Synthesis of iodine-123 labelled analogues of imidazenil and ethyl-imidazenil for studying benzodiazepine receptors using SPECT

✍ Scribed by Andrew Katsifis; Filomena Mattner; Branko Dikic; Ljubco Najdovski; Michael Kassiou

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: French
• Weight: 608 KB
• Volume: 38
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/(sici)1099-1344(199612)38:12<1121::aid-jlcr948>3.0.co;2-v

✦ Synopsis

The [ 1Z31]iodinated analogues of the benzodiazepine receptor partial agonist imidazenil and N-ethyl imidazenil have been synthesised for the study of the central benzodiazepine receptor using SPECT. [1231]Iodoimidazenil and [ 1231]Nethyliodoimidazenil were prepared by nucleophilic bromine-iodine exchange in acetic acid at 150". The products were purified by semi-preparative reverse-phase HPLC with average radiochemical yields of 80% in a total synthesis time of 80 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%. Alternatively, iododestannylation reactions via the trimethyltin precursors with Na [1231] in the presence of Chloramine-T or peracetic acid resulted in yields of only 20-25% with the bulk of activity being lost as volatile methyl [1231]iodide.