A simple synthesis of highly functionalized 2,5-diaminofurans based pyrimidine derivatives from 1-（carboxymethyl）uracil via a multi-component reaction is described. The reactive 1：1 intermediate produced from the r...A simple synthesis of highly functionalized 2,5-diaminofurans based pyrimidine derivatives from 1-（carboxymethyl）uracil via a multi-component reaction is described. The reactive 1：1 intermediate produced from the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped at room temperature by 1-（carboxymethyl）uracil derivatives to yield polyfunctio- nalized furan rings in fairly good yields.展开更多
Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable ...Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable strategy for constructing new carbon-oxygen bonds.In comparison with traditional thermal or metal-mediated carbene transfer reactions,visible-light-promoted multi-component reaction strategy provides a mild and eco-friendly approach to access densely functionalized molecules.Recently,visible-light-induced multi-component carbene transfer reactions of diazo compounds have been rapidly developed and attracted a great deal of research interest of chemists owing to their advantages of simple operation,mild condition,high atom economy and rich structural diversity.This paper summarizes the recent research progress on the visible-light-promoted multi-component carbene transfer reactions of diazo compounds via ring-opening of cyclic ethers with various nucleophiles.The reaction patterns of different nucleophiles and their corresponding mechanism are described in this review.The future research direction and challenges in this area are also discussed.展开更多
The sulfation and decomposition process has proven effective in selectively extracting lithium from lepidolite.It is essential to clarify the thermochemical behavior and kinetic parameters of decomposition reactions.A...The sulfation and decomposition process has proven effective in selectively extracting lithium from lepidolite.It is essential to clarify the thermochemical behavior and kinetic parameters of decomposition reactions.Accordingly,comprehensive kinetic study by employing thermalgravimetric analysis at various heating rates was presented in this paper.Two main weight loss regions were observed during heating.The initial region corresponded to the dehydration of crystal water,whereas the subsequent region with overlapping peaks involved complex decomposition reactions.The overlapping peaks were separated into two individual reaction peaks and the activation energy of each peak was calculated using isoconversional kinetics methods.The activation energy of peak 1 exhibited a continual increase as the reaction conversion progressed,while that of peak 2 steadily decreased.The optimal kinetic models,identified as belonging to the random nucleation and subsequent growth category,provided valuable insights into the mechanism of the decomposition reactions.Furthermore,the adjustment factor was introduced to reconstruct the kinetic mechanism models,and the reconstructed models described the kinetic mechanism model more accurately for the decomposition reactions.This study enhanced the understanding of the thermochemical behavior and kinetic parameters of the lepidolite sulfation product decomposition reactions,further providing theoretical basis for promoting the selective extraction of lithium.展开更多
Metal halide perovskites(MHPs)with striking electrical and optical properties have appeared at the forefront of semiconductor materials for photocatalytic redox reactions but still suffer from some intrinsic drawbacks...Metal halide perovskites(MHPs)with striking electrical and optical properties have appeared at the forefront of semiconductor materials for photocatalytic redox reactions but still suffer from some intrinsic drawbacks such as inferior stability,severe charge-carrier recombination,and limited active sites.Heterojunctions have recently been widely constructed to improve light absorption,passivate surface for enhanced stability,and promote charge-carrier dynamics of MHPs.However,little attention has been paid to the review of MHPs-based heterojunctions for photocatalytic redox reactions.Here,recent advances of MHPs-based heterojunctions for photocatalytic redox reactions are highlighted.The structure,synthesis,and photophysical properties of MHPs-based heterojunctions are first introduced,including basic principles,categories(such as Schottky junction,type-I,type-II,Z-scheme,and S-scheme junction),and synthesis strategies.MHPs-based heterojunctions for photocatalytic redox reactions are then reviewed in four categories:H2evolution,CO_(2)reduction,pollutant degradation,and organic synthesis.The challenges and prospects in solar-light-driven redox reactions with MHPs-based heterojunctions in the future are finally discussed.展开更多
The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titaniumcontaining and silicon-containing minerals during the Bayer digestion process were investigated.Thermodynamic analys...The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titaniumcontaining and silicon-containing minerals during the Bayer digestion process were investigated.Thermodynamic analysis,artificial mineral experiments,and an evaluation of the digestion effect of natural diasporic bauxite were conducted.The results indicate that hydrogarnet shows a preferential reaction with anatase,and this preference becomes more pronounced as the silicon saturation coefficient increases.In contrast,quicklime participates in non-selective reactions with both anatase and desilication products(DSP).The preference of hydrogarnet for anatase significantly enhances the utilization efficiency of CaO in the high-temperature Bayer digestion process.展开更多
