反应详情

A mixture of ethyl 5-phenylisoxazole-3-carboxylate (406 mg, 1.87 mmol) and N-iodosuccinimide (505 mg, 2.24 mmol) in trifluoroacetic acid (10 mL) was stirred at room temperature for 1.5 h. The volatiles were removed under reduced pressure, and the residue was partitioned between ethyl acetate (50 mL) and water (50 mL). The organic layer was washed with a 1N aqueous solution of sodium hydroxide (50 mL), washed with a 2.5% aqueous solution of sodium bisulfate (50 mL), washed with brine (50 mL), and dried over anhydrous magnesium sulfate. Concentration under reduced pressure afforded ethyl 4-iodo-5-phenylisoxazole-3-carboxylate (641 mg, 1.87 mmol, 100% yield) as a light yellow oil. The compound had an HPLC retention time=3.36 minutes (YMC-Combi 4.6×50 mm S-5 ODS column) eluting with 10-90% aqueous methanol+0.2% phosphoric acid over a 4 minute gradient. MS:(M+H)=343.97. 1H-NMR (400 MHz, CDCl3) δ ppm 1.47 (t, J=7.1 Hz, 3H), 4.50 (q, J=7.0Hz, 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 (50 mL) and water (50 mL)
3. washThe organic layer was washed with a 1N aqueous solution of sodium hydroxide (50 mL)
4. washwashed with a 2.5% aqueous solution of sodium bisulfate (50 mL)
5. washwashed with brine (50 mL)
6. dry with materialdried over anhydrous magnesium sulfate
7. concentrationConcentration under reduced pressure