Anthranilic Acid → 5-methyl-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

HRID 1603007Notes

Reaction equation

HRID 1603007 reaction equation
C1N=CN([C:6](N2C=NC=C2)=[O:7])C=1.[C:13]([OH:22])(=[O:21])[C:14]1[C:15](=[CH:17][CH:18]=[CH:19][CH:20]=1)[NH2:16].O1CCOC[CH2:24]1>>[CH3:24][C:20]1[C:14]2[C:13](=[O:22])[O:21][C:6](=[O:7])[NH:16][C:15]=2[CH:17]=[CH:18][CH:19]=1

Participants

4

Reactant 3

HCID 227Anthranilic AcidHCID 312751,4-Dioxane2×HCID 682631,1'-Carbonyldiimidazole

Product 1

HCID 104875225-methyl-2,4-dihydro-1H-3,1-benzoxazine-2,4-dioneYield 87%

Procedure

To a suspension of CDI (49.35 g, 305 mmol) in 100 mL of dioxane was added at room temperature a solution of the anthanilic acid (20 g, 132 mmol) in 100 mL of dioxane over 30 minutes. The reaction was stirred at ambient temperature until the mild exotherm subsided. The reaction mixture was filtered through a bed of silica gel (dioxane), concentrated then diluted with about 200 mL of water. The resulting precipitate was filtered, washed with water and dried affording 20.3 g (87%) of 5-methyl-2H-3,1-benzoxazin-2,4(1H)-dione.

Workup

  1. filtrationThe reaction mixture was filtered through a bed of silica gel (dioxane)
  2. concentrationconcentrated
  3. additionthen diluted with about 200 mL of water
  4. filtrationThe resulting precipitate was filtered
  5. washwashed with water
  6. customdried

Sources & evidence

ORD record
ord-a588cf775a88477b8a5606c78e18ba30
Source dataset
uspto-grants-1999_11
Patent number
US05985872

Reaction notes

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