Analytical characterization of "etonitazepyne," a new pyrrolidinyl-containing 2-benzylbenzimidazole opioid sold online

Abstract

This paper reports on the identification and full chemical characterization of the substance colloquially called "etonitazepyne" or "N-pyrrolidino etonitazene" (2-(4-ethoxybenzyl)-5-nitro-1-(2-(pyrrolidin-1-yl)ethyl)-1H-benzo[d]imidazole), a potent NPS opioid of the 5-nitrobenzimidazole class. Identification of etonitazepyne was performed, on a sample purchased during routine monitoring of the drug market, using GC-MS, HRAM LC-MS/MS, ¹ H NMR, and FTIR. The chromatographic data, together with the FTIR data, indicated the presence of a highly pure compound and already indicated a benzimidazole structure. The specific benzimidazole regio-isomer was confirmed using ¹ H NMR spectroscopy, resulting in the unambiguous identification of etonitazepyne.

Keywords: benzimidazoles; etonitazene; new psychoactive substances; opioid NPS; pyrrolidine analogue.