Sodium Cyanate → 4-Bromoisatoic anhydride

Participants

Reaction Steps

87.0 g (1.33 mol) of sodium cyanate were added to 269.0 g (1.17 mol) of methyl 2-amino-4-bromobenzoate in 1.2 l of acetic acid with stirring at room temperature, and the mixture was subsequently stirred for a further 22 h. The reaction mixture was diluted with 1.5 l of water, and the residue was filtered off with suction. 0.42 l of sodium hydroxide solution (32%) was added to the solid, the mixture was diluted with 3.5 l of water and heated on a steam bath for 4 h. After cooling, the solid residue was filtered off with suction. Conventional work-up gave 205.2 g of 7-bromo-1H-benzo[d]-1,3-oxazine-2,4-dione; HPLC/MS (M+H)+=243 as solid.

Provenance & Evidence