Details

Autor(en) / Beteiligte

• Kudrimoti, Sucheta
• Machin, Jacob
• Arojojoye, Adedamola S.
• Awuah, Samuel G.
• Eisenberg, Rodney
• Fenger, Clara
• Maylin, George
• Lehner, Andreas F.
• Tobin, Thomas

Titel

Synthesis and characterization of d5‐barbarin for use in barbarin‐related research

Ist Teil von

• Drug testing and analysis, 2023-01, Vol.15 (1), p.42-46

Ort / Verlag

Chichester: Wiley Subscription Services, Inc

Erscheinungsjahr

2023

Quelle

Wiley Online Library

Beschreibungen/Notizen

• 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 d5‐barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D5‐barbarin synthesis commenced with production of d5‐2‐oxo‐2‐phenylacetaldehyde oxime (d5‐oxime) from d5‐acetophenone via butylnitrite in an ethoxide/ethanol solution. This d5‐oxime was then reduced with lithium aluminum hydride (LiAlH4) to produce the corresponding d5‐2‐amino‐1‐phenylethan‐1‐ol (d5‐phenylethanolamine). Final ring closure of the d5‐phenylethanolamine was performed by the addition of carbon disulfide (CS2) 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 d5‐barbarin as the product. Further characterization by high resolution mass spectrometry supports the successful synthesis of d5‐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 d5‐barbarin for use as an internal standard in barbarin‐related and equine forensic research. We now report the synthesis of d5‐barbarin for use in research concerning the role of barbarin in glucobarbarin‐related identifications of aminorex in experimental and postcompetitive event urine samples from horses fed plants containing glucobarbarin. We also propose a synthetic pathway for aminorex formation from glucobarbarin.