Evaluation of tetraethylammonium bicarbonate as a phase-transfer agent in the formation of [18F]fluoroarenes

Tetraethylammonium bicarbonate, Et4N·HCO3, was found to be an efficient phase-transfer agent, in a microreactor, for the production of [18F]fluoroarenes from a range of precursors (diaryliodonium salt, nitroarene and [19F]fluoroarene). This study has established Et4N·HCO3 as a practical alternative to the conventional phase-transfer system – Kryptofix® 222/K2CO3 – as the radiolabelled products were generated in comparable radiochemical yields. The use of Et4N·HCO3 also dramatically increased productivity by eliminating the frequent blockages of the microreactor experienced with the traditional system.