Our understanding of the mechanisms of glycopyranosyl transfer that occur in solution, both for the chemical synthesis of complex structures and that for the cleavage of glycosidic bonds has allowed us to design biologically active molecules. Recent efforts on the reactivity of glycopyranosides, which are critical entities in all biological systems, coupled with the advent of modern spectroscopic instrumentation have allowed physical organic chemists to broaden our knowledge of glycosyl transfer reaction transition states, both in solution and for enzyme-catalyzed processes, and of critical high energy intermediates. This review details recent physical organic, kinetic and structural studies that have led to elucidation of several different mechanism for the transfer of glycopyranosyl moieties from various substrates to acceptors, such as water or a sugar hydroxyl group.
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http://dx.doi.org/10.1016/j.cbpa.2019.08.003 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Laboratoire de Géologie, Ecole Normale Supérieure, CNRS, Institut Pierre-Simon Laplace, Université Paris Sciences et Lettres, Paris 75005, France.
The insulative properties of soil organic carbon (SOC) and surface organic layers (moss, lichens, litter) regulate surface-atmosphere energy exchanges in the Arctic through a coupling with soil temperatures. However, a physical description of this process is lacking in many climate models, potentially biasing their high-latitude climate predictions. Using a coupled surface-atmosphere model, we identified a strong feedback loop between soil insulation, surface air temperature, and snowfall.
View Article and Find Full Text PDFChemSusChem
January 2025
Polish Academy of Sciences, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, POLAND.
We demonstrate the application of mechanochemistry in the synthesis of indolone-based photoswitches (hemiindigos, hemithioindigos, and oxindoles) via Knoevenagel condensation reactions. Utilizing ball-milling and an organic base (piperidine) acting as catalyst and solvent for liquid assisted grinding (LAG) conditions, we achieve rapid, solvent-free transformations, obtaining a set of known and previously unreported photoswitches, including highly functional amino acid-based photoswitches, multichromophoric derivatives and photoswitchable cavitands based on resorcin[4]arenes. The reaction under mechanochemical conditions gives moderate-to-high yields and is highly stereoselective leading to Z-isomers of hemiindigos and hemithioindigos and E-isomers of oxindoles.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Tokyo Electron America, Inc., 2400 Grove Blvd., Austin, Texas 78741, United States.
Photoresists are thin film materials designed to transform an optimal image into a mechanical mask. Diverse exposure techniques such as photolithography induce modifications in the exposed areas that result in solubility changes that can then be selectively removed with appropriate agents (developers). Photoresist materials need to keep pace with the increasingly demand for feature size reduction.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Department of Organic Chemistry, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine.
Lipophilicity and acidity/basicity are fundamental physical properties that profoundly affect the compound's pharmacological activity, bioavailability, metabolism, and toxicity. Predicting lipophilicity, measured by (1-octanol-water distribution coefficient logarithm), and acidity/basicity, measured by (negative of acid ionization constant logarithm), is essential for early drug discovery success. However, the limited availability of experimental data and poor accuracy of standard and assessment methods for saturated fluorine-containing derivatives pose a significant challenge to achieving satisfactory results for this compound class.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
State Key Laboratory of Applied Organic Chemistry (SKLAOC), Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China.
Conjugated polymers have attracted extensive attention as semiconducting materials in wearable and flexible electronics. In this study, we utilize atom-economical Knoevenagel reaction to construct two conjugated polymers, PTDPP-CNTT and PFDPP-CNTT, based on dialdehyde-thiophene/furan-flanked diketopyrrolopyrrole (DPP) and 2,2'-(thieno[3,2-b]thiophene-2,5-diyl)diacetonitrile (CNTT). The resulting polymers exhibited suitable highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energy levels, small bandgaps, and broad UV-vis-NIR absorptions (≈400-1000 nm), endowing them with photothermal and balanced ambipolar semiconducting properties with hole and electron mobilities over 10 cmVs.
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