Synthesis of methoxyaryl sulfonium salts

Positron Emission Tomography (PET) scans are a non-invasive mechanical imaging study performed in order to diagnose a variety of conditions including cancer, infections, and heart disease. PET radiotracers are used ln these studies to assist in identifying a disease, its location, and its extent. Radiolabeled PET tracers are derived from biologically active molecules and contain a radioisotope that has the ability to bind to and be taken up by desired cells at a higher rate versus other areas of the body. The specificity of these biomolecules additionally provides information regarding the site itself. A variety of sulfonium salts exhibit great reactivity in radiolabeling experiments and tolerate the presences of a greater variety of functional groups than other radiolabeling methods, easing purification procedures. A plethora of these sulfonium salts have been widely used in literature, but they have yet to be tested under microfluidic conditions. Microfluidic reactors have been shown in the past to generally increase yields. Increased yields are important because it would allow for a more efficient production of PET tracers. By increasing efficiency, it could Improve the ability to identify diseases. By improving this ability, it would potentially reduce the need for certain invasive diagnostic procedures. This study will make a comparison between the radiolabeling of sulfonium salts under normal conditions and under microfluidic conditions. Sulfonium Salts are being synthesized from a variety of arly iodide precursors by literature procedure. These molecules incorporate a variety of functional groups that may provide insight into their relativity and applicability for PET tracer production. The following process of radiolabeling these sulfonium salts will be performed by outside collaborators. An important aspect of these studies is selecting the appropriate reactions to form the diarylthioether intermediates. These generally involve a deprotonation of the thiol followed by nucleophilic aromatic substitution to form the diarylthioether. Literature procedures vary greatly in the base, catalyst, solvent, reaction time, and temperature. Our studies are currently investigating the optimal conditions based on the functional groups of the desired sulfonium salts