Methanol → 3-Oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylic acid

HRID 2394260Notes

Reaction equation

HRID 2394260 reaction equation
[O:1]1[C:6]2[CH:7]=[CH:8][C:9]([C:11]([O:13]C)=[O:12])=[CH:10][C:5]=2[NH:4][C:3](=[O:15])[CH2:2]1.[OH-].[Na+].CO>O>[O:1]1[C:6]2[CH:7]=[CH:8][C:9]([C:11]([OH:13])=[O:12])=[CH:10][C:5]=2[NH:4][C:3](=[O:15])[CH2:2]1

Participants

5

Reactant 3

HCID 887MethanolHCID 14798Sodium HydroxideHCID 2974054Methyl 3-oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate

Product 1

HCID 7061213-Oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylic acidYield 94.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

In a 250 ml round-bottomed flask were place the preceding methyl 1,4-benzoxazine-3-one-6-carboxylate (5.8 g, 28 mmole), 50% aqueous sodium hydroxide (9.0 g, 112 mmole), methanol (125 ml), and water (19 ml). The resulting mixture was refluxed for 4 hours. The reaction mixture was cooled to room temperature and the solvent eliminated in the rotary evaporator. The crude reaction product was taken up in water and the resulting aqueous solution was washed with hexane (2×50 ml) and acidified to pH=1 with concentrated aqueous hydrochloric acid. The solid which formed was separated by suction filtration, and dried in a vacuum oven yielding 5.1 g of the expected 1,4-benzoxazine-3-one-6-carboxylic acid.

Workup

  1. customIn a 250 ml round-bottomed flask were place
  2. temperatureThe resulting mixture was refluxed for 4 hours
  3. customthe solvent eliminated in the rotary evaporator
  4. customThe crude reaction product
  5. washthe resulting aqueous solution was washed with hexane (2×50 ml)
  6. customThe solid which formed
  7. customwas separated by suction filtration
  8. customdried in a vacuum oven

Sources & evidence

ORD record
ord-e66077dc35784dba86a1aa72e4487698
Source dataset
uspto-grants-1998_09
Patent number
US05811427

Reaction notes

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