(±)Lespedezaflavanone D,8,5'-di(γ,γ-dimethylallyl)-5,7,2',4'-tetrahydroxyflavanone,has been synthesized by the condensation of 4,6-dimethoxymethoxy-3-(γ,γ-dimethylallyl)-2-hydroxy- acetophenone wi...(±)Lespedezaflavanone D,8,5'-di(γ,γ-dimethylallyl)-5,7,2',4'-tetrahydroxyflavanone,has been synthesized by the condensation of 4,6-dimethoxymethoxy-3-(γ,γ-dimethylallyl)-2-hydroxy- acetophenone with 2,4-dimethoxymethoxy-5-(γ,γ-dimethylallyl)benzaldehydc followed by cyclization and demethoxymethylation.展开更多
Recent years,many novel complexes have been prepared by using hetero-bidentate ligands.However,complexes with such ligands as 4-vinylpyridine which has two different coordinating sites have not been reported,and only ...Recent years,many novel complexes have been prepared by using hetero-bidentate ligands.However,complexes with such ligands as 4-vinylpyridine which has two different coordinating sites have not been reported,and only a few complexes of Cu(I)have been published^(1-3).The title complex Cu_2(C_5H_4N·CH=CH_2)_3Cl was prepared and characterized by elemental analyses,ICP,IR,and electronic spectra.Its conductivity,oxidation potential and reduction potential were measured.展开更多
A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride ...A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)展开更多
In this article, using the four-directional core and quaternary carbon branching point, adendritic polyestrone with twelve estrone units was synthesized by convergent strategy. Itsstructure was confirmed by IR and NMR...In this article, using the four-directional core and quaternary carbon branching point, adendritic polyestrone with twelve estrone units was synthesized by convergent strategy. Itsstructure was confirmed by IR and NMR spectra.展开更多
The reactions of nickel group M2+ with thiolate and phosphine inMeOH yield mononuclear and binuclear complexes. Ni2 (PEt3 ), (pdt )2 (pdt = 1, 2propanedithiolate) was synthesized and analyzed by single crystal X--ray ...The reactions of nickel group M2+ with thiolate and phosphine inMeOH yield mononuclear and binuclear complexes. Ni2 (PEt3 ), (pdt )2 (pdt = 1, 2propanedithiolate) was synthesized and analyzed by single crystal X--ray diffractionmethod. The complex is monoclinic with space group P21 /c, Mr= 566. 16 a = 18. 737(5), b=9. 906(4), c= 14. 540(10) A; V=2697. 65 A3, Dc = 1. 394 g/cm3 for Z=4; the final R(Rw) = 0. 062(0. 072). The complex is a dimer, where the Ni atoms arelinked by two sulphur atoms from SC3H6S2- (pdt2- ) ligands and each Ni atom is fourcoordinated by one P and three S atoms with distorted square--planar geometry. The Ni--Ni distance is 3. 025 .A, the average Ni--S, Ni--P distances are 2. 187 and 2. 194A, respectively.展开更多
A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylene...A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylenediamine in the presence pyridine POCl 3 . Three compounds were tested as plant virucide against tobacco mosaic virus and they exhibited some activities.展开更多
(±)Euchrenonc a_8,7,2'-dihydroxy-8,5'-di(γ,γ-dimethylallyl)-4'-methoxyflavanone,has been synthesized by the condensation of 2-hydroxy-4-methoxymethoxy-3-(γ,γ-dimethylallyl) acctophenonc with 4-met...(±)Euchrenonc a_8,7,2'-dihydroxy-8,5'-di(γ,γ-dimethylallyl)-4'-methoxyflavanone,has been synthesized by the condensation of 2-hydroxy-4-methoxymethoxy-3-(γ,γ-dimethylallyl) acctophenonc with 4-methoxy-2-methoxymethoxy-5-(γ,γ-dimethylallyl)benzaldchyde followed by cyclization and demethoxymethylation.展开更多
Euchrcnonc a_7 has been prcparcd by condensation of 2-hydroxy-4- mcthoxy-3-prcnylacctophcnone with 2,4-dimethoxymethoxybenzaldehyde followed by cyclization and demethoxymethylation.
Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynam...Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynamic size and slower degradation.It is key to develop facile methods to large-scale synthesis of polymer rings with tunable compositions and microstructures.Recent progresses in large-scale synthesis of polymer rings against single-chain dynamic nanoparticles,and the example applications in synchronous enhancing toughness and strength of polymer nanocomposites are summarized.Once there is the breakthrough in rational design and effective large-scale synthesis of polymer rings and their functional derivatives,a family of cyclic functional hybrids would be available,thus providing a new paradigm in developing polymer science and engineering.展开更多
We report an immobilized enzyme-catalyzed batch and continuous-flow synthesis of optically pure ethyl(R)-pantothenate((R)-PaOEt),the direct precursor of d-pantothenic acid.Firstly,a ketoreductase mutant designated as ...We report an immobilized enzyme-catalyzed batch and continuous-flow synthesis of optically pure ethyl(R)-pantothenate((R)-PaOEt),the direct precursor of d-pantothenic acid.Firstly,a ketoreductase mutant designated as M2,carrying two-point mutations of F97L and M242F relative to the wild-type SSCR,was constructed by site-directed mutagenesis,exhibited simultaneously improved activity toward ethyl 2′-ketopantothenate(K-PaOEt)and isopropanol,and could effectively catalyze the stereoselective reduction of K-PaOEt to(R)-PaOEt by using isopropanol as the sacrificial co-substrate to regenerate NADPH.After screening six commercially available carriers,an amino resin LXTE-700 was identified as the best solid support for the immobilization of M2 via the glutaraldehyde activation method.Upon optimization of the immobilization process and reaction conditions,the fabricated immobilized enzyme M2@amino resin demonstrated excellent recyclability and reusability,with the complete conversion of K-PaOEt to(R)-PaOEt being still realized after 12 cycles of reuse.Finally,M2@amino resin-catalyzed synthesis of(R)-PaOEt was successfully implemented in continuous-flow,accomplishing a 6.3 times higher space-time yield than that with the batch synthesis(529.2 versus 84 g L^(-1) d^(-1)).Our developed flow biocatalysis system also features an outstanding operational stability,as evidenced by the 100%conversion rate achieved after 15 consecutive days of operation.展开更多
ADPr-ATP is a natural nucleotide with three sugar rings and five pentavalent phosphorus,and can be produced through TIR-catalyzed ADP-ribosylation reactions for plant immunity.Here,we report the first total synthesis ...ADPr-ATP is a natural nucleotide with three sugar rings and five pentavalent phosphorus,and can be produced through TIR-catalyzed ADP-ribosylation reactions for plant immunity.Here,we report the first total synthesis of ADPr-ATP(1)with a total yield of 6.4%through 14 steps,featuring late-stage P(V)−N activation reaction of pyrophosphate(4)and 5′-phosphoromorpholidate(25).The protected adenosine 5′-phosphoromorpholidate(24)was prepared on the basis of a scalable to adenosine 5′′-monophosphate(2).The construction of P(V)−N bond in phosphoramidate is esteemed as a critical step as they are sufficiently stable in deprotection reactions.The chemical synthesis of ADPr-ATP can offer an appealing alternative to traditional enzymatic synthesis and fractionation methods.Furthermore,the pRib-AMP and its prodrug are also synthesized to evaluate cytotoxicity and anti-influenza activity in vitro.展开更多
Transition metal nitrides(TMNs)have been considered as promising alternative catalysts to noble metals in various electrocatalytic applications due to their noble metal-like electronic structures,high conductivity,low...Transition metal nitrides(TMNs)have been considered as promising alternative catalysts to noble metals in various electrocatalytic applications due to their noble metal-like electronic structures,high conductivity,low cost,as well as strong chemical stability,which could resist corrosion and oxidation in harsh operation conditions.Therefore,the rational design and controlled synthesis of TMNs with distinct structures play a vital role in developing highly efficient electrocatalysts toward electrochemical applications.This review provides a comprehensive summary of representative synthetic strategies for TMNs,such as direct nitridation,solidstate reaction,sol-gel assisted reaction,and wet-chemical reaction,presents the distinct structural characterizations,and demonstrates their advances in the electrochemical applications.Finally,we propose the remaining challenges and the future research directions on the exploration of TMNs with well-defined structures for electrocatalytic applications,which could shed light on the future development of high-performance electrocatalysts.展开更多
α-Chiral amides are common in pharmaceuticals,agrochemicals,natural products,and peptides,prompting the need for new synthetic methods.Here,we introduce a nickel-catalyzed asymmetric reductive amidation method to syn...α-Chiral amides are common in pharmaceuticals,agrochemicals,natural products,and peptides,prompting the need for new synthetic methods.Here,we introduce a nickel-catalyzed asymmetric reductive amidation method to synthesizeα-chiral amides from benzyl ammonium salts and isocyanates.The key to success is using a chiral 2,2-bipyridine ligand(-)-Ph-SBpy,enabling high yield(up to 95%)and enantiomeric ratio(up to 98:2 er)under mild conditions.Addition of phenol prevents isocyanate polymerization by reversibly forming a carbamate intermediate,enhancing selectivity and efficiency.The synthetic utility is showcased through transformations of the enantioenriched amides,and the mechanism and enantioselectivity are supported by experimental and computational studies.展开更多
