反应详情

温度

95 °C

To acetic anhydride (1.61 L) at 90° C. was added 2,5-dimethyl-pyridine 1-oxide (1000 g) dropwise over 3 hours, maintaining a temperature between 90-100° C. The reaction was stirred at 90° C. for 1.5 hours, and then cooled with stirring overnight. The mixture was slowly poured into aqueous 25% sodium hydroxide (3 L) over 4 hours, and then dichloromethane (8 L) and water (8 L) were added, and the mixture was allowed to separate for 2 days. The aqueous layer was separated and extracted separately with dichloromethane and ethyl acetate, and the combined organic layers were concentrated to dryness. The crude material was applied to the top of a pad of silica (˜1 kg) and eluted with ethyl acetate until no product was observed in the eluant. The filtrate was concentrated under vacuum to give the desired product (320 g).

1. temperaturecooled
2. stirringwith stirring overnight
3. customto separate for 2 days
4. customThe aqueous layer was separated
5. extractionextracted separately with dichloromethane and ethyl acetate
6. concentrationthe combined organic layers were concentrated to dryness
7. washeluted with ethyl acetate until no product
8. concentrationThe filtrate was concentrated under vacuum