反应详情

To a solution of 3-(4-fluoro-phenyl)-5-((E)-styryl)-isoxazole-4-carboxylic acid (19.0 g, 61.4 mmol) and triethylamine (8.6 mL, 61.4 mmol) in THF (475 mL) was added at room temperature a solution of ethyl chloroformate (5.97 mL, 61.4 mmol) in THF (55 mL). After 1 h the triethylamine hydrochloride salt was filtered off and washed with a small amount of THF. The mixture was added to a solution of sodium borohydride (6.05 g, 154 mmol) and water (55 mL). After stirring overnight at room temperature aqueous sodium hydroxide solution (1 N, 180 mL) was added. Extraction with tert-butylmethylether, removal of the solvent by distillation and chromatography (silica, dichloromethane:methanol=1:0 to 95:5) afforded the title compound (11.4 g, 63%) as light yellow solid. MS: m/e=296.2 [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
5. customwith tert-butylmethylether, removal of the solvent
6. distillationby distillation and chromatography (silica, dichloromethane:methanol=1:0 to 95:5)