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991.
Comprehensive Two-dimensional Gas Chromatography for Analysis of the Volatile Compounds and Fishy Odor Off-flavors from Heated Rapeseed Oil 总被引:1,自引:0,他引:1
992.
Origin of the Enantioselectivity in Organocatalytic Michael Additions of β‐Ketoamides to α,β‐Unsaturated Carbonyls: A Combined Experimental,Spectroscopic and Theoretical Study 下载免费PDF全文
Dr. Adrien Quintard Dr. Diana Cheshmedzhieva Dr. Maria del Mar Sanchez Duque Dr. Anouk Gaudel‐Siri Dr. Jean‐Valère Naubron Dr. Yves Génisson Dr. Jean‐Christophe Plaquevent Dr. Xavier Bugaut Prof. Jean Rodriguez Prof. Thierry Constantieux 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):778-790
The organocatalytic enantioselective conjugate addition of secondary β‐ketoamides to α,β‐unsaturated carbonyl compounds is reported. Use of bifunctional Takemoto’s thiourea catalyst allows enantiocontrol of the reaction leading either to simple Michael adducts or spirocyclic aminals in up to 99 % ee. The origin of the enantioselectivity has been rationalised based on combined DFT calculations and kinetic analysis. This study provides a deeper understanding of the reaction mechanism, which involves a predominant role of the secondary amide proton, and clarifies the complex interactions occurring between substrates and the catalyst. 相似文献
993.
A Tris(triazolate) Ligand for a Highly Active and Magnetically Recoverable Palladium Catalyst of Selective Alcohol Oxidation Using Air at Atmospheric Pressure 下载免费PDF全文
Dr. Dong Wang Christophe Deraedt Dr. Lionel Salmon Christine Labrugère Laetitia Etienne Dr. Jaime Ruiz Prof. Didier Astruc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6501-6510
High efficiency and selectivity, easy magnetic recovery and recycling, and use of air as the oxidant at atmospheric pressure are major objectives for oxidation catalysis in terms of sustainable and green processes. A tris(triazolyl) ligand, so far only used in copper‐catalyzed alkyne azide cycloadditions, was found to be extremely efficient in SiO2/γ‐Fe2O3‐immobilized palladium complexes. It was characterized by inductively coupled plasma (ICP) analysis, transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray photoelectron spectra (XPS) and found to fulfill the combined conditions for the selective oxidation of alcohols to aldehydes and ketones. 相似文献
994.
Evaluation of a combined glycomics and glycoproteomics approach for studying the major glycoproteins present in biofluids: Application to cerebrospinal fluid 下载免费PDF全文
995.
996.
Stable Isotope Labeling by Amino acid in Vivo (SILAV): a new method to explore protein metabolism 下载免费PDF全文
997.
12/14/14‐Helix Formation in 2:1 α/β‐Hybrid Peptides Containing Bicyclo[2.2.2]octane Ring Constraints
Dr. Baptiste Legrand Dr. Christophe André Laure Moulat Dr. Claude Didierjean Dr. Patrick Hermet Prof. Jean‐Louis Bantignies Prof. Jean Martinez Dr. Muriel Amblard Dr. Monique Calmès 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):11986-11990
The highly constrained β‐amino acid ABOC induces different types of helices in β urea and 1:1 α/β amide oligomers. The latter can adopt 11/9‐ and 18/16‐helical folds depending on the chain length in solution. Short peptides alternating proteinogenic α‐amino acids and ABOC in a 2:1 α/β repeat pattern adopted an unprecedented and stable 12/14/14‐helix. The structure was established through extensive NMR, molecular dynamics, and IR studies. While the 1:1 α‐AA/ABOC helices diverged from the canonical α‐helix, the helix formed by the 9‐mer 2:1 α/β‐peptide allowed the projection of the α‐amino acid side chains in a spatial arrangement according to the α‐helix. Such a finding constitutes an important step toward the conception of functional tools that use the ABOC residue as a potent helix inducer for biological applications. 相似文献
998.
Christophe J.‐M. Frédéric Dr. Abdellatif Tikad Jian Fu Dr. Weidong Pan Ruixiang B. Zheng Dr. Akihiko Koizumi Dr. Xiaochao Xue Prof. Todd L. Lowary Prof. Stéphane P. Vincent 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15913-15920
This study reports a new methodology to synthesize exo‐glycals bearing both a sulfone and a phosphonate. This synthetic strategy provides a way to generate exo‐glycals displaying two electron‐withdrawing groups and was applied to eight different carbohydrates from the furanose and pyranose series. The Z/E configurations of these tetrasubstituted enol ethers could be ascertained using NMR spectroscopic techniques. Deprotection of an exo‐glycal followed by an UMP (uridine monophosphate) coupling generated two new UDP (uridine diphosphate)‐galactofuranose analogues. These two Z/E isomers were evaluated as inhibitors of UGM, GlfT1, and GlfT2, the three mycobacterial galactofuranose processing enzymes. Molecule 46‐(E) is the first characterized inhibitor of GlfT1 reported to date and was also found to efficiently inhibit UGM in a reversible manner. Interestingly, GlfT2 showed a better affinity for the (Z) isomer. The three enzymes studied in the present work are not only interesting because, mechanistically, they are still the topic of intense investigations, but also because they constitute very important targets for the development of novel antimycobacterial agents. 相似文献
999.
1000.