Potassium Iodide → 2-Amino-5-bromo-3-iodopyridine
Reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([NH2:8])=[N:6][CH:7]=1.[I:9]([O-])(=O)=O.[K+].[I-].[K+]>S(=O)(=O)(O)O.O>[Br:1][C:2]1[CH:3]=[C:4]([I:9])[C:5]([NH2:8])=[N:6][CH:7]=1Participants
6
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([NH2:8])=[N:6][CH:7]=1.[I:9]([O-])(=O)=O.[K+].[I-].[K+]>S(=O)(=O)(O)O.O>[Br:1][C:2]1[CH:3]=[C:4]([I:9])[C:5]([NH2:8])=[N:6][CH:7]=1A stirred solution of 5-bromo-pyridin-2-ylamine (50 g, 289 mmol) in 2M sulfuric acid (500 mL) was treated portionwise with potassium iodate (30.8 g, 144 mmol) and the mixture heated to 100° C. A solution of potassium iodide (26.5 g, 160 mmol) in water (50 mL) was added dropwise over ca. 1 hour. The mixture was allowed to stir for a further 30 minutes then cooled to ambient temperature. The pH of the aqueous phase was adjusted to 8-9 and the mixture extracted with ethyl acetate (×3). The combined organic layer was washed with aqueous sodium thiosulfate solution, water and brine, dried (Na2SO4) and evaporated to afford the title compound as a brown solid (77.4 g, 90%). 1H NMR (300 MHz, CDCl3): 8.06 (d, J=2.2 Hz, 1H), 7.96 (d, J=2.2 Hz, 1H), 4.96 (s, 2H).
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