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

HRID 2415796Notes

Reaction equation

HRID 2415796 reaction equation
C(=O)([O-])[O-].[K+].[K+].[NH2:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[OH:14].Br[CH2:16][C:17]([C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1)=O>O.C(Cl)Cl.S([O-])(O)(=O)=O.C([N+](CCCC)(CCCC)CCCC)CCC>[C:19]1([C:17]2[CH2:16][O:14][C:9]3[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=3[N:7]=2)[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1

Participants

7

Reactant 3

HCID 58012-AminophenolHCID 6259Phenacyl bromideHCID 11430Potassium Carbonate

Product 1

HCID 14817833-phenyl-2H-1,4-benzoxazineYield 61.1%

Reagents, catalysts & solvents 3

HCID 94433Tetrabutylammonium hydrogen sulfateCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolvent2×

Procedure

To potassium carbonate (72 g, 521 mmol) in water (360 mL) and CH2Cl2 (400 mL) is added 2-aminophenol (10.05 g, 92.1 mmol) and tetra-n-butyl ammonium hydrogensulfate (0.156 g, 0.46 mmol). With vigorous stirring a solution of 2-bromoacetophenone (18.33 g, 92.1 mmol) in CH2Cl2 (150 mL) is added dropwise over a period of 45 min. The mixture is allowed to stir overnight. The layers are separated and the organic layer is washed 3 times with water (300 mL), dried over magnesium sulfate and concentrated to dryness. The resulting solid is recrystallized from absolute ethanol (50 mL) to yield 11.78 g (61%) of 3-phenyl-2H-1,4-benzoxazine; mp 108-111° C.

Workup

  1. additionis added dropwise over a period of 45 min
  2. customThe layers are separated
  3. washthe organic layer is washed 3 times with water (300 mL)
  4. dry with materialdried over magnesium sulfate
  5. concentrationconcentrated to dryness
  6. customThe resulting solid is recrystallized from absolute ethanol (50 mL)

Sources & evidence

ORD record
ord-5ec69762b0004307a2950ca980daf23c
Source dataset
uspto-grants-2004_11
Patent number
US06821970B2

Reaction notes

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