During the oxygen evolution reaction(OER),reconstruction of transition metal sulfides(TMSs)is inevitable.However,the lack of a clear theoretical understanding of this process has impeded the development of effective r...During the oxygen evolution reaction(OER),reconstruction of transition metal sulfides(TMSs)is inevitable.However,the lack of a clear theoretical understanding of this process has impeded the development of effective reconstruction regulation strategies.In this study,we first explored the reconstruction mechanism of CoS_(2)during OER from the perspective of electronic structure and identified two possible pathways:the OH-assisted mechanism and the O-assisted mechanism.Further verification showed that these mechanisms are universally applicable to other TMSs(e.g.,FeS_(2)).Based on the reconstruction mechanism,we investigated the basic reasons for the influence of various regulation strategies,such as vacancy modification and facet engineering,on the reconstruction ability.This verified that the method of analyzing the change in the reconstruction ability of catalysts based on the reconstruction mechanism has a high degree of applicability.Importantly,we proposed a core regulation strategy:the coordination symmetry regulation strategy.Specifically,by breaking the symmetry of the surface coordination environment of TMSs(such as introducing heteroatom doping or strain),the reconstruction process will be facilitated.Our findings provide a comprehensive mechanistic explanation for the reconstruction of TMS catalysts and offer a new idea for the rational design of OER catalysts with controllable reconstruction capacity.展开更多
A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employ...A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employing 4Cz IPN as the metal-free photocatalyst and dioxygen(air) as the environmentally benign oxidant. A number of sulfonated quinoxalin-2(1H)-ones were obtained in satisfactory yields with favorable functional group tolerance. Radical trapping experiment and fluorescence quenching experiments were performed to elucidate this visible-light mediated radical reaction process.展开更多
An efficient,convenient and environmentally benign procedure for the synthesis of novel 3-oxo-3Hbenzo[a]pyrano[2.3-c]phenazine-l-carboxylate and 3-（5-hydroxybenzo[a]phenazin-6-yl） acrylate derivatives has been devel...An efficient,convenient and environmentally benign procedure for the synthesis of novel 3-oxo-3Hbenzo[a]pyrano[2.3-c]phenazine-l-carboxylate and 3-（5-hydroxybenzo[a]phenazin-6-yl） acrylate derivatives has been developed by domino three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione,benzene-1,2-diamines and acetylenic esters in the presence of a catalytic amount of DABCO as an expedient,eco-friendly and reusable base catalyst in water.This green process produces biologically and pharmacologically significant heterocycles in a one-pot single operation and offers considerable advantages such as：operational simplicity,short reaction time,high yields,reusability of catalyst,absence of any tedious workup or purification and avoids hazardous reagents/solvents.展开更多
An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.Thi...An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.This method is applied to the primary fragments of antisymmetrized molecular dynamics(AMD)simulations for ^(46)Fe+^(46)Fe,^(40)Ca+^(40)Ca and ^(48)Ca+^(48)Ca at 35 MeV/nucleon,in order to make direct comparison to the results from the K(N,Z)method of Ono et al.In our improved method,the extracted values of a_(sym)/T increase as the size of isotopes increases whereas,in the K(N,Z)method,the results show rather constant behavior.This increase in our result is attributed to the surface contribution of the symmetry energy in finite nuclei.In order to evaluate the surface contribution,the relation a_(sym)/T=[a_(sym)^((V))(1-k_(S/V) A^(-1/3))]/T is applied and k_(S/V)=1.20~1.25 was extracted.This value is smaller than those extracted from the mass table,reflecting the weakened surface contribution at higher temperature regime.Δμ/T,the difference of the neutron-proton chemical potentials relative to the temperature,is also extracted in this method at the same time.The average values of the extractedΔμ/T,Δμ/T show a linear dependence on the proton-neutron a_(sym)metry parameter of the system,δ_(sys),andΔμ/T=(15.1±0.2)δ_(sys)-(0.5±0.1)is obtained.展开更多
An efficient and novel procedure for the preparation of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or cyanoacetate in [bmim][B...An efficient and novel procedure for the preparation of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or cyanoacetate in [bmim][BF4] is described in this paper. Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.展开更多
Oxonium ylide intermediates generated from α-diazocarbonyl compounds and water were trapped by Zn（Ⅱ）-activated α- dicarbonyl compounds. The reaction gave α,β-dihydroxyl acid derivatives in moderate yield.
