IDENTIFICAÇÃO DE PRODUTOS DA OXIDAÇÃO DE ÓLEOS COMESTÍVEIS ATRAVÉS DA ESPECTROSCOPIA DE RMN DE 1H / IDENTIFICATION OF OXIDATION PRODUCTS IN EDIBLE OIL BY MEANS OF 1H NMR SPECTROSCOPY

An electron-deficient series of 1,2,4-triazines and quinazoline have been used for cross-dehydrogenative coupling with 1,3-dihydroxy and 1,3-dimethoxyxanthones to give stable nucleophilic addition products. The adducts and their subsequent oxidation products were obtained in good yields and the structures of the compounds were confirmed by 1H NMR spectroscopy. These results expand the scope of the methodology of nucleophilic substitution of hydrogen with the participation of xanthones with azines. Moreover, this methodology makes it possible to obtain new organic materials based on xanthones, which have a wide spectrum of biological activity.

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Interlaboratory Comparison Test as an Evaluation of Applicability of an Alternative Edible Oil Analysis by 1H NMR Spectroscopy

Journal of AOAC International ◽

10.5740/jaoacint.17-0063 ◽

2017 ◽

Vol 100 (6) ◽

pp. 1819-1830 ◽

Cited By ~ 2

Author(s):

Elina Zailer ◽

Ulrike Holzgrabe ◽

Bernd W K Diehl

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Interlaboratory Comparison ◽

Edible Oils ◽

Lipid Analysis ◽

Spectroscopic Method ◽

Edible Oil ◽

Oil Analysis ◽

Edible Oil Analysis

Abstract A proton (1H) NMR spectroscopic method was established for the quality assessment of vegetable oils. To date, several research studies have been published demonstrating the high potential of the NMR technique in lipid analysis. An interlaboratory comparison was organized with the following main objectives: (1) to evaluate an alternative analysis of edible oils by using 1H NMR spectroscopy; and (2) to determine the robustness and reproducibility of the method. Five different edible oil samples were analyzed by evaluating 15 signals (free fatty acids, peroxides, aldehydes, double bonds, and linoleic and linolenic acids) in each spectrum. A total of 21 NMR data sets were obtained from 17 international participant laboratories. The performance of each laboratory was assessed by their z-scores. The test was successfully passed by 90.5% of the participants. Results showed that NMR spectroscopy is a robust alternative method for edible oil analysis.

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Study of Molecular Interaction in Binary Mixtures of Poly (Propylene Glycol) Monobutyl Ether(PPGMBE) 1000 with 2-(Methylamino) Ethanol (MAE) and 1-Butanol using Thermodynamic and 1H NMR Spectroscopy

International Conference on Machine Learning, Electrical and Mechanical Engineering (ICMLEME'2014) Jan. 8-9, 2014 Dubai (UAE) ◽

10.15242/iie.e0114073 ◽

2014 ◽

Keyword(s):

Nmr Spectroscopy ◽

Propylene Glycol ◽

Binary Mixtures ◽

1H Nmr ◽

Molecular Interaction ◽

1H Nmr Spectroscopy ◽

Monobutyl Ether ◽

Glycol Monobutyl Ether ◽

Poly Propylene

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Asymetrical Dimer - allyl-palladiu Complexes II. Data from Infrared Spectra and Chemical Behaviour

Revista de Chimie ◽

10.37358/rc.08.7.1888 ◽

2008 ◽

Vol 59 (7) ◽

Author(s):

Maria Maganu ◽

Filip Chiraleu ◽

Constantin Draghici ◽

Gheorghe Mihai

Keyword(s):

Carbon Monoxide ◽

Nmr Spectroscopy ◽

1H Nmr ◽

Infrared Spectra ◽

Analytical Methods ◽

1H Nmr Spectroscopy ◽

Chemical Behaviour ◽

The Asymmetry ◽

Pd Complexes

The previous data obtained by 1H-NMR spectroscopy established the existence of an asymmetry of the bond between Pd and p-allylic groups, even in the p-allyl-Pd complexes dimers which are considered usually symmetric dimers. The asymmetry of the bond depends by the substitutes of the allylic group. Other analytical methods were investigated for additional proof of the obtained results. Thus, this paper discusses how this asymmetry would be reflected in the infrared spectra and in the reaction of the complexes with carbon monoxide.

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Diastereoselective Reduction of Selected α-substituted β-keto Esters and the Assignment of the Relative Configuration by 1H-NMR Spectroscopy

Current Organocatalysis ◽

10.2174/2213337207666201207212540 ◽

2020 ◽

Vol 07 ◽

Author(s):

Christian Trapp ◽

Corinna Schuster ◽

Chris Drewniok ◽

Dieter Greif ◽

Martin Hofrichter

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Selective Reduction ◽

Reducing Agents ◽

Relative Configuration ◽

Curtius Rearrangement ◽

Keto Esters ◽

Hydroxy Esters ◽

Diastereoselective Reduction

Background:: Chiral β-hydroxy esters and α-substituted β-hydroxy esters represent versatile building blocks for pheromones, β-lactam antibiotics and 1,2- or 1,3-aminoalcohols. Objective:: Synthesis of versatile α-substituted β-keto esters and their diastereoselective reduction to the corresponding syn- or anti-α-substituted β-hydroxy esters. Assignment of the relative configuration by NMR-spectroscopy after a CURTIUS rearrangement of α-substituted β-keto esters to 4-substituted 5-methyloxazolidin-2-ones. Method:: Diastereoselective reduction was achieved by using different LEWIS acids (zinc, titanium and cerium) in combination with complex borohydrides as reducing agents. Assignment of the relative configuration was verified by 1H-NMR spectroscopy after CURTIUS-rearrangement of α-substituted β-hydroxy esters to 4-substituted 5-methyloxazolidin-2-ones. Results:: For the syn-selective reduction, titanium tetrachloride (TiCl4) in combination with a pyridine-borane complex (py BH3) led to diastereoselectivities up to 99% dr. High anti-selective reduction was achieved by using cerium trichloride (CeCl3) and steric hindered reducing agents such as lithium triethylborohydride (LiEt3BH). After CURTIUS-rearrangement of each α-substituted β-hydroxy ester to the corresponding 4-substituted 5-methyloxazolidin-2-one, the relative configuration was confirmed by 1H NMR-spectroscopy. Conclusion:: We have expanded the procedure of LEWIS acid-mediated diastereoselective reduction to bulky α-substituents such as the isopropyl group and the electron withdrawing phenyl ring.

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Conformational study on ribonucleoside O-phosphonylmethyl derivatives by 1H NMR spectroscopy

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19851899 ◽

1985 ◽

Vol 50 (8) ◽

pp. 1899-1905 ◽

Cited By ~ 4

Author(s):

Milena Masojídková ◽

Jaroslav Zajíček ◽

Miloš Buděšínský ◽

Ivan Rosenberg ◽

Antonín Holý

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Conformational Study ◽

H Nmr ◽

Conformational Properties

Conformational properties of ribonucleoside 5'-O-phosphonylmethyl derivatives have been determined by 1H NMR spectroscopy and compared with those of natural nucleosides and 5'-nucleotides.

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