Identification and quantitation of two new naphthoylindole drugs-of-abuse, (1-(5-hydroxypentyl)-1H-indol-3-yl)(naphthalen-1-yl)methanone (AM-2202) and (1-(4-pentenyl)-1H-indol-3-yl)(naphthalen-1-yl)methanone, with other synthetic cannabinoids in unregulated “herbal” products circulated in the Tokyo area

During our continual surveillance of unregulated drugs in May–June 2011, we found two new compounds as adulterants in herbal products obtained at shops in the Tokyo area. These compounds were identified by liquid chromatography–mass spectrometry, gas chromatography–mass spectrometry, accurate mass spectrometry, and nuclear magnetic resonance spectroscopy. The first compound identified was a naphthoylindole (1-(5-hydroxypentyl)-1H-indol-3-yl)(naphthalen-1-yl)methanone (AM-2202, 1), which is a side-chain hydroxyl analogue of JWH-018. The second compound was (1-(4-pentenyl)-1H-indol-3-yl)(naphthalen-1-yl)methanone (2), which is side-chain double bond analogue of JWH-018. This is the first report to identify 1 and 2 in a commercial “herbal” product to our knowledge. For quantitation of the above compounds 1 and 2, and chemical analysis for previously reported compounds (AM-2201, 3; JWH-203, 4; JWH-019, 7; JWH-210, 8; mitragynine, 9), each product was extracted with methanol under ultrasonication to prepare solutions for analysis by liquid chromatography with ultraviolet detection. For the sake of identifying JWH-203 (4) and its positional isomers [JWH-203-3-chloroisomer (5) and 4-chloroisomer (6)] correctly, simultaneous liquid chromatography analysis on fluorocarbon-bonded silica gel column was performed. And a case report of commercially available products containing synthetic cannabinoids 7 and 8, and a natural occurring alkaloid 9, was also shown. Each of 6 commercially circulated products contained compounds 1–4 and 7–9; the amounts of the compounds ranged from 4.1 to 222 mg per pack.