Phosgene → 6,7-Dimethoxy-2H-3,1-benzoxazine-2,4(1H)-dione

HRID 635516Notes

Reaction equation

HRID 635516 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([NH2:14])[C:6](=[CH:10][C:11]=1[O:12][CH3:13])[C:7]([OH:9])=[O:8].[C:15](Cl)(Cl)=[O:16]>O1CCOCC1.C1(C)C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[NH:14][C:15](=[O:16])[O:9][C:7](=[O:8])[C:6]2=[CH:10][C:11]=1[O:12][CH3:13]

Participants

5

Reactant 2

HCID 6371PhosgeneHCID 797364,5-Dimethoxyanthranilic acid

Product 1

HCID 27584236,7-Dimethoxy-2H-3,1-benzoxazine-2,4(1H)-dioneYield 97.2%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 312751,4-DioxaneSolvent

Procedure

To a mixture of 10.0 g (51.0 mmol) of 4,5-dimethoxyanthranilic acid in 80 mL of 1,4-dioxane was slowly added 100 mL (193 mmol) of a 1.93 molar solution of phosgene in toluene, at room temperature. The mixture was stirred overnight. The mixture was concentrated to yield a residue which was triturated with ethyl acetate-hexane (1:4), filtered, washed with hexane and dried to afford 11.0 g (97.2%) of the 4,5-dimethoxyisatoic anhydride as a gray solid. MS (Cl mode) m/z 206 (M-18, 100%), 224 (M+H, 51%).

Workup

  1. customat room temperature
  2. concentrationThe mixture was concentrated
  3. customto yield a residue which
  4. customwas triturated with ethyl acetate-hexane (1:4)
  5. filtrationfiltered
  6. washwashed with hexane
  7. customdried

Sources & evidence

ORD record
ord-bca5ab6831b341a89e2df5896735eb8b
Source dataset
uspto-grants-2001_02
Patent number
US06187923B1

Reaction notes

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