反应详情

To a solution of 3-pyridin-2-yl-5-([E]-styryl)-isoxazole-4-carboxylic acid (1.1 g, 4 mmol) and triethylamine (0.53 mL, 4 mmol) in THF (15 mL) was added dropwise at room temperature a solution of ethyl chloroformate (0.36 mL, 4 mmol) in THF (15 mL). After 1 h the triethylamine hydrochloride salt was filtered off and washed with a small amount of THF. The filtrate was added to a solution of sodium borohydride (0.36 g, 10 mmol) in water (10 mL). After stirring for 1 h at 5° C. aqueous sodium hydroxide (2 M, 22 mL) was added. Extraction with ethyl acetate, drying over sodium sulfate, filtering and evaporation of the solvent followed by trituration with diisopropylether afforded the title compound (0.76 g, 72%) as a white solid. MS: m/e=279.2 [M+H]+.

1. filtrationAfter 1 h the triethylamine hydrochloride salt was filtered off
2. washwashed with a small amount of THF
3. additionwas added
4. extractionExtraction with ethyl acetate
5. dry with materialdrying over sodium sulfate
6. filtrationfiltering
7. customevaporation of the solvent