（-）-Tetrahydrolipstatin 1 was synthesized in three steps and 33.8% overall yield from aldehyde 6 by tandem Mukaiyama-aldol lactonization, which offered a concise, efficient and highly diastereoselective route to thi...（-）-Tetrahydrolipstatin 1 was synthesized in three steps and 33.8% overall yield from aldehyde 6 by tandem Mukaiyama-aldol lactonization, which offered a concise, efficient and highly diastereoselective route to this antiobesity drug. We also presented a resolution method for preparation of the crucial intermediate, β- （t-butyldimethylsilyloxy）tetradecanal.展开更多
From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1.The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites...From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1.The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites of the sub-strate yielding the 2-oxoaustroeupatol(2)and 2,19-dioxoaustroeupatol(3).The treatment of 2 with sodium periodate yields a heterocyclic derivative(ε-caprolactone derivate 4)formed by oxidative cleavage and unexpected intramo-lecular attack of the hydroxymethylene(C-19)oxygen to the ketonic carbon(C-2).A plausible mechanistic pathway for the obtention of compound 4 is proposed.展开更多
?-Phenyl－4－aroylfuran－3－carboxylic acids were reduced in aqueous alkaline solutions ofNaBH4 to afford hydroxy acids in excellent yields． Under the catalysis of boron trifluoride etherate，the hydroxy acids were c...?-Phenyl－4－aroylfuran－3－carboxylic acids were reduced in aqueous alkaline solutions ofNaBH4 to afford hydroxy acids in excellent yields． Under the catalysis of boron trifluoride etherate，the hydroxy acids were converted to lactones smoothly．展开更多
Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO2 through C--H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, ...Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO2 through C--H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO2 from the electron-rich alkene is demonstrated for this reaction.展开更多
Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for t...Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for the oxidative lactonization of benzylic C(sp^(3))–H bonds enabled by the synergistic interactions of organic dye-type rose bengal,n-Bu_(4)N∙Br,O_(2) and Na_(2)HPO_(4) under visible light irradiation.This reaction does not require transition metal catalysts or strong oxidants.A range of structurally diverse phthalides has been synthesized with excellent selectivity and high functional group compatibility.The late-stage application of this reaction to the preparation of structurally complex phthalides demonstrates its synthetic utility.展开更多
Traumatic axonal lesions of peripheral nerves disrupt neuronal connections with their targets,resulting in the loss of motor and sensory functions.Despite the peripheral nervous system’s capacity for axonal regrowth,...Traumatic axonal lesions of peripheral nerves disrupt neuronal connections with their targets,resulting in the loss of motor and sensory functions.Despite the peripheral nervous system’s capacity for axonal regrowth,this may lead to permanent impairements resulting in a loss of quality of life and a high socioeconomic burden.展开更多
Due to its unique electronic properties,the difluoromethylene group(CF2)has served as a valuable unity in the design of biologically active molecules.Sinceγ-lactones display a broad range of biological properties,α,...Due to its unique electronic properties,the difluoromethylene group(CF2)has served as a valuable unity in the design of biologically active molecules.Sinceγ-lactones display a broad range of biological properties,α,α-difluoro-γ-lactones may exhibit unexpected biological activities,and thus their synthesis has received increasing attention.Traditional synthetic methods suffer from tedious multi-step processes,and very few effective methods have been reported recently.Herein,we describe the difunctionalization of alkenes with BrCF_(2)CO_(2)K under photoredox catalysis with the use of a boron-Lewis acid for the access toα,α-difluoro-γ-lactones.In this transformation,the alkene substrates and the used reagents,including BrCF_(2)CO_(2)K and the boron-Lewis acid,PhB(OH)2 or BF3·THF,are cheap and widely available.High efficiency and atom economy may make this protocol attractive.展开更多
Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The tra...Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.展开更多
The inhibitory effects of zinc oxide nanoparticles(ZnO NPs)and impacts of N-acylhomoserine lactone(AHL)-based quorum sensing(QS)on biological nitrogen removal(BNR)performance have beenwell-investigated.However,the eff...The inhibitory effects of zinc oxide nanoparticles(ZnO NPs)and impacts of N-acylhomoserine lactone(AHL)-based quorum sensing(QS)on biological nitrogen removal(BNR)performance have beenwell-investigated.However,the effects of ammonia nitrogen(NH_(4)^(+)-N)concentrations on NP toxicity and AHL regulation have seldom been addressed yet.This study consulted on the impacts of ZnO NPs on BNR systems when high NH_(4)^(+)-N concentrationwas available.The synergistic toxic effects of high-strength NH_(4)^(+)-N(200 mg/L)and ZnO NPs resulted in decreased ammonia oxidation rates and dropped the nitrogen removal efficiencies by 17.5%±0.2%.The increased extracellular polymeric substances(EPS)production was observed in response to the high NH_(4)^(+)-N and ZnO NP stress,which indicated the defensemechanism against the toxic effects in the BNR systemswas stimulated.Furthermore,the regulatory effects of exogenous N-decanoyl-homoserine lactone(C_(10)-HSL)-mediated QS system on NP-stressed BNR systems were revealed to improve the BNR performance under different NH_(4)^(+)-N concentrations.The C_(10)-HSL regulated the intracellular reactive oxygen species levels,denitrification functional enzyme activities,and antioxidant enzyme activities,respectively.This probably synergistically enhanced the defense mechanism against NP toxicity.However,compared to the low NH_(4)^(+)-N concentration of 60 mg/L,the efficacy of C_(10)-HSL was inhibited at high NH_(4)^(+)-N levels of 200 mg/L.The findings provided the significant application potential of QS system for BNR when facing toxic compound shock threats.展开更多
Direct converting carbon dioxide(CO_(2))and propane(C_(3)H_(8))into aromatics with high carbon utilization offers a desirable opportunity to simultaneously mitigate CO_(2)emission and adequately utilize C_(3)H_(8) in ...Direct converting carbon dioxide(CO_(2))and propane(C_(3)H_(8))into aromatics with high carbon utilization offers a desirable opportunity to simultaneously mitigate CO_(2)emission and adequately utilize C_(3)H_(8) in shale gas.Owing to their thermodynamic resistance,converting CO_(2)and C_(3)H_(8) respectively remains difficult.Here,we achieve 60.2%aromatics selectivity and 48.8%propane conversion over H-ZSM-5-25 via a zeolite-catalyzing the coupling of CO_(2)and C_(3)H_(8).Operando dual-beam FTIR spectroscopy combined with ^(13)C-labeled CO_(2)tracing experiments revealed that CO_(2)is directly involved in the generation of aromatics,with its carbon atoms selectively embedded into the aromatic ring,bypassing the reverse water-gas shift pathway.Accordingly,a cooperative aromatization mechanism is proposed.Thereinto,lactones,produced from CO_(2)and olefins,are proven to be the key intermediate.This work not only provides an opportunity for simultaneous conversion of CO_(2)and C_(3)H_(8),but also expends coupling strategy designing of CO_(2)and alkanes over acidic zeolites.展开更多
As a recently emerging wastewater treatment technology,Algal-bacterial granular sludge(ABGS)process shows significant advantages.However,current research on the ABGS system is a lack of a clear and complete understand...As a recently emerging wastewater treatment technology,Algal-bacterial granular sludge(ABGS)process shows significant advantages.However,current research on the ABGS system is a lack of a clear and complete understanding of the potential mechanism of signal molecules on the growth of ABGS.This study comprehensively explores the variations in the ABGS under different N-acyl-homoserine lactone(AHL)conditions by constructing