二维核磁共振技术解析盐酸帕罗西汀

报道了盐酸帕罗西汀的分子结构解析方法,利用国产核磁共振波谱仪测试了盐酸帕罗西汀核磁氢谱(^(1)H-NMR)、核磁碳谱(^(13)C-NMR、DEPT 135°)、二维核磁相关谱(^(1)H-^(1)HCOSY、^(13)C-^(1)H HSQC、^(13)C-^(1)H HMBC),实现了盐酸帕罗西汀氢碳的全部归属.     

核磁共振法测定高聚物的结构—核磁共振二维谱

介绍了核磁共振(NMR)波谱,尤其是核磁共振二维谱(2D NMR)在最近几年内的进展。内容包括怎样用NMR测定高聚物的序列分布、共聚物结构、聚合物的混溶性、聚合物液晶的取向度、分子量、短链度和长链支化度、凝聚态高聚物的多相结构等。     

核磁共振的几种新技术及其在结构解析中的应用

核磁共振(NMR)波谱法是结构解析中不可缺少的最重要的工具之一。而现代脉冲技术在核磁共振中的应用导致了许多新的测定方法不断以惊人的速度得到开发,使人们能够按照实际需要控制核的磁化运动,从而得到结构解析所必要的丰富信息。在一维核磁共振(1D-NMR)基础上发展起来的二维核磁共振(2D-NMR)改变了     

聚丁二烯的核磁共振二维谱研究

<正> 聚丁二烯分子中有三种微观结构,顺式-1,4,反式-1,4和-1,2。这三种结构单元的含量和序列长度对聚丁二烯的物性有很大影响。异构单元的含量可用IR和氢谱测定。序列分布可用氢谱和碳谱测定。已经有许多工作致力于聚丁二烯碳谱的谱图解析。因为各作者使用不同的经验式或半经验式,统计方法也不一样,结论不尽相同。最近Sato等     

核磁共振的若干新技术在天然化合物结构解析中的应用

核磁共振是天然有机化合物结构解析中最重要的手段之一。近年来,随着超导磁体高磁场核磁共振仪的普及应用,也出现了一些新的测定技术,例如,氘代高场位移法,远程选择氢核去偶法,远程C—HJ分解法及二维INADEQUATE法等。本文现结合具体实例介绍这些新技术在天然化合物结构解析中的应用。1.氚代高场位移(deuterium induced upfield shift)在~(13)CNMR中,若碳原子上的氢被氘取代时,则其信号向高场位移。在酰胺及醇类等具有~(13)C-X-H(X=O,或N)的化合物中,这种现象尤易发生。与XH直接相连的α-碳及相邻的β-碳均可观察列高场位移,并可用于结     

核磁共振研究蛋白二级结构的方法

核共振共振法常规应用于解析化学物质结构和反应性能,现已发展成为生物化学和分子生物学的重要实验技术,尤其是在确定溶液中蛋白和多肽结构方面起着其它物理分析方法不可比拟的作用。文章综述了化学位移,偶合常数。核Ｏｖｅｒｈａｕｓｅｒ效应（ＮＯＥ）以及同位素交换等确定蛋白或多肽二级结构的方法。     

应用二维核磁共振系列技术鉴定罕见的19-羟基多羟基甾醇的结构

本文应用COSY, TOCSY, 13C-1H COSY, ROESY, NOE差谱等NMR技术, 对新的19-羟基多羟基甾醇(Nephalstenol-A)的结构进行了鉴定, 并确定了其立体构型。     

西贝素β-氮氧化物及其二维核磁共振谱

本文报告应用化学和光谱法(^1H, ^1^3C NMR, ^1^3C,^1H COLOC, noeds和NOESY) , 对分自川产家种华西贝母(F. siechuanica S. C. Che)藓茎中的碱N确证为西贝素β-氮氧化物(imperialine β-N-oxide )3以及3的二维核磁共振谱的研究. 同时, 对文献[4]报告的3中某些^1^3C信号化学位移的归属也进行了纠正.     

基于脉冲序列DEPT-(90+45)的二维核磁共振谱编辑技术

基于作者提出的脉冲序列ＤＥＰＴ（ｄｉｓｔｏｒｔｉｏｎｌｅｓｓ ｅｎｈａｎｃｅｍｅｎｔ ｂｙ ｐｏｌａｒｉｚａｔｉｏｎ ｔｒａｎｓｆｅｒ）－（９０＋４５）,拟定了一个二维碳－氢相关实验,用于测定所有甲基的碳－氢相关信息,联合应用二维ＤＥＰＴ－１３５实验,从而实现了二维碳－氢相关谱的编辑,对于简化二维碳－氢相关谱具有实用价值。     

structural elucidation of novel phosphocholine-containing glycosylinositol-phosphoceramides in filamentus fungi: (2). Spectral analysis of the sugar-inositol portion by 2D-NMR

The sugar-inositol portion of the novel glycosylinositol-phosphoceramides, ZGL1 and ZGL2, from the filamentus fungi, Acremonium sp., were elucidated by a combination of NMR techniques including (1)H-(1)H (COSY and HOHAHA) and (1)H-(13)C (HMQC and HMBC) spectroscopy. Further, examination of the (1)H-(31)P HMQC spectrum showed connectivity of inositol and ceramide through phosphate.     

