SYNTHESIS OF META-SUBSTITUTED [18F]-3-FLUORO-4-AMINOPYRIDINES BY DIRECT RADIOFLUORINATION OF PYRIDINE N-OXIDES
申请人:The University of Chicago
公开号:US20170355648A1
公开(公告)日:2017-12-14
Disclosed herein are methods for the fluorination aromatic N-heterocyclic N-oxides that comprise at least one leaving group. The N-oxides may be reduced to the fluorinated aromatic N-heterocyclic amine analogs. This novel fluorination approach may be successfully applied for synthesizing aromatic N-heterocyclic compounds labeled with
18
F.
Development, Optimization, and Scope of the Radiosynthesis of 3/5-[<sup>18</sup>F]Fluoropyridines from Readily Prepared Aryl(pyridinyl) Iodonium Salts: The Importance of TEMPO and K<sub>2</sub>CO<sub>3</sub>
A robust process for the radiosynthesis of 3/5-[F-18]fluoropyridines has been developed by radiofluorination of iodonium triflates using (KF)-F-18/(KCO3)-C-2/K-222 complex in the presence of TEMPO. Both electronically deficient and enriched iodonium salts were readily obtained from the corresponding 3/5-iodopyridines and afforded the corresponding 3/5-[F-18]fluoropyridines in 6-78% yields. The concentrations of K2CO3 and TEMPO were found to be crucial for the radiofluorination efficiency. The process was validated using two automated systems for the F-18-radiolabeling of 2-chloro and 2-carboxamido-5-fluoropyridines carried out in 10-20% yields.
US11845749
申请人:——
公开号:——
公开(公告)日:——
Synthesis of meta-substituted [<sup>18</sup>F]3-fluoro-4-aminopyridine via direct radiofluorination of pyridine N-oxides
Due to their electron-rich aromatic structure, nucleophilic (radio)fluorination of pyridines is challenging, especially at the meta position. In this paper, we describe the first example of direct fluorination of a...