[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)=[CH:4][CH:3]=1.[I:14](O)(=O)=O.II>C(O)(=O)C.S(=O)(=O)(O)O.O>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[CH:13]=[CH:12][C:11]([I:14])=[CH:10][CH:9]=2)=[CH:6][CH:7]=1
A 4-neck one liter round bottom flask equipped with mechanical stirrer, thermometer and reflux condenser topped with nitrogen bubbler inlet was charged with 4-bromobiphenyl (23.31 g, 100 mmol) in acetic acid (400 mL), sulfuric acid (10 mL) and water (20 mL). To this stirring mixture was added iodic acid (4.84 g, 27.5 mmol) followed immediately by addition of iodine chips (11.17 g, 44.0 mmol). The reaction flask was immersed in a preheated tri(ethylene glycol) heating bath and heated at 65° C. internal temperature. After 30 min the bath temperature was increased such that the internal temperature raised to 85° C. after 20 min. Heating at this temperature was continued for 4.5 hours at which point HPLC analysis showed the reaction to be complete. After stirring overnight at room temperature the reaction mixture was vacuum filtered through a coarse fritted funnel and the solids were rinsed with water. The resulting white solid (32.1 g, 89% yield) had mp 177-179° C. and was used without further purification in the next step. NMR analysis confirmed the structure of Intermediate Compound 3,4-bromo-4′-iodobiphenyl. Purity (HPLC): >99%.
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