应用从头计算和ABEEM方法研究一种特殊的亚胺加成物

利用从头计算方法计算了鸟苷与联苯酰基胺离子反应生成C8加成物的NMR化学位移, 结果与实验所测到的NMR化学位移符合得很好, 并且根据原子-键电负性均衡方法中的σπ模型(ABEEM σπ)计算所得到的电荷与NMR化学位移也有很好的对应关系; 但采用相同的方法计算腺苷与联苯酰基胺离子反应生成的亚胺加成物时, 得到的NMR化学位移与实验值在个别关键的碳原子处有很大差别. 根据研究得到的结果推测, 实验上得到的构型不仅仅是亚胺加成物, 而可能是一种含有亚胺和氮杂形式加成物的混合物.

Study on a Special Imine Adduct by Ab Initio and Atom-bond Electronegativity Equalization Methods

NMR chemical shifts of C8 adduct in the reaction of guanosine with N-acetyl-4-biphenyl nitrenium ion were studied using ab initio calculations. The results were in good agreement with experimental data. Additionally, the charges obtained by atom-bond electronegativity equalization method σπ (ABEEM σπ) also corresponded with the NMR chemical shifts. For imine adduct in the reaction of adenosine with N-acetyl-4-biphenyl nitrenium ion, theoretical NMR chemical shifts of some key C atoms were very different to the experimental values. Hence, it was predicted that the final adduct in studied reaction should include azepine adduct besides imine adduct.