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Radiosynthesis of a 2‐substituted 4,5‐dihydro‐1H‐[2‐ 11 C] imidazole: the I 2 imidazoline receptor ligand [ 11 C] benazoline
Author(s) -
Roeda D.,
Hinnen F.,
Dollé F.
Publication year - 2003
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.746
Subject(s) - chemistry , ethylenediamine , radiosynthesis , imidazole , ligand (biochemistry) , imidazoline receptor , yield (engineering) , medicinal chemistry , ring (chemistry) , bromide , carbon 14 , radiochemistry , nuclear chemistry , stereochemistry , inorganic chemistry , organic chemistry , receptor , medicine , biochemistry , materials science , microbiology and biotechnology , physics , quantum mechanics , in vivo , metallurgy , biology
Abstract Benazoline (2‐naphthalen‐2‐yl‐4,5‐dihydro‐1H‐imidazole) is a selective high‐affinity ligand for the imidazoline I 2 receptor. This compound was labelled with carbon‐11 (T 1/2 =20.4 min) at the number two carbon atom of its 2‐imidazoline ring. Cyclotron‐produced [ 11 C]carbon dioxide reacted with 2‐naphthylmagnesium bromide to give 2‐[carboxyl‐ 11 C]naphthoic acid in 60% radiochemical yield. The latter was heated with a mixture of ethylenediamine and its dihydrochloride at 300°C to give [ 11 C]benazoline in 16% overall yield, relative to [ 11 C]carbon dioxide and with a specific radioactivity of 54 GBq/μmol, decay corrected for end of irradiation. The procedure requires about 45 min from end of cyclotron irradiation. This method should be extendable to other imidazolines. Copyright © 2003 John Wiley & Sons, Ltd.