运用ＭＯＰＡＣ程序中ＡＭ１方法模拟了三种单环β-内酰胺抗生素分子与ＯＨ－的反应过程，得到了可行性机理．研究结果表明，在反应过程中活性四员环上出现了电荷迁移，酰胺键上的Ｎ原子上的负电荷逐渐增多，Ｃ原子所带正电荷亦相应增多，有利于亲核反应的进行．通过计算反应活化能，发现三种物质的活化能都比较小，说明在碱性条件下有利于该反应的进行．同时研究还发现反应的活化能与反应物的活性有一定的联系：当反应活化能越小，分子的生物活性越强． The reaction mechanism of three monocyclic β-lactam antibiotics and OH- was simulated by AM1 method in MOPAC program, and the feasibility mechanism was obtained. The results show that charge transfer occurs on the active four-membered ring during the reaction, the negative charge on the N atom on the amide bond gradually increases, and the positive charge on the C atom increases accordingly, which is in favor of the nucleophilic reaction. By calculating the activation energy of activation, we find that the activation energy of all three materials is relatively small, which indicates that the reaction is favorable under basic conditions. At the same time, the study also found that the activation energy of the reaction has a certain relationship with the activity of the reactants: the smaller the activation energy, the stronger the biological activity of the molecule.