α-Trifluoromethyl ketones are a class of useful compounds with versatile applications.Their synthetic application via the transformation of the C—F bonds is of particular interest by allowing the synthesis of organi...α-Trifluoromethyl ketones are a class of useful compounds with versatile applications.Their synthetic application via the transformation of the C—F bonds is of particular interest by allowing the synthesis of organic compounds with diverse structures.Herein,the advances in the research areas ofα-trifluoromethyl ketone synthesis and their defluorination reactions are reviewed.Discussion on the mechanisms of the typical reactions has also been provided,in hope of affording some guides to the chemistry ofα-trifluoromethyl ketones in the synthetic methods toward themselves and their derivatives.展开更多
An expedient,synthetic method to fused polycyclic derivatives of isoquinoline is described via tandem reaction of isoquinoline,dialkyl acetylenedicarboxylates and dialkyl chloromalonate.
Li-rich oxides are considered as promising candidate cathode materials for high-energy Li-ion batteries due to their high specific capacity.However,the widespread adoption of Li-rich materials is hindered because of t...Li-rich oxides are considered as promising candidate cathode materials for high-energy Li-ion batteries due to their high specific capacity.However,the widespread adoption of Li-rich materials is hindered because of the lack of a stable surface structure to inhibit interfacial side reactions.In this study,a stable LiF@spinel dual shell was constructed on the surface of Li-rich materials,in which spinel is formed by in situ surface recon-struction,and LiF is bonded to the spinel through the Ni–F bond.The spinel serves as a buffer layer between the LiF coating and the Li-rich oxide,providing a three-dimensional Li-ion diffusion channel to improve the Li-ion diffusion coefficient,while the outer LiF plays a critical role in isolating the cathode from the electrolyte.Under the abovementioned dual effect,the interfacial side reactions of Li-rich materials are inhibited,thereby improving their cycle stability.The obtained LiF@spinel-coated Li-rich cathode exhibits an enhanced capacity retention of 81.5%after 150 cycles at a current density of 2 C,which is better than the pristine Li-rich sample(63.2%).These findings indicate that the construction of the LiF@spinel dual shell is a successful strategy for the modification of Li-rich materials.展开更多
A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficie...A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.展开更多
Three efficient methods for the synthesis of a series of Cu(Ⅱ) and Cu(Ⅰ) complexes based on imidazo[1,5-a]pyridine derivatives were developed.These methods include the following:(ⅰ)Cu(Ⅱ) salts were used as metal s...Three efficient methods for the synthesis of a series of Cu(Ⅱ) and Cu(Ⅰ) complexes based on imidazo[1,5-a]pyridine derivatives were developed.These methods include the following:(ⅰ)Cu(Ⅱ) salts were used as metal sources and N,N-dimethylformamide was employed as a solvent as well as a reductant to produce Cu(Ⅰ) complexes.(ⅱ) An iodide-containing compound was utilized as a ligand and iodide source to prepare complexes.An in situ metalligand reaction occurred and an iodide-bridged copper complex was generated.(ⅲ) A series of aldehydes were added to the reaction systems to induce in situ metal-ligand reactions between the aldehydes and the imidazo[1,5-a]pyridine derivatives,producing polydentate ligand scaffolds.Eight complexes were prepared and characterized.The catalytic activities of these complexes toward the ketalization of ketones by ethylene glycol were investigated.With the exception of complex4,the remaining seven complexes all showed high catalytic activity.The lower activity of 4 may be due to the larger radius of bridging iodide ions and the shorter Cu(Ⅰ)…Cu(Ⅰ) distance.CCDC:2357696,1·2CH_(2)Cl_(2);2357697,2;2018292,3;2092192,4;2092190,5;2155557,6;2406155,7;2406156,8·EtOH.展开更多
