EMCDDA Framework for Naming Synthetic Cannabinoids

Synthetic cannabinoids (SCs) are the largest and structurally most heterogeneous group of NPS. Several independent naming conventions have been employed, leading to inconsistent and sometimes ambiguous short names. All SCs monitored by the EMCDDA were assessed, and letter codes were assigned to each building block. An expanded syntax was developed to combine building blocks and their substitution. Established letter codes, including the highly recognizable ‘FUB’ and ‘GaClone’ letter codes, were kept unchanged. The chemical diversity is presented in graphical and tabular format, providing a structural library of SCs. Examples of previous inconsistencies include multiple letter codes describing the same structural feature (benzyl – B/BENZ/BZ), inconsistent abbreviation of the systematic name (methyl dimethylbutanoate – MDMB, amino dimethyloxobutane – ADMB), missing representation of important parts (e.g. 5F-AB-FUPPYCA: 5-fluoropentyl tail, AB-CHMFUPPYCA: cyclohexylmethyl–CHM tail) and multiple approaches to the abbreviation of halogenated structures. The principles of the framework are unambiguous, consistent, and easy-to-understand letter codes with abbreviations of common features shared across building blocks. The EMCDDA framework applies only to SCs that have emerged on the drug market because the time of notification significantly impacts the letter code assigned to the respective SC. The EMCDDA framework on naming SCs provides a valuable resource for practical information, guidance on consistent naming, and the rationale for how the names are derived. With the globalization of the market in SCs, there is a need for a concerted effort and international collaboration towards harmonized naming of emerging SCs.