共查询到20条相似文献,搜索用时 0 毫秒
1.
Aline Lima de Oliveira Carlos Henrique Alves de Oliveira Laura Maia Mairink Francine Pazini Ricardo Menegatti Luciano Morais Lião 《Magnetic resonance in chemistry : MRC》2011,49(8):537-542
Complete assignment of 1H and 13C NMR chemical shifts and J(1H/1H and 1H/19F) coupling constants for 22 1‐phenyl‐1H‐pyrazoles' derivates were performed using the concerted application of 1H 1D and 1H, 13C 2D gs‐HSQC and gs‐HMBC experiments. All 1‐phenyl‐1H‐pyrazoles' derivatives were synthesized as described by Finar and co‐workers. The formylated 1‐phenyl‐1H‐pyrazoles' derivatives were performed under Duff's conditions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
2.
Nelson L. C. Domingues Paulo R. Olivato Adriana K. C. A. Reis Mirta G. Mondino Filipe S. Lima Roberto Rittner 《Magnetic resonance in chemistry : MRC》2009,47(3):270-272
The complete assignment of the 1H and 13C NMR spectra of the diastereomeric pairs of some α‐arylsulfinyl‐substituted N‐methoxy‐N‐methylpropionamides with the substituents methoxy, methyl, chloro, nitro is reported. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
3.
M. Dora Carrión Luisa C. López‐Cara Mariem Chayah Duane Choquesillo‐Lazarte Miguel A. Gallo Antonio Espinosa Antonio Entrena M. Encarnación Camacho 《Magnetic resonance in chemistry : MRC》2012,50(7):515-522
The 1H and 13C NMR resonances of twenty‐seven 2,2‐dimethyl‐5‐(2‐nitrophenyl‐5‐substituted)‐2,3‐dihydro‐1,3,4‐thiadiazoles, and twenty‐seven 3‐acyl‐5‐(2‐amino‐5‐substituted)‐2,2‐dimethyl‐2,3‐dihydro‐1,3,4‐thiadiazoles were assigned completely using the concerted application of one‐dimensional and two‐dimensional experiments (DEPT, HMQC and HMBC). NOESY experiments, X‐ray crystallography and conformational analysis confirm the preferred conformation of these compounds. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
4.
Stefano Provera Giuseppe Guercio Lucilla Turco Ornella Curcuruto Giuseppe Alvaro Tino Rossi Carla Marchioro 《Magnetic resonance in chemistry : MRC》2010,48(7):523-530
Liquid chromatography‐NMR (LC–NMR) spectroscopy was used to obtain detailed information regarding the structure of the major bulk drug impurities present in GW597599 (vestipitant). The one‐dimensional 1H LC–NMR experiments were performed in both continuous and stop‐flow modes on a sample of GW597599 (vestipitant) enriched with mother liquor impurities. The information derived from both LC–NMR and LC–MS data provided the structural information of all major impurities. The full characterisation of the impurities by high‐resolution NMR spectroscopy was ultimately performed on appropriately synthesised compounds. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
5.
《Magnetic resonance in chemistry : MRC》2003,41(1):77-79
The complete assignment of the 1H and 13C NMR spectra of the title enediones, bearing as substituents N‐aziridinyl (a novel compound), methoxy, chloro and methylsulfanyl, is reported. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
6.
Rafael Germano Santana Derisvaldo Rosa Paiva Roberto da Silva Gomes Adriana Karla C. A. Reis 《Magnetic resonance in chemistry : MRC》2013,51(5):316-319
The complete assignment of the 1H and 13C NMR spectra of various 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamide‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamides with p‐methoxy, o‐chloro and m‐chloro substituents is reported. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
7.
