The first radiosynthesis of 2-amino-5-[18F]fluoropyridines via a “minimalist” radiofluorination/palladium-catalyzed amination sequence from anisyl(2-bromopyridinyl)iodonium triflate

Abstract

The synthesis of 2-amino-5-[¹⁸F]fluoropyridines was achieved in 8–85% yields by palladium-catalyzed reaction of 2-bromo-5-[¹⁸F]fluoropyridine with piperidine, dimethylamine, butylamine, methylpiperazine, benzylamine, aniline and 3-aminopyridine. 2-Bromo-5-[¹⁸F]fluoropyridine was obtained by radiofluorination of anisyl(2-bromopyridinyl-5)iodonium triflate (88% yield). The radiofluorination step was performed under “minimalist” conditions to guarantee a successful subsequent amination reaction.