title: NCA nucleophilic radiofluorination on substituted benzaldehydes for the preparation of [18F]fluorinated aromatic amino acids.
abstract: Nucleophilic aromatic substitution is a challenging task in radiochemistry. Therefore, a thorough evaluation and optimisation of this step is needed to provide a satisfactory tool for the routine preparation of [(18)F]fluorinated aromatic amino acids. Two methods, already proposed elsewhere, were evaluated and improved. The yields for the radiofluorination were increased whereas activity loss during solid phase extraction was observed. Radiochemical yields for the two methods were 92.7+/-5.5% (method 1) and 92.1+/-12.3% (method 2) for conversion and 11.1+/-2.8% (method 1) and 34.8+/-0.6% (method 2) for purification, respectively. In total, we demonstrate an optimised method for the preparation of this important class of [(18)F]fluorinated synthons for PET.
authors.affiliation: Department of Nuclear Medicine, Medical University of Vienna, Austria. wolfgang.wadsak@meduniwien.ac.at
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wadsak
authors.forename: Barbara
authors.initials: B
authors.lastname: Wirl-Sagadin
authors.forename: Markus
authors.initials: M
authors.lastname: Mitterhauser
authors.forename: Leonhard-Key
authors.initials: LK
authors.lastname: Mien
authors.forename: Dagmar E
authors.initials: DE
authors.lastname: Ettlinger
authors.forename: Bernhard K
authors.initials: BK
authors.lastname: Keppler
authors.forename: Robert
authors.initials: R
authors.lastname: Dudczak
authors.forename: Kurt
authors.initials: K
authors.lastname: Kletter
mesh_terms: D024322:Amino Acids, Aromatic / Q000032:analysis* / Q000737:chemistry*; D001547:Benzaldehydes / Q000737:chemistry*; D005462:Fluorine Radioisotopes / Q000032:analysis* / Q000737:chemistry*; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D007553:Isotope Labeling / Q000379:methods*; D019275:Radiopharmaceuticals / Q000032:analysis / Q000138:chemical synthesis
chemical_list: D024322:Amino Acids, Aromatic; D001547:Benzaldehydes; D005462:Fluorine Radioisotopes; D006841:Hydrocarbons, Aromatic; D019275:Radiopharmaceuticals