A β-Keto Ester as a Novel, Efficient, and Versatile Ligand for Copper(I)-Catalyzed C−N, C−O, and C−S Coupling Reactions

Employing ethyl 2-oxocyclohexanecarboxylate as a novel, efficient, and versatile ligand, the copper-catalyzed coupling reactions of various N/O/S nucleophilic reagents with aryl halides could be successfully carried out under mild conditions. A variety of products including N-arylamides, N-arylimidazoles, aryl ethers, and aryl thioethers were synthesized in good to excellent yields

Copper-Catalyzed Cascade Addition/Cyclization: An Efficient and Versatile Synthesis of <i>N</i>-Substituted 2-Heterobenzimidazoles

A novel and efficient one-pot synthesis of various N-substituted 2-heterobenzimidazoles has been developed. Through a Cu(I)-catalyzed cascade intermolecular addition/intramolecular C−N coupling process, a wide variety of 2-heterobenzimidazoles could be synthesized from o-haloarylcarbodiimides and N- or O-nucleophiles

A β-Keto Ester as a Novel, Efficient, and Versatile Ligand for Copper(I)-Catalyzed C−N, C−O, and C−S Coupling Reactions

Employing ethyl 2-oxocyclohexanecarboxylate as a novel, efficient, and versatile ligand, the copper-catalyzed coupling reactions of various N/O/S nucleophilic reagents with aryl halides could be successfully carried out under mild conditions. A variety of products including N-arylamides, N-arylimidazoles, aryl ethers, and aryl thioethers were synthesized in good to excellent yields

Cu₂O-Catalyzed Tandem Ring-Opening/Coupling Cyclization Process for the Synthesis of 2,3-Dihydro-1,4-benzodioxins

2, 3-Dihydro-1, 4-benzodioxins can be prepared in a tandem one-pot procedure by reaction of o-iodophenols with epoxides catalyzed by Cu2O/1, 10-phenanthroline/Cs2CO3 system. The reaction is suggested to occur via a novel ring-opening/coupling mechanism, giving moderate to good yields. Moreover, both aryl and aliphatic epoxides are tolerated under these conditions

Synthesis of Unsymmetrical 2,2′-Biindolyl Derivatives by a Cu-Catalyzed <i>N</i>-Arylation/Pd-Catalyzed Direct Arylation Sequential Process

A one-pot synthesis of unsymmetrical 2,2′-biindolyl derivatives through a Cu-catalyzed N-arylation/Pd-catalyzed direct arylation sequence was described. The reaction involved easily prepared o-gem-dibromovinyl substrates, and the desired biindolyls were obtained in moderate to good yields

Cu₂O-Catalyzed Tandem Ring-Opening/Coupling Cyclization Process for the Synthesis of 2,3-Dihydro-1,4-benzodioxins

2, 3-Dihydro-1, 4-benzodioxins can be prepared in a tandem one-pot procedure by reaction of o-iodophenols with epoxides catalyzed by Cu2O/1, 10-phenanthroline/Cs2CO3 system. The reaction is suggested to occur via a novel ring-opening/coupling mechanism, giving moderate to good yields. Moreover, both aryl and aliphatic epoxides are tolerated under these conditions

Sustainable Approach for Paraffin Wax Removal Using CO₂ Switchable Solvents

In this work, a sustainable approach for paraffin wax removal by using CO2 switchable-hydrophilicity solvents (SHSs) is developed, where paraffin wax exhibits better solubility in SHSs and can be simply separated by introducing CO2. Here, SHSs exhibit an excellent dissolving capacity for paraffin wax, especially, N,N-dimethylcyclohexylamine (DMCHA). All SHSs can effectively dissolve paraffin wax at a dissolution rate > 0.03 g/min. The detection using differential scanning calorimetry and the rheology behavior demonstrated that the decreased viscosity, melting points, and wax appearance temperature of paraffin wax in SHSs (especially in DMCHA) are lower than in traditional solvents, such as kerosene and petroleum ether, which contributes to improvement in the paraffin wax removal. Furthermore, the polarizing microscope images of paraffin wax reveal that the changed properties of paraffin wax in SHS are attributed to the dispersion of needle-shaped wax crystals in solvent. Interestingly, the paraffin wax is separated from SHS by introducing CO2, and the SHS is recovered under N2 at 65 °C after separating paraffin wax. Here, the recovery of paraffin wax can be improved by increasing water content, temperature, and aeration rate. Based on the molecular dynamics simulation, it is revealed that paraffin wax containing hydrocarbons (the main component of wax) with different alkane carbon numbers exhibits good dissolution behavior in DMCHA. After introducing CO2, the separation of paraffin wax is caused by the transformation from the hydrophobic state to the hydrophilic state of DMCHA

Image_1_A Novel Strategy for Predicting 72-h Mortality After Admission in Patients With Polytrauma: A Study on the Development and Validation of a Web-Based Calculator.tif

BackgroundEarly and accessible screening of patients with polytrauma at a high risk of hospital death is essential. The purpose of this research was to seek an accurate and convenient solution to predict deaths occurring within 72 h after admission of these patients.MethodsA secondary analysis was conducted on 3,075 patients with polytrauma from the Dryad database. We imputed missing values in eligible individuals with the k-nearest neighbor algorithm and then randomly stratified them into the training group (n = 2,461) and the validation group (n = 614) based on a proportion of 8:2. The restricted cubic spline, univariate, backward stepwise, and multivariate logistic regression methods were employed to determine the suitable predictors. Calibration and receiver operating characteristic (ROC) curves were applied to assess the calibration and discrimination of the obtained model. The decision curve analysis was then chosen as the measure to examine the clinical usage.ResultsAge, the Glasgow Coma Scale score, the Injury Severity Score, base excess, and the initial lactate level were inferred as independent prognostic factors related to mortality. These factors were then integrated and applied to construct a model. The performance of calibration plots, ROC curves, and decision curve analysis indicated that the model had satisfactory predictive power for 72-h mortality after admission of patients with polytrauma. Moreover, we developed a nomogram for visualization and a web-based calculator for convenient application (https://songandwen.shinyapps.io/DynNomapp/).ConclusionsA convenient web-based calculator was constructed to robustly estimate the risk of death in patients with polytrauma within 72 h after admission, which may aid in further rationalization of clinical decision-making and accurate individual treatment.</p

Ethanol Inhomogeneous Lean Combustion Under Different Ambient Temperatures and Pressures with Hydrogen Enrichment

The effects of different ambient temperatures and pressures on the combustion of hydrogen-enriched liquid ethanol spray were studied in a constant-volume vessel, using experimental and numerical methods. The inhomogeneous combustion experiment was conducted under ultra-lean conditions at an overall equivalence ratio of 0.3 (33% spray ethanol/67% premixed hydrogen). The spray and flame images and combustion pressures were obtained. The spray simulation models used were the RANS k-ε turbulence model, KH-RT model, and wall film interaction model. The experimental results showed that the inhomogeneous combustion of the liquid ethanol spray can be divided into two stages: a rapid-burning and a slow-burning stage. The slow-burning stage was sensitive to changes in ambient temperature and pressure. Combustion duration decreased with elevated pressure and declined temperature. Under low pressure and medium temperature conditions, the flame reached its fastest propagation speed. The simulation results showed that the fuel concentration and concentration gradient around the ignition position are the key factors that affect inhomogeneous lean combustion. When the equivalence ratio was over 0.8 around the ignition position and the gradient of the equivalence ratio increased no less than 0.1/mm, the optimal combustion characteristics were achieved.</p