Synthesis of N-(2-[18F]fluoroethyl)-N′-methylthiourea: a hydrogen peroxide scavenger
摘要:
N-(2-[F-18]fluoroethyl)-N'-methylthiourea ([F-18]FEMTU), a fluorine-18 labelled derivative of the hydrogen peroxide scavenger dimethylthiourea (DMTU), has been synthesized by reaction of 2-[F-18]fluoroethylamine with methylisothiocyanate. 2-[F-18]Fluoroethylamine was obtained in modest radiochemical yields (39+/-6%, mean+/-sd, n=5, decay corrected) by nucleophilic substitution with [F-18]fluoride on N-[2(p-toluenesulfonyloxy)ethyl] phthalimide followed by deprotection with hydrazine and distillation.The distilled 2-[F-18]fluoroethylamine was trapped in CH2Cl2 and reacted with methylisothiocyanate to yield [F-18]FEMTU that was purified by reversed phase HPLC. The total synthesis takes 150 min and provides [F-18]FEMTU with a specific activity of 3.3+0.5 GBq/mu mol (mean+/-sd, n=3) at end of synthesis, with an overall decay corrected radiochemical yield of 25+/-8% (mean+/-sd, n=5).