Structural engineering of Pt-based nanoalloys is crucial for the rational design and manufacturing of high-performance and low-cost electrocatalysts for hydrogen evolution reaction(HER).Here,we reported PtNi nanoparti...Structural engineering of Pt-based nanoalloys is crucial for the rational design and manufacturing of high-performance and low-cost electrocatalysts for hydrogen evolution reaction(HER).Here,we reported PtNi nanoparticles with a refined size of 2.71 nm and regular strains loaded on carbon black,synthesized using the high-temperature liquid shock(HTLS)method.This approach offers significant advantages over conventional synthesis methods,including high scalability,rapid reaction rates,and precise control over the size and shape of nanocrystals.Importantly,the synthesized PtNi electrocatalysts demonstrate outstanding catalytic activity and long-term stability for HER,achieving low overpotentials of 19 and 203 mV at current densities of 10 and 1000 mA/cm^(2),respectively.The superior performance can be attributed to the combination of a refined particle size,lattice strains,and synergistic effects between Pt and Ni.This rapid liquid-state synthesis demonstrated here holds great potential for scalable and industrial manufacturing of micro-/nano-catalysts.展开更多
The deuterium labeling has garnered significant interest in drug discovery due to its critical role on improving pharmacokinetic and metabolic properties.However,despite its pharmaceutical value,the general and rapid ...The deuterium labeling has garnered significant interest in drug discovery due to its critical role on improving pharmacokinetic and metabolic properties.However,despite its pharmaceutical value,the general and rapid syntheses of aromatic scaffolds that contains deuterium remain an important yet elusive task.State-of-the-art approaches mainly relied on the transition metal-catalyzed C-H deuteration via the assistance of directing groups(DGs),which often suffered from over-deuteration and lengthy step counts required for installation and/or removal of DG.Herein,we report a generalizable synthetic linchpin strategy for the facile preparation of the ortho-deuterated aromatic core.Through capture of aryne-derived 1,3-zwitterion with heavy water,we synthesized an array of ortho-deuterated aryl sulfonium salts.These novel linchpins not only participated the transition metal catalyzed cross-coupling reaction as nucleophiles,but also served as aryl radical reservoirs under photochemical or electrochemical conditions,enabling facile and precise access to structurally diverse deuterated aromatics.Moreover,we have disclosed a novel EDA complex enabled direct arylation of phosphines under visible-light irradiation,further expanding the utility of our platform approach.展开更多
High temperature stress (HT) significantly reduces maize yield by impairing starch accumulation in kernels.However,the mechanism by which HT affects starch synthesis remains controversial-whether through reduced assim...High temperature stress (HT) significantly reduces maize yield by impairing starch accumulation in kernels.However,the mechanism by which HT affects starch synthesis remains controversial-whether through reduced assimilate supply or direct inhibition on kernel metabolism.To clarify these mechanisms,a heat-sensitive maize hybrid,Xianyu 335 (XY),was exposed to 30℃/20℃ (maximum/minimum temperature,control) and 40℃/30℃ for seven consecutive days during the seed setting stage.Synchronous pollination (SP),apical pollination (AP),and shading treatments were applied to manipulate the inherent source–sink ratio in maize plants.Results showed that apical kernel weight decreased by 11.9%under 40℃ in the SP treatment.The ^(13)C content,starch accumulation,and cell-wall invertase (CWIN) activity also declined by 15.9,36.7,and 16.4%,respectively,under HT.In the shading treatment,40℃/30℃ caused even greater reductions in^(13)C content,starch accumulation,and CWIN activity due to diminished assimilate supply.Conversely,in the AP treatment,starch content and CWIN activity increased by 22.0 and 18.5%,respectively,under 40℃/30℃,resulting in kernel weight and ^(13)C content similar to those in SP and shading treatments regardless of temperature.Consistent with apical kernels under AP,HT did not negatively affect middle kernels in either SP or shading treatments,as kernel weight and starch content remained unchanged under HT.Although all kernels were exposed to the same HT or control environment,their responses varied a lot.The impaired starch synthesis in apical kernels under HT was rescued by increasing carbon supply via AP treatment.The contrasting performance among middle kernels,apical kernels under AP,and apical kernels under SP or shading indicates that reduced carbon supply is a critical factor underlying inhibited starch accumulation.Our findings provide a theoretical basis for further understanding kernel abortion under HT.展开更多
Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for...Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for additional energy input.Enhancing catalyst activity by introducing oxygen vacancies has been used extensively in heterogeneous catalytic ozonation.This paper reviews prevalent methods for the construction and characterization of oxygen vacancies.Based on a thorough examination of existing research,the role of oxygen vacancies is categorized according to their primary mechanisms of action in heterogeneous catalytic ozonation.For example,modulation of the catalyst electronic structure to enhance electron transfer;participation in the reaction as an active site to generate radicals and non-radicals;and exposure of more metal sites to enhance the reaction.Lastly,the paper delineates the limitations and future research directions concerning the role of oxygen vacancies in catalytic ozonation.This review addresses the gap in existing literature concerning the role of oxygen vacancies in catalytic ozone systems,establishes a comprehensive theoretical framework to aid in the design of efficient ozone catalysts,and delves into the functionality of oxygen vacancies in heterogeneous catalytic ozone reactions.展开更多
Pseudomonas aeruginosa is an opportunistic pathogen responsible for severe nosocomial infections.This multidrug-resistant bacterium can cause pneumonia and cystic fibrosis,both of which are associated with high morbid...Pseudomonas aeruginosa is an opportunistic pathogen responsible for severe nosocomial infections.This multidrug-resistant bacterium can cause pneumonia and cystic fibrosis,both of which are associated with high morbidity and mortality rates.The lipopolysaccharide of P.aeruginosa serves as an attractive target for the development of effective glycoconjugate vaccines.In this article,we report the first chemical synthesis of the highly challenging tetrasaccharide repeating unit of the P.aeruginosa serotype O3 O-antigen using a two-directional[1+(2+1)]glycosylation strategy.The synthesis is particularly challenging due to the poor nucleophilicity of the axial C4 hydroxyl group of l-galactose and the steric hindrance imposed by the 3S-hydroxybutyryl(Hb)chain.Furthermore,the presence of an acetyl group at the ortho position relative to the glycosylation site on l-galactose can lead to undesirable acetyl migration.Additionally,it is noteworthy that the selective removal of a 2-naphthylmethyl ether(Nap)during the late stages of synthesis,particularly in the presence of multiple benzyl groups,can be somewhat challenging to predict.Through the careful selection of synthetic strategies,building blocks,and optimized reaction conditions,we achieved the stereoselective glycosylations,selective oxidation of primary alcohols,remarkable enhancement of acceptor activity,and efficient introduction of the 3S-Hb group.The synthetic methodology presented in this work serves as a valuable reference for the preparation of structurally related oligosaccharides.By incorporating an aminopropyl linker,the target tetrasaccharide facilitates glycan microarray preparation and in vivo immunological assessments,thereby accelerating progress toward a synthetic glycoconjugate vaccine for P.aeruginosa.展开更多
For decades,the central dogma of oncology has been that a cancer’s identity is inextricably linked to its anatomical origin.This principle underpins the entire diagnostic and therapeutic framework,from histology-base...For decades,the central dogma of oncology has been that a cancer’s identity is inextricably linked to its anatomical origin.This principle underpins the entire diagnostic and therapeutic framework,from histology-based classification to site-specific treatment guidelines.Yet,this framework catastrophically fails for a substantial population of patients diagnosed with cancer of unknown primary(CUP).These patients present metastatic disease,yet their primary tumors remain elusive despite exhaustive clinical workup1.CUP,accounting for 1%-3%of all cancer diagnoses,is an enigma with devastating consequences;the median overall survival is only 2-12 months2-4.The inability to pinpoint an origin forces clinicians to rely on broad-spectrum empirical chemotherapy,such as taxane-carboplatin regimens,which have limited efficacy and exclude patients from the promise of targeted therapies and clinical trials5.CUP is not only a diagnostic challenge but also an indictment of the siloed approach to understanding malignancy:this cancer highlights the limitations of origin-based diagnostic frameworks.However,the confluence of high-dimensional biological data and advanced artificial intelligence(AI)is now poised to address this long-standing diagnostic limitation and to herald a new era for not only CUP but also oncology as a whole(Figure 1).展开更多
The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,...The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,2].Consequently,organofluorine compounds are frequently encountered in pharmaceuticals and agrochemicals.Significant advances have been made in the introduction of fluoroalkyl groups into small molecules since the beginning of the 21st century.展开更多
文摘(±)Lespedezaflavanone D,8,5'-di(γ,γ-dimethylallyl)-5,7,2',4'-tetrahydroxyflavanone,has been synthesized by the condensation of 4,6-dimethoxymethoxy-3-(γ,γ-dimethylallyl)-2-hydroxy- acetophenone with 2,4-dimethoxymethoxy-5-(γ,γ-dimethylallyl)benzaldehydc followed by cyclization and demethoxymethylation.