three sequencing batch reactor(SBR)systems.The results indicate that N-hexanoyl-l-homoserine lactone(C6-HSL)accelerates the granulation process in the early stages by promoting the loosely bound extracellular polymeric substances(LB-EPS)secretion and filamentous bacteria growth,thereby shortening required time for initial granule formation.On the other hand,N-(3-oxodecanoyl)-l-homoserine lactone(3-oxo-C12-HSL)expedites the granulation process by promoting the tightly bound extracellular polymeric substances(TB-EPS)and aromatic protein secretion,benefiting structural stability and nitrogen and phosphorus removal efficiency of mature ABGS.展开更多
Quorum quenching (QQ)-based strategies are efficient for biofouling control.However,the feasibility of using QQ bacteria in antibiotic-stressed membrane bioreactors (MBRs) remains unknown.In this study,we isolated thr...Quorum quenching (QQ)-based strategies are efficient for biofouling control.However,the feasibility of using QQ bacteria in antibiotic-stressed membrane bioreactors (MBRs) remains unknown.In this study,we isolated three novel QQ strains (Bacillus sp.QX01 and QX03,Delftia sp.QX14) from the activated sludge of an actual MBR.They can degrade 11 N-acylhomoserine lactones (AHLs) with high efficiencies and rates through intracellular QQ pathways involving putative acylases and lactonases.Running two lab-scale MBRs,we found that introducing antibiotics (sulfamethoxazole,azithromycin,and ciprofloxacin,each at100μg/L) shortened the fouling cycle by 71.4%.However,the immobilized inoculation of QX01 into one MBR extended the fouling cycle by 1.5-2.0 times.Quantitative detection revealed that QX01 significantly reduced the concentrations of two AHLs (C4-HSL and C8-HSL),which were positively correlated with the contents of extracellular polymeric substances(EPS)(Pearson’s r=0.62-0.83,P<0.01).This suggests that QX01 could perform its QQ activity robustly under antibiotic stress,thereby inhibiting EPS production (proteins especially) and biofilm formation.Moreover,QX01 notably altered the succession patterns of both sludge and fouling communities,with more pronounced effects on abundant taxa.Genera associated with AHL synthesis and EPS production,such as Terrimonas and Rhodobacter,were significantly depleted,contributing to the mitigated biofouling.Additionally,QX01 increased the bacterial community diversity (evenness especially),which was inhibited by antibiotics.Overall,we demonstrate that the novel QQ bacteria could be effective for biofouling control in antibiotic-stressed MBRs,though future work is needed to develop practical approaches for prolonging QQ activity.展开更多
Chiral aryl cyclohex-3-en ether scaffold is widely present in bioactive natural products and drugs.The exploitation of efficient and enantioselective methods for the construction of aryl cyclohex-3-en ether scaffold i...Chiral aryl cyclohex-3-en ether scaffold is widely present in bioactive natural products and drugs.The exploitation of efficient and enantioselective methods for the construction of aryl cyclohex-3-en ether scaffold is significant.Herein we disclose a chiral N,N’-dioxide/Lewis acid complex-catalyzed asymmetric inverse-electron-demand Diels-Alder(IEDDA)reaction using electron-deficient 3-carboalkoxyl-2-pyrones and less electron-enriched aryl enol ethers as reactants.A wide range of non-and 1,2-disubstituted acyclic aryl enol ethers are applicable to deliver diverse chiral bridged bicyclic lactones in high yields and stereoselectivities(up to 96%yield,>20:1 dr,97:3 er).The bridged bicyclic lactone core can be easily converted into chiral aryl cyclohex-3-en ether scaffold.Notably,DFT calculations revealed a stepwise and endo mechanism to explain the high enantioselectivity controlled by the cooperative effect of the steric factors and the dispersion interactions between ligands and enol ethers.展开更多
A chemical investigation of the aerial parts ofArtemisia vestita Wall. led to the isolation of 12 known sesquiterpenes, including 2 furan-containing sesquiterpenoids and 10 eudesmane sesquiterpene lactones. Their stru...A chemical investigation of the aerial parts ofArtemisia vestita Wall. led to the isolation of 12 known sesquiterpenes, including 2 furan-containing sesquiterpenoids and 10 eudesmane sesquiterpene lactones. Their structures were identified as negunfurol （1）, schensianol A （2）, artemine （3）, erivanin （4）, 1,5-diepi-artemin （5）, acetylartemin （6）, naphtho[1,2-b]furan-2（3H）-one, 6-（acetyloxy） decahydro-9a-hydroxy-3,Sa-dimethyl-9-methylene-（3S,3aS,5aS,6S,9aS, ghS） （7）, naphtho[1,2-b]furan-2（3H）-one, 6-（acetyloxy）- 3a,4,5,5a,6,7,8,9b-octahydro-8-hydroxy-3,Sa,9-trimethyl- （3S,3aS, SaR,6S, SS,9bS） （8）, isoerivanin （9）, harrelierin （10）, （11S）-1- oxoeudesm-4（14）-eno-13,6a-lactone （11）, 1-epi-dehydroisoeranin （12）, respectively. All of these compounds were isolated from Artemisia vestita for the first time, and compounds 1 and 2 were isolated from the genus Artemisia for the first time.展开更多
[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acet...[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acety-homoserine lactones（AHLs）,the morphology of cell apoptosis was observed through staining with DAPI.[Result]Microcystis aeruginosa cell apoptosis was induced by signal molecule N-acetyhomoserine lactones（AHLs） with the concentration of 1 μmol/L to inhibit the growth and proliferation of Microcystis aeruginosa.[Conclusion] The results provided the important scientific basis and new management ideas for the treatment of water bloom of Microcystis aeruginosa.展开更多
The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Gi...The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.展开更多
From the dried roots and leaves of Tripterygium wilfordii^(1.2),a new diter- penoid triepoxide,16-hydroxytriptolide was isolated,and its structure and stereochemistry elucidated as 16-(S)-hydroxy-triptolide on the bas...From the dried roots and leaves of Tripterygium wilfordii^(1.2),a new diter- penoid triepoxide,16-hydroxytriptolide was isolated,and its structure and stereochemistry elucidated as 16-(S)-hydroxy-triptolide on the basis of spectral data(IR, MS, UV,~1HNMR,^(13)CNMR,2d-NMR,Selective Long-range DEPT)and x-ray crystallographic analysis.This compound showed definite antiinflammatory action,strong immunosuppressive and antifertile activities.In addition,a known compound,triptolide was also isolated and all the spectral signals of^1 HNMR and ^(13)CNMR were assigned.展开更多
Stereoselective functionalization at C-2 and C-3 of the gibberellin skeleton was achieved via an intramolecular free radical cyclization approach using a tethered C-19 halomethyl ester as the radical precursor.
文摘（-）-Tetrahydrolipstatin 1 was synthesized in three steps and 33.8% overall yield from aldehyde 6 by tandem Mukaiyama-aldol lactonization, which offered a concise, efficient and highly diastereoselective route to this antiobesity drug. We also presented a resolution method for preparation of the crucial intermediate, β- （t-butyldimethylsilyloxy）tetradecanal.
基金supported by the National Fund of Science,Technology and Innovation (FONACIT) (Grant N°201300288)within the framework of the project PCP France-Venezuelaby the CDCHTA-ULA (Grant N°C-1935-15-08-ED).
文摘From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1.The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites of the sub-strate yielding the 2-oxoaustroeupatol(2)and 2,19-dioxoaustroeupatol(3).The treatment of 2 with sodium periodate yields a heterocyclic derivative(ε-caprolactone derivate 4)formed by oxidative cleavage and unexpected intramo-lecular attack of the hydroxymethylene(C-19)oxygen to the ketonic carbon(C-2).A plausible mechanistic pathway for the obtention of compound 4 is proposed.
文摘?-Phenyl－4－aroylfuran－3－carboxylic acids were reduced in aqueous alkaline solutions ofNaBH4 to afford hydroxy acids in excellent yields． Under the catalysis of boron trifluoride etherate，the hydroxy acids were converted to lactones smoothly．
文摘Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO2 through C--H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO2 from the electron-rich alkene is demonstrated for this reaction.
基金supported by the National Natural Science Foundation of China(21502086)the Natural Science Foundation of Fujian Province(2019J01744)+1 种基金the Key Project of Foundation of Fujian Province(2020J02044)the Natural Science Foundation of Zhangzhou City(ZZ2021J13)。
文摘Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for the oxidative lactonization of benzylic C(sp^(3))–H bonds enabled by the synergistic interactions of organic dye-type rose bengal,n-Bu_(4)N∙Br,O_(2) and Na_(2)HPO_(4) under visible light irradiation.This reaction does not require transition metal catalysts or strong oxidants.A range of structurally diverse phthalides has been synthesized with excellent selectivity and high functional group compatibility.The late-stage application of this reaction to the preparation of structurally complex phthalides demonstrates its synthetic utility.
文摘Traumatic axonal lesions of peripheral nerves disrupt neuronal connections with their targets,resulting in the loss of motor and sensory functions.Despite the peripheral nervous system’s capacity for axonal regrowth,this may lead to permanent impairements resulting in a loss of quality of life and a high socioeconomic burden.
基金We thank the National Key Research and Development Program of China(2021YFF0701700)the National Natural Science Foundation of China(21971252,21991122,22271181)the Science and Technology Commission of Shanghai Municipality(22ZR1423600)for financial support.
文摘Due to its unique electronic properties,the difluoromethylene group(CF2)has served as a valuable unity in the design of biologically active molecules.Sinceγ-lactones display a broad range of biological properties,α,α-difluoro-γ-lactones may exhibit unexpected biological activities,and thus their synthesis has received increasing attention.Traditional synthetic methods suffer from tedious multi-step processes,and very few effective methods have been reported recently.Herein,we describe the difunctionalization of alkenes with BrCF_(2)CO_(2)K under photoredox catalysis with the use of a boron-Lewis acid for the access toα,α-difluoro-γ-lactones.In this transformation,the alkene substrates and the used reagents,including BrCF_(2)CO_(2)K and the boron-Lewis acid,PhB(OH)2 or BF3·THF,are cheap and widely available.High efficiency and atom economy may make this protocol attractive.
基金financial support from the Marine S&T Fund of Shandong Province for Qingdao Marine Science and Technology Center(No.2022QNLM030003-2)the National Key Research&Development Program of China(No.2022YFA2104902)the National Natural Science Foundation of China(Nos.21977088 and22377114)。
文摘Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.
基金supported by the National Natural Science Foundation of China(No.52270119).
文摘The inhibitory effects of zinc oxide nanoparticles(ZnO NPs)and impacts of N-acylhomoserine lactone(AHL)-based quorum sensing(QS)on biological nitrogen removal(BNR)performance have beenwell-investigated.However,the effects of ammonia nitrogen(NH_(4)^(+)-N)concentrations on NP toxicity and AHL regulation have seldom been addressed yet.This study consulted on the impacts of ZnO NPs on BNR systems when high NH_(4)^(+)-N concentrationwas available.The synergistic toxic effects of high-strength NH_(4)^(+)-N(200 mg/L)and ZnO NPs resulted in decreased ammonia oxidation rates and dropped the nitrogen removal efficiencies by 17.5%±0.2%.The increased extracellular polymeric substances(EPS)production was observed in response to the high NH_(4)^(+)-N and ZnO NP stress,which indicated the defensemechanism against the toxic effects in the BNR systemswas stimulated.Furthermore,the regulatory effects of exogenous N-decanoyl-homoserine lactone(C_(10)-HSL)-mediated QS system on NP-stressed BNR systems were revealed to improve the BNR performance under different NH_(4)^(+)-N concentrations.The C_(10)-HSL regulated the intracellular reactive oxygen species levels,denitrification functional enzyme activities,and antioxidant enzyme activities,respectively.This probably synergistically enhanced the defense mechanism against NP toxicity.However,compared to the low NH_(4)^(+)-N concentration of 60 mg/L,the efficacy of C_(10)-HSL was inhibited at high NH_(4)^(+)-N levels of 200 mg/L.The findings provided the significant application potential of QS system for BNR when facing toxic compound shock threats.
