Recent Advances of S–¹⁸F Radiochemistry for Positron Emission Tomography

Abstract

The click chemistry of sulfur(VI) fluoride exchange (SuFEx) has facilitated the widespread application of sulfur−fluoride compounds such as sulfonyl fluorides, fluorosulfates, and sulfamoyl fluorides in various fields, especially in the development of 18 F ligands for PET (positron emission tomography) imaging. In recent years, the prominent progress of sulfur− [ 18 F]fluoride compounds has been achieved through the combination of 18 F and sulfur− fluoride chemistry. These compounds serve as potential 18 F tracers, 18 F synthons, and reagents for 18 F-fluorination, thereby complementing the range of 18 F ligands, typically C− 18 F structures, used in PET studies. This review aims to provide an overview of S− 18 F labeling reactions through examples of relevant 18 F compounds and highlight the advancements and breakthroughs achieved in the past decade.

Rapid and Convenient Potentiometric Method for Determining Fluorosulfate, a Byproduct of the Fumigant and Greenhouse Gas Sulfuryl Fluoride

“…Fluorosulfate (FSO 3 – ), the conjugate base of fluorosulfuric acid (p K a , −10), is a chemical intermediate in inorganic − and organic synthesis, − and is produced in certain reactions of interest in agricultural and environmental contexts. , A major source of FSO 3 – is the decomposition of sulfuryl fluoride (SO 2 F 2 ), which is widely used to rid pests in buildings and structures, agricultural soils, and postharvest commodities in quarantine and preshipment operations. − Sulfuryl fluoride is increasingly used as a replacement fumigant for the ozone-depleting gas, methyl bromide. Foods treated with SO 2 F 2 include wheat, flours, animal-based stored products, cereals and cereal products, pulses and pulse products, dried fruits, tree nuts, dried beef, gluten, and many others .…”

“…Fluorosulfate was identified in the urine and blood of rats exposed to SO 2 F 2 . Sulfuryl fluoride has also been used in click chemistry to convert alcohols and amines to fluorosulfonate derivatives; − the fluorosulfonate group is then removed by base hydrolysis, producing FSO 3 – . − Metal fluorosulfates (such as Li + ) have been proposed for use as electrolytes in batteries . Lastly, FSO 3 – is found naturally in the mineral Reederite-(Y) from Mont-Saint-Hilaire .…”

Green and Efficient Protocols for the Synthesis of Sulfonyl Fluorides Using Potassium Fluoride as the Sole Fluorine Source

“…Additionally, the hydrogen-bonding requirements of the fluoride ion can alter the characteristics of this bond under certain mild experimental conditions, making it an excellent leaving group . This interplay between the reactivity and stability of these chemical entities makes them well-suited for a wide range of biochemical and material-based applications such as irreversible enzyme inhibitors, ,, 18 F-radiolabeling agents, − and deoxy-fluorinating agents. − Furthermore, sulfonyl fluorides have been employed to modify polymers; enhance their solubility, stability, and reactivity; and develop novel materials for organic electronics (Scheme A). , The synthesis of sulfonyl fluorides is of paramount importance given their demonstrated value. It is imperative to develop an efficient synthetic route that employs readily available, abundant, and stable starting materials while circumventing the use of hazardous, toxic, or expensive reagents. − Various synthetic approaches have been introduced starting from the fluorosulfonylation of aromatic arenes using fluorosulfonic acid, dating back almost a century .…”