The invention relates to the chemical synthesis of pharmaceutical API, and specifically to a method of synthesizing diclofenac sodium, which is a kind of nonsteroidal anti-inflammatory drug for relieving pain. The method includes: nitrating phenylacetate to prepare o-nitrophenylacetate (2); hydrogenating o-nitrophenylacetate (2) to prepare o-aminophenylacetate (3); amidating an amino group of o-aminophenylacetate (3) to obtain 2-(2-benzoylaminophenyl) acetate (4); 2-(2-benzoylaminophenyl) acetate (4) reacting with thionyl chloride to prepare a chloroimine intermediate, and then condensing the intermediate of chloroimine with 2,6-dichlorophenol using an inorganic base to prepare (E)-methyl-2-(2-((2,6-dichlorophenoxy)(phenyl)methyleneamino) phenyl ester (5); subjecting (E)-methyl-2-(2-((2,6-dichlorophenoxy)(phenyl)methyleneamino) phenyl ester (5) to Chapman rearrangement to afford methyl 2-(2-(N-(2,6-dichlorophenyl)benzoylamino)phenyl) ester (6); and hydrolyzing methyl 2-(2-(N-(2,6-dichlorophenyl)benzoylamino)phenyl) ester (6) to provide the target compound as of diclofenac sodium API. The overall yield is up to 67% based on methyl phenylacetate.
本发明涉及药物
原料药的
化学合成,具体涉及一种合成
双氯芬酸钠的方法,
双氯芬酸钠是一种用于缓解疼痛的非甾体类消炎药。该方法包括硝化
苯乙酸,制备邻
硝基苯乙酸酯(2);氢化邻
硝基苯乙酸酯(2),制备邻
氨基
苯乙酸酯(3);酰胺化邻
氨基
苯乙酸酯(3)的
氨基,得到 2-(2-苯甲酰基
氨基苯基)
乙酸酯(4);2-(2-苯甲酰基
氨基苯基)
乙酸酯(4)与亚
硫酰氯反应,制备
氯亚胺中间体,然后用
无机碱将
氯亚胺中间体与
2,6-二氯苯酚缩合,制备(E)-甲基-2-(2-((2,6-二
氯苯氧基)(苯基)亚甲基
氨基)苯基酯(5)将(E)-甲基-2-(2-((2,6-二
氯苯氧基)(苯基)亚甲基
氨基)苯基酯(5)进行查普曼重排,得到甲基-2-(2-(N-(2,6-二
氯苯基)苯甲酰
氨基)苯基)酯(6)并
水解 2-(2-(N-(2,6-二
氯苯基)苯甲酰
氨基)苯基)甲基酯 (6),得到
双氯芬酸钠原料药的目标化合物。以
苯乙酸甲酯为基准,总产率高达 67%。