Chromone studies. Part 3. NMR analysis of rotational isomerism in 4-oxo-4H-chromene-2-carboxamides

1991 ◽  
pp. 927 ◽  
Author(s):  
Deborah N. Davidson ◽  
Perry T. Kaye
Keyword(s):  
Rotational Isomerism ◽  
Nmr Analysis

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

2006 ◽  
Vol 71 (10) ◽  
pp. 1470-1483 ◽  
Author(s):  
David Šaman ◽  
Pavel Kratina ◽  
Jitka Moravcová ◽  
Martina Wimmerová ◽  
Zdeněk Wimmer
Keyword(s):  
Analytical Data ◽  
Chiral Hplc ◽  
Nmr Analysis ◽  
Target Structure ◽  
Enantiomerically Pure ◽  
Whole Cells ◽  
H Nmr ◽  
Structure Assignment ◽  
Related Compounds ◽  
C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

scholarly journals Structural Characterization of a Polysaccharide from Gastrodia elata and Its Bioactivity on Gut Microbiota

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4443
Author(s):  
Jiangyan Huo ◽  
Min Lei ◽  
Feifei Li ◽  
Jinjun Hou ◽  
Zijia Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Citric Acid ◽  
Gut Microbiota ◽  
Structural Characterization ◽  
Hot Water ◽  
Nmr Analysis ◽  
Gastrodia Elata ◽  
Hot Water Extraction ◽  
Hydroxybenzyl Alcohol

A novel homogeneous polysaccharide named GEP-1 was isolated and purified from Gastrodia elata (G. elata) by hot-water extraction, ethanol precipitation, and membrane separator. GEP-1, which has a molecular weight of 20.1 kDa, contains a polysaccharide framework comprised of only glucose. Methylation and NMR analysis showed that GEP-1 contained 1,3,6-linked-α-Glcp, 1,4-linked-α-Glcp, 1,4-linked-β-Glcp and 1,4,6-linked-α-Glcp. Interestingly, GEP-1 contained citric acid and repeating p-hydroxybenzyl alcohol as one branch. Furthermore, a bioactivity test showed that GEP-1 could significantly promote the growth of Akkermansia muciniphila (A. muciniphila) and Lacticaseibacillus paracasei (L.paracasei) strains. These results implied that GEP-1 might be useful for human by modulating gut microbiota.

scholarly journals Mono- and Dinitro-BN-Naphthalenes: Formation and Characterization

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4209
Author(s):  
Mao-Xi Zhang ◽  
Nathaniel B. Zuckerman ◽  
Philip F. Pagoria ◽  
Bradley A. Steele ◽  
I-Feng Kuo ◽  
...  
Keyword(s):  
Electron Density ◽  
Nmr Analysis ◽  
X Ray ◽  
Boron Nitrogen

Mono- and dinitro-BN-naphthalenes, i.e., 1-nitro-, 3-nitro-, 1,6-dinitro-, 3,6-dinitro-, and 1,8-dinitro-BNN, were generated in the nitration of 9,10-BN-naphthalene (BNN), a boron–nitrogen (BN) bond-embedded naphthalene, with AcONO2 and NO2BF4 in acetonitrile. The nitrated products were isolated and characterized by NMR, GC-MS, IR, and X-ray single crystallography. The effects of the nitration on the electron density and aromaticity of BNN were evaluated by B-11 NMR analysis and HOMA calculations.

scholarly journals NMR lipid profiles of cells, tissues, and body fluids: proton NMR analysis of human erythrocyte lipids.

1994 ◽  
Vol 35 (11) ◽  
pp. 1925-1931
Author(s):  
R K Adosraku ◽  
G T Choi ◽  
V Constantinou-Kokotos ◽  
M M Anderson ◽  
W A Gibbons
Keyword(s):  
Human Erythrocyte ◽  
Proton Nmr ◽  
Body Fluids ◽  
Lipid Profiles ◽  
Nmr Analysis ◽  
Erythrocyte Lipids

scholarly journals Dynamic 13C NMR analysis of oxidative metabolism in the in vivo canine myocardium.

1993 ◽  
Vol 268 (35) ◽  
pp. 26296-26301
Author(s):  
P M Robitaille ◽  
D P Rath ◽  
A M Abduljalil ◽  
J M O'Donnell ◽  
Z Jiang ◽  
...  
Keyword(s):  
13C Nmr ◽  
Oxidative Metabolism ◽  
Nmr Analysis ◽  
13C Nmr Analysis ◽  
Canine Myocardium
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