反应详情

To a stirred mixture of 3-isopropylisoxazole-5-amine (250 mg, 1.98 mmol) and potassium carbonate (634 mg, 4.59 mmol) in dry tetrahydrofuran (6 mL) was added phenyl chloroformate (341 mg, 2.18 mmol). The reaction mixture was stirred at room temperature for 3.5 h, then additional phenyl chloroformate (341 mg, 2.18 mmol) was added and stirring was continued for a further 15 h. The resulting mixture was partitioned between water (50 mL) and dichloromethane (50 mL). The organic layer was separated, washed with brine (50 mL), dried over MgSO4, then concentrated under reduced pressure to give a yellow oil. Purification via silica gel chromatography eluting with 4% to 40% ethyl acetate in hexanes afforded phenyl 3-isopropylisoxazol-5-ylcarbamate as a colorless solid (330 mg, 68%). 1H NMR (300 MHz, CDCl3) δ 7.76 (brs, 1H), 7.40-7.45 (m, 2H), 7.18-7.31 (m, 3H), 6.07 (s, 1H), 3.02 (septet, J=6 Hz, 1H), 1.28 (d, J=6 Hz, 6H); LC-MS (ESI) m/z 247 (M+H)+.

1. stirringstirring
2. waitwas continued for a further 15 h
3. customThe resulting mixture was partitioned between water (50 mL) and dichloromethane (50 mL)
4. customThe organic layer was separated
5. washwashed with brine (50 mL)
6. dry with materialdried over MgSO4
7. concentrationconcentrated under reduced pressure
8. customto give a yellow oil
9. customPurification via silica gel chromatography
10. washeluting with 4% to 40% ethyl acetate in hexanes