Ethyl Acetate → 4-Chloro-2-(2-chloro-6-fluorophenyl)-2H-pyrazolo[4,3-c]pyridine

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Reaction Conditions

Reaction Steps

2-(2-Chloro-6-fluorophenyl)-2H-pyrazolo[4,3-c]pyridine 5-oxide (2.13 g, 8.1 mmol) was added to a solution of tetrabutylammonium chloride (2.24 g, 8.1 mmol) in phosphorous oxychloride (16 mL) and the reaction mixture was heated at 85° C. for 5 hours. The reaction mixture was cooled to room temperature and poured into a mixture of ethyl acetate and sodium hydrogen carbonate (sat. aq.). The organic phase was separated, washed with sodium hydrogen carbonate (sat. aq.) and brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (20% ethyl acetate in cyclohexane) to afford the title compound as a white solid (606 mg, 27% yield). 1H NMR (400 MHz, CDCl3): δ 8.36 (s, 1H), 8.12 (d, J=6.3 Hz, 1H), 7.57 (d, J=6.5 Hz, 1H), 7.55-7.50 (m, 1H), 7.45 (d, J=8.3 Hz, 1H), 7.27 (m, 1H). LCMS (Method D): RT=3.29 min, m/z: 282 [M+H+].

Provenance & Evidence