Phosgene → 6,7-Difluoroisatoic anhydride

Participants

Reaction Steps

A solution of phosgene (45 g) in toluene (160 ml) was added during 20 minutes to a stirred solution of 2-amino-4,5-difluorobenzoic acid (26 g) in aqueous sodium carbonate (20.7 g anhydrous sodium carbonate in 350 ml water), keeping the temperature below 40°. The mixture was stirred at room temperature for 15 hours. The solid product was collected by filtration, washed with water and dried to give the novel compound 6,7-difluoro-1H-3,1-benzoxazine-2,4-dione, m.p. 223°-226° (dec.).

Provenance & Evidence