Ethyl bromoacetate → 7-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-one

HRID 1534977Notes

Reaction equation

HRID 1534977 reaction equation
Br[CH2:2][C:3](OCC)=[O:4].[F-].[K+].[NH2:10][C:11]1[CH:16]=[CH:15][C:14]([N+:17]([O-:19])=[O:18])=[CH:13][C:12]=1[OH:20]>CN(C=O)C>[N+:17]([C:14]1[CH:15]=[CH:16][C:11]2[NH:10][C:3](=[O:4])[CH2:2][O:20][C:12]=2[CH:13]=1)([O-:19])=[O:18]

Participants

5

Reactant 3

HCID 7748Ethyl bromoacetateHCID 522689Potassium FluorideHCID 49847212-Amino-5-Nitrophenol

Product 1

HCID 27638307-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-one

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent2×

Procedure

Under argon, ethyl bromoacetate (7.2 ml, 65 mmol) was added to a solution of anhydrous potassium fluoride (10 g, 172.1 mmol) in 50 ml anhydrous DMF. The solution was stirred for 30 minutes at room temperature. 2-Amino-5-nitrophenol (Aldrich, 10 g, 65 mmol) was then dissolved in 25 ml of DMF and added dropwise to the reaction with stirring. After the final addition the reaction was warmed to 70 degrees and stirred for 16-24 hours. The reaction was then poured into 300 mls of an ice/water mixture with stirring. A yellow precipitate was formed immediately. The solid was filtered off and dried in vacuo. The product was recrystallized from hot THF. Collected 8.3 g (72.5%) of tan crystals: m.p. 227-230; 'H NMR (300 MHz, DMSO) δ 4.752 (s, 2H, CH2), 7.0835 (d, J=8.73, Hz, 1H, ACH), 7.769 (d, J=2.44 Hz, 1 H) 7.9185 (dd, J=2.525, 8.705 Hz, 1H, ACH); 13C NMR (300 MHz, DMSO) δ 66.560, 111.344, 115.776, 118.738, 134.464, 142.643, 142.861, 164.891. Mass spectrum (EI) m/z 194 M+

Workup

  1. additionadded dropwise to the reaction
  2. stirringwith stirring
  3. additionAfter the final addition the reaction
  4. temperaturewas warmed to 70 degrees
  5. stirringstirred for 16-24 hours
  6. stirringwith stirring
  7. customA yellow precipitate was formed immediately
  8. filtrationThe solid was filtered off
  9. customdried in vacuo
  10. customThe product was recrystallized from hot THF
  11. customCollected 8.3 g (72.5%) of tan crystals

Sources & evidence

ORD record
ord-6cd029a7d4984467972b9f9646b158ae
Source dataset
uspto-grants-1992_02
Patent number
US05091528

Reaction notes

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