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.

Graphical abstractFor a range of [18F]radiofluorinations the use of tetraethylammonium bicarbonate as a phase-transfer agent has eliminated microreactor blockages experienced using the traditional system Kryptofix® 222/K2CO3.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We report tetraethylammonium bicarbonate, TEA·HCO3, is a suitable phase-transfer agent for [18F]radiofluorinations. ► Good yields have been achieved for a range of [18F]radiofluorination methods generating [18F]fluoroarenes. ► The use of TEA·HCO3 has eliminated microreactor blockages experienced using the traditional system Kryptofix® 222/K2CO3.