Article
Chemistry, Organic
Jie Wen, Lei Feng, Hongmei Zhao, Li Zheng, Pericles Stavropoulos, Lin Ai, Jiaxin Zhang
Summary: This study successfully established an unconventional enantiomeric discrimination method for hydantoin derivatives, representatives of five-membered N,N-heterocycles, and observed non-equivalent chemical shifts through H-1 NMR spectroscopy. Additionally, theoretical calculations were performed to understand the intermolecular interactions between chiral solvating agents and enantiomers.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Reilly E. Sonstrom, Donald M. Cannon, Justin L. Neill
Summary: Chiral tagging molecular rotational resonance (MRR) spectroscopy has been developed for the chiral analysis of terpenes in complex essential oil mixtures. In this technique, the use of a chiral tag allows for the resolution of enantiomers by creating distinct diastereomeric complexes with unique spectral signatures. The relative stereochemistry of the complexes can be accurately determined by comparing calculated spectroscopic parameters with experimentally determined parameters, allowing for the quantification of absolute configuration and enantiomeric excess of linalool in complex essential oil mixtures without the need for reference samples or chromatographic separation.
Article
Chemistry, Multidisciplinary
Svitlana Kulyk, Susan M. De Paul, Matthew A. Marx, Torren M. Peakman, Christopher R. Smith
Summary: In this study, the chiral phosphoric acid solvating agent (+)-TiPSY was used to distinguish the signals of atropisomers in F-19 NMR, and the data obtained were used to study the kinetics of racemization and determine the rotational energy barrier of clinical compound MRTX1719. This method serves as a complementary approach to traditional chiral high-performance liquid chromatography (HPLC) and enhances the toolkit for chiral analysis techniques.
Article
Chemistry, Multidisciplinary
Pooja Chaudhary, Geeta Devi Yadav, Surendra Singh
Summary: A rapid and simple protocol for determining the enantiopurity of primary and secondary amines using chiral solvating agents and spectroscopic analysis was developed. By mixing the analyte and chiral solvating agent, well-resolved resonance peaks for both enantiomers are obtained quickly. The enantiomeric excess of 1,2-diphenylethylenediamine was successfully determined using this method, and the binding constant and ΔG values for diastereomeric complexes were calculated.
Article
Chemistry, Medicinal
Niklas Feuge, Rene Wilhelm
Summary: New sulfonate-based chiral salts were synthesized from amino alcohols and sodium hydroxymethanesulfonate, vinyl sulfonate, or sultone. The synthesis involved just four steps starting from various amino acids obtained from the chiral pool. After cation metathesis, the salts were used as chiral solvating agents (CSAs) in NMR studies. The chiral ionic liquids (CILs) exhibited interactions with different chiral guest molecules and formed diastereomeric aggregates, sometimes resulting in baseline separation. The impact of structural differences in the CILs and the structural requirements of the guest molecules are discussed.
Article
Chemistry, Multidisciplinary
Xuebo Zhang, Jing Xu, Zhaofeng Sun, Guangling Bian, Ling Song
Summary: A new boric agent, boric acid D, with a bridged structure has been synthesized and used as a highly efficient chiral derivative agent for distinguishing between various diols. The derivatization reaction is fast and complete, easy to operate, and provides accurate measurements of enantiomeric excess (ee) values. The characteristic split NMR signals are well-distinguishable with a large chemical shift difference (up to 0.39 ppm).
Article
Chemistry, Organic
Astha M. Dwivedi, Ashutosh Bedekar
Summary: Four derivatives of chiral bis-thiourea were synthesized from (S)-(1-isocyanatoethyl) benzene and diamines. These bis-thiourea derivatives were used as Chiral Solvating Agents (CSA) for discriminating optically pure acids through 1H NMR spectroscopy. Addition of amine was found necessary for deprotonation of carboxylic acid substrates during NMR experiments. The presented CSA showed effective chiral discrimination of neutral analytes like tetrahydropyrimidine derivatives and good molecular recognition for 1,4-dihydropyridine carboxylic acid, an intermediate of cardiovascular drug Benidipine-HCl and ibuprofen.
