Five-membered pyrroline nitroxides with high-potential is fascinating as catholyte for aqueous organic redox flow batteries(AORFBs),however,it suffers from a primary deficiency of insufficient stability due to ring-op...Five-membered pyrroline nitroxides with high-potential is fascinating as catholyte for aqueous organic redox flow batteries(AORFBs),however,it suffers from a primary deficiency of insufficient stability due to ring-opening side reaction.Herein we report a spatial structure regulation strategy by host-vip chemistry,encapsulating 3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl(CPL)into hydrosoluble cyclodextrins(CDs)with an inclusion structure of N–O⋅head towards cavity bottom,to boost the solubility and cyclability of pyrroline nitroxides significantly.The armor-clad CPL(CPL⊂HP-β-CD)catholyte in 0.05–0.5 M presents a battery capacity fade rate as low as 0.002%/cycle(0.233%/day)compared to the sole CPL in 0.05 M(0.039%/cycle or 5.23%/day)over 500 cycles in assembled AORFBs.The optimized reclining spatial structure with N–O⋅head towards CD cavity bottom effectively inhibits the attack of Lewis base species on the hydrogen abstraction site in pyrroline ring,and thus avoids the ring-opening side reaction of pyrroline nitroxides.展开更多
A Silver-catalyzed enantioselective[3+2]cycloaddition of azomethine ylides with activated alkenes by using a P-stereogenic ligand Ganphos is reported.The method provides an efficient strategy for the effective synthes...A Silver-catalyzed enantioselective[3+2]cycloaddition of azomethine ylides with activated alkenes by using a P-stereogenic ligand Ganphos is reported.The method provides an efficient strategy for the effective synthesis of spirocyclic scaffolds containing a pyrroline motif.Notable features of this approach include good yields,remarkable enantioselectivity,as well as a broad substrate scope and significant step efficiency.展开更多
In order to screen the aroma characteristics of soybean,a new method was established which can quickly quantify the content of 2-acetyl-1pyrroline(2-AP),an important compound related to soybean aroma,using gas chromat...In order to screen the aroma characteristics of soybean,a new method was established which can quickly quantify the content of 2-acetyl-1pyrroline(2-AP),an important compound related to soybean aroma,using gas chromatography-mass spectrometry(GC-MS).Based on peak profile,total peak area and retention time as test indexes,an accurate identification method for fragrant soybeans was established.The optimum parameters of the protocol consisted of column temperature70℃,sample injector temperature 180℃,optimum extraction alcohol content 1 m L,Na Cl content 0.1 g,ultrasonication time10 min,and extraction time 1 h,which were established by using the orthogonal test of single factors and three factors with four levels(L_9(3)^4).2-AP content of leaves had significant correlations with seeds,which were easier to measure.The protocol was simple and easy to carry out,consumed only small amounts of reagents,and provided accurate and reliable results with good reproducibility.A total of 101 soybean genotypes from different geographical sources were analyzed using this protocol.The results showed that the average content of 2-AP was 0.29 mg L^(–1),ranging from 0.094 to 1.816 mg L^(–1),and the genetic diversity index was 0.54.Among all genotypes-tested,they were classified into three grades,including seven elite genotypes identified as"grade one fragrant soybeans",which were Zhonglong 608,Heinong 88,Ha13-2958,Hongmiandou,Heinong 82,Huangmaodou,and Jiyu 21.These results provide both an identification technique and several elite aroma genotypes for gene discovery and good quality breeding in soybean.展开更多
The electron spin resonance spectra of N-carbamoyl-N-(l-oxyl-2,2,5,5-tetramethyl-pyrrolin-3-yl) urea compounds in ten solvents with different polarities were determined. It was found that the hyperfine splitting const...The electron spin resonance spectra of N-carbamoyl-N-(l-oxyl-2,2,5,5-tetramethyl-pyrrolin-3-yl) urea compounds in ten solvents with different polarities were determined. It was found that the hyperfine splitting constant AN and spin density pN. as well as the energy difference between two adjacent energy levels E of different pyrroline nitroxides in the same solvent increase with the increase of electron-withdrawing α-bility of the substituted groups on the aromatic ring. There was a linear correlation between AN and Reichardt ET value, and between AN and Z value as well. Such a linear correlation was also found between solvent viscosity n and ESR rotational correlation time r. On the other hand, the correlation between T and the relative height hr of peak on high field was reverse. The results are discussed in the paper.展开更多
