4-(N-苯氨基)苯甲酸的合成研究

将对氨基苯甲酸加入到用HCl气饱和的无水乙醇中 ,回流反应 2 4h ,然后将反应液加水并加固体碳酸钠 ,调体系的 pH =8,得对氨基苯甲酸乙酯 ,产率 77 7%。将对氨基苯甲酸乙酯与乙酸酐在 130～ 14 0℃下反应 8h ,得对 乙酰氨基苯甲酸乙酯 ,产率 93 3%。对 乙酰氨基苯甲酸乙酯在铜粉、碳酸钾存在下 ,以硝基苯做溶剂 ,与碘苯在回流下反应 18h ,水蒸气蒸馏除去溶剂硝基苯后 ,加入氢氧化钠后回流水解 1 5h ,然后在酸化下得 4 (N 苯氨基 )苯甲酸 ,产率 6 1 3%。

Synthesis of 4-(N-Phenylamino)-benzoic Acid

N Phenylamino) benzoic acid(Ⅲ) was synthesized from p aminobenzoic acid.Esterification of p aminobenzoic acid was carried out by adding p aminobenzoic acid into ethanol in the presence of dry hydrogen chloride and refluxing for 12 h.Then the reaction mixture was regulated to pH=8 with solution of sodium carbonate to give ethyl p aminobenzoate(Ⅰ) in 77.7% yield.Ⅰwas treated with acetic anhydride for 8 h at 130-140 ℃,giving ethyl p acetylaminobenzoate(Ⅱ) in 93.3% yield.The mixture of Ⅱ ,copper dust and potassium carbonate was refluxed for 18 h in nitrobenzene.Then nitrobenzene was removed through steam distillation,and sodium hydroxide was added to the mixture which was refluxed for 1 5 hours.At last the reaction mixture was acidified to give the title product Ⅲ in 61.3% yield.