Premium
A three‐step radiosynthesis of 6‐[ 18 F]fluoro‐ L‐meta ‐tyrosine starting with [ 18 F]fluoride
Author(s) -
Castillo Meleán Johnny,
Ermert Johannes,
Coenen Heinz H.
Publication year - 2015
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.3273
Subject(s) - chemistry , radiosynthesis , carboxylate , electrophile , hydrolysis , fluorine , fluoride , medicinal chemistry , biocatalysis , halogenation , enantiomer , radiochemistry , stereochemistry , organic chemistry , reaction mechanism , inorganic chemistry , catalysis , microbiology and biotechnology , in vivo , biology
The radiosynthesis of 6‐[ 18 F]fluoro‐L‐ m ‐tyrosine has generally been performed by electrophilic radiofluorination, which exhibits several drawbacks. In the present work, a three‐step radiochemical synthesis is described starting from [ 18 F]fluoride. The synthetic sequence, including isotopic exchange, Baeyer–Villiger oxidation, and hydrolysis, were examined comparing four fluorobenzophenone derivatives as labeling precursors. Of those, (2 S ,5 S )‐ tert ‐butyl 5‐(5‐acetyl‐2‐fluorobenzyl)‐2‐ tert ‐butyl‐3‐methyl‐4‐oxoimidazolidine‐1‐carboxylate (1a) and (2 S ,5 S )‐ tert ‐butyl 2‐ tert ‐butyl‐5‐(2‐fluoro‐5‐(2,2,2‐trifluoroacetyl)benzyl)‐3‐methyl‐4‐oxoimidazolidine‐1‐carboxylate (1d) proved to be the most suitable ones. 6‐[ 18 F]Fluoro‐L‐ m ‐tyrosine was obtained with overall radiochemical yields of 8–13% and an enantiomeric excess of up to 98%.