The enantioselective construction of bis-heterocyclic frameworks containing pyrroline and indole motifs is achieved through a cooperative palladium-catalyzed tandem process.This methodology efficiently couples oxime e...The enantioselective construction of bis-heterocyclic frameworks containing pyrroline and indole motifs is achieved through a cooperative palladium-catalyzed tandem process.This methodology efficiently couples oxime esters and 2-alkynylanilines via a sequential Narasaka-Heck cyclization/Cacchi coupling reaction,providing direct access to complex chiral architectures in high yields with excellent enantioselectivity.The protocol demonstrates broad substrate scope and functional group tolerance.A diverse range of oxime esters,bearing both electron-donating and electron-withdrawing groups,as well as heterocyclic and polyarene substituents,undergo the transformation smoothly,delivering the desired products in 80%-96%yields and up to 98%ee.The reaction also accommodates various ortho-alkynylanilines with para-,meta-,and even sterically demanding ortho-substituents,yielding products with high stereocontrol.Preliminary mechanistic investigations reveal that the reaction is facilitated by a single palladium catalyst operating in synergy with two distinct supporting ligands.The system features two concurrent catalytic cycles:a Pd/Sadphos cycle that drives the enantioselective Narasaka-Heck cyclization of the oxime ester to form the pyrroline ring,and a Pd/Xantphos cycle that mediates the anti-aminopalladation(Cacchi reaction)of the 2-alkynylaniline to construct the indole core.A key transmetallation step between the alkyl-Pd(II)and alkenyl-Pd(II)intermediates from the respective cycles enables the coupling,followed by reductive elimination to furnish the final bis-heterocyclic product.The synthetic utility is highlighted by a gram-scale synthesis without erosion of yield or enantioselectivity,and the product could be readily derivatized to other valuable chiral nitrogen-containing scaffolds.This work establishes a streamlined and efficient route to enantioenriched bis-heterocycles,showcasing the power of single-metal,dual-ligand cooperative catalysis in complex molecule synthesis.展开更多
Tomato(Solanum lycopersicum L.) is one of the world's most widely cultivated and consumed vegetables,and its fruits are highly valued for its vibrant color,culinary versatility,and nutritional benefits(Yu et al.20...Tomato(Solanum lycopersicum L.) is one of the world's most widely cultivated and consumed vegetables,and its fruits are highly valued for its vibrant color,culinary versatility,and nutritional benefits(Yu et al.2025).China leads global tomato production,with an output of approximately 70 million tons in 2023,contributing to a worldwide yield exceeding192 million tons(FAO 2025).Fragrance significantly enhances the sensory appeal and flavor quality of food,thereby influencing the consumption and market price of agricultural products.For example,fragrant rice(Oryza sativa L.) varieties like Basmati and Jasmine have gained increasing popularity worldwide due to their distinct aroma,and their prices are often more than twice that of regular rice(Shan et al.2015).Among the more than 200 volatile organic compounds(VOCs) characterized in aromatic rice,2-acetyl-1-pyrroline(2-AP) is a dominant VOC responsible for the delightful "popcorn-like" aroma(Okpala et al.2019).展开更多
Ruthenium polypyridyl complexes have been widely used in photodynamic therapy,during which singlet oxygen(^(1)O_(2))plays a crucial role.Here,we synthesized a unique Ru complex Ru(bpy)2PhenHA(bpy-bipyridine,Phen-1,10-...Ruthenium polypyridyl complexes have been widely used in photodynamic therapy,during which singlet oxygen(^(1)O_(2))plays a crucial role.Here,we synthesized a unique Ru complex Ru(bpy)2PhenHA(bpy-bipyridine,Phen-1,10-phenanthroline,HA-hydroxamic acid)and unexpectedly found that not only^(1)O_(2),but also reactive hydroxyl radical(^(•)OH)could be produced under visible-light irradiation of Ru(bpy)2PhenHA in the presence of a classic spin trapping agent,5,5-dimethyl-1-pyrroline N-oxide(DMPO).Analogous^(•)OH production was also observed with 3,3,5,5-tetramethyl-1-pyrroline-N-oxide(TMPO),but not with other spin trapping