Trifluoromethanesulfonic anhydride → 6-chloro-4-(4-fluoro-1H-indol-2-yl)pyridin-3-yl trifluoromethanesulfonate

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Reaction Conditions

Reaction Steps

To a solution of 6-chloro-4-(4-fluoro-1H-indol-2-yl)pyridin-3-ol (prepared using similar method described in Example 1, 500 mg, 1.9 mmol), DIPEA (490 mg, 3.8 mmol) and DMAP (5 mg, 0.02 mmol) in DCM (2 mL) was added Tf2O (1.07 g, 3.8 mmol) dropwise at 0° C. under nitrogen. The mixture was stirred at 25° C. for 5 hours. The mixture was diluted with H2O extracted with EtOAc, then the combined organic phase was washed with brine, dried over Na2SO4 and concentrated in vacuo to give the crude product. It was purified by column (PE:EA=5:1) to obtain the product of 6-chloro-4-(4-fluoro-1H-indol-2-yl)pyridin-3-yl trifluoromethanesulfonate (600 mg, yield: 80%). 1H-NMR (CDCl3, 400 MHz) δ 8.71 (s, 1H), 8.39 (s, 1H), 7.64 (s, 1H), 7.18˜7.20 (m, 3H), 6.77˜6.82 (m, 1H). MS (M+H)+: 395/397.

Provenance & Evidence