Efficient alkali iodide promoted F-fluoroethylations with 2-[F]fluoroethyl tosylate and 1-bromo-2-[F]fluoroethane

Radiochemical ¹⁸F-fluorination yields of several compounds using the secondary labelling precursors 2-¹⁸F]fluoroethyl tosylate (¹⁸F]FETos) and 1-bromo-2-¹⁸F]fluoroethane (¹⁸F]BFE) could be considerably enhanced by the addition of an alkali iodide. The radiochemical yield of ¹⁸F]fluoroethyl choline for example could be doubled with ¹⁸F]BFE and increased from 13% to ≈80% with ¹⁸F]FETos. By addition of alkali iodide to the precursor, the ¹⁸F-fluoroethylation yields of established radiopharmaceuticals, especially in the case of automated syntheses, could be significantly increased without major changes of the reaction conditions.