Dimethylformamide → 2-Fluoro-5-methoxypyridine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of 6-fluoropyridin-3-ol (75 g, 663 mmol) in DMF (265 mL, 663 mmol) were added potassium carbonate (59.7 g, 995 mmol) and iodomethane (108 g, 763 mmol). The resulting slurry was heated at 100° C. for 3 hours. The reaction was diluted with water (1000 mL) and poured into a separatory funnel containing diethyl ether (1000 mL). The layers were separated and the aqueous layer was extracted with diethyl ether (4×500 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a yellow oil. This oil was diluted with 500 mL of DCM and concentrated to provide a yellow oil with a large amount of an off white precipitate. The mixture was filtered and the derived solid was washed well with DCM. The filtrate was concentrate to provide a mixture consisting of a yellow oil and an off white solid. The solid eas filtered, washing with DCM. Repeat this procedure again and then concentrated the filtrate to provide a yellow oil. The oil was taken up in 100 mL of ether and flashed through a plug of silica gel with 10:1 hexanes:ether to provide 2-fluoro-5-methoxypyridine as a yellow oil.

Herkunft & Nachweise