Identification and characterization of α-PVT, α-PBT, and their bromothienyl analogs found in illicit drug products

Recently, thienyl derivatives of cathinones have appeared on the market as new psychoactive substances (NPS). In this study, identification and characterization of 2-(pyrrolidin-1-yl)-1-(thiophen-2-yl)pentan-1-one (α-PVT), 2-(pyrrolidin-1-yl)-1-(thiophen-2-yl)butan-1-one (α-PBT), and their bromothienyl analogs disclosed in illicit products are described. In our analysis, some analogous compounds of α-PVT, which had a bromine substitution on the thiophene ring, were identified in the samples containing α-PVT; 1-(4-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)pentan-1-one, 1-(5-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)pentan-1-one, and 1-(4,5-dibromothiophen-2-yl)-2-(pyrrolidin-1-yl)pentan-1-one by comparing the analytical data with synthetic reference standards. We also observed 1-(4-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)butan-1-one and 1-(5-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)butan-1-one from a powder product, in which α-PBT was detected. The brominated α-PVTs were also found when overbrominated 1-(thiophen-2-yl)pentan-1-one reacted with pyrrolidine, and they are suspected to be the by-products of α-PVT synthesis. In Japan, cathinone derivatives with a phenyl group as the aromatic ring have been widely controlled by generic scheduling. To escape from such a regulation, analogs with different aromatic groups such as α-PVT and α-PBT appeared on the illicit market of psychoactive compounds. To our knowledge, this is the first report describing identification of α-PBT, and bromothienyl analogs of both α-PVT and α-PBT in illicit drug products. The synthetic method and analytical data shown in this study will be useful for identification of the thienyl derivatives of cathinone analogs.