agents.In contrast,much less^(•)OH was produced when substituting Ru(bpy)2PhenHA with Ru(bpy)2Phen lacking the HA group.However,when N-methyl-benzohydroxamic acid(a typical HA with reducing properties)was added into the DMPO/Ru(bpy)2Phen/VIS system,not only^(•)OH,but also the corresponding secondary nitroxide radical was clearly detected.Similar results were also observed with other structurally-different reducing agents.Further studies with other known spin trapping agents suggest that the[DMPO-OOH]•intermediate might be transiently produced and then rapidly decomposed to produce^(•)OH.Taken together,the molecular mechanism for the unusual^(•)OH production was proposed:visible-light irradiation of Ru(bpy)2PhenHA produced^(1)O_(2),which electrophilically added on DMPO,forming a peroxide intermediate,which then quickly decomposed to a biradical[DMPO-OO]^(••).Then,H-abstraction took place between[DMPO-OO]^(••)and the reducing hydroxamic acid,forming the unstable[DMPO-OOH]•,which decomposed homolytically to produce^(•)OH.These findings revealed a novel^(•)OH-generating system mediated by Ru complexes,which were not only dependent on DMPO,but also on^(1)O_(2)and the presence of H-donating agents.These findings may have broad chemical and biomedical implications.展开更多
Dear Editor,Rice serves as a staple food for over half of the global population,with fragrant varieties particularly valuable for their distinctive aroma,superior taste,and favorable cooking qualities.These attributes...Dear Editor,Rice serves as a staple food for over half of the global population,with fragrant varieties particularly valuable for their distinctive aroma,superior taste,and favorable cooking qualities.These attributes have been methodically perpetuated through generations via selective breeding(Prodhan and Qingyao,2020).The aroma quality of rice is predominantly determined by the concentration of 2-acetyl-1-pyrroline(2-AP),the key compound responsible for its characteristic fragrance(Okpala et al.,2019).The identification of the first aroma-causing gene in rice,BADH2,marked a critical advance in elucidating the genetic basis of rice aroma.This breakthrough was attributed to the discovery of a specific 8-bp deletion in the BADH2 gene on chromosome 8,which is closely associated with the aromatic trait across diverse rice varieties(Bradbury et al.,2005).The targeted genetic manipulation of the BADH2 gene via genetic engineering and genome-editing techniques has facilitated the development of multiple aromatic rice varieties(Shan et al.,2015;Tang et al.,2021;Hui et al.,2022).Nevertheless,the observed variability in 2-AP concentrations across different fragrant rice varieties,including those with a functional OsBADH2 gene,highlights the complexity of the genetic mechanisms that govern rice aroma.This suggests that,in addition to OsBADH2,other genetic alleles might also contribute to the synthesis of this key aromatic compound(Huang et al.,2008).展开更多
Aza-Heck cyclization of alkene-tethered oxime esters has received considerable attention as an effective strategy for synthesizing 1-pyrroline derivatives.However,the achievement of tandem aza-Heck reaction with alkyl...Aza-Heck cyclization of alkene-tethered oxime esters has received considerable attention as an effective strategy for synthesizing 1-pyrroline derivatives.However,the achievement of tandem aza-Heck reaction with alkyl electrophiles remains a challenge.Herein,we report a palladium-catalyzed tandem aza-Heck reaction of alkenetethered oxime esters with cyclopropanols.This catalytic system features mild conditions and broad substrate scopes,allowing the direct synthesis of structurally diverse 1-pyrroline derivatives in good yields.展开更多
Electron paramagnetic resonance(EPR)is a spectroscopic approach that can directly and non-destructively detect and char-acterize species with unpaired electrons,such as radicals,transi-tion metal ions,defects in mater...Electron paramagnetic resonance(EPR)is a spectroscopic approach that can directly and non-destructively detect and char-acterize species with unpaired electrons,such as radicals,transi-tion metal ions,defects in materials,and the excited triplet state of molecules[1].To date,the EPR technique has become an indis-pensable component in the toolbox of environmental studies.Using various diamagnetic probes(e.g.,5,5-dimethyl-1-pyrroline-N-oxide(DMPO))as the spin traps,transient reactive species can be transformed to EPR-detectable(meta)stable spin adducts,which enables radical identification and mechanism interpretation.Therefore,EPR constitutes a versatile platform for the mechanistic investigation of advanced oxidation processes(AOPs)in the field of water purification and contaminated groundwater remediation[2].展开更多
