10.1016/j.tet.2018.05.005
The research focuses on the development of an effective method to prepare optically pure stereoisomers of the IDO1 inhibitor NLG919. The study involves the chiral resolution of the racemic intermediate 2 using di-p-toluoyl-L-tartaric acid (L-7) in a dichloromethane and n-pentane solvent system. The absolute configurations of the stereoisomers were determined through electronic circular dichroism (ECD) spectra, quantum-chemical calculations, and transition metal methods. The pharmacological evaluation revealed that the S configuration at the C5 position is crucial for the IDO1 inhibitory activity, while the stereochemistry at the C2’ position has less impact.
10.1007/BF02496342
The study investigates the influence of the acid-base properties of alumina supports on the performance of 12-tungstophosphoric heteropolyacid (HPWA)-supported catalysts containing platinum in n-pentane isomerization. The study employs DRIFT spectroscopy to analyze the interaction of HPWA with alumina and fluorinated alumina supports. It reveals that the Pt/HPWA/Al2O3 system is nearly inactive due to the interaction of HPWA with basic sites on alumina, leading to partial decomposition of HPWA. In contrast, fluorinated alumina, which has enhanced acidic sites, prevents HPWA destruction and promotes uniform HPWA distribution on the support surface. This results in significantly improved activity and selectivity for the Pt/HPWA/Al2O3-F catalyst in n-pentane isomerization. The study highlights the importance of support properties in determining the catalytic behavior of HPWA-based systems and demonstrates that fluorination can enhance the acidic properties of alumina supports, thereby improving the performance of HPWA catalysts in alkane isomerization.
10.1016/j.molcata.2010.09.006
The study presents the preparation and evaluation of ruthenium nanoparticles supported on multi-walled carbon nanotubes (RuL-MWCNT) for their catalytic efficiency in hydrogenation reactions. The nanoparticles were synthesized using a ligand stabilization method and characterized by elemental analysis and transmission electronic microscopy. The catalytic performance of the supported RuL-MWCNT was compared with non-supported ruthenium nanoparticles and ruthenium nanoparticles supported on other materials like silica, alumina, and activated carbon. The study found that the RuL-MWCNT catalyst demonstrated superior activity and selectivity in converting various unsaturated substrates to fully hydrogenated products, maintaining its catalytic behavior even after recycling. The support's nature significantly influenced the catalytic activity, with MWCNT showing the best results among the tested supports. The study concludes that the RuL-MWCNT system is an effective catalyst for hydrogenation processes, offering high activity, selectivity, and recyclability.
10.1039/c2dt30448a
The research focuses on the utilization of a bifunctional frustrated Lewis pair (FLP), specifically 1-[bis(pentafluorophenyl)boryl]-3,5-di-tert-butyl-1H-pyrazole (1), for the fixation of carbon dioxide (CO2) and related small molecules. The study explores the reactivity of this FLP with CO2, paraformaldehyde, tert-butyl isocyanate, tert-butyl isothiocyanate, methyl isothiocyanate, benzonitrile, and phenylacetylene, resulting in the formation of zwitterionic, bicyclic boraheterocycles (adducts 3–8) and other complexes (adducts 9 and 10). The experiments involved treating the FLP with these reactants in toluene solutions, followed by stirring, solvent evaporation, and in some cases, washing with pentane to isolate the products. The molecular structures of the products were established using X-ray diffraction analyses, and Density Functional Theory (DFT) calculations at the M06-2X/6-311++G(d,p) level of theory were performed to understand the energetics of the CO2 fixation process. The analyses included NMR (1H, 13C, 11B, and 19F), IR spectroscopy, and elemental analysis to characterize the products and confirm the fixation of the small molecules.
10.1016/j.jorganchem.2008.01.023
The research delves into the reaction pathway for the formation of trimethylsiloxysilyllithium compounds, specifically (Me3SiO)RR'SiLi, starting from the corresponding trimethylsiloxychlorosilanes (Me3SiO)RR'SiCl in the presence of excess lithium in a mixture of THF/diethyl ether/n-pentane at -110°C. The purpose of the study was to explore the mechanism of formation, including the yield and stability of these compounds. The research concluded that the formation of these compounds involves an initial reaction of siloxychlorosilanes with lithium, followed by partial coupling with more siloxychlorosilanes to form siloxydisilanes, and bimolecular self-condensation to afford siloxydisilanyllithium compounds. These intermediates can then be cleaved by excess lithium to regenerate silyl lithium compounds. A variety of chemicals were used in the process, including siloxychlorosilanes with different substituents, lithium metal, solvents such as tetrahydrofuran (THF), diethyl ether, and n-pentane, and chlorodimethylsilane as a reaction terminator.
F+,
Xn,
F,
N
F+:Highly flammable;