Chiral carbonyl compounds frequently occur in natural products and pharmaceuticals. Additionally, they serve as important intermediates in organic synthesis. Transition metal-catalyzed asymmetric carbonylative cross-c...Chiral carbonyl compounds frequently occur in natural products and pharmaceuticals. Additionally, they serve as important intermediates in organic synthesis. Transition metal-catalyzed asymmetric carbonylative cross-coupling reactions are among the most straightforward and effective methods for synthesizing chiral carbonyl compounds, including esters, amides, and ketones. The advances in asymmetric carbonylative cross-coupling reactions using various O-, N-, C-, and S-containing nucleophiles or electrophiles over the past decade are summarized.展开更多
Paclitaxel is one of the commonly used drugs in postoperative chemotherapy for ovarian cancer patients. However, affected by drug dosage and individual differences in the course of medication, patients will have diffe...Paclitaxel is one of the commonly used drugs in postoperative chemotherapy for ovarian cancer patients. However, affected by drug dosage and individual differences in the course of medication, patients will have different degrees of adverse reactions, which will cause damage to the patient’s body once they occur. This paper retrospectively analyzed the clinical data of patients with severe allergic reactions such as fecal incontinence and numbness of hands and feet caused by the use of paclitaxel liposome during postoperative chemotherapy in a case of ovarian cancer admitted to our hospital. The causes and corresponding treatment measures were analyzed, in order to provide the reference for medical staff to take effective countermeasures in advance in the future.展开更多
Chiral quaternary phosphonium salts have recently been extensively developed as robust organic catalysts for asymmetric synthesis.Asymmetric addition reactions have been dominating in the chiral phosphonium salt-catal...Chiral quaternary phosphonium salts have recently been extensively developed as robust organic catalysts for asymmetric synthesis.Asymmetric addition reactions have been dominating in the chiral phosphonium salt-catalyzed construction of stereogenic carbon centers,heteroatom centers,axes and planes.The recent achievements in the chiral phosphonium-catalyzed asymmetric addition reactions are summarized.展开更多
The investigation of reaction kinetics is the key to understanding the nature of reaction processes.However,monitoring fast photochemical reactions by mass spectrometry remains challenging.Herein,we developed an optic...The investigation of reaction kinetics is the key to understanding the nature of reaction processes.However,monitoring fast photochemical reactions by mass spectrometry remains challenging.Herein,we developed an optical focusing inductive electrospray(OF-iESI)mass spectrometry platform for real-time and in-situ photoreaction monitoring.Coaxial irradiation from back of nanoelectrospray emitter with a taper section was utilized,so the emitter could act as optical lens to help achieving much larger optical power density at emitter tip compared to other sections,which allowed for in-situ reaction monitoring of photoreactions.Through theoretical calculations,the highest optical power density region volume was ca.45 nL.We also integrated a controller for the laser source(450 nm),enabling the modulation of pulse duration(>1 ms).This facilitates the study of photochemical reaction kinetics.The in-situ capability of this device was proved by capturing the short-lived photogenerated intermediates during the dehydrogenation of tetrahydroquinoline.This device was further used to investigate the kinetics of triplet energy transfer based Paternò-Büchi reaction.The reaction order has hitherto remained undetermined while the result of OF-iESI suggested it followed pseudo-second-order reaction kinetics.The short-lived donor-acceptor collision complex intermediate was also successfully identified by tandem mass spectrometry.展开更多
基金supported by the Research Council of the University of Mazandaran,Iran
文摘A simple synthesis of highly functionalized 2,5-diaminofurans based pyrimidine derivatives from 1-（carboxymethyl）uracil via a multi-component reaction is described. The reactive 1：1 intermediate produced from the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped at room temperature by 1-（carboxymethyl）uracil derivatives to yield polyfunctio- nalized furan rings in fairly good yields.
