共查询到20条相似文献,搜索用时 31 毫秒
1.
E. Bednarek J. Sitkowski W. Bocian W. Łuniewski M. Kobylińska Ł. Kaczmarek L. Kozerski 《Magnetic resonance in chemistry : MRC》2013,51(9):569-573
The complete NMR signal assignment of title compounds were carried out by extensive use of 1D and 2D NMR techniques (1H, 13C, COSY, HSQC and HMBC). Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
2.
2‐Styrylchromones, although scarce in nature, constitute a group of oxygen heterocyclic compounds which have shown significant biological activities. New nitro‐2‐styrylchromones have been synthesised by the Baker–Venkataraman method, and the structure elucidation was accomplished using extensive 1D (1H, 13C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC experiments). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
3.
Yang Gao Jia‐Liang Zhong Tai‐Zhi Wu Lin‐Yong Jin Fu‐Li Zhang 《Journal of heterocyclic chemistry》2016,53(2):579-582
(R)‐3‐(2′‐hydroxyprop‐1‐yl) adenine 4 was obtained by alkylation of adenine 1 with R‐propylene carbonate 2 in the presence of pulverized sodium hydroxide in the synthetic process of tenofovir. The elucidation of the structure of 4 was confirmed by single crystal X‐ray diffraction and NMR experiments such as 1D 1H, 13C, and DEPT, as well as 2D COSY, HSQC, and HMBC spectra. 相似文献
4.
The chemical structure and stereochemistry of 12 intermediates in the total synthesis of (+)‐biotin starting from D ‐mannose as chiral pool were completely assigned using one‐ and two‐dimensional NMR experiments, including 1D selective NOE, DEPT, COSY, HSQC and HMBC. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
5.
Aslan Esmurziev Nebojša Simić Eirik Sundby Bård Helge Hoff 《Magnetic resonance in chemistry : MRC》2009,47(5):449-452
Complete assignments of 1H‐ and 13C‐NMR resonances of five methyl tetra‐O‐benzoyl‐D‐pyranosides based on 1H, 13C, 2D DQF–COSY, HMQC, HMBC and HSQC–TOCSY experiments have been performed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
6.
《Magnetic resonance in chemistry : MRC》2003,41(8):636-638
Complete assignments of 1H and 13C NMR chemical shifts for oleanolic acid, 18α‐oleanolic acid, ursolic acid and their 11‐oxo derivatives based on 1H, 13C, 2D DQF‐COSY, NOESY, HSQC, HMBC and HSQC‐TOCSY experiments were achieved. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
7.
Two new 3,4‐seco‐cycloartane triterpenes, named sootepin F ( 1 ) and sootepin G ( 2 ), together with two known compounds, coronalolide methyl ester ( 3 ) and sootepin D ( 4 ), were isolated from the leaves and twigs of Gardenia sootepensis. Their structures were elucidated on the basis of 1D‐ and 2D‐NMR experiments, including HMBC, HSQC, 1H,1H‐COSY, and ROESY, as well as HR‐MS. 相似文献
8.
Brigida D'Abrosca Severina Pacifico Monica Scognamiglio Nikolaos Tsafantakis Emanuela Pagliari Pietro Monaco Antonio Fiorentino 《Helvetica chimica acta》2013,96(7):1273-1280
Four novel γ‐pyrone (=4H‐pyran‐4‐one) metabolites, petrorhagiosides A–D, along with four known analogs, have been isolated from the MeOH extract of Petrorhagia saxifraga, a perennial herbaceous plant typical of Mediterranean vegetation. The structures of the new compounds were established on the basis of extensive spectroscopic analyses including 1D‐ an 2D‐NMR (1H,1H‐DQ‐COSY, TOCSY, HSQC, CIGAR‐HMBC, and HSQC‐TOCSY) experiments. 相似文献
9.
Christopher A. Waudby Tom Frenkiel John Christodoulou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(26):8876-8880
Two‐dimensional correlation measurements such as COSY, NOESY, HMQC, and HSQC experiments are central to small‐molecule and biomolecular NMR spectroscopy, and commonly form the basis of more complex experiments designed to study chemical exchange occurring during additional mixing periods. However, exchange occurring during chemical shift evolution periods can also influence the appearance of such spectra. While this is often exploited through one‐dimensional lineshape analysis (“dynamic NMR”), the analysis of exchange across multiple chemical shift evolution periods has received less attention. Here we report that chemical exchange‐induced cross‐peaks can arise in even the simplest two‐dimensional NMR experiments. These cross‐peaks can have highly distorted phases that contain rich information about the underlying exchange process. The quantitative analysis of such peaks, from a single 2D spectrum, can provide a highly accurate characterisation of underlying exchange processes. 相似文献
10.
Colombo D Ferraboschi P Grisenti P Legnani L 《Magnetic resonance in chemistry : MRC》2008,46(1):99-102
The complete 1H and 13C NMR assignments are reported for the antithrombotic (21R)- and (21S)-argatroban by 1D and 2D NMR experiments (HSQC, HMBC, NOESY and 1H--1H COSY). Some well-resolved signals could be used for an accurate measurement of the diastereomeric composition of argatroban. 相似文献
11.
Gevrenova R Voutquenne-Nazabadioko L Harakat D Prost E Henry M 《Magnetic resonance in chemistry : MRC》2006,44(7):686-691
The assignments of 1H and 13C NMR spectra of two new aminoacyl triterpene saponins from roots of Gypsophila trichotoma Wend. are reported. In addition to 1D NMR methods, 2D NMR techniques (COSY, TOCSY, ROESY, HSQC, HMBC, and HSQC-TOCSY) were used for the assignments. The structures were completed by analysis of HR-ESI-MS and ESI-MS(n). 相似文献
12.
