5-Iodouracil

66-22-8

696-07-1

The general procedure for the synthesis of 5-iodouracil (5-IUra) from pyrimidine-2,4(1H,3H)-dione (Ura) is as follows: Example 1 Synthesis of 5-halogenated uracil (5-X-Ura) Preparation of 5-iodouracil (5-IUra) and 5-bromouracil (5-BrUra) from Ura: 1. Prepare a solution of 1,3,4,6-tetrachloro-3a,6a-diphenylglycuronium in chloroform (concentration 0.5 mg/mL). All reagents were available from Sigma Chemical Co. (St. Louis, MO) unless otherwise noted. 2. Dry 0.5 mL (containing 250 μg, 578 μmol) of the above solution using a stream of nitrogen. 3. 300 μL of Ura (2610 μmol, 8.7 M, dissolved in 0.25 M potassium phosphate buffer, pH 7.5) was added. 4. 100 μL NaI or NaBr (670 μmol, 6.7 M aqueous solution) was subsequently added to the reaction system. 5. The reaction mixture was heated at 60 °C for 15 min. 6. Upon completion of the reaction, the yield was 79% for 5-IUra and 56% for 5-BrUra, depending on the halide used. 7. At the end of the reaction, the reaction mixture was diluted with water and the products were analyzed by reversed-phase high performance liquid chromatography (HPLC). 8. HPLC mobile phase conditions: 20-50 mM acetic acid and 6-16% acetonitrile (ACN). Note: This method is suitable for the synthesis of materials on a small scale and also for the therapeutic isotope labeling of Ura by replacing non-radioactive halides with radioisotopes such as [82Br] or [125I].