Phosphorus oxybromide → 4-Bromo-2-(2,6-dichloro-4-fluorophenyl)-7-fluoro-2H-pyrazolo[4,3-c]pyridine

Participants

Reaction Conditions

Reaction Steps

To a cooled (0° C.) suspension of 2-(2,6-dichloro-4-fluorophenyl)-7-fluoro-2H-pyrazolo[4,3-c]pyridine-5-oxide (2.95 g, 9.3 mmol) in DCE (50 mL) was added phosphorus oxybromide (8.0 g, 28 mmol). The reaction mixture was stirred at 0° C. for 1 hour, warmed to room temperature, and stirred for a further 3 hours. The reaction mixture was diluted with DCM and washed with sodium carbonate (sat. aq.). The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (0-20% ethyl acetate in cyclohexane) to afford the title compound as a white solid (1.0 g, 28% yield). LCMS (Method D): RT=3.82 min, m/z: 380 [M+H+].

Provenance & Evidence