1,2-Dibromoethane → 7-Methyl-3,4-dihydro-2H-1,4-benzoxazine

HRID 1515341Notes

Reaction equation

HRID 1515341 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[OH:9].C(=O)([O-])[O-].[K+].[K+].Br[CH2:17][CH2:18]Br>CN(C)C=O>[CH3:8][C:5]1[CH:6]=[CH:7][C:2]2[NH:1][CH2:17][CH2:18][O:9][C:3]=2[CH:4]=1

Participants

5

Reactant 3

HCID 78391,2-DibromoethaneHCID 11430Potassium CarbonateHCID 760822-Amino-5-methylphenol

Product 1

HCID 125105457-Methyl-3,4-dihydro-2H-1,4-benzoxazine

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
130 °C

Procedure

To a solution of 2-amino-5-methylphenol (5.0 g) in N,N-dimethylformamide (50 ml), potassium carbonate (28.3 g) and 1,2-dibromoethane (10.6 ml) were added and stirred at 130° C. for 11 hours. After insoluble materials were filtered off, the filtrate was diluted with ethyl acetate and washed sequentially with water and brine. The organic layer was dried over anhydrous sodium sulfate and then filtered to remove the desiccant, followed by distilling off the solvent under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluting solvent: n-hexane:ethyl acetate=20:1 to 9:1) to give the titled compound, i.e., 7-methyl-3,4-dihydro-2H-1,4-benzoxazine (980 mg) as a brown oil.

Workup

  1. filtrationAfter insoluble materials were filtered off
  2. additionthe filtrate was diluted with ethyl acetate
  3. washwashed sequentially with water and brine
  4. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  5. filtrationfiltered
  6. customto remove the desiccant
  7. distillationby distilling off the solvent under reduced pressure
  8. customThe resulting residue was purified by silica gel column chromatography (eluting solvent: n-hexane:ethyl acetate=20:1 to 9:1)

Sources & evidence

ORD record
ord-56e45d5e28934131adb0e0f50448e64c
Source dataset
uspto-grants-2012_07
Patent number
US08222417B2

Reaction notes

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