Treatment of 2,6-di-tert-butyl-4-methylphenyl 2-methoxybenzoate (5) with 4-methylphenylmagnesium bromide (6) in diethyl ether-benzene affords the 4’-methylbiphenyl-2-carboxylate (7) in excellent yield via an ester-assisted nucleophilic aromatic substitution (SNAr) reaction. Carboxylate 7 is in turn readily and quantitatively saponified to 4’-methylbiphenyl-2-carboxylic acid (2a) via transesterification by treatment with sodium methoxide in toluene-1-methyl-2-pyrrolidone followed by aqueous hydrolysis.
在
乙醚-苯体系中,将2,6-二叔丁基-4-甲基
苯甲酸甲氧基苯酯(5)与4-甲基
苯基溴化镁(6)反应,通过酯辅助的亲核芳香取代(SNAr)反应,以优异的产率得到
4'-甲基联苯-2-羧酸乙酯(7)。接着,通过在
甲苯-1-甲基-
2-吡咯烷酮中用
甲醇钠处理后进行
水解,
4'-甲基联苯-2-羧酸乙酯(7)可迅速且定量地转化为
4'-甲基联苯-2-羧酸(2a)。