Dicyclohexylcarbodiimide → 6-Hydroxy-2-methyl-4H-benzo[D][1,3]oxazin-4-one

HRID 1089393Notes

Reaction equation

HRID 1089393 reaction equation
[OH-].[Na+].C([O:6][C:7]1[CH:8]=[CH:9][C:10]2[N:15]=[C:14]([CH3:16])[O:13][C:12](=[O:17])[C:11]=2[CH:18]=1)(=O)C.C1(N=C=NC2CCCCC2)CCCCC1>O.CO.C1COCC1>[OH:6][C:7]1[CH:8]=[CH:9][C:10]2[N:15]=[C:14]([CH3:16])[O:13][C:12](=[O:17])[C:11]=2[CH:18]=1

Participants

7

Reactant 3

HCID 10868DicyclohexylcarbodiimideHCID 14798Sodium HydroxideHCID 46092582-Methyl-4-oxo-4H-benzo[d][1,3]oxazin-6-yl acetate

Product 1

HCID 541316176-Hydroxy-2-methyl-4H-benzo[D][1,3]oxazin-4-oneYield 38.1%

Reagents, catalysts & solvents 3

HCID 887MethanolSolvent2×HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent2×

Procedure

Sodium hydroxide (4 g. 0.1 mol) was dissolved in water (4 ml) and methanol (50 ml). The 6-acetoxy-2-methyl (4H)3,1-benzoxazin-4-one (8.2 g, 0.04 mol), prepared above, in methanol (30 ml) was added, and the mixture refluxed for 3 hours. The solvent was removed by evaporation and the resulting sodium salt dissolved in water and acidified with hydrochloric acid. 5-Hydroxy N-acetyl anthranilic acid was collected as a beige solid and dried under vacuum. The dry solid (7.8 g, 0.04 mol) was then dissolved in dry THF (100 ml) and added to dicyclohexylcarbodiimide (8.24 g, 0.04 mol) in dry THF (50 ml). The mixture was stirred at room temperature for 18 hours and the insoluble urea removed by filtration. The filtrate was evaporated to dryness to give 6-hydroxy-2-methyl (4H)3,1-benzoxazin-4-one (2.7 g, 38%).

Workup

  1. additionwas added
  2. temperaturethe mixture refluxed for 3 hours
  3. customThe solvent was removed by evaporation
  4. dissolutionthe resulting sodium salt dissolved in water
  5. custom5-Hydroxy N-acetyl anthranilic acid was collected as a beige solid
  6. customdried under vacuum
  7. customthe insoluble urea removed by filtration
  8. customThe filtrate was evaporated to dryness

Sources & evidence

ORD record
ord-8b2f3434de0e4c9fb4662068483a1e08
Source dataset
uspto-grants-1990_10
Patent number
US04966723

Reaction notes

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