Pyridine → 5-Bromoisatoic Anhydride

Participants

Reaction Steps

To a suspension of 2-amino-5-bromo-benzoic acid (270 g, 1.25 mol) in acetonitrile (1250 mL) was added a solution of triphosgene (123.8 g, 416.7 mmol) in dichloromethane (DCM) (500 mL) and pyridine (197.5 g, 2.5 mol) simultaneously at 55° C. The resultant mixture was stirred for another 3 hours then cooled to room temperature. The precipitate was collected by filtration, washed with acetonitrile and dried to afford 6-bromo-1H-benzo[d][1,3]oxazine-2,4-dione as a pale powder (280 g, 93%). 1H NMR (DMSO-d6): δ 11.83 (s, 1H), 7.98 (s, 1H), 7.89-7.87 (d, 1H,), 7.09-7.07 (d, 1H).

Provenance & Evidence