Ascertaining the Suitability of Aryl Sulfonyl Fluorides for [18F]Radiochemistry Applications: A Systematic Investigation using Microfluidics

Optimization of [18F]radiolabeling conditions and subsequent stability analysis in mobile phase, PBS buffer, and rat serum of 12 aryl sulfonyl chloride precursors with various substituents (electron-withdrawing groups, electron-donating groups, increased steric bulk, heterocyclic) were performed using an Advion NanoTek Microfluidic Synthesis System. A comparison of radiochemical yields and reaction times for a microfluidics device versus a conventional reaction vessel is reported. [18F]Radiolabeling of sulfonyl chlorides in the presence of competing nucleophiles, H-bond donors, and water was also assessed and demonstrated the versatility and potential utility of [18F]sulfonyl fluorides as synthons for indirect radiolabeling.