Bromotrimethylsilane → 4-Bromo-2-(2,6-dichloro-4-nitrophenyl)-7-fluoro-2H-pyrazolo[4,3-c]pyridine

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Reaction Conditions

Reaction Steps

4-Chloro-2-(2,6-dichloro-4-nitrophenyl)-7-fluoro-2H-pyrazolo[4,3-c]pyridine (1.78 g, 4.93 mmol) was suspended in propionitrile (30 mL), under an atmosphere of nitrogen and bromo trimethylsilane (5.1 mL, 38.3 mmol) was added. The reaction mixture was heated at 105° C. overnight. The resultant mixture was cooled to room temperature and partitioned between ethyl acetate and saturated aqueous sodium bicarbonate solution. The layers were separated and the aqueous layer was further extracted with ethyl acetate (×2). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was triturated with pentane and the solid obtained was dried under reduced pressure to afford the title compound as a pale yellow solid (2.06 g, quantitative yield). 1H NMR (300 MHz, CDCl3): δ 8.44 (s, 2H), 8.33 (d, J=2.2 Hz, 1H), 8.05 (d, J=3.0 Hz, 1H).

Provenance & Evidence