文摘Direct converting carbon dioxide(CO_(2))and propane(C_(3)H_(8))into aromatics with high carbon utilization offers a desirable opportunity to simultaneously mitigate CO_(2)emission and adequately utilize C_(3)H_(8) in shale gas.Owing to their thermodynamic resistance,converting CO_(2)and C_(3)H_(8) respectively remains difficult.Here,we achieve 60.2%aromatics selectivity and 48.8%propane conversion over H-ZSM-5-25 via a zeolite-catalyzing the coupling of CO_(2)and C_(3)H_(8).Operando dual-beam FTIR spectroscopy combined with ^(13)C-labeled CO_(2)tracing experiments revealed that CO_(2)is directly involved in the generation of aromatics,with its carbon atoms selectively embedded into the aromatic ring,bypassing the reverse water-gas shift pathway.Accordingly,a cooperative aromatization mechanism is proposed.Thereinto,lactones,produced from CO_(2)and olefins,are proven to be the key intermediate.This work not only provides an opportunity for simultaneous conversion of CO_(2)and C_(3)H_(8),but also expends coupling strategy designing of CO_(2)and alkanes over acidic zeolites.
基金financially supported by the Open Project of Sanya Science and Education Innovation Park of Wuhan University of Technology(No.2022KF0005)Researchers Supporting Project(No.RSP-2024-R20)King Saud University,Riyadh,Saudi Arabia.
文摘As a recently emerging wastewater treatment technology,Algal-bacterial granular sludge(ABGS)process shows significant advantages.However,current research on the ABGS system is a lack of a clear and complete understanding of the potential mechanism of signal molecules on the growth of ABGS.This study comprehensively explores the variations in the ABGS under different N-acyl-homoserine lactone(AHL)conditions by constructing three sequencing batch reactor(SBR)systems.The results indicate that N-hexanoyl-l-homoserine lactone(C6-HSL)accelerates the granulation process in the early stages by promoting the loosely bound extracellular polymeric substances(LB-EPS)secretion and filamentous bacteria growth,thereby shortening required time for initial granule formation.On the other hand,N-(3-oxodecanoyl)-l-homoserine lactone(3-oxo-C12-HSL)expedites the granulation process by promoting the tightly bound extracellular polymeric substances(TB-EPS)and aromatic protein secretion,benefiting structural stability and nitrogen and phosphorus removal efficiency of mature ABGS.
基金supported by the National Natural Science Foundation of China (Nos.51938001 and 52300073)。
文摘Quorum quenching (QQ)-based strategies are efficient for biofouling control.However,the feasibility of using QQ bacteria in antibiotic-stressed membrane bioreactors (MBRs) remains unknown.In this study,we isolated three novel QQ strains (Bacillus sp.QX01 and QX03,Delftia sp.QX14) from the activated sludge of an actual MBR.They can degrade 11 N-acylhomoserine lactones (AHLs) with high efficiencies and rates through intracellular QQ pathways involving putative acylases and lactonases.Running two lab-scale MBRs,we found that introducing antibiotics (sulfamethoxazole,azithromycin,and ciprofloxacin,each at100μg/L) shortened the fouling cycle by 71.4%.However,the immobilized inoculation of QX01 into one MBR extended the fouling cycle by 1.5-2.0 times.Quantitative detection revealed that QX01 significantly reduced the concentrations of two AHLs (C4-HSL and C8-HSL),which were positively correlated with the contents of extracellular polymeric substances(EPS)(Pearson’s r=0.62-0.83,P<0.01).This suggests that QX01 could perform its QQ activity robustly under antibiotic stress,thereby inhibiting EPS production (proteins especially) and biofilm formation.Moreover,QX01 notably altered the succession patterns of both sludge and fouling communities,with more pronounced effects on abundant taxa.Genera associated with AHL synthesis and EPS production,such as Terrimonas and Rhodobacter,were significantly depleted,contributing to the mitigated biofouling.Additionally,QX01 increased the bacterial community diversity (evenness especially),which was inhibited by antibiotics.Overall,we demonstrate that the novel QQ bacteria could be effective for biofouling control in antibiotic-stressed MBRs,though future work is needed to develop practical approaches for prolonging QQ activity.
