Synthesis of 131I, 125I and 82Br labelled (E)-5-(2-halovinyl)-2'-deoxyuridines.

Radiohalogenated (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU, 4) and (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU, 5) were synthesized by reaction of (E)-5-(2-carboxyvinyl)-2'-deoxyuridine (1) with radiolabelled iodide or bromide in the presence of chloramine-T. A "no-carrier-added" synthesis of [131I]IVDU was completed within 30 min providing a radiochemical yield of 65%. Alternatively, radioactive iodine was incorporated into IVDU using a halogen isotope exchange reaction catalyzed by cuprous ion. [82Br]BVDU was also prepared by direct neutron activation of unlabelled BVDU.