Biosynthesis of 6a-hydroxypterocarpans: deuterium nmr evidence for direct hydroxylation of pterocarpans

2H-NMR analysis of the 6a-hydroxypterocarpan phytoalexin pisatin derived in CuCl2-treated pea (Pisum sativum) pods from [6,11a-2H2]maackiain has demonstrated the retention of all 2H labels. This establishes that no pterocarp-6a-ene or pterocarp-6-ene intermediate is involved, and thus confirms a direct 6a-hydroxylation mechanism for the biosynthesis of 6a-hydroxypterocarpans from pterocarpans

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

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20061470 ◽

2006 ◽

Vol 71 (10) ◽

pp. 1470-1483 ◽

Cited By ~ 3

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.

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1H-NMR Analysis of Degree of Substitution in N,O-Carboxymethyl Chitosans from Various Chitosan Sources and Types

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.506.158 ◽

2012 ◽

Vol 506 ◽

pp. 158-161 ◽

Cited By ~ 5

Author(s):

A. Jaidee ◽

Pornchai Rachtanapun ◽

S. Luangkamin

Keyword(s):

Chemical Structure ◽

Carboxymethyl Chitosan ◽

Degree Of Substitution ◽

Resonance Spectroscopy ◽

Nmr Analysis ◽

Reaction Conditions ◽

H Nmr ◽

Fourier Transformed Infrared Spectroscopy ◽

Chitosan Oligomer ◽

Ft Ir

N,O-Carboxymethyl chitosans were synthesized by the reaction between shrimp, crab and squid chitosans with monochloroacetic acid under basic conditions at 50°C. The mole ratio of reactants was obtained from various reaction conditions of shrimp chitosan polymer and oligomer types. The mole ratio 1:12:6 of chitosan:sodium hydroxide:monochloroacetic acid was used for preparing carboxymethyl of chitosan polymer types while carboxymethyl of chitosan oligomer types were used the mole ratio 1:6:3 of chitosan:sodium hydroxide:monochloroacetic acid. The chemical structure was analyzed by fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnatic resonance spectroscopy (1H-NMR). The FT-IR was used for confirm the insertion of carboxymethyl group on chitosan molecules. The 1H-NMR was used for determining the degree of substitution (DS) of carboxymethylation at hydroxyl and amino sites of chitosans. Carboxymethyl chitosan samples had the total DS of carboxymethylation ranging from 1.0-2.2. The highest of DS of carboxymethylation was from shrimp chitosan oligomer type.

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Plain 1 H NMR Analysis Streamlines the Quality Control of Antiviral Favipiravir and Congeneric WHO Essential Medicines

Magnetic Resonance in Chemistry ◽

10.1002/mrc.5154 ◽

2021 ◽

Author(s):

Prabhakar S. Achanta ◽

Shao‐Nong Chen ◽

Guido F. Pauli

Keyword(s):

Quality Control ◽

Essential Medicines ◽

Nmr Analysis ◽

H Nmr

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Prediction of physical-chemical properties of crude oils by 1 H NMR analysis of neat samples and chemometrics

Magnetic Resonance in Chemistry ◽

10.1002/mrc.3872 ◽

2012 ◽

Vol 50 (11) ◽

pp. 729-738 ◽

Cited By ~ 26

Author(s):

Alice Masili ◽

Sonia Puligheddu ◽

Lorenzo Sassu ◽

Paola Scano ◽

Adolfo Lai

Keyword(s):

Chemical Properties ◽

Crude Oils ◽

Nmr Analysis ◽

H Nmr ◽

Physical Chemical

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Lactose quantification in bovine milk by nuclear magnetic resonance without deuterated solvent (No-D qNMR)

Analytical Methods ◽

10.1039/d0ay01268h ◽

2020 ◽

Vol 12 (40) ◽

pp. 4892-4898

Author(s):

Danyelle Alves da Cunha ◽

Thays Cardoso Valim ◽

Paulo Roberto Filgueiras ◽

Valdemar Lacerda Junior ◽

Alvaro Cunha Neto

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Bovine Milk ◽

Nmr Analysis ◽

H Nmr ◽

Nuclear Magnetic

Validation of a method to quantify low lactose content in commercial lactose-free milk by 1H NMR analysis.

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NMR analysis of budding yeast metabolomics: a rapid method for sample preparation

Molecular BioSystems ◽

10.1039/c4mb00452c ◽

2015 ◽

Vol 11 (2) ◽

pp. 379-383 ◽

Cited By ~ 14

Author(s):

C. Airoldi ◽

F. Tripodi ◽

C. Guzzi ◽

R. Nicastro ◽

P. Coccetti

Keyword(s):

Nmr Spectroscopy ◽

Sample Preparation ◽

Rapid Method ◽

Budding Yeast ◽

Yeast Cells ◽

Intracellular Metabolite ◽

Nmr Analysis ◽

H Nmr ◽

Metabolite Extraction

We present a rapid and reproducible protocol for intracellular metabolite extraction from yeast cells analyzed by1H-NMR spectroscopy.

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Folded conformations due to arene interactions in dissymmetric and symmetric butylidene-linker models based on pyrazolo[3,4-d]pyrimidine, purine and 7-deazapurine

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229614009449 ◽

2014 ◽

Vol 70 (6) ◽

pp. 555-561 ◽

Cited By ~ 20

Author(s):

Kamlakar Avasthi ◽

Lakshmi Shukla ◽

Ruchir Kant ◽

Krishnan Ravikumar

Keyword(s):

Solid State ◽

Crystal Structures ◽

Crystalline State ◽

Nmr Analysis ◽

First Report ◽

Π Interactions ◽

H Nmr

The butylidene-linker models 1-[2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl]-4,6-bis(methylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine, C18H20N8S4, (XI), 7,7′-(2-methylidenepropane-1,3-diyl)bis[3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one], C20H22N6O2S2, (XIV), and 7-[2-(4,6-dimethylsulfanyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylidenepropyl]-3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one, C19H21N7OS3, (XV), show folded conformations in solution, as shown by1H NMR analysis. This folding carries over to the crystalline state. Intramolecular π–π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C—H...π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3-d]pyrimidine nucleus for such a study. In addition to the π–π interactions, the crystal structures are also stabilized by other weak intermolecular C—H...S/N/O and/or S...N/S interactions.

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