Acetic Anhydride → 2-methyl-4-oxo-4H-3,1-benzoxazine-8-carboxylic acid

HRID 2369811Notes

Reaction equation

HRID 2369811 reaction equation
[NH2:1][C:2]1[C:10]([C:11]([OH:13])=[O:12])=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[CH3:14][C:15](OC(C)=O)=O>>[CH3:14][C:15]1[O:5][C:4](=[O:6])[C:3]2[CH:7]=[CH:8][CH:9]=[C:10]([C:11]([OH:13])=[O:12])[C:2]=2[N:1]=1

Participants

3

Reactant 2

HCID 7918Acetic AnhydrideHCID 2929162-Aminoisophthalic acid

Product 1

HCID 667144972-methyl-4-oxo-4H-3,1-benzoxazine-8-carboxylic acidYield 89%

Conditions

Temperature
140 °C

Procedure

2-Aminoisophthalic acid (50.0 g; 276.0 mmol) and Ac2O (250.0 ml; 5.00 V) were combined and heated to 140° C. for 4 h. The reaction mixture was cooled to room temperature and distilled under high vacuum on the rotary evaporator. The remaining AcOH was removed by azeotropic distillation with toluene. The residue was slurried with ethyl ether, filtered, and the solid was dried under vacuum to provide the desired intermediate (50.3 g, 89% yield).

Workup

  1. temperatureThe reaction mixture was cooled to room temperature
  2. distillationdistilled under high vacuum on the rotary evaporator
  3. customThe remaining AcOH was removed by azeotropic distillation with toluene
  4. filtrationfiltered
  5. customthe solid was dried under vacuum

Sources & evidence

ORD record
ord-b202d87796ea496fb6e530972b370ce1
Source dataset
uspto-grants-2014_04
Patent number
US08710044B2

Reaction notes

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