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Unraveling the condensation reactions of heterometallic {BiNb_(4)} moieties into hybrid Bi_(x)Nb_(y)-oxo clusters with mass spectrometry 认领
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作者 Lv-Bing Yuan Ya-Yong Sun +1 位作者 Jian Zhang Lei Zhang 《中国科学:化学英文版》 SCIE EI CAS 2021年第3期413-418,共6页
The most effective methodologies for the construction of polynuclear complexes usually take advantage of preorganized building blocks.Herein,we successfully developed a new versatile heterometallic{BiNb_(4)}moiety,whi... The most effective methodologies for the construction of polynuclear complexes usually take advantage of preorganized building blocks.Herein,we successfully developed a new versatile heterometallic{BiNb_(4)}moiety,which can be applied for the assembly of less explored organic-inorganic hybrid polyoxoniobates.Through controlled condensation reactions,three{BiNb_(4)}moieties can be assembled into a pair of isomeric Bi_(3)Nb_(18)clusters at different temperatures;whilst four{BiNb_(4)}moieties can be combined into two unique Bi_(4)Nb_(16)and Bi_(4)Nb_(18)tetramers in different solvents.Interestingly,we have used mass spectrometry to probe the above condensation reactions,which clearly confirmed a stepwise bottom-up assembly process by capturing the presence of bismuth subsalicylate precursors,salicylate coordinated intermediates,Nb incorporated{BiNb_(4)}moieties and the final Bi_(x)Nb_(y)-oxo clusters,respectively.Moreover,the packing modes of the{BiNb_(4)}units induce different solution behaviors,and the{BiNb_(4)}units in Bi4Nb16can be recombined by post-synthetic recrystallization in acetonitrile to produce a new tetramer Bi_(4)Nb_(18)-R.Therefore,this work provides not only a useful{BiNb_(4)}building unit but also the mechanism for their condensation,both of which will promote the future development of metal-oxo clusters. 展开更多
关键词 CONDENSATION CLUSTERS MOIETY
Asymmetric dimethylarginine-induced oxidative damage leads to cerebrovascular dysfunction 认领
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作者 Mushfiquddin Khan Inderjit Singh Jeseong Won 《中国神经再生研究:英文版》 SCIE CAS 2021年第9期1793-1794,共2页
Asymmetric dimethylarginine(ADMA) and its enantiomer, symmetric dimethylarginine(SDMA), are naturally-occurring methylated metabolites of the L-arginine amino acid moiety of proteins followed by proteolysis(Grosse et ... Asymmetric dimethylarginine(ADMA) and its enantiomer, symmetric dimethylarginine(SDMA), are naturally-occurring methylated metabolites of the L-arginine amino acid moiety of proteins followed by proteolysis(Grosse et al., 2020). These metabolites were first identified in human urine in 1970. 展开更多
关键词 OXIDATIVE MOIETY SYMMETRIC
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An A-D-A′-D-A type unfused nonfullerene acceptor for organic solar cells with approaching 14%efficiency 认领
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作者 Xingzheng Liu Yanan Wei +3 位作者 Xin Zhang Linqing Qin Zhixiang Wei Hui Huang 《中国科学:化学英文版》 SCIE EI CAS 2021年第2期228-231,共4页
In recent years,power conversion efficiency(PCE)of organic solar cells(OSCs)has made significant improvement.A large number of studies were reported to achieve high PCEs through exploring new active layer materials,es... In recent years,power conversion efficiency(PCE)of organic solar cells(OSCs)has made significant improvement.A large number of studies were reported to achieve high PCEs through exploring new active layer materials,especially the high efficiency fused ring acceptors(FRAs).Compared with FRAs,another type of so-called unfused-ring acceptors(UFAs),possessing some advantages such as simple synthesis and low cost,have attracted a lot of attention.Herein,a new UFA BTzO-4F,incorporating with a benzotriazole moiety and S···O intramolecular noncovalent interactions,has been successfully synthesized.The photovoltaic device based on PBDB-T:BTzO-4F achieved a record PCE of 13.8%for UFAs,which indicates that introducing the benzotriazole moiety is an effective strategy for high quality acceptors.Thus,these findings of this work demonstrate the great potential of UFAs for high performance OSCs. 展开更多
