Synthesis of high specific activity ^80mBr and ¹²³I labeled 5‐halodeoxyuridines and other ^80mBr compounds for the study of auger electron toxicity

Convenient preparations of ^80mBr and ¹²³I‐labeled 5‐halodeoxyuridines, required for basic investigations of Auger electron radiotoxicity, are described. These radioactive thymidine analogs were synthesized from deoxyuridine, radiohalide and N‐chlorosuccinimide in dilute sulfuric acid. Yields were 50–60% for ^80mBr and 60–70% for ¹²³I. Apparent specific radioactivities (based on UV absorption under the radioactive HPLC peaks) were 150–550 Ci/mmol and over 2000 Ci/mmol for ^80mBr and ¹²³I, respectively. 5‐[^80mBr]bromouracil was produced in 89% yield when uracil was used. [^80mBr]Bromoantipyrine was produced in higher yield and specific activity using peroxyacetic acid, rather than N‐chlorosuccinimide as oxidant (90% and 4,000 Ci/mmol versus 50% and 2000 Ci/mmol).