Test purchase, identification and synthesis of 2-amino-1-(4-bromo-2, 5-dimethoxyphenyl)ethan-1-one (bk-2C-B).

A substance called bk-2C-B, a cathinone analogue of the psychoactive phenethylamine 2C-B, has become available from online retailers. Its identity was confirmed through multiple analytical methods, including nuclear magnetic resonance spectroscopy, gas and liquid chromatography, and high-resolution mass spectrometry. The compound was also synthesized using the Delépine reaction. Gas chromatography-mass spectrometry showed potential for artificial formation of byproducts, but these were not seen with liquid chromatography. Analysis revealed the purchased material was a mixture of hydrochloride and hydrobromide salts, suggesting a specific synthetic route, and X-ray crystallography showed it exists as polymorphs.

Study at a glance

Abstract

2-Amino-1-(4-bromo-2,5-dimethoxyphenyl)ethan-1-one (bk-2C-B) has been recently offered for purchase by a variety of Internet retailers. This substance may be considered a cathinone analogue of the phenethylamine 2-(4-bromo-2,5-dimethoxyphenyl)ethan-1-amine (2C-B) which suggests that it may have psychoactive effects in humans. A test purchase of bk-2C-B was carried out and its identity was confirmed by a range of analytical techniques including nuclear magnetic resonance spectroscopy, gas and liquid chromatography, and high-resolution mass spectrometry. Confirmation was also obtained from the synthesis of bk-2C-B based on the implementation of the Delépine reaction in which the α-brominated intermediate was reacted with hexamethylenetetramine to afford the primary amine. Analysis of underivatized bk-2C-B by gas chromatography-mass spectrometry (GC-MS) showed that there was potential for artificial formation of 1-(4-bromo-2,5-dimethoxyphenyl)ethanone and a pyrazine dimer, these substances were not detected when employing liquid chromatographic analysis. Ion chromatography and X-ray crystallography analysis confirmed that the purchased bk-2C-B consisted of a hydrochloride and hydrobromide salt mixture, which indicated that it might have been prepared by the hexamethylenetetramine route followed by hydrochloric acid hydrolysis of the quaternary ammonium salt. X-ray crystallography also revealed that the purchased (mixed HCl/HBr salt) and synthesized bk-2C-B (HCl salt) exists as polymorphs.