Acetonitrile → ethyl (3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H1,4-benzoxazin-4-yl)acetate

HRID 37122Notes

Reaction equation

HRID 37122 reaction equation
[CH3:1][C:2]1([CH3:16])[C:7](=[O:8])[NH:6][C:5]2[CH:9]=[C:10]([N+:13]([O-:15])=[O:14])[CH:11]=[CH:12][C:4]=2[O:3]1.Br[CH2:18][C:19]([O:21][CH2:22][CH3:23])=[O:20].C(=O)([O-])[O-].[K+].[K+].C(#N)C>CN(C)C=O>[CH3:1][C:2]1([CH3:16])[C:7](=[O:8])[N:6]([CH2:18][C:19]([O:21][CH2:22][CH3:23])=[O:20])[C:5]2[CH:9]=[C:10]([N+:13]([O-:15])=[O:14])[CH:11]=[CH:12][C:4]=2[O:3]1

Participants

6

Reactant 4

HCID 6342AcetonitrileHCID 7748Ethyl bromoacetate2×HCID 11430Potassium Carbonate2×HCID 106566312,2-Dimethyl-6-nitro-2H-benzo[B][1,4]oxazin-3(4H)-one

Product 1

HCID 10781103ethyl (3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H1,4-benzoxazin-4-yl)acetateYield 80.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
80 °C

Procedure

A mixture of 6.66 g of 3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H-1,4-benzoxazine, 5.51 g of ethyl bromoacetate, 4.5.6 g of potassium carbonate and 20 ml of acetonitrile was refluxed under heating for 2.5 hours. Then, 10 ml of N,N-dimethylformamide was added and the mixture was stirred at 80° C. for 2 hours. To this mixture was added 2-80 g of ethyl bromoacetate. After an hour of stirring at 80° C., 2.28 g of potassium carbonate was added and the mixture was further stirred at 80° C. for 1 hour. The reaction mixture was then concentrated under reduced pressure and the residue was chromatographed on a silica gel column, elution being carried out with hexane-ethyl acetate (10:.1). The crystals from the eluate were recrystallized from ethyl acetate-hexane to give 7.4 g of ethyl (3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H1,4 -benzoxazin-4-yl)acetate. This compound has the following physicochemical properties.

Workup

  1. temperaturewas refluxed
  2. temperatureunder heating for 2.5 hours
  3. stirringAfter an hour of stirring at 80° C.
  4. stirringthe mixture was further stirred at 80° C. for 1 hour
  5. concentrationThe reaction mixture was then concentrated under reduced pressure
  6. customthe residue was chromatographed on a silica gel column, elution
  7. customThe crystals from the eluate were recrystallized from ethyl acetate-hexane

Sources & evidence

ORD record
ord-f6a3d207553a4ea898c1aee20ab2d785
Source dataset
uspto-grants-1995_05
Patent number
US05420126

Reaction notes

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