scholarly journals A Holothurian Triterpene Glycoside Holothurin A2 (= Echinoside A) Isolated From the Starfish Choriaster granulatus

2019 ◽  
Vol 14 (6) ◽  
pp. 1934578X1985852
Author(s):  
Natalia V. Ivanchina ◽  
Anatoly I. Kalinovsky ◽  
Timofey V. Malyarenko ◽  
Alla A. Kicha ◽  
Pavel S. Dmitrenok
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Triterpene Glycoside ◽  
Food Source ◽  
Sea Cucumbers ◽  
The Family ◽  
Esi Mass Spectrometry ◽  
Tropical Sea ◽  
Source Markers

A triterpene glycoside identified as holothurin A2 (= echinoside A) was isolated from the extract of the tropical starfish Choriaster granulatus and identified by extensive nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization (ESI) mass spectrometry techniques. The fact of obtaining this typical for tropical sea cucumbers metabolite in starfish may be explained by feeding of C. granulatus on sea cucumbers of the family Holothuriidae that allows to use triterpene glycosides as food source markers in predators of sea cucumbers.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

Comparison of hydrogenolysis with thioacidolysis for lignin structural analysis

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Daniel J. van de Pas ◽  
Bernadette Nanayakkara ◽  
Ian D. Suckling ◽  
Kirk M. Torr
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Gas Chromatography ◽  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Magnetic Resonance ◽  
Gas Chromatography Mass Spectrometry ◽  
Aryl Ether ◽  
Chromatography Mass Spectrometry

Abstract Mild hydrogenolysis has been compared with thioacidolysis as a method for degrading lignins in situ and in isolated form before analysis by gas chromatography/mass spectrometry and quantitative 31P nuclear magnetic resonance (NMR) spectroscopy. Both degradation methods gave similar levels of β-aryl ether-linked phenylpropane units that were released as monomers. Degradation by hydrogenolysis generally gave lower levels of total phenylpropane units when analyzed by 31P NMR, especially in the case of lignins with high levels of condensed units. Overall, these results indicate that mild hydrogenolysis could offer an alternative to thioacidolysis for probing lignin structure.

scholarly journals Argentate(i) and (iii) complexes as intermediates in silver-mediated cross-coupling reactions

2018 ◽  
Vol 54 (40) ◽  
pp. 5086-5089 ◽  
Author(s):  
Sebastian Weske ◽  
Richard A. Hardin ◽  
Thomas Auth ◽  
Richard A. J. O’Hair ◽  
Konrad Koszinowski ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Esi Mass Spectrometry

Silver-mediated cross-coupling reactions proceed via anionic ate complexes, which have been characterized by a combination of NMR spectroscopy, ESI mass spectrometry, and quantum-chemical calculations.

scholarly journals Special Issue: NMR-Based Metabolomics

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3283
Author(s):  
Miriam Pérez-Trujillo ◽  
Toby J. Athersuch
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Dynamic Range ◽  
Chemical Information ◽  
Special Issue ◽  
The Core ◽  
Analytical Platforms ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) spectroscopy remains one of the core analytical platforms for metabolomics, providing complementary chemical information to others, such as mass spectrometry, and offering particular advantages in some areas of research on account of its inherent robustness, reproducibility, and phenomenal dynamic range [...]

Characterization of cyclodextrin complexes of camostat mesylate by ESI mass spectrometry and NMR spectroscopy

2009 ◽  
Vol 938 (1-3) ◽  
pp. 192-197 ◽  
Author(s):  
Soonho Kwon ◽  
Woonhyoung Lee ◽  
Hye-Jin Shin ◽  
Sung-il Yoon ◽  
Yun-tae Kim ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Cyclodextrin Complexes ◽  
Esi Mass Spectrometry

scholarly journals Dudley Howard Williams. 25 May 1937 — 3 November 2010

2017 ◽  
Vol 63 ◽  
pp. 567-583
Author(s):  
Jeremy K. M. Sanders ◽  
Dame Carol V. Robinson
Keyword(s):  
Organic Chemistry ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Molecular Recognition ◽  
Mode Of Action ◽  
Academic Research ◽  
Spectroscopic Methods ◽  
Structural Problems

Dudley Williams was a pioneer in using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) to solve important structural problems in Chemistry and Biology. His 35-year quest to understand the structure and mode of action of the vancomycin antibiotics led him to fundamental thinking about the nature and thermodynamics of molecular recognition, in particular the roles of solvation, flexibility, entropy, enthalpy and cooperativity. He was always keen that his expertise be used for practical benefit through his academic research and industrial consulting. His legacy also includes a set of textbooks that transformed the use of spectroscopic methods in organic chemistry, and a school of former PhD students and postdoctoral colleagues who have themselves made major contributions across a broad swathe of science.

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