Boron tribromide → 2-Fluoro-3-hydroxy-4-methoxybenzonitrile

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Reaction Steps

2.0 g of 2-fluoro-3,4-dimethoxybenzonitrile are dissolved in 60 ml of methylene chloride, treated with 1.1 ml of boron tribromide, stirred at 23° for 1 hour, subsequently treated with an additional 1.0 ml of boron tribromide and stirred at 23° for an additional 80 minutes. Thereupon, the reaction mixture is poured into 100 ml of ice-cold saturated sodium hydrogen carbonate solution, whereupon the mixture is extracted twice with 300 ml of ether, the combined ether phases are washed twice with sodium chloride solution, dried over sodium sulfate, evaporated and the residue is chromatographed on 50 g of silica gel with methylene chloride and methylene chloride/methanol (97:3). There is obtained 2-fluoro-3-hydroxy-p-anisonitrile of m.p. 198°-200°.

Provenance & Evidence