Abstract:

To prevent the oxidation of raw materials(pyrogallic acid and p-hydroxybenzoic acid)during the traditional synthesis of 2, 3, 4, 4'-tetrahydroxybenzophenone(4HBP), an intermediate compound, 2, 3, 4, 4'-tetramethoxydibenzone(4TMP), was synthesized for the first time by the hydroxyl protection method. 1, 2, 3-trimethoxybenzene(TMB) and p-anisic acid(p-AA) were used as the raw materials, and Eaton reagent and 1, 2-dichloroethane were used as the catalyst and solvent, respectively. The target product, 2, 3, 4, 4'-tetrahydroxybenzophenone, was synthesized by demethylation of the intermediate in a BBr₃/CH₂Cl₂ system with anhydrous, anaerobic and low temperature conditions. The yield of the target product was approximately 86.4%, and the purity was ≥98.8%, the content of each metal ion was less than 18.60 mg/kg.The structures of the intermediate and target products were investigated by IR, NMR, and MS.

Key words: hydroxyl protection, 2, 3, 4, 4'-tetrahydroxybenzophenone, 2, 3, 4, 4'-tetramethoxybenzophenone, Eaton reagent