Article
Chemistry, Analytical
Alessandra Recchimurzo, Fabio Maccabruni, Gloria Uccello Barretta, Federica Balzano
Summary: The hydrogen-bond accepting and enantiodiscriminating abilities of quinine were utilized to discriminate N-trifluoroacetyl derivatives of amino acids by nuclear magnetic resonance (NMR) spectroscopy. Quinine acted as both an enantiodiscriminating agent and a solubility promoter. The method achieved high-quality enantiodifferentiation and was applied to detect and quantify mixtures of amino acid derivatives using single point measurements.
Article
Chemistry, Organic
Federica Balzano, Anna Iuliano, Gloria Uccello-Barretta, Valerio Zullo
Summary: A new family of chiral selectors was synthesized in a single step, and the influence of different structural features on the enantiodifferentiation was determined. The best chiral solvating agent for separating the enantiomers of the analyte was optimized.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Physics, Applied
H. R. Barnard, G. R. Nash
Summary: The characteristics of four-layer chiral metamaterials, optically active in the mid-infrared region, have been studied through simulations and experiments. The spectral response of the materials can be tailored while maintaining the magnitude of circular dichroism relative to standard double layer metamaterials. Analysis shows that these four-layer structures offer greater design freedom in coupling than expected from simple consideration of double layer structures.
APPLIED PHYSICS LETTERS
(2021)
Article
Plant Sciences
Le Zhou, Rui Guo, Han Zhang, Li-Wei Lu, Ye-Qing Du, Qing-Bo Liu, Xiao-Xiao Huang, Shao-Jiang Song
Summary: Efficient H-1 NMR spectroscopic approaches were developed for assigning the erythro and threo configurations of 1-oxygenated 1,2-diarylpropan-3-ols. The configurations can be rapidly and conveniently determined through chemical shift analysis in different solvents.
JOURNAL OF NATURAL PRODUCTS
(2021)
Article
Chemistry, Physical
Philippe Berdague, Boris Gouilleux, Markus Noll, Stefan Immel, Michael Reggelin, Philippe Lesot
Summary: This study focuses on the molecular factors involved in the orientation/discrimination phenomena of analytes in polymer-based chiral liquid crystals. The researchers propose a method to quantify and compare the enantiodiscrimination power of different polymer-based liquid crystals. The results show that the l-MSP phase exhibits promising enantiodiscrimination capacities.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Gabriel Schnoering, Samuel Albert, Antoine Canaguier-Durand, Cyriaque Genet
Summary: The study investigates the dynamics and energetics of overdamped Brownian chiral nanoparticles diffusing in symmetric bistable optical potentials, created by controlling the polarizations of two counterpropagating Gaussian beams. The chiral densities and fluxes in the optical environment exert reactive or dissipative chiral forces on the nanoparticles, leading to modifications in the thermal activation process depending on enantiomer type and optical field enantiomorphism. This optomechanical chiral coupling results in changes to the Helmholtz free energy and asymmetric barrier-crossing rates, unveiling new opportunities for chiral sensing and discrimination at the nanoscale.
Article
Chemistry, Organic
Puracheth Rithchumpon, Neeranuth Intakaew, Nopawit Khamto, Saranpong Yimklan, Piyarat Nimmanpipug, Praput Thavornyutikarn, Puttinan Meepowpan
Summary: The novel chiral derivatising agents (CDAs) such as methyl itaconate-anthracene adducts (MIAs) were used for determining the absolute configuration of chiral secondary alcohols through H-1 NMR technique. These MIAs were easily prepared from well-known reactions and commercially available starting materials. The desired MIAs were obtained in 6 steps with 49% overall yield from dimethyl itaconate, showing significantly large differences in chemical shift values (Delta delta(SR)) without observed racemisation from the tertiary characteristics of the adjacent alpha carbon.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Gabor Szalontai
Summary: Diffusion-ordered spectroscopy (DOSY) is a 2D NMR method used to separate signals from different species in a mixture, with known limitations in chemical shift and diffusion dimensions. The study focuses on matrix-assisted DOSY approaches, examining the modulation effect of chemical exchange on DOSY maps and the utility of diffusion coefficient-molecular mass correlations. Commercially available small organic molecules were selected as ligands, and the effects of agent/ligand ratios, molecular size ratios, and solvent properties on resolution were investigated. Results show significant effects of exchange processes on diffusion coefficients and predicted molecular masses.
NEW JOURNAL OF CHEMISTRY
(2021)