基金supported by grants from the National Natural Science Foundation of China(No.21875181,22209130,and 22279100)the Natural Science Basic Research Program of Shaanxi(No.2019JLP-13)the China Postdoctoral Science Foundation(No.2022M722524)。
文摘Five-membered pyrroline nitroxides with high-potential is fascinating as catholyte for aqueous organic redox flow batteries(AORFBs),however,it suffers from a primary deficiency of insufficient stability due to ring-opening side reaction.Herein we report a spatial structure regulation strategy by host-vip chemistry,encapsulating 3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl(CPL)into hydrosoluble cyclodextrins(CDs)with an inclusion structure of N–O⋅head towards cavity bottom,to boost the solubility and cyclability of pyrroline nitroxides significantly.The armor-clad CPL(CPL⊂HP-β-CD)catholyte in 0.05–0.5 M presents a battery capacity fade rate as low as 0.002%/cycle(0.233%/day)compared to the sole CPL in 0.05 M(0.039%/cycle or 5.23%/day)over 500 cycles in assembled AORFBs.The optimized reclining spatial structure with N–O⋅head towards CD cavity bottom effectively inhibits the attack of Lewis base species on the hydrogen abstraction site in pyrroline ring,and thus avoids the ring-opening side reaction of pyrroline nitroxides.
文摘A Silver-catalyzed enantioselective[3+2]cycloaddition of azomethine ylides with activated alkenes by using a P-stereogenic ligand Ganphos is reported.The method provides an efficient strategy for the effective synthesis of spirocyclic scaffolds containing a pyrroline motif.Notable features of this approach include good yields,remarkable enantioselectivity,as well as a broad substrate scope and significant step efficiency.
基金the National Key R&D Program for Crop Breeding(2016YFD0100201)Scientific Innovation Program of of the Chinese Academy of Agricultural Sciences(CAAS)。
文摘In order to screen the aroma characteristics of soybean,a new method was established which can quickly quantify the content of 2-acetyl-1pyrroline(2-AP),an important compound related to soybean aroma,using gas chromatography-mass spectrometry(GC-MS).Based on peak profile,total peak area and retention time as test indexes,an accurate identification method for fragrant soybeans was established.The optimum parameters of the protocol consisted of column temperature70℃,sample injector temperature 180℃,optimum extraction alcohol content 1 m L,Na Cl content 0.1 g,ultrasonication time10 min,and extraction time 1 h,which were established by using the orthogonal test of single factors and three factors with four levels(L_9(3)^4).2-AP content of leaves had significant correlations with seeds,which were easier to measure.The protocol was simple and easy to carry out,consumed only small amounts of reagents,and provided accurate and reliable results with good reproducibility.A total of 101 soybean genotypes from different geographical sources were analyzed using this protocol.The results showed that the average content of 2-AP was 0.29 mg L^(–1),ranging from 0.094 to 1.816 mg L^(–1),and the genetic diversity index was 0.54.Among all genotypes-tested,they were classified into three grades,including seven elite genotypes identified as"grade one fragrant soybeans",which were Zhonglong 608,Heinong 88,Ha13-2958,Hongmiandou,Heinong 82,Huangmaodou,and Jiyu 21.These results provide both an identification technique and several elite aroma genotypes for gene discovery and good quality breeding in soybean.
文摘The electron spin resonance spectra of N-carbamoyl-N-(l-oxyl-2,2,5,5-tetramethyl-pyrrolin-3-yl) urea compounds in ten solvents with different polarities were determined. It was found that the hyperfine splitting constant AN and spin density pN. as well as the energy difference between two adjacent energy levels E of different pyrroline nitroxides in the same solvent increase with the increase of electron-withdrawing α-bility of the substituted groups on the aromatic ring. There was a linear correlation between AN and Reichardt ET value, and between AN and Z value as well. Such a linear correlation was also found between solvent viscosity n and ESR rotational correlation time r. On the other hand, the correlation between T and the relative height hr of peak on high field was reverse. The results are discussed in the paper.
