Semi-systematic Frameworks for Naming of NPS in Europe: Synthetic Cannabinoids and Cathinones

Inherent to the heterogeneous groups of synthetic cannabinoids (SCs) and cathinones is a broad structural diversity. Historically, semi-systematic names were chosen for NPS upon first identification to convey structural information. Due to the lack of documentation, naming approaches have been applied inconsistently, leading to names only loosely associated with structural features and several alternative names. One of the roles of the EMCDDA is to share information on NPS with forensic and toxicology laboratories. Because many SCs and cathinones are identified for the first time in Europe, the EMCDDA is responsible for setting best practices and hands-on guidance on naming NPS. The structural diversity and current naming approaches of SCs and cathinones monitored by the EMCDDA in Europe were reviewed. The structural inventory of SCs and cathinones is visualized in graphical and tabular formats. Naming syntaxes were developed for SCs and cathinones, considering current names and established naming rationale. For the naming of SCs, an expanded syntax based on the letter code system was developed to combine building blocks and substitution(s). The naming of cathinones was developed based on the main motifs ‘cathinone’ and ‘phenone,’ and incorporates earlier naming approaches. The framework name is composed of a parent element, which, combined with information on the keto alkyl chain or the amine substitution, yields the principal name. A web-based naming tool will complement the theoretical frameworks. The EMCDDA naming frameworks provide practical guidance through examples and explanations of the rationale on how consistent semi-systematic names can be derived.