关键词 organic solar cells unfused nonfullerene acceptor benzotriazole moiety
Effects of Different Eelectron-withdrawing Moieties on the General Photoelectric Properties of Fluorene-based Dimers 认领
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作者 YUAN Xinlei LI Jie +2 位作者 LU Zhiwei YE Shanghui JIANG Hongji 《高等学校化学研究:英文版》 SCIE CAS CSCD 2020年第6期1174-1182,共9页
Here,9,9.9'-tris(4-butoxyphenyl)-9H-9'Hl-2,2'-difluorene(DF)was synthesized as a reference for compa rison,and diphenyl sulfone and triphenylphosphine oxygen were introduced to the 9-position of fluorene t... Here,9,9.9'-tris(4-butoxyphenyl)-9H-9'Hl-2,2'-difluorene(DF)was synthesized as a reference for compa rison,and diphenyl sulfone and triphenylphosphine oxygen were introduced to the 9-position of fluorene througha C-H coupling reaction to produce two fluorene-based oligomers 9′,9′″-sulfonylbis(4.1-phenylene)bis9,9′,9′tris(4-butoxyphenyl)-9H,9'H-2.2'-bifluorene(DF)SOz and phenylbis(4-{9.9,9-tris(4-butoxyphenyl)-9H,9'H-12.2-bif-luorenel-9-yl} phenyl)phosphine oxidel(DF)2POI.Solid powders of all the three compounds exhibit excellent therma stability with thermal temperature at 5%mass loss of 375,429 and 383 C for(DF)2SO2,(DF)PO and DF.In addition,owing to the distorted molecular structure and weak electron-absorbing ability of the acceptor,(DF)Soz and(DF)2PO do not have obvious intramolecular charge transfer characteristics.and exhibit stable localized 394 nm/375 nm fluorescence emission peaks in different polar solvents.The absolute luminescence quantumefficiencies of(DF)2S02,(DF)PO and DF solid powders are 20.83%,10.03%and 59.46%,Compound DF has the highest quantum yield as an electron donor.The chromaticity coordinates of the blue OLED devices based on DF and DF2SO2 fabricated by solution spin coating were(0.19.0.10)and(0.19.0.11).which were closest to the deep blue region,and the corresponding maximum external quantum efficiencies are 1.45%and 0.87%,respectively,which are higher than that of(DF)2PO(0.25%)and consistent with the difference in the solid-state quantum efficiency between them. 展开更多
关键词 Organic light emitting-diode:Electron-withdrawing moiety FLUORENE Diphenyl sulfone:Tri-phenylphosphine oxide
Atomically Dispersed Fe-N_4 Modified with Precisely Located S for Highly Efficient Oxygen Reduction 认领
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作者 Yin Jia Xuya Xiong +9 位作者 Danni Wang Xinxuan Duan Kai Sun Yajie Li Lirong Zheng Wenfeng Lin Mingdong Dong Guoxin Zhang Wen Liu Xiaoming Sun 《纳微快报:英文版》 SCIE EI CAS CSCD 2020年第9期123-135,共13页
Immobilizing metal atoms by multiple nitrogen atoms has triggered exceptional catalytic activity toward many critical electrochemical reactions due to their merits of highly unsaturated coordination and strong metal-s... Immobilizing metal atoms by multiple nitrogen atoms has triggered exceptional catalytic activity toward many critical electrochemical reactions due to their merits of highly unsaturated coordination and strong metal-substrate interaction.Herein,atomically dispersed Fe-NC material with precise sulfur modification to Fe periphery(termed as Fe-NSC) was synthesized,X-ray absorption near edge structure analysis confirmed the central Fe atom being stabilized in a specific configuration of Fe(N3)(N-C-S).By enabling precisely localized S doping,the electronic structure of Fe-N4 moiety could be mediated,leading to the beneficial adjustment of absorption/desorption properties of reactant/intermediate on Fe center.Density functional theory simulation suggested that more negative charge density would be localized over Fe-N4 moiety after S doping,allowing weakened binding capability to *OH intermediates and faster charge transfer from Fe center to O species.Electrochemical measurements revealed that the Fe-NSC sample exhibited significantly enhanced oxygen reduction reaction performance compared to the S-free Fe-NC material(termed as Fe-NC),showing an excellent onset potential of 1.09 V and half-wave potential of 0.92 V in 0.1 M KOH.Our work may enlighten relevant studies regarding to accessing improvement on the catalytic performance of atomically dispersed M-NC materials by managing precisely tuned local environments of M-Nx moiety. 展开更多
