4-Fluorophenol → 3-Bromo-5-(4-fluorophenoxy)pyridine

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Reaction Steps

Sodium hydride (1.53 g of 80% in mineral oil, 51 mmol) was slowly added to a solution of 4-fluorophenol (5.6 g, 50 mmol) in DMF (100 mL) as it was stirred and cooled (ice water bath) under a nitrogen atmosphere. The resulting mixture was warmed to ambient temperature and stirred for 1 h. 3,5-Dibromopyridine (5.9 g, 25 mmol) was added and the mixture was then heated at 90° C. (bath temperature) for 62 h. The mixture was cooled, diluted with water (150 mL), poured into 5N sodium hydroxide (150 mL), and extracted with diethyl ether (2×150 mL). The combined ether extracts were washed with water, dried (MgSO4), filtered and concentrated by rotary evaporation. The residue was purified by flash chromatography on silica gel, using 5% ethyl acetate: hexane as eluent, to yield 1.4 g (21%) of a colorless oil.

Provenance & Evidence