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Recent advances in transition-metal-free C–H functionalization of imidazo[1,2-a]pyridines

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Green Synthesis and Catalysis

Green Synthesis and Catalysis 2022年第3期3卷 227-242页

作者： Linlin Shi Tiantian Li guang-jian mei Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450001China

Imidazo[1,2-a]pyridines are unique nitrogen-containing organic compounds with wide applications in pharma-ceuticals,natural products,material science and organometallics.Due to their significant biological and synthetic value,the construction of imidazo[1,2-a]pyridine scaffolds has been a highly intriguing research topic,and substantial progress had been made in the past decades.In this review,we aim to summarize the current advances in direct C–H functionalization of imidazo[1,2-a]pyridines under transition-metal-free conditions.For the selected examples,we focused on the design and catalytic cycle mechanism,as well as on representative outcomes and applications.

关键词： Imidazo[1,2-a]pyridines Transition metal-free Iodo-mediated Organocatalyst Oxidant-mediated Base-mediated Catalyst-free

Diastereodivergent formal[4+1]cycloaddition of azoalkenes as one-carbon synthons

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绿色合成与催化(英文)

绿色合成与催化(英文) 2023年第3期4卷 258-262页

作者： Chun-Yan Guan Tian-Jiao Han Shi-Kun Jia Yuan-Zhao Hua guang-jian mei Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou 450001China

The first diastereodivergent formal[4+1]cycloaddition reactions of azoalkenes with p-quinone methides(pQMs)have been accomplished.The reported reaction occurred via a domino oxa-1,4-addition/1,6-addition process,allowing the use of common azoalkenes as C1 synthons.A broad range of 2,3-dihydrobenzofurans was smoothly prepared in good yields and with reversible diastereoselectivities.The steric hindrance and hydrogenbonding interaction were proposed to account for the two different modes of diastereo-control.The projected reaction features the employment of azoalkene as carbene-like C1 synthon,mild conditions,broad substrate scope and tunable diastereoselectivity.

关键词： Azoalkene One-carbon synthon Diastereodivergent [4+1]Cycloaddition para-Quinone methides

Azo group-enabled metal-and oxidant-free alkenyl C-H thiolation:Access to stereodefined tetrasubstituted acyclic olefins

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绿色合成与催化(英文)

绿色合成与催化(英文) 2023年第1期4卷 67-70页

作者： Hao-Jie Gao Yu-Hang Miao Shi-Kun Jia Na Li Li-Ping Xu Wei Wang Min-Can Wang guang-jian mei Green Catalysis Center And College of ChemistryZhengzhou UniversityZhengzhou 450001China School of Chemistry and Chemical Engineering Shandong University of TechnologyZibo 255000China Department of Pharmacology and Toxicology Department Chemistry and BiochemistryUniversity of Arizona Cancer CenterBIO5 InstituteUniversity of ArizonaArizona 85721United States

Metal-and oxidant-free alkenyl C–H thiolation enabled by the azo group had been established for the modular synthesis of tetrasubstituted acyclic olefins.The reaction was performed under mild reaction conditions with a broad substrate scope.The intramolecular 6-membered hydrogen-bonding network accounts for the observed excellent stereo-control.

关键词： Tetrasubstituted acyclic olefins Azo group C-H thiolation Metal-free

Design and Application of Indole-Based Allylic Donors for Pd-Catalyzed Decarboxylative Allylation Reactions

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Chinese Journal of Chemistry 2020年第12期38卷 1612-1618页

作者： Qing-Qing Hang Si-Jia Liu Lei Yu Ting-Ting Sun Yu-Chen Zhang guang-jian mei Feng Shi School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhouJiangsu 221116China

of main observation and conclusion A new class of indole-based allylic donors have been designed and developed for palladium-catalyzed decarboxylative allylations.In addition,the first application of these indole-based allylic donors in palladium-catalyzed decarboxylative[3+2]cydoaddition and allylic amination has been achieved by reacting with isocyanates and sulfonyl amines,respectively.This approach represents the first design of indole-based allylic donors,which is helpful for settling the challenge of designing and developing new class of heterocycle-based allylic donors for Pd-catalyzed decarboxylative allylation reactions.Moreover,the application of this new class of allylic donors in cycloadditions and substitutions will add new contents to the research field of decarboxylative allylation.

