Synthesis ofN-(3-[18F]Fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl)nortropane ([18F]FP-β-CIT)

Abstract

N-(3-[18F]fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl)nortropane ([18F]FP-β-CIT) was synthesized in a two-step reaction sequence. In the first reaction, 1-bromo-3-(nitrobenzene-4-sulfonyloxy)-propane was fluorinated with no-carrier-added fluorine-18. The resulting product, 1-bromo-3-[18F]-fluoropropane, was distilled into a cooled reaction vessel containing 2β-carbomethoxy-3β-(4-iodophenyl)-nortropane, diisopropylethylamine and potassium iodide. After 30 min, the reaction mixture was subjected to a preparative HPLC purification. The product, [18F]FP-β-CIT, was isolated from the HPLC eluent with solid-phase extraction and formulated to yield an isotonic, pyrogen-free and sterile solution of [18F]FP-β-CIT. The overall decay-corrected radiochemical yield was 25 ± 5%. Radiochemical purity was > 98% and the specific activity was 94 ± 50 GBq/µmol at the end of synthesis. Copyright © 2006 John Wiley & Sons, Ltd.