基金Science and Technology Foundation of Guizhou Province(No.QKHJC-ZK[2024]654)Guizhou Provincial University Key Laboratory of Advanced Functional Electronic Materials(No.QJ[2023]021).
文摘Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable strategy for constructing new carbon-oxygen bonds.In comparison with traditional thermal or metal-mediated carbene transfer reactions,visible-light-promoted multi-component reaction strategy provides a mild and eco-friendly approach to access densely functionalized molecules.Recently,visible-light-induced multi-component carbene transfer reactions of diazo compounds have been rapidly developed and attracted a great deal of research interest of chemists owing to their advantages of simple operation,mild condition,high atom economy and rich structural diversity.This paper summarizes the recent research progress on the visible-light-promoted multi-component carbene transfer reactions of diazo compounds via ring-opening of cyclic ethers with various nucleophiles.The reaction patterns of different nucleophiles and their corresponding mechanism are described in this review.The future research direction and challenges in this area are also discussed.
基金financially supported by the National Natural Science Foundation of China(Nos.52034002 and U2202254)the Fundamental Research Funds for the Central Universities,China(No.FRF-TT-19-001)。
文摘The sulfation and decomposition process has proven effective in selectively extracting lithium from lepidolite.It is essential to clarify the thermochemical behavior and kinetic parameters of decomposition reactions.Accordingly,comprehensive kinetic study by employing thermalgravimetric analysis at various heating rates was presented in this paper.Two main weight loss regions were observed during heating.The initial region corresponded to the dehydration of crystal water,whereas the subsequent region with overlapping peaks involved complex decomposition reactions.The overlapping peaks were separated into two individual reaction peaks and the activation energy of each peak was calculated using isoconversional kinetics methods.The activation energy of peak 1 exhibited a continual increase as the reaction conversion progressed,while that of peak 2 steadily decreased.The optimal kinetic models,identified as belonging to the random nucleation and subsequent growth category,provided valuable insights into the mechanism of the decomposition reactions.Furthermore,the adjustment factor was introduced to reconstruct the kinetic mechanism models,and the reconstructed models described the kinetic mechanism model more accurately for the decomposition reactions.This study enhanced the understanding of the thermochemical behavior and kinetic parameters of the lepidolite sulfation product decomposition reactions,further providing theoretical basis for promoting the selective extraction of lithium.
基金financially supported by National Natural Science Foundation of China(No.22302155)the Fundamental Research Funds of the Center Universities(No.D5000240188)the research program of ZJUT(YJY-ZS-20240001)。
文摘Metal halide perovskites(MHPs)with striking electrical and optical properties have appeared at the forefront of semiconductor materials for photocatalytic redox reactions but still suffer from some intrinsic drawbacks such as inferior stability,severe charge-carrier recombination,and limited active sites.Heterojunctions have recently been widely constructed to improve light absorption,passivate surface for enhanced stability,and promote charge-carrier dynamics of MHPs.However,little attention has been paid to the review of MHPs-based heterojunctions for photocatalytic redox reactions.Here,recent advances of MHPs-based heterojunctions for photocatalytic redox reactions are highlighted.The structure,synthesis,and photophysical properties of MHPs-based heterojunctions are first introduced,including basic principles,categories(such as Schottky junction,type-I,type-II,Z-scheme,and S-scheme junction),and synthesis strategies.MHPs-based heterojunctions for photocatalytic redox reactions are then reviewed in four categories:H2evolution,CO_(2)reduction,pollutant degradation,and organic synthesis.The challenges and prospects in solar-light-driven redox reactions with MHPs-based heterojunctions in the future are finally discussed.
