A water-soluble, enantiopure lanthanide complex, SSS-[Ln x L3], has been assessed as an effective chiral derivatizing agent for the determination of the enantiomeric purity of alpha-hydroxy acids in aqueous solution. The complex displays superior chemical shift non-equivalence (DeltaDeltadelta approximately 2-11 ppm) for the diastereomeric resonances of interest compared to lanthanide shift reagents reported in the literature (DeltaDeltadelta <0.1 ppm, typically). 1H NMR studies have also revealed that SSS-[Ln x L3] can be used to determine the absolute configuration of alpha-amino acids at physiological pH, in water. The ability of SSS-[Ln x L3] to signal anion binding and, in particular, to distinguish between diastereomers through optical techniques such as lanthanide luminescence and circular dichroism has also been assessed.
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http://dx.doi.org/10.1039/b513814k | DOI Listing |
J Org Chem
December 2024
Department of Pharmacy, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
Nine new structurally diverse filicinic acid-based meroterpenoids (-) with four kinds of carbon skeletons were isolated from the rhizomes of . Their structures, including the absolute configurations, were elucidated by comprehensive analysis of spectroscopic data, quantum chemical calculations, and single-crystal X-ray diffraction. Structurally, compounds - feature an unprecedented 6/6/5/6/6/6 hexacyclic system with a rare oxaspiro[4.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Kraków 30-387, Poland.
Oxidized derivatives of cholesterol play an important role in the functioning of biomembranes. Unlike other biomolecules, which are physiologically active in only one enantiomeric form, some oxysterols exist endogenously as two stereoisomers that exhibit strictly different biological effects. In this paper, we focused our attention on 22-hydroxycholesterol (22-OH) epimers, 22()-OH and 22()-OH, and examined their properties in Langmuir monolayers spread at the air/water interface, using classical surface manometry complemented with Brewster angle microscopy (BAM) images of the film texture.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy.
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View Article and Find Full Text PDFMolecules
December 2024
Faculty of Medicine, The John Paul II Catholic University of Lublin, Konstantynów 1J/4.03, 20-708 Lublin, Poland.
Improved methods for the synthesis of nicotine are of great importance due to the wide range of applications of synthetic nicotine, which is free from contamination with nitrosamines. Herein, we present a four-step chemical synthesis of ()-nicotine, involving the reduction in myosmine, enantiomeric separation of nornicotine, and subsequent methylation of the appropriate enantiomer of nornicotine obtained. The reduction in myosmine was investigated using both electrochemical and chemical approaches, achieving up to 90% yields of pure nornicotine.
View Article and Find Full Text PDFPlants (Basel)
November 2024
Biodiversidad de Ecosistemas Tropicales-BIETROP, Herbario HUTPL, Departamento de Ciencias Biológicas y Agropecuarias, Universidad Técnica Particular de Loja (UTPL), San Cayetano s/n, Loja 1101608, Ecuador.
L., commonly known as sweet pea, is a plant with a distinctive aroma that can develop in various habitats. An analysis of the aromatic profile of the species was conducted using the HS-SPME (solid-phase microextraction headspace) technique.
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