In this communication, we describe the design of an online multi-chromatographic approach to the routine NMR analyses of low-level components ( approximately 0.1%) in complex mixtures. The technique, termed LC(2)-SPE-NMR, optimally combines multi-dimensional liquid chromatography with SPE technology for isolating, enriching and delivering trace analytes to the NMR probe. The fully automated LC(2)-SPE-NMR system allows for maximal loading capacity (in the first, preparative LC dimension), close to optimal peak resolution (in the second, analytical LC dimension) and enhanced sample concentration (through SPE). Using this system, it is feasible to conveniently conduct a wide range of NMR experiments on, for example, drug impurities at the low microgram per milliliter level, even for components poorly resolved in the first dimension. Such a sensitivity gain significantly elevates the analytical power of online NMR technology in terms of the level at which substances of pharmaceutical significance can be structurally characterized. 相似文献
8.
Raimund Marx Nikolas Pomplun Wolfgang Bermel Heinz Zeiger Frank Engelke Amr F. Fahmy Steffen J. Glaser 《Magnetic resonance in chemistry : MRC》2015,53(6):442-447
The realization of an all‐heteronuclear 5‐qubit nuclear magnetic resonance quantum computer is reported, from the design and synthesis of a suitable molecule through the engineering of a prototype 6‐channel probe head. Full control over the quantum computer is shown by a benchmark experiment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
Belén Rubio‐Ruiz Ana Conejo‐García Miguel A. Gallo Antonio Espinosa Antonio Entrena 《Magnetic resonance in chemistry : MRC》2012,50(6):466-469
1H and 13 C NMR spectral data of 13 new compounds containing a 4‐(dimethylamino)‐ or 4‐(pyrrolidin‐1‐yl)pyridinium moiety linked to the N‐9 or N‐3 nitrogen atom of an adenine moiety were assigned. 1D and 2D NMR experiments (DEPT, HSQC and HMBC) allowed the unequivocal identification of N‐9 and N‐3 isomers. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
《Magnetic resonance in chemistry : MRC》2003,41(7):541-544
Treatment of 2‐acetyl‐2‐methylcyclopentanone with hydrazine hydrate yielded a new condensed hexahydro‐1,3,5‐triazine (3b), which is the first example of the ketimine‐type trimers. A complete 1H, 13C and 15N NMR assignment of the compound was achieved. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
11.
《Magnetic resonance in chemistry : MRC》2002,40(8):541-544
Two novel oligosaccharides, mono‐ and difructosyllactosucrose {[O‐β‐D ‐fructofuranosyl‐(2 → 1)]n‐β‐D ‐fructofuranosyl‐O‐[β‐D ‐galactopyranosyl‐(1 → 4)]‐α‐D ‐glucopyranoside, n = 1 and 2} were synthesized using 1F‐fructosyltransferase purified form roots of asparagus (Asparagus officinalis L.). Their 1H and 13C NMR spectra were assigned using several NMR techniques. The spectral analysis was started from two anomeric methines of aldose units, galactose and glucose, since they showed separate characteristic signals in their 1H and 13C NMR spectra. After assignments of all the 1H and 13C signals of two units of aldose, they were discriminated as galactose and glucose using proton–proton coupling constants. The HMBC spectrum revealed the galactose residue attached to C‐4 of glucose, fructose residue attached to the C‐1 of glucose, and further fructosyl fructose linkage extended from the glucosyl fructose residues. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
12.
M. Dora Carrión Mariem Chayah Duane Choquesillo‐Lazarte Miguel A. Gallo Antonio Espinosa Antonio Entrena M. Encarnación Camacho 《Magnetic resonance in chemistry : MRC》2012,50(1):58-61
The 13 C NMR resonances of 19 1‐acyl‐3‐(2‐nitro‐5‐substitutedphenyl)‐4,5‐dihydro‐1H‐pyrazoles, and 19 1‐acyl‐3‐(2‐amino‐5‐substituted)‐4,5‐dihydro‐1H‐pyrazoles, were completely assigned using the concerted application of one‐ and two‐dimensional NMR experiments (DEPT, gs‐HSQC and gs‐HMBC). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
13.
