Phenacyl bromide → 7-methyl-3-phenyl-2H-1,4-benzoxazine

HRID 585443Notes

Reaction equation

HRID 585443 reaction equation
C(=O)([O-])[O-].[K+].[K+].[NH2:7][C:8]1[CH:9]=[CH:10][C:11]([CH3:15])=[CH:12][C:13]=1[OH:14].Br[CH2:17][C:18]([C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1)=O>O.C(Cl)Cl.S([O-])(O)(=O)=O.C([N+](CCCC)(CCCC)CCCC)CCC>[CH3:15][C:11]1[CH:10]=[CH:9][C:8]2[N:7]=[C:18]([C:20]3[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=3)[CH2:17][O:14][C:13]=2[CH:12]=1

Participants

7

Reactant 3

HCID 6259Phenacyl bromideHCID 11430Potassium CarbonateHCID 760822-Amino-5-methylphenol

Product 1

HCID 109111697-methyl-3-phenyl-2H-1,4-benzoxazineYield 49.4%

Reagents, catalysts & solvents 3

HCID 94433Tetrabutylammonium hydrogen sulfateCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

To potassium carbonate (63.89 g, 462 mmol) in water (300 mL) and CH2Cl2 (200 mL) is added 6-amino-m-cresol (10.0 g, 81.2 mmol) and tetra-n-butyl ammonium hydrogensulfate (0.139 g, 0.41 mmol). With vigorous stirring a solution of 2-bromoacetophenone (16.16 g, 81.2 mmol) is added dropwise over a period of 45 min. The mixture is allowed to stir overnight. The layers are then separated and the organic layer is washed with 1N NaOH (500 mL) and water (2×300 mL), dried over magnesium sulfate and concentrated. Column chromatography (400 g silica gel) using ethyl acetate/hexane (20/80) as eluent gave 8.96 g (49%) of 7-methyl-3-phenyl-2H-1,4-benzoxazine.

Workup

  1. additionis added dropwise over a period of 45 min
  2. customThe layers are then separated
  3. washthe organic layer is washed with 1N NaOH (500 mL) and water (2×300 mL)
  4. dry with materialdried over magnesium sulfate
  5. concentrationconcentrated

Sources & evidence

ORD record
ord-52f066ce07e3455d9be8871aa7dfda8a
Source dataset
uspto-grants-2005_08
Patent number
US06932961B1

Reaction notes

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