文摘Recent years,many novel complexes have been prepared by using hetero-bidentate ligands.However,complexes with such ligands as 4-vinylpyridine which has two different coordinating sites have not been reported,and only a few complexes of Cu(I)have been published^(1-3).The title complex Cu_2(C_5H_4N·CH=CH_2)_3Cl was prepared and characterized by elemental analyses,ICP,IR,and electronic spectra.Its conductivity,oxidation potential and reduction potential were measured.
文摘A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)
文摘In this article, using the four-directional core and quaternary carbon branching point, adendritic polyestrone with twelve estrone units was synthesized by convergent strategy. Itsstructure was confirmed by IR and NMR spectra.
文摘The reactions of nickel group M2+ with thiolate and phosphine inMeOH yield mononuclear and binuclear complexes. Ni2 (PEt3 ), (pdt )2 (pdt = 1, 2propanedithiolate) was synthesized and analyzed by single crystal X--ray diffractionmethod. The complex is monoclinic with space group P21 /c, Mr= 566. 16 a = 18. 737(5), b=9. 906(4), c= 14. 540(10) A; V=2697. 65 A3, Dc = 1. 394 g/cm3 for Z=4; the final R(Rw) = 0. 062(0. 072). The complex is a dimer, where the Ni atoms arelinked by two sulphur atoms from SC3H6S2- (pdt2- ) ligands and each Ni atom is fourcoordinated by one P and three S atoms with distorted square--planar geometry. The Ni--Ni distance is 3. 025 .A, the average Ni--S, Ni--P distances are 2. 187 and 2. 194A, respectively.
文摘A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylenediamine in the presence pyridine POCl 3 . Three compounds were tested as plant virucide against tobacco mosaic virus and they exhibited some activities.
文摘(±)Euchrenonc a_8,7,2'-dihydroxy-8,5'-di(γ,γ-dimethylallyl)-4'-methoxyflavanone,has been synthesized by the condensation of 2-hydroxy-4-methoxymethoxy-3-(γ,γ-dimethylallyl) acctophenonc with 4-methoxy-2-methoxymethoxy-5-(γ,γ-dimethylallyl)benzaldchyde followed by cyclization and demethoxymethylation.
文摘Euchrcnonc a_7 has been prcparcd by condensation of 2-hydroxy-4- mcthoxy-3-prcnylacctophcnone with 2,4-dimethoxymethoxybenzaldehyde followed by cyclization and demethoxymethylation.
基金Supported by the National Natural Science Foundation of China(Nos.52293472,22473096 and 22471164)。
文摘Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynamic size and slower degradation.It is key to develop facile methods to large-scale synthesis of polymer rings with tunable compositions and microstructures.Recent progresses in large-scale synthesis of polymer rings against single-chain dynamic nanoparticles,and the example applications in synchronous enhancing toughness and strength of polymer nanocomposites are summarized.Once there is the breakthrough in rational design and effective large-scale synthesis of polymer rings and their functional derivatives,a family of cyclic functional hybrids would be available,thus providing a new paradigm in developing polymer science and engineering.
基金the Science and Technology R&D Major Project of Jiangxi Province(No.20244AFI92001)the National Natural Science Foundation of China(Nos.22071033 and 21801047)for the financial supports.
