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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence