反应详情

A mixture of ethyl 5-(1-methylcyclopropyl)isoxazole-3-carboxylate (Preparation 4C, 1.5 g, 7.68 mmol) and 1-iodopyrrolidine-2,5-dione (2.07 g, 9.22 mmol) in TFA (25 mL) was stirred at room temperature for 2 h. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in ethyl acetate (50 mL) and washed sequentially with water (50 mL), 1N aqueous sodium hydroxide (50 mL), 2.5 M aqueous sodium bisulfate (50 mL), brine (50 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give ethyl-4-iodo-5-(1-methylcyclopropyl)isoxazole-3-carboxylate (1.93 g, 75% yield) as a yellow liquid. The product had an HPLC ret. time=2.49 min. (condition B); LC/MS M+1=321.9; 1H NMR (400 MHz, CDCl3) δ ppm 0.85 (m, 2H), 1.12 (m, 2H), 1.40 (t, J=7.15 Hz, 3H), 1.42 (s, 3H), and 4.41 (q, J=7.15 Hz, 2H).

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. dissolutionThe residue was dissolved in ethyl acetate (50 mL)
3. washwashed sequentially with water (50 mL), 1N aqueous sodium hydroxide (50 mL), 2.5 M aqueous sodium bisulfate (50 mL), brine (50 mL)
4. dry with materialdried over anhydrous sodium sulfate
5. concentrationconcentrated under reduced pressure