基金support of National Key R&D Program of China(No.2021YFFO701600)NSFC(22271053,22031004,21921003)Shanghai Municipal Education Commission(20212308).
文摘The enantioselective construction of bis-heterocyclic frameworks containing pyrroline and indole motifs is achieved through a cooperative palladium-catalyzed tandem process.This methodology efficiently couples oxime esters and 2-alkynylanilines via a sequential Narasaka-Heck cyclization/Cacchi coupling reaction,providing direct access to complex chiral architectures in high yields with excellent enantioselectivity.The protocol demonstrates broad substrate scope and functional group tolerance.A diverse range of oxime esters,bearing both electron-donating and electron-withdrawing groups,as well as heterocyclic and polyarene substituents,undergo the transformation smoothly,delivering the desired products in 80%-96%yields and up to 98%ee.The reaction also accommodates various ortho-alkynylanilines with para-,meta-,and even sterically demanding ortho-substituents,yielding products with high stereocontrol.Preliminary mechanistic investigations reveal that the reaction is facilitated by a single palladium catalyst operating in synergy with two distinct supporting ligands.The system features two concurrent catalytic cycles:a Pd/Sadphos cycle that drives the enantioselective Narasaka-Heck cyclization of the oxime ester to form the pyrroline ring,and a Pd/Xantphos cycle that mediates the anti-aminopalladation(Cacchi reaction)of the 2-alkynylaniline to construct the indole core.A key transmetallation step between the alkyl-Pd(II)and alkenyl-Pd(II)intermediates from the respective cycles enables the coupling,followed by reductive elimination to furnish the final bis-heterocyclic product.The synthetic utility is highlighted by a gram-scale synthesis without erosion of yield or enantioselectivity,and the product could be readily derivatized to other valuable chiral nitrogen-containing scaffolds.This work establishes a streamlined and efficient route to enantioenriched bis-heterocycles,showcasing the power of single-metal,dual-ligand cooperative catalysis in complex molecule synthesis.
基金funded by the National Natural Science Foundation of China (32401217)the Zhejiang Provincial “Three Rural Areas and Nine Parties” Science and Technology Collaboration Program, China (2024SNJF037)the China Postdoctoral Foundation (2024M762711)。
文摘Tomato(Solanum lycopersicum L.) is one of the world's most widely cultivated and consumed vegetables,and its fruits are highly valued for its vibrant color,culinary versatility,and nutritional benefits(Yu et al.2025).China leads global tomato production,with an output of approximately 70 million tons in 2023,contributing to a worldwide yield exceeding192 million tons(FAO 2025).Fragrance significantly enhances the sensory appeal and flavor quality of food,thereby influencing the consumption and market price of agricultural products.For example,fragrant rice(Oryza sativa L.) varieties like Basmati and Jasmine have gained increasing popularity worldwide due to their distinct aroma,and their prices are often more than twice that of regular rice(Shan et al.2015).Among the more than 200 volatile organic compounds(VOCs) characterized in aromatic rice,2-acetyl-1-pyrroline(2-AP) is a dominant VOC responsible for the delightful "popcorn-like" aroma(Okpala et al.2019).
基金supported by NSF China Grants(22336005,22021003,22376213)the Strategic Priority Research Program of CAS Grant(XDB0750300)the“From 0 to 1”Original Innovation Project,the Basic Frontier Scientific Research Program,CAS(ZDBS-LY-SLH027).
