To a solution of isoxazole-5-carboxylic acid (1.0 g, 8.8 mmol) in tetrahydrofuran (THF, 10 mL) was slowly added borane-THF complex (26.4 mL, 1 M in THF, 26.4 mmol) at 0 °C. The reaction mixture was stirred at room temperature and the progress of the reaction was monitored by thin layer chromatography (TLC) until isoxazole-5-carboxylic acid was completely consumed. Upon completion of the reaction, ethanol (5 mL) was added slowly at 0 °C to quench the reaction. The reaction mixture was transferred to a dispensing funnel and partitioned with ethyl acetate and water. The organic phase was separated and the aqueous phase was back-extracted with ethyl acetate. All organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the crude product isoxazol-5-ylmethanol. The crude product was purified by silica gel column chromatography with the eluent of petroleum ether/ethyl acetate (2:1, v/v) to give the pure isoxazol-5-ylmethanol (670 mg, 77.0% yield) as a light yellow oil. The product was analyzed by liquid chromatography-mass spectrometry (LC-MS) with a retention time of 0.329 min and a molecular ion peak (MH+) of 100.