基金National Natural Science Foundation of China(Nos.22001177,22203023)Guangdong Pearl River Talent Program(no.2021QN020268)+3 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515012381,2022A1515011859)Shenzhen Bay Laboratory Startup Fund(No.S201100003)Major Program of Shenzhen Bay Laboratory(No.S211101001-4)Shenzhen Bay Qihang Fellow Program(No.QH23001)for generous financial support.
文摘Chiral aryl cyclohex-3-en ether scaffold is widely present in bioactive natural products and drugs.The exploitation of efficient and enantioselective methods for the construction of aryl cyclohex-3-en ether scaffold is significant.Herein we disclose a chiral N,N’-dioxide/Lewis acid complex-catalyzed asymmetric inverse-electron-demand Diels-Alder(IEDDA)reaction using electron-deficient 3-carboalkoxyl-2-pyrones and less electron-enriched aryl enol ethers as reactants.A wide range of non-and 1,2-disubstituted acyclic aryl enol ethers are applicable to deliver diverse chiral bridged bicyclic lactones in high yields and stereoselectivities(up to 96%yield,>20:1 dr,97:3 er).The bridged bicyclic lactone core can be easily converted into chiral aryl cyclohex-3-en ether scaffold.Notably,DFT calculations revealed a stepwise and endo mechanism to explain the high enantioselectivity controlled by the cooperative effect of the steric factors and the dispersion interactions between ligands and enol ethers.
基金National Natural Science Foundation of China(Grant No.30973629)National Key Technology R&D Program "New Drug Innovation" of China(Grant No.2012ZX09301002-002-002,2012ZX09304-005)
文摘A chemical investigation of the aerial parts ofArtemisia vestita Wall. led to the isolation of 12 known sesquiterpenes, including 2 furan-containing sesquiterpenoids and 10 eudesmane sesquiterpene lactones. Their structures were identified as negunfurol （1）, schensianol A （2）, artemine （3）, erivanin （4）, 1,5-diepi-artemin （5）, acetylartemin （6）, naphtho[1,2-b]furan-2（3H）-one, 6-（acetyloxy） decahydro-9a-hydroxy-3,Sa-dimethyl-9-methylene-（3S,3aS,5aS,6S,9aS, ghS） （7）, naphtho[1,2-b]furan-2（3H）-one, 6-（acetyloxy）- 3a,4,5,5a,6,7,8,9b-octahydro-8-hydroxy-3,Sa,9-trimethyl- （3S,3aS, SaR,6S, SS,9bS） （8）, isoerivanin （9）, harrelierin （10）, （11S）-1- oxoeudesm-4（14）-eno-13,6a-lactone （11）, 1-epi-dehydroisoeranin （12）, respectively. All of these compounds were isolated from Artemisia vestita for the first time, and compounds 1 and 2 were isolated from the genus Artemisia for the first time.
基金Supported by National Natural Science Fund(30960036)Key Schoollevel Project of Kunming University(20091016)~~
文摘[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acety-homoserine lactones（AHLs）,the morphology of cell apoptosis was observed through staining with DAPI.[Result]Microcystis aeruginosa cell apoptosis was induced by signal molecule N-acetyhomoserine lactones（AHLs） with the concentration of 1 μmol/L to inhibit the growth and proliferation of Microcystis aeruginosa.[Conclusion] The results provided the important scientific basis and new management ideas for the treatment of water bloom of Microcystis aeruginosa.
文摘The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.
文摘From the dried roots and leaves of Tripterygium wilfordii^(1.2),a new diter- penoid triepoxide,16-hydroxytriptolide was isolated,and its structure and stereochemistry elucidated as 16-(S)-hydroxy-triptolide on the basis of spectral data(IR, MS, UV,~1HNMR,^(13)CNMR,2d-NMR,Selective Long-range DEPT)and x-ray crystallographic analysis.This compound showed definite antiinflammatory action,strong immunosuppressive and antifertile activities.In addition,a known compound,triptolide was also isolated and all the spectral signals of^1 HNMR and ^(13)CNMR were assigned.
文摘Stereoselective functionalization at C-2 and C-3 of the gibberellin skeleton was achieved via an intramolecular free radical cyclization approach using a tethered C-19 halomethyl ester as the radical precursor.
