Hydrochloric Acid → 6-hydroxy-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

HRID 395726Notes

Reaction equation

HRID 395726 reaction equation
[OH:1][C:2]1[CH:10]=[C:6]([C:7]([OH:9])=[O:8])[C:5]([NH2:11])=[CH:4][CH:3]=1.[C:12](Cl)(Cl)=[O:13].C1(C)C=CC=CC=1.Cl>O1CCOCC1>[OH:1][C:2]1[CH:10]=[C:6]2[C:7]([O:9][C:12](=[O:13])[NH:11][C:5]2=[CH:4][CH:3]=1)=[O:8]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 1140TolueneHCID 6371PhosgeneHCID 1645925-Hydroxyanthranilic acid

Product 1

HCID 27593156-hydroxy-2,4-dihydro-1H-3,1-benzoxazine-2,4-dioneYield 76%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Conditions

Temperature
65 °C

Procedure

To a solution of 5-hydroxyanthranilic acid (46.0 g, 300 mmol) in p-dioxane was added 1.93 M phosgene in toluene (186 mL, 360 mmol) and the resulting mixture stirred for 30 min. The mixture was heated at 65° C. for 4 h. After cooling, 1 N aqueous hydrochloric acid (150 mL) was added and the mixture stirred vigorously. The resulting precipitate was filtered and vacuum dried at 70° C./0.1 mm for 14 h to give 40.7 g (76%) of the title compound as a gray solid.

Workup

  1. temperatureAfter cooling
  2. stirringthe mixture stirred vigorously
  3. filtrationThe resulting precipitate was filtered
  4. customvacuum dried at 70° C./0.1 mm for 14 h

Sources & evidence

ORD record
ord-73b4020ad70545f6b6c09d9a75f86c05
Source dataset
uspto-grants-2003_08
Patent number
US06605626B2

Reaction notes

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