[N+:1]([C:4]1[C:5]([NH2:10])=[N:6][CH:7]=[CH:8][CH:9]=1)([O-:3])=[O:2].[I:11](O)(=O)(=O)=O.II>C(O)(=O)C.O.S(=O)(=O)(O)O>[I:11][C:8]1[CH:9]=[C:4]([N+:1]([O-:3])=[O:2])[C:5]([NH2:10])=[N:6][CH:7]=1To a solution of 3-nitropyridin-2-amine (1.2 g, 8.63 mmol) in acetic acid (5 ml), water (1 ml) and sulfuric acid (0.2 ml) was added periodic acid (0.4 g, 1.72 mmol, 0.2 eq.) and the mixture was stirred at 90° C. for 15 min. Iodine (0.87 g, 3.45 mmol, 0.4 eq.) was added portionwise and the mixture was heated at 90° C. for 1 h. The mixture was quenched by the addition of water and extracted with ethylacetate (3×150 ml). The combined organic layer was washed with water, aqueous sodium thiosulfate, brine and dried over sodium sulphate. The solvent was distilled off to give the product in 57% yield (1.3 g). 1H NMR (300 MHz, DMSO-d6): δ 8.58 (d, 1H), 8.54 (d, 1H) 8.04 (br s, 2H); LC-MS (ESI); Calculated mass: 265.01: Observed mass: 265.9 [M+H]+ (rt: 1.36 min).
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