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Development of highly sensitive NMR spectroscopic techniques and their application to structural analysis of natural products

高灵敏度核磁共振波谱技术的发展及其在天然产物结构分析中的应用

基本信息

批准号：
62860014
负责人：
SETO Haruo
金额：
$ 9.6万
依托单位：
Institute of Applied Microbiology, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

In order to develop highly sensitive NMR techniques, which enable to obtain satisfactory structural information of complicated natural products only available in a small quantity, we attempted to create new pulse sequences by modification of 2D-NMR techniques to 1D-NMR version. During these process, we found that an irradiation field with very high selectivity, which could be created by the use time sharing gated decoupling (TSD), gave very good results for these purposes. By employing this irradiation field and 90゜ composite pulse, we succeeded in developing a new noe technique named time sharing gated decoupling noe (TSD-NOE) which has several advantages over conventional noe experiments.As a next step, we applied TSD for obtaining decoupling difference spectra and could develop new pulse techniques named TSD-COSY and TSD-relayed-COSY. In these techniques, a highly selective irradiation field created by TSD was employed to saturate a specific proton to cause the decrease of signal intensities of the protons coupled to the saturated protons. After further detailed experiments, we succeeded in set up best experimental conditions which relied upon several experimental factors such as delay time and field strength.Next we developed a new technique named selective HOHAHA-CH which facilitated to reveal the relationship of a given proton and the carbons attached to the protons involved in the same proton spin system. Thus, by application of this technique, it has become possible to carry out very efficiently the structural analytical works of complex molecules. The structure of a new nucleoside antibiotic portmicin was determined by application of this new pulse sequence. In addition, we reported that HMBC wasparticularly useful for structural studies of natural products such as polyketides and terpenes with many methyl groups.

为了开发高灵敏度的NMR技术，使其能够获得令人满意的结构信息的复杂的天然产物，只有在少量，我们试图创建新的脉冲序列的修改2D-NMR技术的1D-NMR版本。在这些过程中，我们发现，具有非常高的选择性，这可以通过使用分时门控去耦（TSD）创建的照射场，给出了非常好的结果，为这些目的。利用该辐射场和90 μ m复合脉冲，我们成功地发展了一种新的噪声探测技术--分时选通去偶噪声（TSD-NOE），该技术与传统的噪声探测技术相比具有许多优点，下一步，我们将利用TSD获得去偶差谱，并可能发展新的脉冲技术--TSD-COSY和TSD-relayed-COSY。在这些技术中，采用由TSD产生的高度选择性照射场来饱和特定质子，以引起与饱和质子耦合的质子的信号强度的降低。通过进一步的实验，我们成功地建立了依赖于延迟时间和场强等几个实验因素的最佳实验条件，并发展了一种新的技术，称为选择性HOHAHA-CH，它有助于揭示给定质子与同一质子自旋系统中质子所连接的碳原子之间的关系。因此，通过应用该技术，可以非常有效地进行复杂分子的结构分析工作。应用这种新的脉冲序列测定了一种新的核苷类抗生素波特米星的结构。此外，我们还报道了HMBC对天然产物如聚酮化合物和含多个甲基的萜烯化合物的结构研究特别有用。