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Difluoroalkylative carbonylation of alkenes to access carbonyl difluoro-containing heterocycles:convenient synthesis of gemigliptin

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Science China Chemistry 2023年第1期66卷 139-146页

作者： Zhi-Peng bao Youcan Zhang le-Cheng Wang Xiao-Feng Wu Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China leibniz-Institut für Katalyse e.V.Albert-Einstein-Straße 29a Rostock 18059Germany

Fluorinated heterocycles play a vital role in pharmaceutical and agrochemical industries.Hence,rapid and efficient construction of fluorinated heterocycles remains highly demanded.Herein,a difluoroalkylative carbonylative cyclization of unactivated alkenes and ethylene gas enabled by palladium catalysis has been developed for the first time toward the synthesis ofα-carbonyl difluoro-modified glutarimides.This procedure can also be applied to the synthesis of Ge Migliptin which is a medicine approved for the treatment of type 2 diabetes mellitus.

关键词： difluoroalkylative carbonylative unactivated alkenes ethylene gas heterocycles

Prediction of mechanical properties of cold rolled strip based on improved extreme random tree

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Journal of Iron and Steel Research(International) 2023年第2期30卷 293-304页

作者： Yun-bao Zhao Yong Song Fei-fei Li Xian-le Yan Institute of Engineering Technology University of Science and Technology BeijingBeijing100083China

Taking the 2130 cold rolling production line of a steel mill as the research object,feature dimensionality reduction and decoupling processing were realized by fusing random forest and factor analysis,which reduced the generation of weak decision trees while ensured its diversity.The base learner used a weighted voting mechanism to replace the traditional average method,which improved the prediction accuracy.Finally,the analysis method of the correlation between steel grades was proposed to solve the problem of unstable prediction accuracy of multiple steel grades.The experimental results show that the improved prediction model of mechanical properties has high accuracy:the prediction accuracy of yield strength and tensile strength within the error of±20 MPa reaches 93.20%and 97.62%,respectively,and that of the elongation rate under the error of±5%has reached 96.60%.

关键词： Cold strip rolling Mechanical property prediction Extreme random tree Factor analysis Random forest Correlation analysis Steel grade

Construction of enantioenriched eight-membered lactones via Pd-catalyzed asymmetric(6+2)dipolar annulation

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Science China Chemistry 2022年第12期65卷 2437-2443页

作者： bao-Cheng Wang Yi Wei Feng-Ya Xiong bao-le Qu Wen-Jing Xiao Liang-Qiu Lu Key Laboratory of Pesticide&Chemical Biology Ministry of EducationCollege of ChemistryCentral China Normal UniversityWuhan430079China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang453007China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou730000China

Concise synthesis of eight-membered lactones,a kind of medium-sized heterocycles widespread in many bioactive natural products,is highly significant.However,it still remains a challenge due to unfavorable entropic factor and transannular interaction.Herein,we disclose an enantioselective synthesis of eight-membered lactones through a Pd-catalyzed asymmetric(6+2)dipolar annulation of vinyl oxetanes andα-diazo ketones(20 examples,up to 93%yield and 95:5 er).This reaction features simple operation,mild conditions and good enantiocontrol,especially the challenging chiral all-carbon quaternary stereocenter.A newly developed chiral hybrid P,S ligand and the in-situ photo-generation of ketene dipolarophiles are crucial to this success.

关键词： asymmetric catalysis dipolar annulation eight-membered lactone ketene palladium

Self-assembly of nanoparticles at solid-liquid interface for electrochemical capacitors

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Rare Metals 2022年第11期41卷 3591-3611页

作者： Xue Li Chen Chen Qian Niu Nian-Wu Li le Yu bao Wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China StateKey Lab of Organic-Inorganic Composites Beijing UniversityofChemicalTechnologyBeijing100029China

Self-assembly of nanoparticles at solid-liquid interface could be promising to realize the assembled functions for various applications,such as rechargeable batteries,supercapacitors,and electrocatalysis.This review summarizes the self-assembly of the nanoparticles at solid-liquid interface according to the different driving forces of assembly,including hydrophilic-hydrophobic interactions,solvophobic and electrostatic interaction.To be specific,the self-assembly can be divided into the following two types:surfactant-assisted self-assembly and direct self-assembly of Janus particles(inorganic and amphiphilic copolymer-inorganic Janus nanoparticles).Using the emulsion stabilized by nanoparticles as the template,the self-assembly constructed by the interaction of the nanostructure unit(including metal,metal oxide,and semiconductor,etc.)not only possesses the characteristic of nanostructure unit,but also exhibits the excellent assembly performance in electrochemistry aspect.The application of these assemblies in the area of electrochemical capacitors is presented.Finally,the current research progress and perspectives toward the self-assembly of nanoparticles at stabilized solid-liquid interface are proposed.

