水对5-氟尿嘧啶质子转移影响规律的研究  

Explore the Effect Induced by Water in the Proton Transfer Process of 5-fluorouracil

作　　者：胡兴邦[1] 李浩然[1] 梁婉春[1] 韩世钧[1] 

机构地区：[1]浙江大学化学系,杭州310027

出　　处：《物理化学学报》2005年第9期952-956,共5页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(29976035);浙江省青年人才专项基金(RC01051)资助项目~~

摘　　要：采用密度泛函理论(DFT)B3LYP方法,在6-311++G(d,p)基组上研究了由质子转移引起的5-氟尿嘧啶(5-FU)的异构化反应.共研究了38个含水与不含水的构型,其中包括15个过渡态结构.研究发现,在5-氟尿嘧啶周围存在两类不同的区域,在其中一类区域中,水分子能促进质子转移的发生;而在另一类区域中,水分子却能阻碍质子转移的发生.通过与尿嘧啶质子转移过程相比较,发现在各种情况下5-氟尿嘧啶异构化为烯醇式的几率均比尿嘧啶的大,在一定程度上解释了为什么5-氟尿嘧啶具有优良抗癌作用的同时具有一定的毒副作用.In order to investigate the tautomerism of 5-fluorouracil（5-FU） induced by proton transfer, we describe a study of structural tautomer interconversion using density functional theory （DFT） calculations at B3LYP/6-311＋＋ G（d, p） level of the theory. Thirty-eight geometries including fifteen transition states with and without water molecule were studied. The calculated results indicate that there are two absolutely opposite regions in the vicinity of 5-FU. In one of the regions, water molecules can assist the tautomerism from 5-FU to its enol form （5-FU^＊）, whereas in another region, water molecules can protect 5-FU from tautomerizing to 5-FU^＊. Furthermore, compared with the tautomerizing processes of uracil, the probability of 5-FU to tautomerize to its enol form is much higher. Based on such facts, the reason why 5-FU is an effective anticancer medicament but with some of toxicity is explained to some extent.

关 键 词：密度泛函理论 5-氟尿嘧啶 质子转移 异构化 水 

分 类 号：O626.2[理学—有机化学]