Acetic Anhydride → 6-methoxy-2-methyl-4H-benzo[d][1,3]oxazin-4-one

HRID 570167Notes

Reaction equation

HRID 570167 reaction equation
[CH3:1][O:2][C:3]1[CH:11]=[C:7]([C:8]([OH:10])=[O:9])[C:6]([NH2:12])=[CH:5][CH:4]=1.[C:13](OC(=O)C)(=O)[CH3:14]>>[CH3:13][C:14]1[O:9][C:8](=[O:10])[C:7]2[CH:11]=[C:3]([O:2][CH3:1])[CH:4]=[CH:5][C:6]=2[N:12]=1

Participants

3

Reactant 2

HCID 7918Acetic AnhydrideHCID 2779305-Methoxyanthranilic acid

Product 1

HCID 6055556-methoxy-2-methyl-4H-benzo[d][1,3]oxazin-4-oneYield 77%

Procedure

A solution of 5-methoxyanthranilic acid (7.8 g, 46.5 mmol) was refluxed in acetic anhydride (60 mL) for 2 h15 before being cooled and concentrated under reduced pressure. The crude residue was then concentrated twice in the presence of toluene before being filtered and washed with ether to yield to the title compound (6.8 g, 77% yield) as a beige solid; LC/MS: m/z 192 [M+H]+, Rt 1.69 min.

Workup

  1. temperaturebefore being cooled
  2. concentrationconcentrated under reduced pressure
  3. concentrationThe crude residue was then concentrated twice in the presence of toluene
  4. filtrationbefore being filtered
  5. washwashed with ether

Sources & evidence

ORD record
ord-a369aaa1b46948c3b632be5438e216a0
Source dataset
uspto-grants-2015_05
Patent number
US09023842B2

Reaction notes

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