We explore the influence of two solvents, namely water and the ionic liquid 1-ethyl-3-methylimidazolium acetate (EmimAc), on the conformations of two cellulose models (cellobiose and a chain of 40 glucose units) and the solvent impact on glycosidic bond cleavage by acid hydrolysis by using molecular dynamics and metadynamics simulations. We investigate the rotation around the glycosidic bond and ring puckering, as well as the anomeric effect and hydrogen bonds, in order to gauge the effect on the hydrolysis mechanism. We find that EmimAc eases hydrolysis through stronger solvent-cellulose interactions, which break structural and electronic barriers to hydrolysis. Our results indicate that hydrolysis in cellulose chains should start from the ends and not in the centre of the chain, which is less accessible to solvent.
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http://dx.doi.org/10.1002/chem.201405507 | DOI Listing |
Molecules
January 2025
School of Environment and Public Health, Xiamen Huaxia University, Xiamen 361024, China.
In this study, we present the HOAc-catalyzed selective cleavage of the C=C double bond of enaminones, enabling the formation of a new C-N bond and a new C=N bond for the one-pot synthesis of 2-substituted 3,4-dihydroquinazolines directly from ynones and 2-(aminomethyl)anilines. This method operates in ethanol under transition-metal-free and oxidant-free conditions, offering a sustainable and efficient approach for the synthesis of 3,4-dihydroquinazolines with broad functional group tolerance.
View Article and Find Full Text PDFNat Mater
January 2025
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
Van der Waals materials display rich structural polymorphs with distinct physical properties. An atomistic understanding of the phase-transition dynamics, propagation pathway and associated evolution of physical properties is essential for capturing their potential in practical technologies. However, direct visualization of the rapid phase-transition process is fundamentally challenging due to the inherent trade-offs among atomic resolution, field of view and imaging frame rate.
View Article and Find Full Text PDFNat Commun
January 2025
School of Materials Science and Chemical Engineering, Institute of Drug Discovery Technology, Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, PR China.
C-C bond cleavage and recombination provide an efficient strategy for the modification and reconstruction of molecule structures. Herein, we present a method for achieving amidation of aryl C(sp)-H bond through the cleavage and recombination of C-C triple bond with the involvement of nitrous acid esters. This method marks the instance of precise and controlled stepwise cleavage of C-C triple bond, offering a fresh perspective for the cleavage of such bonds.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Anhui Normal University, School of Chemistry and Materials Science, 189 Jiuhua South Road, 241002, Wuhu, CHINA.
Achieving axially chiral biaryl dialdehydes through asymmetric catalysis remains significantly challenging due to the lack of efficient strategies. In this report, we developed a rhodium-catalyzed enantioselective C-H amidation through chiral transient directing group strategy. With this new approach, a series of axially chiral amido dialdehydes were achieved in up to 86% yields with 99.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Department of Chemistry, Western University, 1151 Richmond St, London, ON, N8K 3G6, Canada.
Studies that independently investigate [M]-C transmetalation reactions using two different metals are uncommon and yet understanding this reactivity is important to unlocking new synthetic approaches and product classes. Here, we show that the strained [Fe]-C complex, [(η-CMe-CH)Fe(diphosphine)] undergoes transmetalation with rhodium(I) and iridium(I) diolefin salts, leading to rapid Fe-C(sp) bond cleavage and M-C(sp) (M = Rh or Ir) bond generation.
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