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4‐[ 18 F]fluorophenyl ureas via carbamate‐4‐nitrophenyl esters and 4‐[ 18 F]fluoroaniline
Author(s) -
Olma Sebastian,
Ermert Johannes,
Coenen Heinz H.
Publication year - 2006
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.1121
Subject(s) - chemistry , yield (engineering) , carbamate , amine gas treating , urea , medicinal chemistry , radiosynthesis , ethyl carbamate , organic chemistry , nuclear chemistry , microbiology and biotechnology , materials science , food science , wine , in vivo , metallurgy , biology
Four different no carrier added (n.c.a.) 4‐[ 18 F]fluorophenylurea derivatives are synthesized as model compounds via two alternative routes. In both cases carbamate‐4‐nitrophenylesters are used as intermediates. Either n.c.a. 4‐[ 18 F]fluoroaniline reacts with carbamates of several amines, or the carbamate of n.c.a. 4‐[ 18 F]fluoroaniline is formed at first and an amine is added subsequently to yield the urea derivative. The choice of the appropriate way of reaction depends on the possibilities of precursor synthesis. The radiochemical yields reach up to 80% after 50 min of synthesis time while no radiochemical by‐products can be determined. These high yields were possible due to an optimized preparation of n.c.a. 4‐[ 18 F]fluoroaniline with a radiochemical yield of up to 90%. From the various ways of its radiosynthesis, the substitution with n.c.a. [ 18 F]fluoride on dinitrobenzene is chosen, using phosphorous acid and palladium black for reduction of the second nitro group. Copyright © 2006 John Wiley & Sons, Ltd.