| |
[摘要]：Positron emission tomography (PET) is an increasingly important biomedical imaging technique that relies on the development of radiotracers labeled with positron emitters to achieve biochemical specificity. Fluorine-18 (t1/2 = 109.7 min) is an attractive positron-emitting radiolabel for organic radiotracers, primarily because of its longer half-life and greater availability relative to those of the main alternative, carbon-11 (t1/2 = 20.4 min). Rapid, simple methods are sought for labeling prospective PET radiotracers with fluorine-18 from cyclotron-produced aqueous [18F]fluoride ion, which must often be converted first into a suitably reactive labeling synthon for use in a subsequent labeling reaction. The use of 18F-labeled synthons in click chemistry is attracting increasing attention for labeling PET radiotracers. Herein we describe rapid, single-step radiosynthesis of azido- or azidomethyl-bearing [18F]fluoroarenes from the reactions of diaryliodonium salts with no-carrier-added [18F]fluoride ion within a microfluidic apparatus to provide previously poorly accessible 18F-labeled click synthons in radiochemical yields of 15?% for 4-[18F]fluorophenyl azide and about 40?% for each of the [18F](azidomethyl)fluorobenzenes. The radiosynthesis of the latter synthons was possible under wet conditions, so obviating the need to dry the cyclotron-produced [18F]fluoride ion and greatly enhancing the practicality of the method. |
|
