C1(C)C=CC(S(OS(C2C=CC(C)=CC=2)(=O)=O)(=O)=O)=CC=1.[I:22][C:23]1[CH:24]=[N+:25]([O-])[CH:26]=[CH:27][C:28]=1[O:29][CH2:30][CH2:31][C:32]1[CH:36]=[CH:35][S:34][CH:33]=1.[C:38]([NH2:42])([CH3:41])([CH3:40])[CH3:39]>C(Cl)(Cl)Cl>[C:38]([NH:42][C:26]1[CH:27]=[C:28]([O:29][CH2:30][CH2:31][C:32]2[CH:36]=[CH:35][S:34][CH:33]=2)[C:23]([I:22])=[CH:24][N:25]=1)([CH3:41])([CH3:40])[CH3:39]A solution of p-toluenesulfonic anhydride (1.47 g, 4.49 mmol) in 15 ml of chloroform was added dropwise to a stirred mixture of 0.78 g (2.25 mmol) of 3-iodo-4-(2-(thiophen-3-yl)ethoxy)pyridine 1-oxide and 1.18 ml (11.2 mmol) of tert-butylamine in 15 ml of chloroform at 0° C. After 30 minutes, the addition of the same quantities of p-toluenesulfonic anhydride and tert-butylamine was repeated to complete the reaction. The reaction mixture was concentrated and partitioned between 100 ml of diethylether and 1 M aqueous sodium carbonate. The aqueous layer was extracted with 50 ml of diethylether again and combined organic extracts were washed with water, brine, dried over sodium sulfate and concentrated in vacuum. The residue was purified by flash chromatography eluting with 10% of ethyl acetate in hexane to give N-tert-butyl-5-iodo-4-(2-(thiophen-3-yl)ethoxy)pyridin-2-amine (0.473 g (52%). 1H NMR (400 MHz, CDCl3) δ 8.15 (s, 1H), 7.28 (dd, J=3.0, 4.8, 1H), 7.18 (s, 1H), 7.12 (d, J=4.9, 1H), 5.85 (s, 1H), 4.44 (s, 1H), 4.15 (t, J=6.5, 2H), 3.18 (t, J=6.5, 2H), 1.39 (s, 9H). MS: (ESI+) 403.2
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