Sodium Thiosulfate → 2-(2,6-Dichloro-4-methanesulfonylphenyl)-2H-pyrazolo[4,3-c]pyridine-5-oxide

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Reaction Steps

mCPBA (569 mg, 3.3 mmol) was added to a cooled (0° C.) solution of 2-(2,6-dichloro-4-methanesulfonylphenyl)-2H-pyrazolo[4,3-c]pyridine (752 mg, 2.2 mmol) in DCM (20 mL) under nitrogen. The reaction was stirred for 1 hour, warmed to room temperature, and stirred for an additional 2 hours. Further mCPBA (150 mg) was added and the reaction mixture was stirred at room temperature for 4 hours before adding sodium thiosulfate (aq.). The organic layer was separated, washed with sodium hydrogen carbonate (sat. aq.) and brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (5-10% methanol in DCM) to afford the title compound as a white solid (640 mg, 81% yield). 1H NMR (300 MHz, DMSO-d6): δ 8.94 (dd, J=1.8, 0.9 Hz, 1H), 8.88 (d, J=1.0 Hz, 1H), 8.33 (s, 2H), 7.96 (dd, J=7.5, 1.8 Hz, 1H), 7.86 (dt, J=7.5, 1.0 Hz, 1H), 3.48 (s, 3H). LCMS (Method D): RT=2.13 min, m/z: 358 [M+H+].

Provenance & Evidence