‘Smoking’ mephedrone: The identification of the pyrolysis products of 4‐methylmethcathinone hydrochloride

Abstract

The ring-substituted cathinone - mephedrone - has gained popularity among recreational drug users over the past several years. It is generally consumed orally or by snorting but reports indicate that it is also ingested by vaporization/inhalation. This study examines the pyrolysis products produced by heating mephedrone under using simulated 'meth pipe' conditions. Thirteen pyrolysis products were identified, the major ones being iso-mephedrone, 4-methylpropiophenone, 4-methylphenylacetone, two pyrazine derivatives formed by dimerization of mephedrone, N-methylated mephedrone (N,N,4-trimethylcatinone), two hydroxylated oxidation products and a diketone. Other minor products formed were identified as 4-methylacetophenone, two α-chloro ketones and N-methylated iso-mephedrone.

Identification of pyrolysis products of the new psychoactive substance 2‐amino‐1‐(4‐bromo‐2,5‐dimethoxyphenyl)ethanone hydrochloride (bk‐2C‐B) and its iodo analogue bk‐2C‐I

“…[16] The pyrolysis products of bk-2C-B differed significantly from those observed with other phenethylamines [15] including methiopropamine and the ring-substituted cathinone, mephedrone. [15,16] Methylation [18] and N,O rearrangement did not occur. [19] Product (1b) was unique in that the C-C bond cleavage appeared to occur at the benzene ring and the corresponding product was not detected in either the pyrolysis of methamphetamine or mephedrone.…”

“…Two halogenated products were detected in the pyrolysis of mephedrone and identified as α-chloro ketones, 1-chloro-1-(4-methylphenyl)-2-propanone and 2-chloro-1-(4-methylphenyl)-1-propanone. [16] The pyrolysis products of bk-2C-B differed significantly from those observed with other phenethylamines [15] including methiopropamine and the ring-substituted cathinone, mephedrone. [15,16] Methylation [18] and N,O rearrangement did not occur.…”

“…1-(4-Bromo-2,5-dimethoxyphenyl)ethanone was formed by loss of the amine group, also seen in the pyrolysis of mephedrone. [16] In mephedrone, however, halogen substitution similar to 1-(4-bromo-2,5-dimethoxyphenyl)-2-chloro-ethanone (9) or 2-bromo-1-(4-bromo-2,5-dimethoxyphenyl)-ethanone (11) was not detected. In the later example, chlorination rather than bromination would occur in the case of mephedrone.…”

“…The mechanism might have been similar to the formation of iso-mephedrone observed during mephedrone pyrolysis, with the formation of a cyclic amine intermediate that would result in the formation of an iso-2C-B intermediate, followed by deamination. [16] The peak eluting at The fragmentation pattern representing the peak at 7.38 min was initially thought to represent 4-bromo-2,5-dimethoxybenzaldehyde but this was not confirmed when compared to a standard. Instead, an alternative structure was proposed, 1-(4-bromo-2-hydroxy-5-methoxyphenyl)ethanone (4), which was confirmed by comparison with a standard and by NMR provided in the Supporting Information.…”

“…A sample of bk-2C-I was donated by an Internet retailer in 2015. (9) This was prepared via the sulfuryl chloride method previously reported for 2-chloro-1-(4-methylphenyl)propanone [16] 5-(4-Bromo-2,5-dimethoxyphenyl)oxazole (10) A mixture of 2-amino-1-(4-bromo-2,5-dimethoxyphenyl)ethanone hydrobromide (177 mg, 0.5 mmol), p-toluenesulfonic acid (5 mg) and triethyl orthoformate (2 mL) was heated at 140°C for 3 h. The volatiles were removed under vacuum and the residue was purified by preparative TLC (silica gel; cyclohexane/EtOAc, 1/1) to afford a light-brown solid ( A mixture of 2-(4-bromo-2,5-dimethoxyphenyl)ethanol (130 mg, 0.5 mmol, prepared by the reduction of 2-(4-bromo-2,5-dimethoxyphenyl)acetic acid with borane-THF) and thionyl chloride (2 mL) was refluxed for 2 h. (Ar-CH), 110.26 (Ar-C), 57.01 (OMe), 56.04 (OMe), 43.46 (CH 2 ), 30.33 (CH 2 ). For this compound, sufficient ionization under the employed HR-ESI-MS conditions was not observed for high accuracy mass analysis.…”