No-carrier-added synthesis of 3-[18F]fluoro-1-(2-nitro-1-imidazolyl)-2-propanol. A potential PET agent for detecting hypoxic but viable tissues

Four different approaches towards the synthesis of [18F]FMISO have been studied. The first approach was based on the reaction of epoxide and [18F]fluoride. Both specific activity and radiochemical yield (<1%) for [18F]FMISO were low. Two new approaches, failed to give [18F]FMISO. The fourth approach, based on the reaction of [18F]epifluorohydrin, prepared from Tosylate and [18F]KF/Kryptofix 222, has provided a reliable, no-carrier added synthesis of [18F]FMISO. The product was obtained in a radiochemical yield of 7-12% at end-of-synthesis (based on [18F]fluoride) with a specific activity of >400 Ci/mmol and a synthesis time of 1.5 h. Preliminary PET studies suggest that [18F]FMISO may be a promising tracer for delineation of ischemic but viable myocardium. (author)