关键词： Self-assembly Solid-liquid interface Driving force Electrochemical capacitors

Foliar Particulate Matter Distribution in Urban Road System of Beijing, China

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Chinese Geographical Science 2019年第4期29卷 591-600页

作者： bao le MA Keming XU Xiaowu YU Xinxiao Beijing Laboratory of Urban and Rural Ecological Environment College of Soil and Water Conservation Beijing Forestry University Beijing 100083 China State Key Laboratory of Urban and Regional Ecology Research Centre for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Particulate matter(PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is a useful indicator for air PM pollution in road systems. To detect the relationships of foliar PM load with road structures, urbanization, and meteorology in road systems, we studied a widely-planted tree Sophora japonica L. in 100 roads and 10 yards of Beijing, China, and found that the foliar PM loads increased with the distances from the urban centre(DUC) linearly, while decreased with the road density. All-subsets regression analysis indicated that DUC, average monthly relative humidity, average monthly wind speed, and mean annual wind speed were the most important factors in predicting foliar PM load, rather than general situation of buildings and road cleanliness. The monthly relative humidity and monthly wind speed had a negative correlation to foliar PM, while the annual relative humidity and annual wind speed had a positive correlation to foliar PM. Suburban areas and these effective factors should be highlighted in PM control in Beijing.

关键词： distance from the urban centre road width road density relative humidity wind speed number of lanes roadside tree road cleanliness

Spatiotemporal patterns of sediment deposition on the northern slope of the South China Sea in the last 150,000 years

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Journal of Palaeogeography 2021年第3期10卷 399-415页

作者： Zhe Hu bao-Qi Huang le-Jun Liu Na Wang Key Laboratory of Orogenic Belts and Crustal Evolution MOESchool of Earth and Space SciencesPeking UniversityBeijing 100871China Marine Engineering Environment Center First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061Shandong ProvinceChina School of Urban Planning and Design Shenzhen Graduate SchoolPeking UniversityShenzhen 518055Guangdong ProvinceChina

The source-to-sink system of the northern South China Sea(SCS) has been widely discussed during the past few decades. Sr–Nd isotope, clay minerals and trace elements were extensively used as the proxies of sediment provenance, however, still little is known about the transport processes and controlling mechanisms on detailed spatiotemporal scales due to the limitations of these methods. Here we put forward the new provenance proxies RAKand RKCNbased on major element compositions to study the spatiotemporal changes in sediment provenance since 150 ka mainly from four sites, DLW3101, MD12-3429, ZHS-176 and MD12-3432, which are located on the northern SCS continental slope. Our results show that, spatially, the pathways and intensities of contour currents and gravity flows play important roles in sediment transport. For alongslope processes, the South China Sea Branch of Kuroshio Current(SCSBKC) and the Deep Water Current(DWC) transport sediments from southwestern Taiwan,while the Intermediate Water Current(IWC) can carry sediments from Hainan, the Red River or the Indochina Peninsula. For downslope processes, gravity flows transport materials from the Pearl River delta and shelf to the slope. Moreover, seafloor bathymetry influences sediment transport by altering the pathways of ocean currents.Temporally, the impacts of sea level and monsoon rainfall fluctuations are always superimposed over the last 150 ka. Sea level fluctuations could significantly change the distance from the Pearl River estuary to the slope, while variations in the East Asian summer monsoon(EASM) rainfall would affect continental erosion rates in the source regions.

关键词： South China Sea Sediment transport Element composition Ocean current Sea level Quaternary

Macro-physical field of large diameter magnesium alloy billet electromagnetic direct-chill casting:A comparative study

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Journal of Magnesium and Alloys 2020年第3期8卷 716-730页

作者： Yonghui Jia Xingrui Chen Qichi le Hang Wang lei bao Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern University314 MailboxShenyang 110819People's Republic of China

