Analysis of NRG 'legal highs' in the UK: identification and formation of novel cathinones

A large number of cathinone derivatives have shown a wide range of bioactive properties, attracting great interest from communities associated with pharmaceutical research. Some of these derivatives have gained popularity as so‐called recreational ‘legal highs’ due to their availability on the Internet and high street shops. A previous study described the qualitative analysis of 24 ‘legal high’ Energy‐1 (NRG‐1) and NRG‐2 products obtained from 18 websites following the ban on mephedrone and derivatives in April 2010. The majority of these products contained a mixture of cathinones just carrying a new label. Here, three additional cathinone products have been detected; two from an NRG‐1 sample and one from an NRG‐3 sample. This report describes their identification. NRG‐1 sample 1 consisted of a mixture of 4 cathinones namely 4‐fluoromethcathinone (1), 1‐(3,4‐methylenedioxyphenyl)‐2‐(methylamino)pentan‐1‐one (pentylone, 2), 3,4‐methylenedioxy‐α‐pyrrolidinobutyrophenone (MDPBP, 3) and 3,4‐methylenedioxypyrovalerone (MDPV, 4). The sample labelled as NRG‐3 (mislabelled with the chemical structure of mephedrone) consisted of a mixture of 4‐methyl‐α‐pyrrolidinopropiophenone (MPPP, 5) and (2), whereas the remaining NRG‐1 sample 2 (also mislabelled with the chemical structure of mephedrone) consisted of a mixture of (2) and (3). Qualitative analyses were carried out by GC‐(EI/CI)‐MS, NMR spectroscopy and confirmation by preparation of standards. The preparation of brominated precursors carrying the 3,4‐methylenedioxyphenyl nucleus revealed extensive α,α‐dibromination: the mass spectral and NMR data of these intermediates are also presented and discussed. Copyright © 2010 John Wiley & Sons, Ltd. A large number of cathinone derivatives have shown a wide range of bioactive properties, attracting great interest from communities associated with pharmaceutical research. Some of these derivatives have gained popularity as so‐called recreational ‘legal highs’ due to their availability on the Internet and high street shops. A previous study described the qualitative analysis of 24 ‘legal high’ Energy‐1 (NRG‐1) and NRG‐2 products obtained from 18 websites following the ban on mephedrone and derivatives in April 2010. The majority of these products contained a mixture of cathinones just carrying a new label. Here, three additional cathinone products have been detected; two from an NRG‐1 sample and one from an NRG‐3 sample.