反应详情

Under vigorous stifling at room temperature, acetyl chloride (1.02 g, 13 mmol) was added dropwise to a mixture of 6-nitro-3,4-dihydro-2H-benzo[1,4]oxazine (1.8 g, 10 mmol) and NaHCO3 (7.14 g, 85 mmol) in CH2Cl2 (50 mL). After addition, the reaction was stirred for 1 h at this temperature. The mixture was filtered and the filtrate was concentrated under vacuum. The residue was treated with Et2O:hexane (1:2, 50 mL) under stifling for 30 min and then filtered to give 4-acetyl-6-nitro-3,4-dihydro-2H-benzo[1,4]oxazine as a pale yellow solid (2 g, 90%).

1. additionAfter addition
2. filtrationThe mixture was filtered
3. concentrationthe filtrate was concentrated under vacuum
4. additionThe residue was treated with Et2O:hexane (1:2, 50 mL)
5. waitunder stifling for 30 min
6. filtrationfiltered