基金the financial support from the Natural Science Foundation of Hunan Province,China(No.2022JJ40616)。
文摘The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titaniumcontaining and silicon-containing minerals during the Bayer digestion process were investigated.Thermodynamic analysis,artificial mineral experiments,and an evaluation of the digestion effect of natural diasporic bauxite were conducted.The results indicate that hydrogarnet shows a preferential reaction with anatase,and this preference becomes more pronounced as the silicon saturation coefficient increases.In contrast,quicklime participates in non-selective reactions with both anatase and desilication products(DSP).The preference of hydrogarnet for anatase significantly enhances the utilization efficiency of CaO in the high-temperature Bayer digestion process.
基金supported by the National Key Research and Development program(2022YFA1504000)the National Natural Science Foundation of China(22302101)+4 种基金the Fundamental Research Funds for the Central Universities(63185015)the Shenzhen Science and Technology Program(JCYJ20210324121002007,JCYJ20230807151503007)the Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202402AO370001)the China Postdoctoral Science Foundation(2022M721699)the Guangdong Basic and Applied Basic Research Foundation(2024A1515010347).
文摘During the oxygen evolution reaction(OER),reconstruction of transition metal sulfides(TMSs)is inevitable.However,the lack of a clear theoretical understanding of this process has impeded the development of effective reconstruction regulation strategies.In this study,we first explored the reconstruction mechanism of CoS_(2)during OER from the perspective of electronic structure and identified two possible pathways:the OH-assisted mechanism and the O-assisted mechanism.Further verification showed that these mechanisms are universally applicable to other TMSs(e.g.,FeS_(2)).Based on the reconstruction mechanism,we investigated the basic reasons for the influence of various regulation strategies,such as vacancy modification and facet engineering,on the reconstruction ability.This verified that the method of analyzing the change in the reconstruction ability of catalysts based on the reconstruction mechanism has a high degree of applicability.Importantly,we proposed a core regulation strategy:the coordination symmetry regulation strategy.Specifically,by breaking the symmetry of the surface coordination environment of TMSs(such as introducing heteroatom doping or strain),the reconstruction process will be facilitated.Our findings provide a comprehensive mechanistic explanation for the reconstruction of TMS catalysts and offer a new idea for the rational design of OER catalysts with controllable reconstruction capacity.
基金supported by Youth Innovation and Technology Project of high School in Shandong Province (No. 2019KJC021)Natural Science Foundation of Qinghai Province of China (No. 2020-ZJ-915)。
文摘A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employing 4Cz IPN as the metal-free photocatalyst and dioxygen(air) as the environmentally benign oxidant. A number of sulfonated quinoxalin-2(1H)-ones were obtained in satisfactory yields with favorable functional group tolerance. Radical trapping experiment and fluorescence quenching experiments were performed to elucidate this visible-light mediated radical reaction process.
基金financial support from the Research Council of Young ResearchersElite Club of the Islamic Azad University of YazdUniversity of Sistan and Baluchestan
文摘An efficient,convenient and environmentally benign procedure for the synthesis of novel 3-oxo-3Hbenzo[a]pyrano[2.3-c]phenazine-l-carboxylate and 3-（5-hydroxybenzo[a]phenazin-6-yl） acrylate derivatives has been developed by domino three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione,benzene-1,2-diamines and acetylenic esters in the presence of a catalytic amount of DABCO as an expedient,eco-friendly and reusable base catalyst in water.This green process produces biologically and pharmacologically significant heterocycles in a one-pot single operation and offers considerable advantages such as：operational simplicity,short reaction time,high yields,reusability of catalyst,absence of any tedious workup or purification and avoids hazardous reagents/solvents.