关键词 Atomic dispersion Iron–nitrogen moiety Electronic structure Sulfur doping Oxygen reduction
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Quantification of the Activation Capabilities of Lewis/Brφnsted Acid for Electrophilic Trifluoromethylthiolating Reagents 认领
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作者 Huiying Kang Biying Zhou +2 位作者 Man Li Xiao-Song Xue Jin-Pei Cheng 《中国化学:英文版》 SCIE CAS CSCD 2020年第2期130-134,共5页
Summary of main observation and conclusion Electrophilic trifluoromethylthiolation has emerged as an important and efficient methodology for installing the SCF3 moiety onto an array of organic molecules.Due to the low... Summary of main observation and conclusion Electrophilic trifluoromethylthiolation has emerged as an important and efficient methodology for installing the SCF3 moiety onto an array of organic molecules.Due to the low reactivities of trifluoromethylthiolating reagents,these transformations often require activation through an exogenous Lewis/Br0nsted acid.We report herein the quantification of the activation capabilities of Lewis/Br0nsted acids for trifluoromethylthiolating reagents through computing the differenee in trifluoromethylthio cation donor ability(Tt+DA)between the"activated"and"unactivated"reagent.A moderate correlation is found to exist between the activation capability and Lewis acidity. 展开更多
关键词 activation MOIETY DONOR
Syntheses and Insecticidal Activity of Spirocyclic Tetronic Acid Derivatives Containing Oxime Ether Moiety 认领
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作者 ZHAO Yang CHENG Jingli +2 位作者 XIE Zhengang FANG Shaowei ZHAO Jinhao 《高等学校化学研究:英文版》 SCIE CAS CSCD 2020年第5期810-815,共6页
In order to develop novel spirocyclic tetronic acid lead compounds,a series of new spirocyclic tetronic acid derivatives containing oxime ether moiety was synthesized and bioassayed.The stmctures of 16 target compound... In order to develop novel spirocyclic tetronic acid lead compounds,a series of new spirocyclic tetronic acid derivatives containing oxime ether moiety was synthesized and bioassayed.The stmctures of 16 target compounds were characterized by lH NMR spectra,13C NMR spectra and high-resolution mass spectrometer(HRMS).Preliminary bioassays indicated that most of the title compounds displayed excellent insecticidal activity against Aphis fabae and Nilapmyata lugens at 100 mg/L.In particular,compound 6k showed the similar activity(LC50=6.87 mg/L)against A.fabae as the spirotetramat(LC50=4.56 mg/L)and had better efIects(LC50=l.64 mg/L)against N.lugens in comparison with spirotetramat(LC5o=7.90 mg/L).The study showed that compound 6k exhibited more promising and broad-spectrum insecticide activity and may serve as a new insecticidal agent for sucking pests. 展开更多
关键词 Spirocyclic tetronic acid derivative Insecticidal activity Oxime ether moiety
Copper-Catalyzed Modular Access to N-Fused Polycyclic Indoles and 5-Aroyl-pyrrol-2-ones via Intramolecular N-H/C-H Annulation with Alkynes:Scope and Mechanism Probes 认领
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作者 Yan-Hua Liu Hong Song +2 位作者 Chi Zhang Yue-Jin Liu Bing-Feng Shi 《中国化学:英文版》 SCIE CAS CSCD 2020年第12期1545-1552,共8页
of main observation and concusion Copper-catalyzed intramolecular N-H/C-H annulation with alkynes has been developed.A vaniety ofdensely functionalized heterocycles,such as pyrrolo[1,2-ajindoles,indolo[1,2-cjquinazoli... of main observation and concusion Copper-catalyzed intramolecular N-H/C-H annulation with alkynes has been developed.A vaniety ofdensely functionalized heterocycles,such as pyrrolo[1,2-ajindoles,indolo[1,2-cjquinazolin-2-ones,oxazolo[3,4-ojindoles,and imidazo[1.5-ojindoles,eresynthesized in an atom-and step-economical manner,owing to the high modularized feature of aniline moiety te linker moiety,as well as the alkynemoiety.By simply changing the oxidant from di-tert-butyl peroxide(DTBP)to 2,2,6.6-tetramethylpiperidine-1-oxyl(TEMPo)the reacton could readily betransformed to the aminooxygenation pathway,which grabs one oxygen atom from the TEMPO to generate 5-aroy'-pyrrol-2-ones.Mechanistic experi-ments indicate that viny radical is involved in this reaction and an amidyl-radical-initiated radical cascade might be responsible for this transformation. 展开更多
