Pyridine → 5-Fluoroisatoic anhydride

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-amino-5-fluorobenzoic acid (1.00 g, 6.40 mmol) in acetonitrile (8 mL) was added a solution of triphosgene (0.64 g, 2.1 mmol) in dichloromethane (5 mL) and pyridine (1.1 mL, 13.0 mmol) simultaneously within 5 min. The resulting pale yellow suspension was heated at 55° C. for 2 hours. The solvents were evaporated under vacuum, and the residue was stirred with water (5 mL). The precipitate obtained was filtered and dried to afford 6-fluoro-1H-benzo[d][1,3]oxazine-2,4-dione. Yield: 1.06 g (91%).

Provenance & Evidence