Phenyl chloroformate → Phenyl 3-oxo-2,3-dihydro-4H-1,4-benzoxazine-4-carboxylate

HRID 1270426Notes

Reaction equation

HRID 1270426 reaction equation
[O:1]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[NH:4][C:3](=[O:11])[CH2:2]1.C([Li])CCC.Cl[C:18]([O:20][C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1)=[O:19]>O1CCCC1.CCCCCC>[O:1]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[N:4]([C:18]([O:20][C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=2)=[O:19])[C:3](=[O:11])[CH2:2]1

Participants

6

Reactant 3

HCID 15891Phenyl chloroformateHCID 727572H-1,4-benzoxazin-3(4H)-oneHCID 178418339Butyllithium

Product 1

HCID 18449778Phenyl 3-oxo-2,3-dihydro-4H-1,4-benzoxazine-4-carboxylate

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Procedure

Under an anhydrous atmosphere, a solution of 10 mmol of 2H-1,4-benzoxazin-3-one in 50 ml of tetrahydrofuran is cooled to −78° C. At that temperature, 11 mmol of a 1.6M solution of n-butyllithium in hexane are added dropwise. After being in contact for 30 minutes at −78° C., 11 mmol of phenyl chloroformate are added dropwise and stirring is carried out for a further 2 hours. After returning to ambient temperature, the solution is hydrolysed and then extracted with ethyl acetate. The organic phase is dried over magnesium sulphate, filtered and evaporated. After purification by chromatography over silica gel (petroleum ether/ethyl acetate: 8/2), the expected product is isolated.

Workup

  1. waitis carried out for a further 2 hours
  2. customAfter returning to ambient temperature
  3. extractionextracted with ethyl acetate
  4. dry with materialThe organic phase is dried over magnesium sulphate
  5. filtrationfiltered
  6. customevaporated
  7. customAfter purification by chromatography over silica gel (petroleum ether/ethyl acetate: 8/2)

Sources & evidence

ORD record
ord-4ab3b9597f504b95a97e2ad77d47495b
Source dataset
uspto-grants-2007_04
Patent number
US07202255B2

Reaction notes

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