反应详情

A mixture of ethyl 5-phenylisoxazole-3-carboxylate (Intermediate I-5A, 3.05 g, 14.0 mmol) and N-iodosuccinimide (3.79 g, 16.9 mmol) in TFA (78 mL) was stirred at room temperature for 3.5 h. The volatiles were removed under reduced pressure, and the residue was partitioned between ethyl acetate (150 mL) and water (150 mL). The organic layer was washed with a 1N aqueous solution of sodium hydroxide (150 mL), washed with a 3% aqueous solution of sodium bisulfite (2×150 mL), washed with brine (150 mL), and dried over anhydrous magnesium sulfate. Concentration under reduced pressure afforded ethyl 4-iodo-5-phenylisoxazole-3-carboxylate (4.69 g, 13.7 mmol, 97% yield) as a light yellow oil. The compound had an HPLC retention time=3.36 minutes (condition A); MS:(M+H)=343.97; 1H NMR (400 MHz, CDCl3) δ ppm 1.47 (t, J=7.1 Hz, 3H), 4.50 (q, J=7.0 Hz, 2H), 7.52-7.56 (m, 3H), and 8.05 (m, 2H).

1. customThe volatiles were removed under reduced pressure
2. customthe residue was partitioned between ethyl acetate (150 mL) and water (150 mL)
3. washThe organic layer was washed with a 1N aqueous solution of sodium hydroxide (150 mL)
4. washwashed with a 3% aqueous solution of sodium bisulfite (2×150 mL)
5. washwashed with brine (150 mL)
6. dry with materialdried over anhydrous magnesium sulfate
7. concentrationConcentration under reduced pressure