Use of a laboratory robot for repetitive solution NMR sample preparation

1993 ◽  
Vol 71 (2) ◽  
pp. 275-279
Author(s):  
Michael A. Jeannot ◽  
R. Stephen Reid
Keyword(s):  
Sample Preparation ◽  
Solution Nmr ◽  
Nmr Analysis ◽  
Acid Base ◽  
H Nmr ◽  
Ligand System ◽  
Base Study ◽  
Nmr Sample Preparation ◽  
Nmr Signals

Observing ligand 1H NMR signals while conditions (e.g., analytical concentrations, pH) are changed in an aqueous metal–proton–ligand system is one of the most potent methods of elucidating the precise details of speciation in such systems. Typically this is performed by changing the conditions in a solution reservoir, while withdrawing a sample for NMR analysis at each stage. However, such sample preparation is tedious and time-consuming. We report here studies, using a Mitsubishi RM-101 laboratory robot, of the feasibility of completely automating such a procedure. A simple acid–base study is used to evaluate performance.

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

2015 ◽  
Vol 11 (2) ◽  
pp. 379-383 ◽  
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.

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 13C and 1H NMR Spectra of Synthetic (25R)-5α-Spirostanes

1999 ◽  
Vol 23 (1) ◽  
pp. 48-49
Author(s):  
Martín A. Iglesias Arteaga ◽  
Carlos S. Pérez Martinez ◽  
Roxana Pérez Gil ◽  
Francisco Coll Manchado
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr ◽  
C 23 ◽  
Main Effects ◽  
Nmr Signals

The assignment of 13C and 1H NMR signals of synthetic (25 R)-5α-spirostanes is presented; the main effects on chemical shifts due to substitution at C-23 are briefly discussed.

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

2012 ◽  
Vol 506 ◽  
pp. 158-161 ◽  
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.

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

2012 ◽  
Vol 50 (11) ◽  
pp. 729-738 ◽  
Author(s):  
Alice Masili ◽  
Sonia Puligheddu ◽  
Lorenzo Sassu ◽  
Paola Scano ◽  
Adolfo Lai
Keyword(s):  
Chemical Properties ◽  
Crude Oils ◽  
Nmr Analysis ◽  
H Nmr ◽  
Physical Chemical

Differentiation of enantiomeric anions by NMR spectroscopy with chiral bisurea receptors

2018 ◽  
Vol 16 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Suguru Ito ◽  
Manami Okuno ◽  
Masatoshi Asami
Keyword(s):  
Nmr Spectroscopy ◽  
H Nmr ◽  
Nmr Signals

Enantiomeric 1H NMR signals of chiral anions are separated by forming 1 : 1 and 1 : 2 host–guest complexes with chiral bisurea.

Synthesis and antiaromatic character of alkyl-substituted di-peri-dinaphthoporphyrin Ni(II) complex

2017 ◽  
Vol 21 (12) ◽  
pp. 850-856 ◽  
Author(s):  
Masataka Umetani ◽  
Koji Naoda ◽  
Takayuki Tanaka ◽  
Atsuhiro Osuka
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Potential Difference ◽  
Planar Structure ◽  
H Nmr ◽  
Antiaromatic Character ◽  
Homo Lumo ◽  
Nmr Signals

Antiaromatic molecules have recently been proven to display unique properties such as small HOMO–LUMO gaps, ambipolar carrier transporting and [Formula: see text]-stack-induced aromatic stabilizations. These intriguing properties have been demonstrated by stable antiaromatic molecules that exhibit a distinct antiaromatic character. Di-peri-dinaphthoporphyrins are peripherally [Formula: see text]-extended porphyrinoids that exhibit a planar structure and a distinct antiaromatic character stemming from their 24[Formula: see text] electron circuit. Herein, we report an alkyl-substituted di-peri-dinaphthoporphyrin Ni(II) complex 5Ni bearing less peripheral bulkiness as compared with phenyl-substituted ones. 5Ni displayed upfield-shifted [Formula: see text]H NMR signals due to [Formula: see text]-protons, indicating its distinct antiaromaticity, and a slightly shorter intermolecular packing distance (ca. 3.402 Å) in the solid state. Cyclic voltammetry shows a larger potential difference between the first and second oxidation waves, implying that this molecule tends to stack favorably in its oxidized state.

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