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Improved synthesis of [ 18 F]fluoromethyl tosylate, a convenient reagent for radiofluoromethylations
Author(s) -
Neal Timothy R.,
Apana Scott,
Berridge Marc S.
Publication year - 2005
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.949
Subject(s) - chemistry , yield (engineering) , reagent , propionate , medicinal chemistry , fluoride , organic chemistry , nuclear chemistry , inorganic chemistry , materials science , metallurgy
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.