文摘Ruthenium polypyridyl complexes have been widely used in photodynamic therapy,during which singlet oxygen(^(1)O_(2))plays a crucial role.Here,we synthesized a unique Ru complex Ru(bpy)2PhenHA(bpy-bipyridine,Phen-1,10-phenanthroline,HA-hydroxamic acid)and unexpectedly found that not only^(1)O_(2),but also reactive hydroxyl radical(^(•)OH)could be produced under visible-light irradiation of Ru(bpy)2PhenHA in the presence of a classic spin trapping agent,5,5-dimethyl-1-pyrroline N-oxide(DMPO).Analogous^(•)OH production was also observed with 3,3,5,5-tetramethyl-1-pyrroline-N-oxide(TMPO),but not with other spin trapping agents.In contrast,much less^(•)OH was produced when substituting Ru(bpy)2PhenHA with Ru(bpy)2Phen lacking the HA group.However,when N-methyl-benzohydroxamic acid(a typical HA with reducing properties)was added into the DMPO/Ru(bpy)2Phen/VIS system,not only^(•)OH,but also the corresponding secondary nitroxide radical was clearly detected.Similar results were also observed with other structurally-different reducing agents.Further studies with other known spin trapping agents suggest that the[DMPO-OOH]•intermediate might be transiently produced and then rapidly decomposed to produce^(•)OH.Taken together,the molecular mechanism for the unusual^(•)OH production was proposed:visible-light irradiation of Ru(bpy)2PhenHA produced^(1)O_(2),which electrophilically added on DMPO,forming a peroxide intermediate,which then quickly decomposed to a biradical[DMPO-OO]^(••).Then,H-abstraction took place between[DMPO-OO]^(••)and the reducing hydroxamic acid,forming the unstable[DMPO-OOH]•,which decomposed homolytically to produce^(•)OH.These findings revealed a novel^(•)OH-generating system mediated by Ru complexes,which were not only dependent on DMPO,but also on^(1)O_(2)and the presence of H-donating agents.These findings may have broad chemical and biomedical implications.
基金supported by the Project of Zhong Shan Laboratory of Biological Breeding(BM2022008-02 and ZSBBL-KY2023-06)the Jiangsu Agricultural Science and Technology Innovation Fund(CX(21)1002)+1 种基金the Jiangsu Key Research and Development Program(BE2022365)the National Natural Science Foundation of China(3217047).
文摘Dear Editor,Rice serves as a staple food for over half of the global population,with fragrant varieties particularly valuable for their distinctive aroma,superior taste,and favorable cooking qualities.These attributes have been methodically perpetuated through generations via selective breeding(Prodhan and Qingyao,2020).The aroma quality of rice is predominantly determined by the concentration of 2-acetyl-1-pyrroline(2-AP),the key compound responsible for its characteristic fragrance(Okpala et al.,2019).The identification of the first aroma-causing gene in rice,BADH2,marked a critical advance in elucidating the genetic basis of rice aroma.This breakthrough was attributed to the discovery of a specific 8-bp deletion in the BADH2 gene on chromosome 8,which is closely associated with the aromatic trait across diverse rice varieties(Bradbury et al.,2005).The targeted genetic manipulation of the BADH2 gene via genetic engineering and genome-editing techniques has facilitated the development of multiple aromatic rice varieties(Shan et al.,2015;Tang et al.,2021;Hui et al.,2022).Nevertheless,the observed variability in 2-AP concentrations across different fragrant rice varieties,including those with a functional OsBADH2 gene,highlights the complexity of the genetic mechanisms that govern rice aroma.This suggests that,in addition to OsBADH2,other genetic alleles might also contribute to the synthesis of this key aromatic compound(Huang et al.,2008).
基金the funding support of the National Key R&D Program of China(No.2021YFF0701601)NSFC(No.22271053,22031004and 21921003)+1 种基金STCSM(No.21ZR1445900)Shanghai Municipal Education Commission(No.20212308).
文摘Aza-Heck cyclization of alkene-tethered oxime esters has received considerable attention as an effective strategy for synthesizing 1-pyrroline derivatives.However,the achievement of tandem aza-Heck reaction with alkyl electrophiles remains a challenge.Herein,we report a palladium-catalyzed tandem aza-Heck reaction of alkenetethered oxime esters with cyclopropanols.This catalytic system features mild conditions and broad substrate scopes,allowing the direct synthesis of structurally diverse 1-pyrroline derivatives in good yields.
文摘Electron paramagnetic resonance(EPR)is a spectroscopic approach that can directly and non-destructively detect and char-acterize species with unpaired electrons,such as radicals,transi-tion metal ions,defects in materials,and the excited triplet state of molecules[1].To date,the EPR technique has become an indis-pensable component in the toolbox of environmental studies.Using various diamagnetic probes(e.g.,5,5-dimethyl-1-pyrroline-N-oxide(DMPO))as the spin traps,transient reactive species can be transformed to EPR-detectable(meta)stable spin adducts,which enables radical identification and mechanism interpretation.Therefore,EPR constitutes a versatile platform for the mechanistic investigation of advanced oxidation processes(AOPs)in the field of water purification and contaminated groundwater remediation[2].
