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

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Reaction Steps

A dried solution of mCPBA (7.2 mmol) in DCM (20 mL) was added to a cooled (0° C.) solution of 2-(2,6-dichlorophenyl)-2H-pyrazolo[4,3-c]pyridine (1.28 g, 4.8 mmol) in DCM (30 mL) under nitrogen. The reaction mixture was stirred for 1 hour, warmed to room temperature, and stirred for a further 2 hours. Sodium thiosulfate (sat. aq.) was added and the layers were partitioned. The organic layer was washed with sodium hydrogen carbonate (sat. aq.) and brine, dried over anhydrous magnesium sulfate, and concentrated to 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 (1.22 g, 91% yield). 1H NMR (400 MHz, DMSO-d6): δ 8.90 (dd, J=1.8, 0.9 Hz, 1H), 8.84 (d, J=1.0 Hz, 1H), 7.95 (dd, J=7.5, 1.8 Hz, 1H), 7.84 (dt, J=7.5, 1.0 Hz, 1H), 7.81-7.78 (m, 2H), 7.70 (dd, J=9.0, 7.3 Hz, 1H).

Provenance & Evidence