反应详情

To a solution of 3-methyl-5-(1-hydroxyethyl)-isoxazole (47.6 g, 367 mM) in acetone (2 L) at 0° C., was added a solution of chromic anhydride (93.3 g, 933 mM), 6N aqueous sulfuric acid (186.15 mL, 1.1M) and water (186 mL) over two hours. After the reaction solution was allowed to warm to room temperature, saturated aqueous sodium chloride was added. The aqueous layer was extracted with dichloromethane (3×400 mL). The combined organic extracts were washed with saturated aqueous sodium sulfite (2×300 mL) and saturated aqueous sodium chloride (2×300 mL). The organic layer was dried over MgSO4, filtered and concentrated under reduced pressure to give 3-methyl-5-acetoxy-isoxazole as a yellow powder (27.8 g, 60%) that was used without further purification. 1H NMR (CDCl3, 100 MHz): δ 7.55 (s, 1H), 2.65 (s, 3H), 2.43 (s, 3H).

1. extractionThe aqueous layer was extracted with dichloromethane (3×400 mL)
2. washThe combined organic extracts were washed with saturated aqueous sodium sulfite (2×300 mL) and saturated aqueous sodium chloride (2×300 mL)
3. dry with materialThe organic layer was dried over MgSO4
4. filtrationfiltered
5. concentrationconcentrated under reduced pressure