A comprehensive two-dimensional axisymmetric mathematical model that couples transient electromagnetic force with fluid flow,heat transfer,and solidification was established to describe the interaction of multiphysics field during DC casting.The melt flow,heat transfer,and solidification characteristics under differential phase pulse magnetic field and differential phase low-frequency electromagnetic field(DP-PMF and DP-LFEF)were numerically investigated by means of numerical simulation during electromagnetic direct-chill(DC)casting of AZ31 alloy at the same casting conditions.The effects of differential phase electromagnetic fields on Lorentz forces distributions,melt flow,heat transfer,and liquid sump shape were discussed systematically.Based on measured current waveform,the results were compared with those obtained without magnetic field(MF)and under conventional pulse magnetic field(PMF)and low-frequency electromagnetic field(LFEF)under the same conditions.The results show that the application of magnetic fields can significantly change the solidification process of DC casting.Differential phase magnetic fields(DP-LFEF and DP-PMF)can effectively reduce the temperature of the melt in the liquid sump,and the shallower liquid sump depth can be obtained under the differential phase magnetic fields.A large velocity vibration amplitude and a lower temperature are available simultaneously under DP-PMF,resulting in more uniform temperature distribution.

关键词： Magnesium alloy Differential phase magnetic field Low-frequency magnetic field Heat transfer Direct-chill casting Numerical simulation

Different aspects of cognitive function in adult patients with moyamoya disease and its clinical subtypes

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Stroke & Vascular Neurology 2020年第1期5卷 86-96页

作者： Zhiyong Shi Yu-Jie Wen Zheng Huang le-bao Yu Dong Zhang Department of Neurosurgery Beijing Tiantan HospitalCapital Medical UniversityBeijingChina The National Clinical Research Center for Mental Disorders&Beijing Key Laboratory of Mental Disorders&Beijing Institute for Brain Disorders Center of Schizophrenia Beijing Anding HospitalCapital Medical UniversityBeijing100088China Advanced Innovation Center for Human Brain Protection Capital Medical UniversityBeijing100069China Department of Neurosurgery Xiangya HospitalXiangya Hospital Central South UniversityChangshaChina

Objective Although a few reports suggested that cognitive function impairment could be found in adult patients with moyamoya disease(MMD),there were still many aspects that are unclear.The aim of our study was to assess the cognitive function of adult patients with MMD and its clinical subtypes.Methods 49 patients with MMD and 23 healthy controls were asked to take cognitive function tests.Cognitive function tests included IQ,prospective memory(PM),immediate memory(IM),verbal fluency(VF),visual breadth,attention,retrospective memory(RM),Stroop test,Wisconsin Card Sorting Test,Trail-Making Test Part A(TMT-A)and Continuous Performance Test(CPT).Independent t-analysis,one-way analysis of variance and Pearson correlation were used to seek for differences between subgroups and the correlation between cognitive variables.results Compared with healthy controls,adult patients with MMD had a comprehensive cognitive impairment,including IQ,PM,VF,attention,RM,Stroop,CPT and TMT-A,with more serious impairment in PM and attention.PM and RM were separated,indicating that they were independent of each other.Pattern of attention was significantly different from healthy controls.Female patients were better than male patients,where significant differences in PM,IM,Stroop and WCST could be found.The haemorrhagic patients exhibited poorer in the dimension of PM and RM than the ischaemic.The headache subtype exhibited poorer than healthy controls.PM,RM,attention and executive function were moderately correlated with each other.Conclusions Adult patients with MMD had a wide range of cognitive impairment with more serious impairment in memory and attention.Differences in cognitive function existed between the different subtypes of adult MMD.

关键词： patients clinical function

Effects of Nd/Gd value on the microstructures and mechanical properties of Mg-Gd-Y-Nd-Zr alloys

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Journal of Magnesium and Alloys 2016年第3期4卷 214-219页

作者： Xuan Liu Zhiqiang Zhang Qichi le lei bao Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern University314MailboxShenyang 1100819China

Four Mg–Gd–Y–Nd–Zr alloys were prepared by mold casting to investigate the effects of Nd/Gd ratios on microstructures and mechanical properties.The as-cast alloys mainly consist ofα-Mg andβ-Mg5(GdYNd).Volume fractions of the second phase increase and grains were slightly refined with the rising Nd/Gd ratio,when the alloying addition is equal.Meanwhile,fibers of second phase also increase in the extruded alloys when the Nd/Gd value increases.However,the Nd/Gd ratio could hardly influence the mechanical properties of the extruded alloys.The aging hardening response of the extruded alloy differs due to different Nd/Gd ratios.The potential mechanisms have also been discussed in detail.

关键词： Mg-Gd-Y-Nd-Zr alloy Microstructure Inverted extrusion Heat treatment Mechanical properties