关键词： palladium catalyzed allyl

Metadherin promotes stem cell phenotypes and correlated with immune infiltration in hepatocellular carcinoma

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World Journal of Gastroenterology 2024年第8期30卷 901-918页

作者： Yi-Ying Wang mei-mei Shen jian Gao Department of Gastroenterology The Second Affiliated Hospital of Chongqing Medical UniversityChongqing 400010China Department of Gastroenterology and Hepatology The Second Affiliated Hospital of Chongqing Medical UniversityChongqing 400010China

BACKGROUND Metadherin(MTDH)is a key oncogene in most cancer types,including hepato-cellular carcinoma(HCC).Notably,MTDH does not affect the stemness pheno-type or immune infiltration of HCC.AIM To explore the role of MTDH on stemness and immune infiltration in HCC.METHODS MTDH expression in HCC tissues was detected using TCGA and GEO databases.Immunohistochemistry was used to analyze the tissue samples.MTDH was stably knocked down or overexpressed by lentiviral transfection in the two HCC cell lines.The invasion and migration abilities of HCC cells were evaluated using Matrigel invasion and wound healing assays.Next,we obtained liver cancer stem cells from the spheroids by culturing them in a serum-free medium.Gene expression was determined by western blotting and quantitative reverse transcri-ption PCR.Flow cytometry,immunofluorescence,and tumor sphere formation assays were used to characterize stem-like cells.The effects of MTDH inhibition on tumor growth were evaluated in vivo.The correlation of MTDH with immune cells,immunomodulators,and chemokines was analyzed using ssGSEA and TISIDB databases.RESULTS HCC tissues expressed higher levels of MTDH than normal liver tissues.High MTDH expression was associated with a poor prognosis.HCC cells overex-pressing MTDH exhibited stronger invasion and migration abilities,exhibited a stem cell-like phenotype,and formed spheres;however,MTDH inhibition attenuated these effects.MTDH inhibition suppressed HCC progression and CD133 expression in vivo.MTDH was positively correlated with immature dendritic,T helper 2 cells,central memory CD8^(+)T,memory B,activated dendritic,natural killer(NK)T,NK,activated CD4^(+)T,and central memory CD4^(+)T cells.MTDH was negatively correlated with activated CD8^(+)T cells,eosinophils,activated B cells,monocytes,macrophages,and mast cells.A positive correlation was observed between the MTDH level and CXCL2 expression,whereas a negative correlation was observed between the MTDH level and CX3CL1 and CXCL12 expression.CONCLUSION High levels of M

关键词： Metadherin Hepatocellular carcinoma Cancer stem cells Immune infiltration

Establishment of a cholangiocarcinoma risk evaluation model based on mucin expression levels

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1344-1360页

作者： Chun-Yuan Yang Li-mei Guo Yang Li guang-Xi Wang Xiao-Wei Tang Qiu-Lu Zhang Ling-Fu Zhang jian-Yuan Luo Department of Pathology Institute of Systems BiomedicineSchool of Basic Medical Sciences Peking UniversityPeking University Third HospitalPeking University Health Science CenterBeijing 100191China Department of General Surgery Peking University Third HospitalBeijing 100191China Department of Medical Genetics Department of Biochemistry and BiophysicsSchool of Basic Medical Sciences Peking UniversityPeking University Health Science CenterBeijing 100191China