文摘We report an immobilized enzyme-catalyzed batch and continuous-flow synthesis of optically pure ethyl(R)-pantothenate((R)-PaOEt),the direct precursor of d-pantothenic acid.Firstly,a ketoreductase mutant designated as M2,carrying two-point mutations of F97L and M242F relative to the wild-type SSCR,was constructed by site-directed mutagenesis,exhibited simultaneously improved activity toward ethyl 2′-ketopantothenate(K-PaOEt)and isopropanol,and could effectively catalyze the stereoselective reduction of K-PaOEt to(R)-PaOEt by using isopropanol as the sacrificial co-substrate to regenerate NADPH.After screening six commercially available carriers,an amino resin LXTE-700 was identified as the best solid support for the immobilization of M2 via the glutaraldehyde activation method.Upon optimization of the immobilization process and reaction conditions,the fabricated immobilized enzyme M2@amino resin demonstrated excellent recyclability and reusability,with the complete conversion of K-PaOEt to(R)-PaOEt being still realized after 12 cycles of reuse.Finally,M2@amino resin-catalyzed synthesis of(R)-PaOEt was successfully implemented in continuous-flow,accomplishing a 6.3 times higher space-time yield than that with the batch synthesis(529.2 versus 84 g L^(-1) d^(-1)).Our developed flow biocatalysis system also features an outstanding operational stability,as evidenced by the 100%conversion rate achieved after 15 consecutive days of operation.
基金supported by the National Natural Science Foundation of China(Nos.82204209 and 82130103)Natural Science Foundation of Henna Province(No.242300421084).
文摘ADPr-ATP is a natural nucleotide with three sugar rings and five pentavalent phosphorus,and can be produced through TIR-catalyzed ADP-ribosylation reactions for plant immunity.Here,we report the first total synthesis of ADPr-ATP(1)with a total yield of 6.4%through 14 steps,featuring late-stage P(V)−N activation reaction of pyrophosphate(4)and 5′-phosphoromorpholidate(25).The protected adenosine 5′-phosphoromorpholidate(24)was prepared on the basis of a scalable to adenosine 5′′-monophosphate(2).The construction of P(V)−N bond in phosphoramidate is esteemed as a critical step as they are sufficiently stable in deprotection reactions.The chemical synthesis of ADPr-ATP can offer an appealing alternative to traditional enzymatic synthesis and fractionation methods.Furthermore,the pRib-AMP and its prodrug are also synthesized to evaluate cytotoxicity and anti-influenza activity in vitro.
基金supported by the National Natural Science Foundation of China(52471219 and 92463305)State Key Laboratory of New Ceramic Materials Tsinghua University(KFZD202402)Fundamental Research Funds for the Central Universities(00007838)。
文摘Transition metal nitrides(TMNs)have been considered as promising alternative catalysts to noble metals in various electrocatalytic applications due to their noble metal-like electronic structures,high conductivity,low cost,as well as strong chemical stability,which could resist corrosion and oxidation in harsh operation conditions.Therefore,the rational design and controlled synthesis of TMNs with distinct structures play a vital role in developing highly efficient electrocatalysts toward electrochemical applications.This review provides a comprehensive summary of representative synthetic strategies for TMNs,such as direct nitridation,solidstate reaction,sol-gel assisted reaction,and wet-chemical reaction,presents the distinct structural characterizations,and demonstrates their advances in the electrochemical applications.Finally,we propose the remaining challenges and the future research directions on the exploration of TMNs with well-defined structures for electrocatalytic applications,which could shed light on the future development of high-performance electrocatalysts.
基金the National Natural Science Foundation of China(Nos.22150410339,W2432012,22301233 and 22171218)the Ministry of Science and Technology China(No.wgxz2022188)。
文摘α-Chiral amides are common in pharmaceuticals,agrochemicals,natural products,and peptides,prompting the need for new synthetic methods.Here,we introduce a nickel-catalyzed asymmetric reductive amidation method to synthesizeα-chiral amides from benzyl ammonium salts and isocyanates.The key to success is using a chiral 2,2-bipyridine ligand(-)-Ph-SBpy,enabling high yield(up to 95%)and enantiomeric ratio(up to 98:2 er)under mild conditions.Addition of phenol prevents isocyanate polymerization by reversibly forming a carbamate intermediate,enhancing selectivity and efficiency.The synthetic utility is showcased through transformations of the enantioenriched amides,and the mechanism and enantioselectivity are supported by experimental and computational studies.
基金supported by the National Natural Science Foundation of China(No.12205165)Hebei Province Innovation Ability Improvement Plan Project(No.225676111H).
