3-Fluoro-4-hydroxybenzoic acid → (S)-2-methylbutyl 3-fluoro-4-hydroxybenzoate

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Reaction Steps

In a 250-ml, round-bottomed flask equipped with a heating mantle, magnetic stirrer, condenser and Dean Stark trap, were placed 2.5 g (16.0 mmol) of 3-fluoro-4-hydroxybenzoic acid, ten g (113.4 mmol) of (S)-2-methyl-1-butanol, 0.347 g of p-toluenesulfonic acid monohydrate and 100 ml of benzene. The reaction mixture was stirred overnight under reflux. The reaction mixture was extracted using saturated aqueous sodium bicarbonate. The organic phase was dried over sodium sulfate, filtered through cotton and evaporated to an oil. The product was purified by flash chromatography on silica gel with 3% diethyl ether in dichloromethane. Fractions containing the desired product were combined and evaporated to a pale-yellow oil. Analysis by NMR showed that considerable starting alcohol remained. The oil was placed under vacuum (at 70° C.) for two days. No alcohol was shown by gas chromatography to be present. The desired product was obtained in the amount of 2.39 g (66% yield) and had the following structure. ##STR30##

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