BACKGROUND Cholangiocarcinoma(CCA)is a highly malignant cancer,characterized by frequent mucin overexpression.MUC1 has been identified as a critical oncogene in the progression of CCA.However,the comprehensive understanding of how the mucin family influences CCA progression and prognosis is still incomplete.AIM To investigate the functions of mucins on the progression of CCA and to establish a risk evaluation formula for stratifying CCA patients.METHODS Single-cell RNA sequencing data from 14 CCA samples were employed for elucidating the roles of mucins,complemented by bioinformatic analyses.Subse-quent validations were conducted through spatial transcriptomics and immuno-histochemistry.The construction of a risk evaluation model utilized the least absolute shrinkage and selection operator regression algorithm,which was further confirmed by independent cohorts and diverse data types.RESULTS CCA tumor cells with elevated levels of MUC1 and MUC4 showed activated nucleotide metabolic pathways and increased invasiveness.MUC5AC-high cells were found to promote CCA progression through WNT signaling.MUC5B-high cells exhibited robust cellular oxidation activities,leading to resistance against antitumoral treatments.MUC13-high cells were observed to secret chemokines,recruiting and transforming macrophages into the M2-polarized state,thereby suppressing antitumor immunity.MUC16-high cells were found to promote tumor progression through interleukin-1/nuclear factor kappa-light-chain-enhancer of activated B cells signaling upon interaction with neutrophils.Utilizing the expression levels of these mucins,a risk factor evaluation formula for CCA was developed and validated across multiple cohorts.CCA samples with higher risk factors exhibited stronger metastatic potential,chemotherapy resistance,and poorer prognosis.CONCLUSION Our study elucidates the functional mechanisms through which mucins contribute to CCA development,and provides tools for risk stratification in CCA.

关键词： Mucin Cholangiocarcinoma Single-cell RNA sequencing Spatial transcriptomics Prognosis

Experimental study on the size effect on the equation of state of concretes under shock loading

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Defence Technology（防务技术） 2024年第3期33卷 160-167页

作者： mei Li jian Cui Yanchao Shi Baijian Tang Xin Chen Key Laboratory of Coast Civil Structural Safety of the Ministry of Education Tianjin UniversityTianjin 300072China School of Civil Engineering Suzhou University of Science and Technology1701 Binhe RoadSuzhou 215011JiangsuChina School of Civil Engineering Tianjin UniversityTianjin 300072China

Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which depicts the shear properties of concrete.The experiments on the EoS of concrete is always challenging due to the technical difficulties and equipment limitations,especially for the specimen size effect on the EoS.Although some researchers investigate the shock properties of concretes by fly-plate impact tests,the specimens used in their tests are usually in one size.In this paper,the fly-plate impact tests on concrete specimens with different sizes are performed to investigate the size effect on the shock properties of concrete materials.The mechanical background of the size effect on the shock properties are revealed,which is related to the lateral rarefaction effect and the deviatoric stress produced in the specimen.According to the tests results,the modified EoS considering the size effect on the shock properties of concrete are proposed,which the bulk modulus of concrete is unpredicted by up to 20% if size effects are not accounted for.

关键词： Concrete Equation of state Size effect Shock wave Fly-plate impact test

Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

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Journal of Iron and Steel Research(International) 2024年第4期31卷 849-860页

作者： guang-mei Yang Cheng Yuan Chang Liu Qiang Wang guang-qiang Li Yong-shun Zou Ao Huang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

关键词： MgO-Cr_(2)O_(3)-based refractory MgO-MgAl O_(4)-based refractory Nonmetallic inclusion Erosion interface layer Steel penetration

Cage-confinement synthesis of MoC nanoclusers as efficient sulfiphilic and lithiophilic regulator for superior Li–S batteries

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Rare Metals 2024年第2期43卷 624-634页

作者： Xing-Yuan Zhang mei-Na Lei Shan Tian jian-Gan Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi’an710072China

High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation.In this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is demonstrated.The sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite growth.As a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are achieved.This study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.

关键词： Li-S batteries Nanocluster Electrocatalyst Polysulfide shuttle Li dendrites