title: Enantioselective synthesis of 6-[fluorine-18]-fluoro-L-dopa from no-carrier-added fluorine-18-fluoride.
abstract: METHODS
  A trimethylammonium veratraldehyde triflate was synthesized and used as a precursor for the asymmetric synthesis of 6-[18F]fluoro-L-dopa.
  
  
  RESULTS
  Its nucleophilic fluorination with 18F-fluoride produced by the 18O(p,n)18F nuclear reaction on enriched 18O-water led to the corresponding no-carrier-added [18F]fluoroveratraldehyde (45 +/- 5% EOB). Diiodosilane was used to prepare the corresponding [18F]fluorobenzyl iodide (36.5 +/- 5.3% EOB). Akylation of (S)-1-tert-boc-2-tert-butyl-3-methyl-4-imidazolidinone with this electrophilic agent, hydrolysis and purification by preparative high-pressure liquid chromatography made 6-[18F]fluoro-L-dopa ready for human injection, in a 23% +/- 6% decay-corrected radiochemical yield. The enantiomeric purity and the specific activity were above 96% and 1 Ci/mumole respectively.
  
  
  CONCLUSIONS
  Through this procedure, starting from 250 mCi of 18F-fluoride, multimillicurie amounts (32 +/- 8.5 mCi) of no-carrier-added 6-[18F]fluoro-L-dopa are now available at the end of synthesis (90 min) with a good radiochemical purity (more than 98%).
authors.affiliation: Cyclotron Research Center, Liège University, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Lemaire
authors.forename: P
authors.initials: P
authors.lastname: Damhaut
authors.forename: A
authors.initials: A
authors.lastname: Plenevaux
authors.forename: D
authors.initials: D
authors.lastname: Comar
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000302:isolation & purification; D005462:Fluorine Radioisotopes; D007202:Indicators and Reagents; D007553:Isotope Labeling / Q000379:methods; D015394:Molecular Structure
chemical_list: D005462:Fluorine Radioisotopes; D007202:Indicators and Reagents; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine