Alkaline hydrolysis of cefotaxime. A HPLC and 1H NMR study.
Alkaline hydrolysis of cefotaxime. A HPLC and 1H NMR study.
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DOI：
10.1002/jps.2600830311
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发表时间：
1994-03
影响因子：
3.8
通讯作者：
B. Vilanova;F. Muñoz;J. Donoso;J. Frau;Francisco Garcia Blanco
中科院分区：
文献类型：
--
作者：
B. Vilanova;F. Muñoz;J. Donoso;J. Frau;Francisco Garcia Blanco
用高效液相色谱和核磁共振氢谱研究了头孢噻肟在pH 10.5和37℃条件下的碱解反应动力学。主要的降解产物已被分离和鉴定。除了众所周知的去乙酰头孢噻肟外，还包括环外亚甲基衍生物、头孢噻肟的7-同分异构体和去乙酰头孢噻肟的7-同分异构体。测定了反应过程中涉及的动力学常数，根据实验结果，羟基对3‘-碳键上的酯功能的攻击是所提出的动力学方案中最快的步骤。应该强调的是，碱催化的氢在7位上的异构化显然取决于C(3‘)上是否存在良好的吸电子基团。另一方面，没有检测到7位上的酰胺的水解。
A kinetic study on the alkaline hydrolysis of cefotaxime at pH 10.5 and 37 degrees C has been carried out by using HPLC and 1H NMR. The main resulting degradation products have been isolated and identified. These include, apart from the well-known deacetylcefotaxime, the exocyclic methylene derivative, the 7-epimer of cefotaxime and the 7-epimer of deacetylcefotaxime. The kinetic constants involved in the process have been determined and according to the experimental results the attack of the hydroxyl group on the ester function bonded to the 3'-carbon is the fastest step in the proposed kinetic scheme. It should be emphasized that the base-catalyzed epimerization of the hydrogen at the 7 position clearly depends on the presence of a good electron-withdrawing group at C(3'). On the other hand, no hydrolysis of the amide at position 7 was detected.