文摘An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.This method is applied to the primary fragments of antisymmetrized molecular dynamics(AMD)simulations for ^(46)Fe+^(46)Fe,^(40)Ca+^(40)Ca and ^(48)Ca+^(48)Ca at 35 MeV/nucleon,in order to make direct comparison to the results from the K(N,Z)method of Ono et al.In our improved method,the extracted values of a_(sym)/T increase as the size of isotopes increases whereas,in the K(N,Z)method,the results show rather constant behavior.This increase in our result is attributed to the surface contribution of the symmetry energy in finite nuclei.In order to evaluate the surface contribution,the relation a_(sym)/T=[a_(sym)^((V))(1-k_(S/V) A^(-1/3))]/T is applied and k_(S/V)=1.20~1.25 was extracted.This value is smaller than those extracted from the mass table,reflecting the weakened surface contribution at higher temperature regime.Δμ/T,the difference of the neutron-proton chemical potentials relative to the temperature,is also extracted in this method at the same time.The average values of the extractedΔμ/T,Δμ/T show a linear dependence on the proton-neutron a_(sym)metry parameter of the system,δ_(sys),andΔμ/T=(15.1±0.2)δ_(sys)-(0.5±0.1)is obtained.
基金the National Natural Science Foundation of China(No.20573034).
文摘An efficient and novel procedure for the preparation of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or cyanoacetate in [bmim][BF4] is described in this paper. Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.
基金supported by National Science Foundation of China(No.20772033)China postdoctoral Science Foundation(No.20080440607)
文摘Oxonium ylide intermediates generated from α-diazocarbonyl compounds and water were trapped by Zn（Ⅱ）-activated α- dicarbonyl compounds. The reaction gave α,β-dihydroxyl acid derivatives in moderate yield.
文摘α-Trifluoromethyl ketones are a class of useful compounds with versatile applications.Their synthetic application via the transformation of the C—F bonds is of particular interest by allowing the synthesis of organic compounds with diverse structures.Herein,the advances in the research areas ofα-trifluoromethyl ketone synthesis and their defluorination reactions are reviewed.Discussion on the mechanisms of the typical reactions has also been provided,in hope of affording some guides to the chemistry ofα-trifluoromethyl ketones in the synthetic methods toward themselves and their derivatives.
基金Sanandaj Branch, Islamic Azad University Research Council for the fnancial support of this research
文摘An expedient,synthetic method to fused polycyclic derivatives of isoquinoline is described via tandem reaction of isoquinoline,dialkyl acetylenedicarboxylates and dialkyl chloromalonate.
基金funded by Science Research Project of Hebei Education Department(Grant No.ZD2022042)the Interdisciplinary Research Program of Hebei University(Grant No.DXK202315)+2 种基金the National Natural Science Foundation of China(NSFC)(Grant Nos.52104304 and 51902081)Central Government Guided Local Science and Technology Development Project of Hebei Province(Grant No.246Z4409G)the Scientific Research and Innovation Team of Hebei University(Grant No.IT2023B07).
文摘Li-rich oxides are considered as promising candidate cathode materials for high-energy Li-ion batteries due to their high specific capacity.However,the widespread adoption of Li-rich materials is hindered because of the lack of a stable surface structure to inhibit interfacial side reactions.In this study,a stable LiF@spinel dual shell was constructed on the surface of Li-rich materials,in which spinel is formed by in situ surface recon-struction,and LiF is bonded to the spinel through the Ni–F bond.The spinel serves as a buffer layer between the LiF coating and the Li-rich oxide,providing a three-dimensional Li-ion diffusion channel to improve the Li-ion diffusion coefficient,while the outer LiF plays a critical role in isolating the cathode from the electrolyte.Under the abovementioned dual effect,the interfacial side reactions of Li-rich materials are inhibited,thereby improving their cycle stability.The obtained LiF@spinel-coated Li-rich cathode exhibits an enhanced capacity retention of 81.5%after 150 cycles at a current density of 2 C,which is better than the pristine Li-rich sample(63.2%).These findings indicate that the construction of the LiF@spinel dual shell is a successful strategy for the modification of Li-rich materials.
基金supported by Sichuan Science and Technology Program(No.2023NSFSC0101)the 2024 Provincial platform project of Chengdu Normal University(No.GNFZ202404)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2021MB065)National Natural Science Foundation of China(No.22101237)。
文摘A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.
