Tetrahydrofuran → 6-bromo-2,4-dimethyl-4-phenyl-1,4-dihydro-2H-3,1-benzoxazine

HRID 277850Notes

Reaction equation

HRID 277850 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][C:3]=1[C:9]([C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)=[O:10].S([O-])([O-])(=O)=O.[NH4+].[NH4+].[C:24](OCC)(=O)[CH3:25].[CH2:30]1COCC1>>[Br:8][C:5]1[CH:6]=[CH:7][C:2]2[NH:1][CH:24]([CH3:25])[O:10][C:9]([CH3:30])([C:11]3[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=3)[C:3]=2[CH:4]=1

Participants

5

Reactant 4

HCID 8028TetrahydrofuranHCID 8857Ethyl AcetateHCID 996772-Amino-5-bromobenzophenoneHCID 6097028Ammonium Sulfate

Product 1

HCID 234355826-bromo-2,4-dimethyl-4-phenyl-1,4-dihydro-2H-3,1-benzoxazineYield 70%

Procedure

To a solution of (2-amino-5-bromophenyl)(phenyl)methanone (1 g, 3.6 mmol) in anhydrous THF (15 mL) was added at room temperature under nitrogen methylmagnesium bromide (3M in ether, 3 mL, 9 mmol). After 3 hours, the mixture was treated with a saturated aqueous ammonium sulfate solution (30 mL) and ethyl acetate (50 mL). The organic layer was separated, dried (MgSO4), and evaporated. The residue was then dissolved in anhydrous toluene and treated at ambient temperature under nitrogen with acetylaldehyde (2 mL). After 2 minutes, the solvent was removed and residue was purified by a column chromatography (silica gel, hexane:ethyl acetate/4:1) to afford 6-bromo-2,4-dimethyl-4-phenyl-1,4-dihydro-2H-3,1-benzoxazine as a yellowish solid (0.8 g, 70%): MS (ESI) m/z 318/320 [M+H]+.

Workup

  1. customThe organic layer was separated
  2. dry with materialdried (MgSO4)
  3. customevaporated
  4. dissolutionThe residue was then dissolved in anhydrous toluene
  5. additiontreated at ambient temperature under nitrogen with acetylaldehyde (2 mL)
  6. waitAfter 2 minutes
  7. customthe solvent was removed
  8. customresidue was purified by a column chromatography (silica gel, hexane:ethyl acetate/4:1)

Sources & evidence

ORD record
ord-17c8211cb7114634b6ed69e28a18cb2c
Source dataset
uspto-grants-2002_03
Patent number
US06358948B1

Reaction notes

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