关键词 moiety Copper radical
Single-atom catalysts: The role of intrinsic intermediate 认领
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作者 Yafei Li 《绿色能源与环境:英文版》 CSCD 2020年第1期4-5,共2页
Metal-N-C single-atom catalysts(SACs)have emerged as alternatives to platinum for catalyzing the otherwise sluggish oxygen reduction reaction(ORR)[1].Fe-N-CSACs rank among the most promising candidates[2],of which the... Metal-N-C single-atom catalysts(SACs)have emerged as alternatives to platinum for catalyzing the otherwise sluggish oxygen reduction reaction(ORR)[1].Fe-N-CSACs rank among the most promising candidates[2],of which the active center is proposed as a carbon-hosted FeN4 moiety with the Fe atombeing single-atom(SA)state(Fig.1a).Such a well-defined configuration renders Fe-N-C a model catalyst to study ORR in an atomistic way.The catalytic process on SA Fe of the FeN4 center has been elucidated by using the modern in silico modeling and structural characterizations.Despite the agreement of the key role ofSAFe in the literature,it is still controversial howSAFe boosts ORRgiven that the predicted potentials calculated using the FeN4 moiety deviate from experimental ones,hampering further development of ideal SACs.Therefore,it is imperative to get deeper understanding of the reaction pathway while considering the dynamic ORR process. 展开更多
关键词 process. MOIETY otherwise
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The crucial role of metabolic regulation in differential hepatotoxicity induced by furanoids in Dioscorea bulbifera 认领
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作者 WU Zi-Tian LI Zhuo-Qing +4 位作者 SHI Wei WANG Ling-Li JIANG Yan LI Ping LI Hui-Jun 《中国天然药物:英文版》 SCIE CAS CSCD 2020年第1期57-69,共13页
Diterpenoid lactones(DLs),a group of furan-containing compounds found in Dioscorea bulbifera L.(DB),have been reported to be associated with hepatotoxicity.Different hepatotoxicities of these DLs have been observed in... Diterpenoid lactones(DLs),a group of furan-containing compounds found in Dioscorea bulbifera L.(DB),have been reported to be associated with hepatotoxicity.Different hepatotoxicities of these DLs have been observed in vitro,but reasonable explanations for the differential hepatotoxicity have not been provided.Herein,the present study aimed to confirm the potential factors that contribute to varied hepatotoxicity of four representative DLs(diosbulbins A,B,C,F).In vitro toxic effects were evaluated in various cell models and the interactions between DLs and CYP3 A4 at the atomic level were simulated by molecular docking.Results showed that DLs exhibited varied cytotoxicities,and that CYP3 A4 played a modulatory role in this process.Moreover,structural variation may cause different affinities between DLs and CYP3 A4,which was positively correlated with the observation of cytotoxicity.In addition,analysis of the glutathione(GSH)conjugates indicated that reactive intermediates were formed by metabolic oxidation that occurred on the furan moiety of DLs,whereas,GSH consumption analysis reflected the consistency between the reactive metabolites and the hepatotoxicity.Collectively,our findings illustrated that the metabolic regulation played a crucial role in generating the varied hepatotoxicity of DLs. 展开更多
关键词 DIOSCOREA bulbifera DITERPENOID LACTONES Metabolic regulation HEPATOTOXICITY FURAN MOIETY
Isoxazolone Reactivity Explained by Computed Electronic Structure Analysis 认领
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作者 Giovanni Bella Antonio Santoro +2 位作者 Massimiliano Cordaro Francesco Nicolò Giuseppe Bruno 《中国化学:英文版》 SCIE CAS CSCD 2020年第2期163-168,共6页
Summary of main observation and conclusion lsoxazol(2H)-5-one was chosen as a model molecule to study the structural features(a,p angles and carbonyl bond length)regarding lactone moiety in the isoxazolone species by ... Summary of main observation and conclusion lsoxazol(2H)-5-one was chosen as a model molecule to study the structural features(a,p angles and carbonyl bond length)regarding lactone moiety in the isoxazolone species by computational calculation.DFT method with B3LYP 6-311++G(2df,2p)basis set was used to carry out the optimization on a series(A and B families)of isoxazolones suitably substituted on double bond. 展开更多
