Pyridine → 7-Fluoroisatoic anhydride

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 2-amino-4-fluoro benzoic acid (L) (1.15 g, 7.40 mmol) in anhydrous acetonitrile (8 mL) at 55° C. were simultaneously added anhydrous pyridine (1.2 mL, 15 mmol) and a solution of triphosgene (0.73 g, 2.5 mmol) in anhydrous CH2Cl2 (5 mL) via syringe over a period of 15-20 minutes. After the addition was completed, the reaction mixture was stirred at 55° C. for another 2 hours. Much solid precipitated out. The solvent was distilled off. After cooling down to room temperature, water was added and the solid was filtered off, washed with water, followed by chilled CH2Cl2. The solid was dried under vacuum to give 7-fluoro-1H-benzo[d][1,3]oxazine-2,4-dione (M) as grayish solid. Yield: 1.02 g (76%).

Provenance & Evidence