Synthesis and characterization of d5 -barbarin for use in barbarin-related research.
Abstract: Based on structural similarities and equine administration experiments, Barbarin, 5-phenyl-2-oxazolidinethione from Brassicaceae plants, is a possible source of equine urinary identifications of aminorex, (R,S)-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine, an amphetamine-related US Drug Enforcement Administration (DEA) controlled substance considered illegal in sport horses. We now report the synthesis and certification of d -barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D -barbarin synthesis commenced with production of d -2-oxo-2-phenylacetaldehyde oxime (d -oxime) from d -acetophenone via butylnitrite in an ethoxide/ethanol solution. This d -oxime was then reduced with lithium aluminum hydride (LiAlH ) to produce the corresponding d -2-amino-1-phenylethan-1-ol (d -phenylethanolamine). Final ring closure of the d -phenylethanolamine was performed by the addition of carbon disulfide (CS ) with pyridine. The reaction product was purified by recrystallization and presented as a stable white crystalline powder. Proton NMR spectroscopy revealed a triplet at 5.88 ppm for one proton, a double doublet at 3.71 ppm for one proton, and double doublet at 4.11 ppm for one proton, confirming d -barbarin as the product. Further characterization by high resolution mass spectrometry supports the successful synthesis of d -barbarin. Purity of the recrystallized product was ascertained by High Performance Liquid Chromatography (HPLC) to be greater than 98%. Together, we have developed the synthesis and full characterization of d -barbarin for use as an internal standard in barbarin-related and equine forensic research.
© 2022 The Authors. Drug Testing and Analysis published by John Wiley & Sons Ltd.
Publication Date: 2022-08-23 PubMed ID: 35975356PubMed Central: PMC10087961DOI: 10.1002/dta.3357Google Scholar: Lookup
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Summary
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The research discusses the successful synthesis and characterization of d5-barbarin, a substance that has structural similarities to aminorex, a controlled substance. This synthesized substance is intended to facilitate studies about the relationship between naturally occurring barbarin in plants and potentially misidentified aminorex in horse urine.
Synthesis of d5-barbarin
The process for creating d5-barbarin started with the following steps:
- Producing d-2-oxo-2-phenylacetaldehyde oxime (d-oxime) from d-acetophenone. This procedure involved the use of butylnitrite in an ethoxide/ethanol solution.
- This newly created d-oxime was then exposed to lithium aluminum hydride (LiAlH) to produce the corresponding d-2-amino-1-phenylethan-1-ol (d-phenylethanolamine).
- The final ring closure of the d-phenylethanolamine was executed by adding carbon disulfide (CS) with pyridine to form the d5-barbarin.
Purification and Characterization of d5-barbarin
After formation, the synthesized d5-barbarin was clarified and embodied as a solid white crystalline powder, using these methods:
- Recrystallization was used to purify the newly synthesized product.
- Characterization of the recrystallised product was performed using Proton Nuclear Magnetic Resonance (NMR) spectroscopy, which detected specified proton patterns, validating d5-barbarin as the end product.
- Further identification of the product was conducted using high resolution mass spectrometry, providing additional support for successful synthesis.
- Lastly, purity testing was done through High Performance Liquid Chromatography (HPLC), confirming the d5-barbarin purity to be over 98%.
These consistent findings provide strong evidence for the successful and pure synthesis of d5-barbarin, which is expected to be invaluable in barbarin-related research and potentially in solving forensics cases in the equestrian world.
Cite This Article
APA
Kudrimoti S, Machin J, Arojojoye AS, Awuah SG, Eisenberg R, Fenger C, Maylin G, Lehner AF, Tobin T.
(2022).
Synthesis and characterization of d5 -barbarin for use in barbarin-related research.
Drug Test Anal, 15(1), 42-46.
https://doi.org/10.1002/dta.3357 Publication
Researcher Affiliations
- The Department of Veterinary Science and the Maxwell H. Gluck Equine Research Center and the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA.
- The Department of Veterinary Science and the Maxwell H. Gluck Equine Research Center and the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA.
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA.
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA.
- Center for Pharmaceutical Research and Innovation, College of Pharmacy and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, USA.
- Frontier BioPharm, LLC, Richmond, Kentucky, USA.
- Equine Integrated Medicine, Georgetown, Kentucky, USA.
- New York Drug Testing and Research Program, Ithaca, New York, USA.
- Veterinary Diagnostic Lab Section of Toxicology, Michigan State University, Lansing, Michigan, USA.
- The Department of Veterinary Science and the Maxwell H. Gluck Equine Research Center and the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA.
MeSH Terms
- Animals
- Horses
- Aminorex
- Protons
- Oxazoles
- Mass Spectrometry
Grant Funding
- The Equine Health and Welfare Alliance, Inc, Versailles, Kentucky,
- The National Horsemen's Benevolent and Protective Association and the Alabama, Arizona, Arkansas, Ontario, Canada; Charles Town, WV; Florida, Indiana, Iowa, Kentucky, Louisiana, Michigan, Minnesota, Nebraska, Ohio, Oklahoma, Oregon, Pennsylvania, Tampa Bay Downs, Florida, Texas, Washington State, and West Virginia Horsemen's Benevolent and Protective Associations
- The United States Trotting Association, Columbus, OH
- US Department of Agriculture
- National Institute of Food and Agriculture
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