文摘Structural engineering of Pt-based nanoalloys is crucial for the rational design and manufacturing of high-performance and low-cost electrocatalysts for hydrogen evolution reaction(HER).Here,we reported PtNi nanoparticles with a refined size of 2.71 nm and regular strains loaded on carbon black,synthesized using the high-temperature liquid shock(HTLS)method.This approach offers significant advantages over conventional synthesis methods,including high scalability,rapid reaction rates,and precise control over the size and shape of nanocrystals.Importantly,the synthesized PtNi electrocatalysts demonstrate outstanding catalytic activity and long-term stability for HER,achieving low overpotentials of 19 and 203 mV at current densities of 10 and 1000 mA/cm^(2),respectively.The superior performance can be attributed to the combination of a refined particle size,lattice strains,and synergistic effects between Pt and Ni.This rapid liquid-state synthesis demonstrated here holds great potential for scalable and industrial manufacturing of micro-/nano-catalysts.
基金supported by the National Natural Science Foundation of China (Nos.22271010 and 21702013)。
文摘The deuterium labeling has garnered significant interest in drug discovery due to its critical role on improving pharmacokinetic and metabolic properties.However,despite its pharmaceutical value,the general and rapid syntheses of aromatic scaffolds that contains deuterium remain an important yet elusive task.State-of-the-art approaches mainly relied on the transition metal-catalyzed C-H deuteration via the assistance of directing groups(DGs),which often suffered from over-deuteration and lengthy step counts required for installation and/or removal of DG.Herein,we report a generalizable synthetic linchpin strategy for the facile preparation of the ortho-deuterated aromatic core.Through capture of aryne-derived 1,3-zwitterion with heavy water,we synthesized an array of ortho-deuterated aryl sulfonium salts.These novel linchpins not only participated the transition metal catalyzed cross-coupling reaction as nucleophiles,but also served as aryl radical reservoirs under photochemical or electrochemical conditions,enabling facile and precise access to structurally diverse deuterated aromatics.Moreover,we have disclosed a novel EDA complex enabled direct arylation of phosphines under visible-light irradiation,further expanding the utility of our platform approach.
基金financially supported by the National Natural Science Foundation of China (32071978)the National Key Research and Development Program of China (2022YFD2300901 and 2022YFD2300905)。
文摘High temperature stress (HT) significantly reduces maize yield by impairing starch accumulation in kernels.However,the mechanism by which HT affects starch synthesis remains controversial-whether through reduced assimilate supply or direct inhibition on kernel metabolism.To clarify these mechanisms,a heat-sensitive maize hybrid,Xianyu 335 (XY),was exposed to 30℃/20℃ (maximum/minimum temperature,control) and 40℃/30℃ for seven consecutive days during the seed setting stage.Synchronous pollination (SP),apical pollination (AP),and shading treatments were applied to manipulate the inherent source–sink ratio in maize plants.Results showed that apical kernel weight decreased by 11.9%under 40℃ in the SP treatment.The ^(13)C content,starch accumulation,and cell-wall invertase (CWIN) activity also declined by 15.9,36.7,and 16.4%,respectively,under HT.In the shading treatment,40℃/30℃ caused even greater reductions in^(13)C content,starch accumulation,and CWIN activity due to diminished assimilate supply.Conversely,in the AP treatment,starch content and CWIN activity increased by 22.0 and 18.5%,respectively,under 40℃/30℃,resulting in kernel weight and ^(13)C content similar to those in SP and shading treatments regardless of temperature.Consistent with apical kernels under AP,HT did not negatively affect middle kernels in either SP or shading treatments,as kernel weight and starch content remained unchanged under HT.Although all kernels were exposed to the same HT or control environment,their responses varied a lot.The impaired starch synthesis in apical kernels under HT was rescued by increasing carbon supply via AP treatment.The contrasting performance among middle kernels,apical kernels under AP,and apical kernels under SP or shading indicates that reduced carbon supply is a critical factor underlying inhibited starch accumulation.Our findings provide a theoretical basis for further understanding kernel abortion under HT.
基金support from the Key R&D Program of Zhejiang province(No.2024C03136).
