反应详情

To a mixture of 3-amino-4-bromo-5-methylisoxazole (2.58 g, 14.6 mmol) and DMAP (893 mg, 7.3 mmol) in 60 mL dichloromethane at −78° C. was added pyridine (6 ml, 74.1 mmol) followed by 2,2,2-trichloroethyl chloroformate (8 ml, 58 mmol). The reaction was allowed to warm to room temperature while stirring over ca. 4 hours. Ice water was added, the aqueous phase neutralized with saturated aq. NaHCO3, and the product extracted with ether (3×), dried over Na2SO4 and concentrated in vacuo. The crude product was purified by flash chromatography (20% ethyl acetate/hexane) to afford 2,2,2-trichloroethyl 4-bromo-5-methylisoxazol-3-ylcarbamate.

1. extractionthe product extracted with ether (3×)
2. dry with materialdried over Na2SO4
3. concentrationconcentrated in vacuo
4. customThe crude product was purified by flash chromatography (20% ethyl acetate/hexane)