Efficient synthesis of 2-bromo-1-[18F]fluoroethane and its application in the automated preparation of 18F-fluoroethylated compounds

An efficient synthesis of 2-bromo-1-[18F]fluoroethane from commercially available 1,2-dibromoethane and its integration into an automated preparation device was developed for the routine synthesis of 18F-fluoroethylated compounds. The 1,2-dibromoethane was reacted with the [18F]fluoride/Kryptofix®2.2.2./carbonate complex in acetonitrile at 70°C for 3 min resulting in 60–70% radiochemical yields. The crude reaction mixture was diluted with water, loaded on a LiChrolute®EN-cartridge, eluted with acetonitrile and passed through an AluminaB®-cartridge. This method provides 2-bromo-1-[18F]fluoroethane with 98% radiochemical purity and <0.1 μmol of 1,2-dibromoethane within 10 min, thus avoiding a purifying distillation step. This method was easily integrated into an automated system for the routine synthesis of 18F-fluoroethylated compounds.