文摘Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for additional energy input.Enhancing catalyst activity by introducing oxygen vacancies has been used extensively in heterogeneous catalytic ozonation.This paper reviews prevalent methods for the construction and characterization of oxygen vacancies.Based on a thorough examination of existing research,the role of oxygen vacancies is categorized according to their primary mechanisms of action in heterogeneous catalytic ozonation.For example,modulation of the catalyst electronic structure to enhance electron transfer;participation in the reaction as an active site to generate radicals and non-radicals;and exposure of more metal sites to enhance the reaction.Lastly,the paper delineates the limitations and future research directions concerning the role of oxygen vacancies in catalytic ozonation.This review addresses the gap in existing literature concerning the role of oxygen vacancies in catalytic ozone systems,establishes a comprehensive theoretical framework to aid in the design of efficient ozone catalysts,and delves into the functionality of oxygen vacancies in heterogeneous catalytic ozone reactions.
基金the National Key R&D Program of China(No.2023YFC2308000)the National Natural Science Foundation of China(Nos.22478153,22477046,22177041)+2 种基金the Max Planck Society International Partner Group Programthe China Scholarship Council(CSC)the Fundamental Research Funds for the Central Universities for funding.
文摘Pseudomonas aeruginosa is an opportunistic pathogen responsible for severe nosocomial infections.This multidrug-resistant bacterium can cause pneumonia and cystic fibrosis,both of which are associated with high morbidity and mortality rates.The lipopolysaccharide of P.aeruginosa serves as an attractive target for the development of effective glycoconjugate vaccines.In this article,we report the first chemical synthesis of the highly challenging tetrasaccharide repeating unit of the P.aeruginosa serotype O3 O-antigen using a two-directional[1+(2+1)]glycosylation strategy.The synthesis is particularly challenging due to the poor nucleophilicity of the axial C4 hydroxyl group of l-galactose and the steric hindrance imposed by the 3S-hydroxybutyryl(Hb)chain.Furthermore,the presence of an acetyl group at the ortho position relative to the glycosylation site on l-galactose can lead to undesirable acetyl migration.Additionally,it is noteworthy that the selective removal of a 2-naphthylmethyl ether(Nap)during the late stages of synthesis,particularly in the presence of multiple benzyl groups,can be somewhat challenging to predict.Through the careful selection of synthetic strategies,building blocks,and optimized reaction conditions,we achieved the stereoselective glycosylations,selective oxidation of primary alcohols,remarkable enhancement of acceptor activity,and efficient introduction of the 3S-Hb group.The synthetic methodology presented in this work serves as a valuable reference for the preparation of structurally related oligosaccharides.By incorporating an aminopropyl linker,the target tetrasaccharide facilitates glycan microarray preparation and in vivo immunological assessments,thereby accelerating progress toward a synthetic glycoconjugate vaccine for P.aeruginosa.
基金supported by the National Natural Science Foundation of China(Grant Nos.32270688,31801117,and 82430107 to X.L.,and 32500589 to H.S.)the China Postdoctoral Science Foundation(Grant Nos.BX20240253 and 2024M762384 to H.S.)+1 种基金the Natural Science Foundation of Tianjin(Grant No.24JCQNJC01280 to H.S.)Tianjin Key Medical Discipline(Specialty)Construction Project(Grant No.TJYXZDXK-3-003A).
文摘For decades,the central dogma of oncology has been that a cancer’s identity is inextricably linked to its anatomical origin.This principle underpins the entire diagnostic and therapeutic framework,from histology-based classification to site-specific treatment guidelines.Yet,this framework catastrophically fails for a substantial population of patients diagnosed with cancer of unknown primary(CUP).These patients present metastatic disease,yet their primary tumors remain elusive despite exhaustive clinical workup1.CUP,accounting for 1%-3%of all cancer diagnoses,is an enigma with devastating consequences;the median overall survival is only 2-12 months2-4.The inability to pinpoint an origin forces clinicians to rely on broad-spectrum empirical chemotherapy,such as taxane-carboplatin regimens,which have limited efficacy and exclude patients from the promise of targeted therapies and clinical trials5.CUP is not only a diagnostic challenge but also an indictment of the siloed approach to understanding malignancy:this cancer highlights the limitations of origin-based diagnostic frameworks.However,the confluence of high-dimensional biological data and advanced artificial intelligence(AI)is now poised to address this long-standing diagnostic limitation and to herald a new era for not only CUP but also oncology as a whole(Figure 1).
基金supported by the National Natural Science Foundation of China(22378205)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Center for Advanced Materials and Technology in Nanjing University of Science and Technology。
文摘The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,2].Consequently,organofluorine compounds are frequently encountered in pharmaceuticals and agrochemicals.Significant advances have been made in the introduction of fluoroalkyl groups into small molecules since the beginning of the 21st century.
