Theoretical and experimental NMR chemical shifts of norsanguinarine and norchelerythrine
Theoretical and experimental NMR chemical shifts of norsanguinarine and norchelerythrine
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DOI：
10.1016/j.molstruc.2003.10.027
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发表时间：
2004-02-03
影响因子：
3.8
通讯作者：
Marek, R
中科院分区：
文献类型：
--
作者：
Tousek, J;Dostál, J;Marek, R
用梯度选择2D核磁共振波谱和大量的理论计算研究了叔苯并[c]菲并[c]菲生物碱去甲肾上腺素和去甲血根碱。用NOE和多键化学位移相关实验(GSQMBC)对标题异喹啉生物碱的H-1、C-13和N-15化学位移进行了归属。核磁共振化学位移的计算采用了多种方法。用分子力学(MM3力场)、AM1方法和从头算方法对其几何构型进行了优化。用密度泛函理论计算了化学屏蔽常数，采用了GIAO和IGLO方法。用各种方法计算的化学位移与实验值有很好的定性一致性。用RHF/6-31G~(**)方法优化几何构型，用B3LYP/6-311G~(**)方法和GIAO方法计算化学屏蔽常数，得到了最好的整体一致性。(C)2003爱思唯尔B.V.保留所有权利。
Norchelerythrine and norsanguinarine, tertiary benzo[c]phenanthridine alkaloids, were examined by gradient-selected 2D NMR spectroscopy and the later also by extensive theoretical calculations. H-1, C-13 and N-15 chemical shifts assignments of the title isoquinoline alkaloids based on NOE and multiple-bond chemical-shift correlation experiments (GSQMBC) are reported. Various methods were used for the NMR chemical shifts calculations. Molecular mechanics (MM3 forcefield), AM1 method and Ab initio methods were used for optimizing the geometry. Chemical shielding constants were computed by density functional theory, GIAO and IGLO approaches were used. Chemical shifts calculated by all methods display good qualitative agreement with experimentally determined values. The best overall agreement was achieved when geometry was optimized by RHF/6-31G** method and chemical shielding constants were calculated by B3LYP/6-311G** method, GIAO approach. (C) 2003 Elsevier B.V. All rights reserved.