7-fluoro-3,4-dihydro-2H-1,4-benzoxazin-3-one → 7-Fluoro-3,4-dihydro-2H-1,4-benzoxazine

HRID 901831Notes

Reaction equation

HRID 901831 reaction equation
O=[C:2]1[CH2:7][O:6][C:5]2[CH:8]=[C:9]([F:12])[CH:10]=[CH:11][C:4]=2[NH:3]1.[H-].[H-].[H-].[H-].[Li+].[Al+3]>C1COCC1>[F:12][C:9]1[CH:10]=[CH:11][C:4]2[NH:3][CH2:2][CH2:7][O:6][C:5]=2[CH:8]=1

Participants

4

Reactant 2

HCID 137312957-fluoro-3,4-dihydro-2H-1,4-benzoxazin-3-oneHCID 21226445Aluminium lithium hydride

Product 1

HCID 144229537-Fluoro-3,4-dihydro-2H-1,4-benzoxazineYield 65%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

3-Oxo-7-fluoro-3,4-dihydro-2H-benzo[b][1,4]oxazine (2.2 g, 1 eq, 13.1 mmol) obtained in step (ii) in dry THF (10 ml) was added drop wise to a refluxing THF (60 ml) containing LAH (1.5 g, 3 eq, 39.5 mmol). It was further refluxed for 3 h and quenched with ethyl acetate. To this water (1.5 ml), 15% sodium hydroxide (1.5 ml) and water (4.5 ml) were added sequentially. Once Al(OH)3.H2O precipitated out, it was filtered though celite. The filtrate was condensed on rotavapour and chromatographed (ethyl acetate and hexane) to yield 7-fluoro-3,4-dihydro-2H-benzo[b][1,4]oxazine (1.3 g, yield 65%) as yellow oil.

Workup

  1. temperatureIt was further refluxed for 3 h
  2. customquenched with ethyl acetate
  3. additionTo this water (1.5 ml), 15% sodium hydroxide (1.5 ml) and water (4.5 ml) were added sequentially
  4. customOnce Al(OH)3.H2O precipitated out
  5. filtrationit was filtered though celite
  6. customcondensed on rotavapour
  7. customchromatographed (ethyl acetate and hexane)

Sources & evidence

ORD record
ord-f7458281483443b192f3d1980b42c05e
Source dataset
uspto-grants-2008_04
Patent number
US07365064B2

Reaction notes

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