Improved synthesis of [18F]fluoromethyl tosylate, a convenient reagent for radiofluoromethylations

✍ Scribed by Timothy R. Neal; Scott Apana; Marc S. Berridge

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: French
• Weight: 144 KB
• Volume: 48
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.949

✦ Synopsis

Abstract

The utility of [^18^F]fluoromethyl tosylate as an [^18^F]fluoromethylation reagent has been reexamined. The preparation of this potentially useful compound from the reaction of bis(tosyloxy) methane with ^18^F‐ was reported several years ago, but it had not found use as a labeling reagent. When the reported reaction of bis(tosyloxy) methane with ^18^F‐ was carried out, [^18^F]fluoromethyl tosylate was formed along with [^18^F]tosyl fluoride. The product ratio depended upon reaction conditions, with the yield of [^18^F]fluoromethyl tosylate usually in the range of 25–40%. Addition of a small amount of water to the reaction mixture resulted in a significant increase in the yield of [^18^F]fluoromethyl tosylate. Reaction conditions were defined that produced a yield of 71±6% of [^18^F]fluoromethyl tosylate (decay corrected). The product was conveniently purified by alumina chromatography. Reaction of [^18^F]fluoromethyl tosylate with the (des‐fluoromethyl) fluticasone propionate thioacid precursor produced [^18^F]fluticasone propionate in improved yield (16%, from fluoride in production‐scale runs) over other synthesis methods. Similarly, formation of [^18^F]choline, [^18^F]fluoromethionine and N‐([^18^F]fluoromethyl)spiperone from the reaction of [^18^F]fluoromethyl tosylate with corresponding precursors was examined. Copyright © 2005 John Wiley & Sons, Ltd.