Pyrolysis-GC-FTIR for structural elucidation of aquatic humic substances

Substructure components of various aquatic humic substances were investigated by a coupled pyrolysis — gas chromatography — Fourier-transform infrared spectroscopy (Py-GC-FTIR) procedure. The humic substances studied gave similar pyrolysis products, but in varying proportions. Many of the pyrolysis products (e.g. methanol, acetone, alkylbenzenes, cyclopentane, aliphatic and aromatic organic acids, acetamide, pyrrole and phenols) could be identified by their FTIR spectra using a digital library for automatic comparison. Some of the compounds are related to lignin fragments which form a large part of the humic substances investigated. Other products give hints to the involvement of tetrapyrroles, fatty acids, furanoses and amino compounds in the structure of humic macromolecules.Dedicated to Professor Dr. Dieter Klockow on the occasion of his 60th birthday     

2D-NMR of natural products,part V Structure elucidation and complete1H- and13C-assignment of resin acid derivatives

Application of 2D-NMR-techniques including heteronuclear 2D-J-resolved spectroscopy and¹H-¹³C-2 D-shift correlation is used to assign the¹H- and¹³C-resonances of resin acid derivatives.

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2D-NMR von Naturprodukten, 5. Mitt.: Strukturaufklärung und komplette ^1H-und ^13C-Zuordnung von Harzsäure-Derivaten

Zusammenfassung 2D-NMR-Methoden (2D-J-resolved-Spektren,¹H-¹³C-Shiftkorrelations-spektren) erlauben die Zuordnung der¹H- und¹³C-Signale von Harzsäurederivaten.

     

Facile solvent-free synthesis and structural elucidation of styrylcyclohex-2-enone derivatives

A remarkably efficient procedure for the synthesis of styrylcyclohex-2-enone derivatives at room temperature is described using a mild reaction medium consisting of lithium perchlorate and N-(trimethylsilyl)diethylamine. Several compounds of this class are synthesized conveniently and rapidly. Spectroscopic and X-ray diffraction experiments confirm the proposed structures. Correspondence: Mohammad M. Mojtahedi and Mohammad Saeed Abaee, Organic Chemistry Laboratory, Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran, Iran.     

Facile solvent-free synthesis and structural elucidation of styrylcyclohex-2-enone derivatives

A remarkably efficient procedure for the synthesis of styrylcyclohex-2-enone derivatives at room temperature is described using a mild reaction medium consisting of lithium perchlorate and N-(trimethylsilyl)diethylamine. Several compounds of this class are synthesized conveniently and rapidly. Spectroscopic and X-ray diffraction experiments confirm the proposed structures.     

选择性远程DEPT技术用于吡咯里西啶类生物碱的结构测定和核磁共振研究

本文从峨眉千里光中分得二个吡咯里西啶类生物碱.经测定,一个为阔叶千里光碱,另一个为新阔叶千里光碱.采用选择性远程^13CDEPT技术对这二个化合物的结构及其^1H和^13CNMR谱峰归属作了研究.     

NMR structural elucidation of photochromic quinolone photoproducts

UV irradiation of 3-benzoyl-2-benzyl-6,7-difluoro-1-propyl-1H-quinolin-4-one leads to the formation of a mixture of photoproducts, with different evolutions. The structure of each of them has been obtained by one- and two-dimensional multinuclear NMR experiments. Two photoenols, which are thermally reversible, have been identified. All of the other photoproducts have been assigned to degradation. Based on the structural identification and the photochemical and thermal evolution of samples, a plausible mechanism is proposed.     

Total synthesis and structural elucidation of khafrefungin.

Total synthesis and structural elucidation of khafrefungin, a novel antifungal agent isolated from the fermentation culture MF6020, have been achieved. Unlike other inhibitors that inhibit the corresponding enzyme in fungi and mammals to the same extent, khafrefungin does not impair sphingolipid synthesis of mammals. The basic strategy for the structural elucidation is to prepare all stereoisomers of the structurally simplified khafrefungin mimics 1 and 2 that were designed for the elucidation of C10,11,12 and C2',3',4' relative stereochemistry, respectively. The comparison of their spectra with those of natural khafrefungin would result in the identification of eight possible stereoisomers, and the analytical details of these eight stereoisomers have led to the complete stereochemical assignment. On the basis of the structural elucidation, the total synthesis of khafrefungin has been accomplished by using tin(II)-catalyzed asymmetric aldol reactions as key steps.     

抗癌药物冬凌草甲素的分子构型研究

本文用同核化学位移相关谱和二维J分解谱归属了冬凌草甲素的^1H谱, 测定了所有的质子标量偶合常数, 根据一系列的Karplus公式计算了二面角, 用自编WUPH计算程序, 计算出冬凌草甲素的分子构型。