Dimethylformamide → 5-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-one

Reaction equation

[NH2:1][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][C:3]=1[OH:11].CN([CH:15]=[O:16])C.[C:17]([O-])([O-])=O.[K+].[K+]>>[N+:8]([C:7]1[C:2]2[NH:1][C:15](=[O:16])[CH2:17][O:11][C:3]=2[CH:4]=[CH:5][CH:6]=1)([O-:10])=[O:9]

Participants

Reactant 3

HCID 6228Dimethylformamide

HCID 11430Potassium Carbonate

HCID 41154952-Amino-3-Nitrophenol

Product 1

HCID 107741655-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-oneYield 80%

Procedure

To a solution of 2-amino-3-nitrophenol (4.62 g, 30 mmol) in DMF (20 ml) ethylbromoacetate (3.3 ml, 30 mmol) and K2CO3 (4.56 g, 33 mmol) were added and the reaction was stirred at room temperature for 20 hours. The solvent was evaporated and the crude was dissolved in AcOEt (30 ml) and washed with water (1×20 ml) and brine. The organic phase was dried over sodium sulfate and concentrated under vacuum. The purification of the crude residue by crystallization from ether/hexane gave 4.65 g of a yellow solid. Yield: 80%. 1HNMR (DMSO, 200 MHz) δ 4.74 (2H, s), 7.15 (1H, t, J=8.4 Hz), 7.41 (1H, dd, J=8.2 Hz, J′=1.6 Hz), 7.77 (1H, dd, J=8.4 Hz, J′=1.2 Hz), 10.38 (1H, bs)