文摘Three efficient methods for the synthesis of a series of Cu(Ⅱ) and Cu(Ⅰ) complexes based on imidazo[1,5-a]pyridine derivatives were developed.These methods include the following:(ⅰ)Cu(Ⅱ) salts were used as metal sources and N,N-dimethylformamide was employed as a solvent as well as a reductant to produce Cu(Ⅰ) complexes.(ⅱ) An iodide-containing compound was utilized as a ligand and iodide source to prepare complexes.An in situ metalligand reaction occurred and an iodide-bridged copper complex was generated.(ⅲ) A series of aldehydes were added to the reaction systems to induce in situ metal-ligand reactions between the aldehydes and the imidazo[1,5-a]pyridine derivatives,producing polydentate ligand scaffolds.Eight complexes were prepared and characterized.The catalytic activities of these complexes toward the ketalization of ketones by ethylene glycol were investigated.With the exception of complex4,the remaining seven complexes all showed high catalytic activity.The lower activity of 4 may be due to the larger radius of bridging iodide ions and the shorter Cu(Ⅰ)…Cu(Ⅰ) distance.CCDC:2357696,1·2CH_(2)Cl_(2);2357697,2;2018292,3;2092192,4;2092190,5;2155557,6;2406155,7;2406156,8·EtOH.
文摘Chiral carbonyl compounds frequently occur in natural products and pharmaceuticals. Additionally, they serve as important intermediates in organic synthesis. Transition metal-catalyzed asymmetric carbonylative cross-coupling reactions are among the most straightforward and effective methods for synthesizing chiral carbonyl compounds, including esters, amides, and ketones. The advances in asymmetric carbonylative cross-coupling reactions using various O-, N-, C-, and S-containing nucleophiles or electrophiles over the past decade are summarized.
文摘Paclitaxel is one of the commonly used drugs in postoperative chemotherapy for ovarian cancer patients. However, affected by drug dosage and individual differences in the course of medication, patients will have different degrees of adverse reactions, which will cause damage to the patient’s body once they occur. This paper retrospectively analyzed the clinical data of patients with severe allergic reactions such as fecal incontinence and numbness of hands and feet caused by the use of paclitaxel liposome during postoperative chemotherapy in a case of ovarian cancer admitted to our hospital. The causes and corresponding treatment measures were analyzed, in order to provide the reference for medical staff to take effective countermeasures in advance in the future.
文摘Chiral quaternary phosphonium salts have recently been extensively developed as robust organic catalysts for asymmetric synthesis.Asymmetric addition reactions have been dominating in the chiral phosphonium salt-catalyzed construction of stereogenic carbon centers,heteroatom centers,axes and planes.The recent achievements in the chiral phosphonium-catalyzed asymmetric addition reactions are summarized.
基金financially supported by the National Natural Science Foundation of China(Nos.22104112 and 22374110)the Fundamental Research Funds for the Central Universities。
文摘The investigation of reaction kinetics is the key to understanding the nature of reaction processes.However,monitoring fast photochemical reactions by mass spectrometry remains challenging.Herein,we developed an optical focusing inductive electrospray(OF-iESI)mass spectrometry platform for real-time and in-situ photoreaction monitoring.Coaxial irradiation from back of nanoelectrospray emitter with a taper section was utilized,so the emitter could act as optical lens to help achieving much larger optical power density at emitter tip compared to other sections,which allowed for in-situ reaction monitoring of photoreactions.Through theoretical calculations,the highest optical power density region volume was ca.45 nL.We also integrated a controller for the laser source(450 nm),enabling the modulation of pulse duration(>1 ms).This facilitates the study of photochemical reaction kinetics.The in-situ capability of this device was proved by capturing the short-lived photogenerated intermediates during the dehydrogenation of tetrahydroquinoline.This device was further used to investigate the kinetics of triplet energy transfer based Paternò-Büchi reaction.The reaction order has hitherto remained undetermined while the result of OF-iESI suggested it followed pseudo-second-order reaction kinetics.The short-lived donor-acceptor collision complex intermediate was also successfully identified by tandem mass spectrometry.
