Triphosgene → 5,6-Dimethoxyisatoic anhydride
Reaction equation
[C:1](=O)(OC(Cl)(Cl)Cl)[O:2]C(Cl)(Cl)Cl.Cl.[NH2:14][C:15]1[C:20]([C:21]([OH:23])=[O:22])=[C:19]([O:24][CH3:25])[C:18]([O:26][CH3:27])=[CH:17][CH:16]=1>O>[CH3:25][O:24][C:19]1[C:20]2[C:21](=[O:23])[O:22][C:1](=[O:2])[NH:14][C:15]=2[CH:16]=[CH:17][C:18]=1[O:26][CH3:27]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
Bis(trichloromethyl) carbonate (24.89 g, 84 mmol) was added into a solution of 6-amino-2,3-dimethoxybenzoic acid, Hydrochloride (28 g, 120 mmol) in Water (1.1 L). The mixture was stirred at r.t. over the weekend. The reaction mixture was filtered, the solid was collected and dried to afford 5,6-dimethoxy-1H-benzo[d][1,3]oxazine-2,4-dione (24 g, 105 mmol, 88% yield) as a light yellow solid. LCMS: (M+H)+: 223.9.