Synthesis of 123I-labelled analogues of imidazobenzodiazepine receptor ligands
Reaction of bromo- or iodo-substituted isatoic anhydrides with N-methylglycine, L-proline or D-proline afforded bromo- or iodo-substituted 1,4-benzodiazepinediones which on condensation with ethyl or t-butyl isocyanoacetates gave ethyl or t-butyl bromo- or iodo-imidazobenzodiazepine carboxylates. These aryl halides were converted into the corresponding tributylstannanes with bis(tributyltin) in the presence of (triphenylphosphine)palladium(0), and the stannanes were treated with sodium (123I)iodide in the presence of chloramine-T to give the required 123I-labelled analogues of the imidazobenzodiazepine receptor ligands flumazenil and bretazenil.
Katsifis, Andrew G.,McPhee, Meredith E.,Mattner, Filomena,Ridley, Damon D.
p. 1061 - 1069
(2007/10/03)
Synthesis of iodine-123 labelled analogues of the partial agonist (S)- and (R)-bretazenil for the study of CNS benzodiazepine receptors using SPECT
The (S) and (R)-[123I]iodinated analogues of the benzodiazepine receptor partial agonist bretazenil have been synthesised for study of the central benzodiazepine receptor using SPECT. (S)- and (R)-[123I]iodobretazenil were prepared from the appropriate tin precursors by electrophilic iododestannylation with Na[123I] in the presence of Chloramine-T. The products were purified by semi-preparative reverse-phase HPLC with radiochemical yields of 80% in a total synthesis time of 50 minutes. The specific activity was determined to be greater than 2500 Ci/mmol. The radiochemical and chemical purity assessed by radio-TLC and HPLC were found to be 98%. The enantiomeric purity of the (S) and (R) isomers were greater than 97% as assessed by analytical chiral HPLC analysis.
Katsifis, Andrew,Mattner, Filomena,McPhee, Meredith,Kassiou, Michael,Najdovski, Ljubco,Dikic, Branko
p. 835 - 845
(2007/10/03)
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