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Analysis of six “neuro-enhancing” phenidate analogs

Klare, H and Neudörfl, JM and Brandt, SD and Mischler, E and Meier-Giebing, S and Deluweit, K and Westphal, F and Laussmann, T (2017) Analysis of six “neuro-enhancing” phenidate analogs. Drug Testing and Analysis. ISSN 1942-7611

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Abstract

Six collected phenidates, i.e. 4-methylmethylphenidate, 3,4-dichloromethylphenidate, ethylphenidate, 3,4-dichloroethylphenidate, ethylnaphthidate and N-benzyl-ethylphenidate were fully characterized by means of X-ray, NMR, GC-MS, ESI-MS2, ATR-FT-IR and GC solid-state IR analysis. Crystallography revealed the exclusive presence of the threo-configuration. Steric crowding induced by N-benzyl substitution at the piperidine moiety prompted an adoption of an unexpected axial positioning of substituents on the piperidine moiety in the crystal state as opposed to the exclusive equatorial positioning encountered in N-unsubstituted phenidate analogs. Gas phase computations of the relative lowest energy conformers confirm that the axial positioning appears to be favored over the equatorial positioning, however in solution equatorial positioning is predominant according to NOE experiments. All samples, mainly originating from China, had a good to very good degree of purity indicative of their professional chemical synthesis. Routine analysis of these drugs by GC-MS revealed thermal decomposition of phenidate analogs in the injection port and/or on column to 2-aryl-ethyl-acetates and 2,3,4,5-tetrahydropyridines. The decomposition pathway was suggested to proceed via a 6-membered transition state which was supported by DFT-computations. Fragmentation pathways of decomposition products as well as the corresponding EI mass spectra are provided. The thermal instability might thus render smoking or “vaping” of these drugs a less effective route of administration. The analytical fingerprints of six structurally diverse phenidate analogs provide a helpful reference to forensic chemists in charge of identifying new psychoactive substances.

Item Type: Article
Additional Information: This is the peer reviewed version of the following article: Klare, H., Neudörfl, J. M., Brandt, S. D., Mischler, E., Meier-Giebing, S., Deluweit, K., Westphal, F., and Laussmann, T. (2017) Analysis of six “neuro-enhancing” phenidate analogs. Drug Test. Analysis, doi: 10.1002/dta.2161., which has been published in final form at http://dx.doi.org/10.1002/dta.2161 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Uncontrolled Keywords: 0301 Analytical Chemistry, 1115 Pharmacology And Pharmaceutical Sciences
Subjects: R Medicine > RM Therapeutics. Pharmacology
Divisions: Pharmacy & Biomolecular Sciences
Publisher: Wiley
Date Deposited: 11 Jan 2017 12:11
Last Modified: 14 Sep 2017 06:52
DOI or Identification number: 10.1002/dta.2161
URI: http://researchonline.ljmu.ac.uk/id/eprint/5244

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