Efficient Radiosynthesis of 2-[18F]Fluoroadenosine: A New Route to 2-[18F]Fluoropurine Nucleosides

An efficient method to incorporate the fluorine-18 radionuclide in 2-nitropurine-based nucleosides was developed. The nucleophilic radiofluorination of the labeling precursor with [F-18]KF under aminopolyether-mediated conditions (Kryptofix 2.2.2/K2CO3) followed by deprotection was straightforward and, after formulation, gave 2-[F-18]fluoroadenosine, ready for injection with a radiochemical yield of 45 +/- 5%, a radiochemical purity of >98%, and a specific radioactivity up to 148 GBq/mu mol. A micropositron emission tomography imaging and biodistribution study on rodents was reported.