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2 Publications
Preparation of 18F-labeled building blocks for peptide conjugation using the "minimalist" approach
Omrane, M. A.; Zlatopolskiy, B. D.; Urusova, E.; Mamat, C.; Feni, L.; Neundorf, I.; Neumaier, B.;
Recently, the “minimalist” protocol for radiofluorination was reported. This method allowed to prepare labeled probes from only [18F]F– and onium salts without base and other additives avoiding time-consuming azeotropic drying. The aim of this work was the implementation of the “minimalist” approach for the preparation of radiofluorinated building blocks via SN2. [18F]Fluoride was eluted from a QMA cartridge with an appropriate azetidinium or onium salt precursor of [18F]AFP, [18F]BFP and 5-[18F]FDR in MeOH. MeOH was evaporated at 55°C (550 mbar) within 2–3 min. MeCN was added and the resulting solutions were heated to give the corresponding 18F-labeled products. Protected 5-[18F]FDR was purified by SPE and thereafter deprotected under acidic conditions. Finally, reaction conditions for the conjugation of 5-[18F]FDR to aminooxy-functionalized peptides via chemoselective oxime ligation were optimized. [18F]F– was eluted from an anion exchange resin almost quantitatively. Under optimized conditions appropriately protected 5-[18F]FDR as well as [18F]AFP and [18F]BFP were prepared from the corresponding 3-N,N,N-trimethylammoniumalkyl(aryl)sulfonyl and azetidinium precursors in RCYs of up to 70%, 90% and 91% (determined by radio-HPLC analysis of the crude product), respectively. After SPE purification 5-[18F]FDR was obtained in 41% RCY (EOB) and excellent RCP >99% after deprotection with 1 m HCl (110 °C, 12 min) . The amount of d-ribose (60–80 μg/batch), a competitor in subsequent oxime ligation, was low enough to allow an efficient conjugation of 5-[18F]FDR with aminooxy-functionalized peptides. The corresponding conjugates were prepared in RCYs of up to 91%. The SN2 radiofluorination under “minimalist” conditions is well suited for the fast production of versatile 18F-labeled building blocks. The positively charged trimethylammonium “tag” of the 5-[18F]FDR precursor enables its simple separation from the labeled product using SPE. The prosthetic group was sufficiently pure for the subsequent labeling of peptides.
  • Poster
    22nd International Symposium on Radiopharmaceutical Sciences (ISRS 2017), Dresden, 14.-19.05.2017, Dresden, Deutschland
  • Open Access LogoJournal of Labelled Compounds and Radiopharmaceuticals 60(2017)S1, S261
    DOI: 10.1002/jlcr.3508

Publ.-Id: 26077 - Permalink