Structure determination of two new indole‐diterpenoids from Penicillium sp. CM‐7 by NMR spectroscopy
Yu‐Hong Zhang Sheng‐Dong Huang Hua‐Qi Pan Xi‐Qing Bian Zai‐Ying Wang Ai‐Hong Han Jiao Bai 《Magnetic resonance in chemistry : MRC》2014,52(6):306-309
Two new indole‐diterpenoids 4b‐deoxy‐1′‐O‐acetylpaxilline (1) and 4b‐deoxypenijanthine A (2) were isolated from the fermentation broth and the mycelia of the soil fungus Penicillium sp. CM‐7, along with three known structurally related compounds, 1′‐O‐acetylpaxilline (3), paspaline (4) and 3‐deoxo‐4b‐deoxypaxilline (5). The structures of compounds 1 and 2 were elucidated by extensive spectroscopic methods, especially 2D NMR, and their absolute configurations were suggested on the basis of the circular dichroism spectral analysis and the NOESY data. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
14.
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
15.
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
16.
《Magnetic resonance in chemistry : MRC》2003,41(9):671-678
Negative photoresists are composed of a photoactive component (aromatic azides/bisazides) and cyclized rubber or novolac resin dissolved in an organic solvent. Hydrogen abstraction and/or insertion reaction of the reactive nitrene intermediate formed during photoirradiation of the azide result in a cross‐linked network of the novolac resin. The molecular weight of novolac resin in the exposed part of the photoresist film thus increases compared with that of the unexposed part. This makes the exposed part insoluble in the alkaline developer. Exploiting this change in physical property, a pattern can be transferred to a substrate from a mask. A better understanding of the exact mechanism of cross‐linking reactions is very important to the design of a high‐performing negative photoresist. A quinone–imine‐type complex has been proposed earlier involving the aromatic moiety of novolac resin as the reaction site. A more recent study focuses the attack of nitrene on the methylenic bridge and hydroxyl group of novolac resins, which were found to be responsible for the cross‐linking reaction along with the aromatic moiety of novolac resin. However, in our study no evidence was found for the involvement of a methylenic hydrogen or aromatic moiety of novolac resin in the cross‐linking reaction. The 1H NMR, 13C NMR and DEPT‐135 spectra before and after photolysis indicate that the cross‐linking site is predominantly the hydroxyl group of novolac resin. Multiple reaction sites of attack for the nitrene intermediate have been demonstrated in cashew nut shell liquid (CNSL)‐based novolac resin by 1H NMR spectroscopy, which in turn further increases the cross‐linked network in the exposed part of a negative photoresist. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
17.
《Magnetic resonance in chemistry : MRC》2002,40(7):461-466
A series of oligo‐bipyridine–phenanthroline hybrids, a new class of potential model ligands, were synthesized and their 1H and 13C NMR spectra assigned. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
18.
Djenisa H. A. Rocha Diana C. G. A. Pinto Raquel S. G. R. Seixas Artur M. S. Silva 《Magnetic resonance in chemistry : MRC》2014,52(1-2):47-50
Ten 3‐methylflavone derivatives were studied. Previously reported NMR data of some derivatives were corrected and/or completed, including the complete assignment of the two known natural derivatives. The complete 1H and 13C NMR assignments were achieved by combination of one‐dimensional and two‐dimensional NMR experiments. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
19.
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
20.
Prakasam Thirumurugan A. Nandakumar Neelakandan Vidhya Lakshmi B. V. N. Phani Kumar Paramasivan T. Perumal 《Magnetic resonance in chemistry : MRC》2010,48(7):554-561
Asimple protocol for the efficient preparation of 6‐(ferrocene‐1‐yl)‐2‐(indol‐3‐yl)pyridine and 2‐(1H‐indol‐3‐yl)‐6‐(2‐thienyl)pyridine derivatives has been achieved through multi‐component reaction, and these compounds were thoroughly characterised by 2D NMR spectral techniques. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献