[I:1]I.[CH3:3][C:4]1[CH:9]=[C:8]([NH2:10])[CH:7]=[CH:6][N:5]=1.C(=O)([O-])[O-].[Na+].[Na+].C(OCC)(=O)C>O>[NH2:10][C:8]1[CH:9]=[C:4]([CH3:3])[N:5]=[CH:6][C:7]=1[I:1].[NH2:10][C:8]1[CH:7]=[CH:6][N:5]=[C:4]([CH3:3])[C:9]=1[I:1]A solution of KI (1.96 g, 11.9 mmol) and I2 (1.87 g, 7.36 mmol) in 10 mL of water was added to a refluxing solution of the 2-methylpyridin-4-ylamine (1.00 g, 9.25 mmol) and sodium carbonate (683 mg, 6.44 mmol) in 5 mL of water. The mixture was heated at reflux for 2 hours, cooled to room temperature, and treated with 20 mL of ethyl acetate (EtOAc). Phases were separated and the aqueous layer was extracted with three 20 mL portions of ethyl acetate. The combined organic layers were washed with a saturated aqueous sodium thiosulfate (Na2S2O3) solution, dried over magnesium sulfate, and concentrated in vacuo. Flash chromatography (30% ethyl acetate in hexanes to 100% ethyl acetate, gradient) of the resulting residue yielded 4-amino-3-iodo-6-methylpyridine (first eluting: 226 mg, 11% yield) and 4-amino-3-iodo-2-methylpyridine (second eluting: 116 mg; 5% yield).
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