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Product ion tandem mass spectrometric differentiation of regioisomeric side‐chain groups in cathinone derivatives
Author(s) -
Abiedalla Younis,
DeRuiter Jack,
Clark C. Randall
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7603
Subject(s) - chemistry , iminium , isopropyl , side chain , tandem mass spectrometry , pyrrolidine , cathinone , mass spectrometry , structural isomer , alkyl , medicinal chemistry , stereochemistry , ion , organic chemistry , chromatography , amphetamine , neuroscience , dopamine , biology , polymer
Rationale Precursor materials are available to prepare aminoketone drugs containing regioisomeric propyl and isopropyl side‐chain groups related to the drug alpha‐pyrrovalerone (Flakka) and MDPV (3,4‐methylenedioxypyrrovalerone). These compounds yield equivalent regioisomeric iminium cation base peaks in electron ionization mass spectrometry (EI‐MS). Methods The propyl and isopropyl side‐chain groups related to alpha‐pyrrovalerone and MDPV were prepared and evaluated in EI‐MS and tandem mass spectrometry (MS/MS) product ion experiments. Deuterium labeling in both the pyrrolidine and alkyl side‐chain groups allowed for the confirmation of the structures for the major product ions formed from the regioisomeric EI‐MS iminium cation base peaks. Results These iminium cation base peaks show characteristic product ion spectra which allow differentiation of the side‐chain propyl and isopropyl groups in the structure. The n‐propyl side chain containing iminium cation base peak ( m / z 126) in the EI‐MS spectrum yields a major product ion at m / z 84 while the regioisomeric m / z 126 base peak for the isopropyl side chain yields a characteristic product ion at m / z 70. Deuterium labeling in both the pyrrolidine ring and the alkyl side chain confirmed the process for the formation of these major product ions. Conclusions Product ion fragmentation provides useful data for differentiation of n‐propyl and isopropyl side‐chain iminium cations from cathinone derivative drugs of abuse. Regioisomeric n‐propyl and isopropyl iminium cations of equal mass yield characteristic product ions identifying the alkyl side‐chain regioisomers in the pyrrolidine cathinone derivatives. Copyright © 2016 John Wiley & Sons, Ltd.