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Radiolabelling optimization of 5‐(4‐[ 125 I]‐iodophenyl)‐2,3 dihydro‐5‐hydroxy‐5H‐imidazo[2,1‐a]isoindole or [ 125 I]‐iodo mazindol : A potential tool for spect explorations
Author(s) -
Galinier E.,
Ombetta J. E.,
Frangin Y.,
Mertens J.,
Besnard J. C.,
Guilloteau D.
Publication year - 1994
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.2580340512
Subject(s) - chemistry , radiosynthesis , tautomer , iodide , nucleophile , isoindole , catalysis , bromide , labelling , medicinal chemistry , combinatorial chemistry , organic chemistry , microbiology and biotechnology , in vivo , biology , biochemistry
The radiolabelling of an iodinated analog of mazindol, 5‐(4‐[ 125 I]‐iodophenyl)‐2,3‐dihydro‐5‐hydroxy‐5H‐imidazo[2,1‐a]isoindole, was performed in order to develop a potential tool for SPECT exploration of the presynaptic dopamine transporter in the human brain. Radiosynthesis was performed by iodide for bromide nucleophilic exchange from a brominated precursor. The reaction was carried out in the presence of the copper I catalyst and reducing and complexing agents. In these radiolabelling conditions, [ 125 I] iodomazindol exhibited a tautomeric equilibrium. Therefore, in order to obtain the best labelling conditions, we studied variables such as copper I catalyst and brominated precursor concentrations, reaction temperature and heating time involved in the reaction. This study of the kinetics could be used as a pattern for the radiosynthesis of other compounds which can be present in a tautomeric equilibrium under particular conditions. Indeed, we describe a convenient procedure to obtain each tautomeric form with high radiochemical purity in optimum radiolabelling conditions.