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运用密度泛函的理论方法(M06//B3LYP)对亚胺引发的关环肽环化的反应机理进行了研究.计算结果表明,由亚胺到环肽的转化过程存在两种不同的反应机理.一种是羰基转移-合环机理:先经历羰基转移,然后H转移与C-O合环同时进行.另一种是H转移-合环-羰基转移-H转移机理:H原子先从O原子转移到N原子然后再进行C-O合环,随后再进行羰基转移与H原子转移.计算结果显示,羰基转移-合环反应历程为有利路径,该反应路径中的H原子转移及C-O成环过程为整个反应的决速步骤.
The reaction mechanism of imine-initiated cyclization of the cyclic peptide was studied by the density functional theory (M06 // B3LYP). The results show that there are two different reaction mechanisms One is the carbonyl transfer - ring mechanism: first undergo carbonyl transfer, and then H transfer and CO ring at the same time the other is H transfer - ring - carbonyl transfer-H transfer mechanism: H atoms from the O atom transfer To N atom and then to CO ring, followed by carbonyl transfer and H atom transfer.The calculated results show that the carbonyl transfer-ring-closure reaction is a favorable route, the H atom transfer and CO ring formation in the reaction path are the whole The rate of the reaction step.