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.