辅酶NAD(P)H模型还原碳-碳双键化合物反应机理研究

On the Mechanism of Reduction of Ethylenic Compounds by NADH Models

辅酶 Ｎ Ａ Ｄ（ Ｐ） Ｈ 因其在生物体内氧化—还原过程中的重要作用而引起了广泛的兴趣．研究焦点在其还原的历程， 即辅酶分子中的一个氢是如何转移给底物的？通常采用 Ｎ Ａ Ｄ Ｈ 的模型来还原一些有结构特征的底物以揭示其还原反应机理．大体上有三种见解： （１） 一步负氢离子转移（２） 电子转移—夺氢 （３） 电子转移—质子转移—电子转移．由于对辅酶模型还原碳—碳双键化合物研究尚不多见，本实验室在这方面开展了一系列的工作，选用 ２溴１苯基亚乙基丙二腈，２溴１苯基亚乙基丙二酸二乙酯，（ Ｚ）α氰基β溴甲基肉桂酸乙酯，芴亚基丙二腈，１， １二硝基２，２二苯基乙烯，苯亚甲基丙二腈和邻溴甲基β，β二取代苯乙烯 （取代基为吸电子基） 等化合物为底物，与 Ｎ Ａ Ｄ Ｈ 模型物进行氧化—还原反应。

Coenzyme NAD(P)H draws wide interest because of its vital role in biological redox reactions. The focus of research is laid on the reduction mechanism, i.e., how does the transfer of a formal hydride from NADH to the substrates take place? In general, chemical models of NADH are used to reduce substrates with characteristic structures in order to elucidate the reduction mechanism. The mechanisms proposed include: (1) one step hydride transfer, (2) electron transfer hydrogen abstraction and (3) electron transfer proton transfer electron transfer. Since compounds with carbon carbon double bonds have been scarcely studied, a series of studies in this area have been carried out in our laboratory. The substrates studied include 2 bromo 1 phenylethylidenemalononitrile, diethyl 2 bromo 1 phenyethylidenemalonate, ethyl (Z) α cyano β bromomethylcinnamate, 9 fluorenylidenemalononitrile, 1,1 dinitro 2,2 diphenylethylene, benzylidenemalononitrile and o bromomethyl β,β disubstituted phenylethylene (with EWG substituents). Systematic studies on the mechanism of the redox reactions of NADH models with these substrates have been carried out. Herein the summarized results are reported.