Iodine labelled radiopharmaceuticals from arylthallium bis(trifluoroacetate) intermediates

A simple, one-step micro-synthesis of aromatic radioiodides which utilizes the in-situ formation of arylthallium bis (trifluoroacetate) intermediates has been developed. Thallium(III) trifluoroacetate was used in the thallation of aryl compounds to yield the intermediate arylthallium bis (trifluoroacetate). The latter was isolated, purified and used for radioiodination. Alternatively, in-situ radioiodination was accomplished by the addition of radioactive aqueous NaI plus excess non-radioactive iodide to complete the reaction. Yields of up to 81% of radiochemically pure compounds were obtained. Using the modified thallation-radioiodination method, aromatic radiopharmaceuticals can be easily and quickly labelled with¹²³I.