinones and the results showed that neither GC-MS nor GC-FTIR alone can successfully differentiate between all synthetic cathinones. However, the two techniques proved to be complementary and their combined use is therefore beneficial. For example, the structural homologues were better differentiated by GC-MS, while GC-FTIR performed better for the regioisomers. Further, new spectroscopic data of the synthesized cathinone analogues is hereby presented for the forensic community. The synthetic work also showed that cathinone reference compounds can be produced in few reaction steps.