反应详情

温度

80 °C

A mixture of 6.66 g of 3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H-1,4-benzoxazine, 5.51 g of ethyl bromoacetate, 4.5.6 g of potassium carbonate and 20 ml of acetonitrile was refluxed under heating for 2.5 hours. Then, 10 ml of N,N-dimethylformamide was added and the mixture was stirred at 80° C. for 2 hours. To this mixture was added 2-80 g of ethyl bromoacetate. After an hour of stirring at 80° C., 2.28 g of potassium carbonate was added and the mixture was further stirred at 80° C. for 1 hour. The reaction mixture was then concentrated under reduced pressure and the residue was chromatographed on a silica gel column, elution being carried out with hexane-ethyl acetate (10:.1). The crystals from the eluate were recrystallized from ethyl acetate-hexane to give 7.4 g of ethyl (3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H1,4 -benzoxazin-4-yl)acetate. This compound has the following physicochemical properties.

1. temperaturewas refluxed
2. temperatureunder heating for 2.5 hours
3. stirringAfter an hour of stirring at 80° C.
4. stirringthe mixture was further stirred at 80° C. for 1 hour
5. concentrationThe reaction mixture was then concentrated under reduced pressure
6. customthe residue was chromatographed on a silica gel column, elution
7. customThe crystals from the eluate were recrystallized from ethyl acetate-hexane