title: Facile Route to 2-Fluoropyridines via 2-Pyridyltrialkylammonium Salts Prepared from Pyridine N-Oxides and Application to (18)F-Labeling.
abstract: Among known precursors for 2-[(18)F]fluoropyridines, pyridyltrialkylammonium salts have shown excellent reactivity; however, their broader utility has been limited because synthetic methods for their preparation suffer from poor functional group compatibility. In this paper, we demonstrate the regioselective conversion of readily available pyridine N-oxides into 2-pyridyltrialkylammonium salts under mild and metal-free conditions. These isolable intermediates serve as effective precursors to structurally diverse 2-fluoropyridines, including molecules relevant to PET imaging. In addition to providing access to nonradioactive analogues, this method has been successfully applied to (18)F-labeling in the radiosynthesis of [(18)F]AV-1451 ([(18)F]T807), a PET tracer currently under development for imaging tau.
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Hui
authors.initials: H
authors.lastname: Xiong
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Adam T
authors.initials: AT
authors.lastname: Hoye
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Kuo-Hsien
authors.initials: KH
authors.lastname: Fan
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ximin
authors.initials: X
authors.lastname: Li
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Clemens
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Carey L
authors.initials: CL
authors.lastname: Horchler
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Nathaniel C
authors.initials: NC
authors.lastname: Lim
authors.affiliation: Avid Radiopharmaceuticals, 3711 Market Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Attardo
mesh_terms: D005462:Fluorine Radioisotopes; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D049268:Positron-Emission Tomography / Q000379:methods; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012492:Salts; D016875:tau Proteins / Q000737:chemistry
chemical_list: C521930:2-fluoropyridine; D005462:Fluorine Radioisotopes; D006845:Hydrocarbons, Fluorinated; D011725:Pyridines; D000644:Quaternary Ammonium Compounds; D012492:Salts; D016875:tau Proteins; C013229:pyridine N-oxide