Synthesis and structure elucidation of five series of aminoflavones using 1D and 2D NMR spectroscopy
Twenty-six new aminoflavones have been synthesised by two different methods and the structure elucidation was accomplished using extensive 1D (1H, 13C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC experiments). 相似文献
13.
Markus Bacher Karl Baumann Hermann Knapp Andrea Steck Sigrid Teibl 《Magnetic resonance in chemistry : MRC》2009,47(1):71-83
The complete 1H and 13C NMR data of 27 pravastatin derivatives are presented. Assignment was achieved by use of 1D and 2D NMR experiments (selective 1D NOE, COSY, NOESY, HSQC, HMBC). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
14.
The validation of a molecular organic structure on the basis of 1D and 2D HSQC, COSY and HMBC NMR spectra is proposed as an alternative to the methods that are mainly based on chemical shift prediction. The CCASA software was written for this purpose. It provides an updated and improved implementation of the preceding computer‐assisted spectral assignment software. CCASA can be downloaded freely from http://www.univ‐reims.fr/LSD/JmnSoft/CASA . Two bioactive natural products, a triterpene and a benzophenone, were selected from literature data as examples. The tentative matching between the structure and the NMR data interpretation of the triterpene unexpectedly leads to the hypothesis of an incorrect structure. The LSD software was used to find an alternative structure that improved the 2D NMR data interpretation and the carbon‐13 chemical shift matching between experimental values and those produced by the nmrshiftdb2 prediction tool. The benzophenone example showed that signal assignment by means of chemical shift prediction can be replaced by elementary user‐supplied chemical shift and multiplicity constraints. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
Ten phenylpiperazine derivatives were designed and synthesized. The first complete assignments of (1)H and (13)C NMR chemical shifts for these phenylpiperazine derivatives were achieved by means of 1D and 2D NMR techniques, including (1)H-(1)H COSY, HSQC and HMBC spectra. 相似文献
16.
El-Atawy Mohamed A. Hegazi Abdelrahman H. Al Khalaf Mohamed Amer Adel 《Structural chemistry》2020,31(3):1065-1072
Structural Chemistry - Based on the analyses of 1D and 2D NMR spectra techniques, such as H–H COSY, HSQC, and HMBC of 3-[L-threo-2,3,4-trihydroxy-1-(phenylhydrazono)butyl]-... 相似文献
17.
I. A. Khotina A. I. Kovalev N. S. Kushakova M. A. Babushkina Yu. V. Vasil’ev A. S. Peregudov 《Russian Chemical Bulletin》2013,62(10):2234-2244
A series of model cyclotrimers was studied by NMR spectroscopy using 2D COSY, HSQC, and HMBC correlations to establish the structures of branched oligophenylenes, whose branching center is the 1,3,5-triphenyl-substituted benzene ring. 相似文献
18.
Tsang‐Lin Hwang Michael Ronk Jacqueline E. Milne 《Magnetic resonance in chemistry : MRC》2013,51(2):89-94
In the pharmaceutical industry, regulatory expectations driven by patient safety considerations make structure elucidation of impurities at levels greater than 0.1% in the active pharmaceutical ingredient (API) of primary interest. Impurities can be generated from isomers in starting materials, or produced from different process steps toward the final API. Proton peaks belonging to different impurities could be potentially identified in the one‐dimensional 1H NMR spectrum, when evaluated in combination with two‐dimensional (2‐D) COSY and HSQC data. However, in 2‐D HMBC data, correlation responses from different impurities may overlap with those from the major component, causing uncertainty of long‐range proton to carbon correlations and quaternary carbon assignments. This observation prompts us to design the 2‐D selective‐TOCSY HMBC experiment to distinguish responses from different impurities in mixtures to obtain 2‐D NMR data for each impurity, thus eliminating the use of a chromatographic isolation step to obtain material for NMR analysis. This methodology is demonstrated for structure elucidation of impurities ranging from 8.2% in the raw material to 0.4% in the API in this study, and would be particularly useful for industrial samples in which the solubility and availability of material are not an issue. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
19.
Two new 11‐hydroxy‐substituted gelsedine‐type indole alkaloids, named 11,14‐dihydroxygelsenicine ( 1 ) and 11‐hydroxygelsenicine ( 2 ), together with six known alkaloids, i.e., koumine, gelsemine, 14‐hydroxygelsenicine, 11‐hydroxyhumantenine, gelsenicine, and (19Z)‐akuammidine, were isolated from the EtOH extract of the stems of Gelsemium elegans Benth. Their structures were determined mainly by means of spectroscopic analyses including HR‐ESI‐MS and 2D‐NMR (HSQC, HMBC, 1H,1H‐COSY). The configuration of 1 was confirmed by X‐ray‐diffraction analysis. 相似文献
20.
Maria Misiak Wiktor Koźmiński Maria Kwasiborska Jacek Wójcik Ewa Ciepichal Ewa Swiezewska 《Magnetic resonance in chemistry : MRC》2009,47(10):825-829
The complete assignment of 1H and 13C chemical shifts of natural abundance prenol‐10 is reported for the first time. It was achieved using 3D NMR experiments, which were based on random sampling of the evolution time space followed by multidimensional Fourier transform. This approach makes it possible to acquire 3D NMR spectra in a reasonable time and preserves high resolution in indirectly detected dimensions. It is shown that the interpretation of 3D COSY–HMBC and 3D TOCSY–HSQC spectra is crucial in the structural analysis of prenol‐10. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献