2-Aminophenol → 3,4-Dihydro-2H-1,4-benzoxazine

HRID 2175685Notes

Reaction equation

HRID 2175685 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[OH:8].C(=O)([O-])[O-].[K+].[K+].Br[CH2:16][CH2:17]Br>CN(C=O)C>[O:8]1[CH2:17][CH2:16][NH:1][C:2]2[CH:7]=[CH:6][CH:5]=[CH:4][C:3]1=2

Participants

5

Reactant 3

HCID 58012-AminophenolHCID 78391,2-DibromoethaneHCID 11430Potassium Carbonate

Product 1

HCID 5850963,4-Dihydro-2H-1,4-benzoxazineYield 65.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
125 °C

Procedure

To a suspension of 2-aminophenol (1.0 g, 9.2 mmol) and potassium carbonate (6.36 g, 46 mmol) in dry DMF (10 mL) was added 1,2-dibromoethane (2.59 g, 13.8 mmol). The mixture was then heated at 125° C. for 15 hours. After cooling, the mixture was treated with crushed ice and extracted with ethyl acetate. The organic extracts were dried over sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by flash chromatography on silica gel using ethyl acetate/petroleum ether 1:10 (v:v) as eluent to give 3,4-dihydro-2H-benzo[b][1,4]oxazine as reddish oil (0.81 g, 65%). LC-MS (ES-API); rt 7.51 min; m/z calculated for C8H9NO [M+H]+ 136.1, found 136.1.

Workup

  1. temperatureAfter cooling
  2. additionthe mixture was treated with crushed ice
  3. extractionextracted with ethyl acetate
  4. dry with materialThe organic extracts were dried over sodium sulfate
  5. customthe solvent was removed under reduced pressure
  6. customThe residue was purified by flash chromatography on silica gel

Sources & evidence

ORD record
ord-c4a4f3fb77904181a220b7f179c595a4
Source dataset
uspto-grants-2015_06
Patent number
US09062076B2

Reaction notes

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