The general procedure for the synthesis of 2-chloro-5-iodo-7H-pyrrolo[2,3-d]pyrimidine using 2-chloro-7H-pyrrolo[2,3-d]pyrimidine as starting material was as follows: to a solution of 2-chloro-7H-pyrrolo[2,3-d]pyrimidine (482.5 g, 3.14 mol) in acetonitrile (2,500 mL) was added slowly at 12 °C with N-iodosuccinimide (742 g, 3.30 mol). The reaction mixture was stirred at room temperature for 1 hour, then aqueous sodium metabisulfite (650 g, dissolved in 4500 mL of water) was added. After continued stirring for 1 h, the solid product was collected by filtration to afford 2-chloro-5-iodo-7H-pyrrolo[2,3-d]pyrimidine as an orange solid in 82% yield (716.2 g). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6): δ 7.83 (s, 1H), 8.63 (s, 1H), 12.73 (s, 1H).
![2-CHLORO-7H-PYRROLO[2,3-D]PYRIMIDINE](/CAS/GIF/335654-06-3.gif)
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