关键词 calculation. MOIETY SUBSTITUTED
Regioselective oxidation of tetracycline by permanganate through alternating susceptible moiety and increasing electron donating ability 认领
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作者 Xiaohua Jiang William AJefferson +6 位作者 Dean Song Hanyang Cheng Fengmin Li Zhimin Qiang Aiqian Zhang Huijuan Liu Jiuhui Qu 《环境科学学报:英文版》 SCIE EI CAS CSCD 2020年第1期281-288,共8页
Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental pollutants.However,few studies have discussed the feature of regioselective reactivity of permangan... Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental pollutants.However,few studies have discussed the feature of regioselective reactivity of permanganate with specific moiety of the target compound.Herein,we studied the reaction between permanganate and tetracycline that is an emerging micropollutant with different species containing several electron-rich groups.The second-order rate constants increased from 6.0 to 9.0 and could be quantitatively modeled by considering the speciation of both reactants,yielding kTC0=11.7(mol/L)^-1 sec^-1,kTC-=35.7(mol/L)^-1 sec^-1,kTC2-=43.1(mol/L)^-1 sec^-1 for individual reaction channels.Degradation products were then identified as the hydroxylated and demethylated compounds.The result suggested a rate-limiting step of simple hydroxylation at the phenolic and/or alkene moieties,while the demethylation should be caused by the unavoidably formed manganese oxide via single electron oxidation.This is supported by the DFT calculation,indicating the primary oxidation of phenolic group of TC0 with activation barrier of 44.5 kcal/mol and of alkene group of TC-and TC2-with activation barriers of 44.0 and 43.4 kcal/mol,respectively.This is in agreement with the experimental results,implying the alternation of regioselectivity associated with the deprotonation process.The result was further supported by performing the Fukui function and electrostatic potential analysis,reflecting the more probable site and better electron donating tendency beneficial to the permanganate oxidation. 展开更多
关键词 PERMANGANATE oxidation of TETRACYCLINE Regioselective reactivity Rate-limiting HYDROXYLATION step Altered SUSCEPTIBLE MOIETY Increased ELECTRONEGATIVITY
Important role of a LAL regulator Sta R in the staurosporine biosynthesis and high-production of Streptomyces fradiae CGMCC 4.576 认领 被引量：1
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作者 Hanye Guan Yue Li +3 位作者 Jiazhen Zheng Ning Liu Jihui Zhang Huarong Tan 《中国科学:生命科学英文版》 SCIE CAS CSCD 2019年第12期1638-1654,共17页
Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clu... Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clusters(cluster A and cluster B),corresponding to biosyntheses of K-252 c(staurosporine aglycone) and sugar moiety, were identified in Streptomyces fradiae CGMCC 4.576 and heterologously expressed in Streptomyces coelicolor M1146 separately or together. Sta R, a cluster-situated LAL family regulator, activates staurosporine biosynthesis by binding to the promoter regions of sta O-sta C and sta G-sta N. The conserved sequences GGGGG and GCGCG were found through gradually truncating promoters of sta O and sta G, and further determined by mutational experiments. Overexpression of sta R with the supplementation of 0.01 g L^–1 Fe SO4 increased staurosporine production to 5.2-fold compared with that of the parental strain Streptomyces fradiae CGMCC 4.576 in GYM medium. Our results provided an approach for improvement of staurosporine production mediated by a positive regulator and established the basis for dissecting the regulatory mechanisms of other indolocarbazole compounds with clinical application value. 展开更多
关键词 value. CLUSTER MOIETY
Synthesis and Antitumor Activity of Sorafenib Analogs Containing a Tetrazole Moiety 认领
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作者 TIAN Ye YU Simiao +5 位作者 CAI Lude GONG Guowei WU Guodong QI Hongxia ZHAO Yanfang QIN Mingze 《高等学校化学研究:英文版》 SCIE CAS CSCD 2019年第1期41-46,共6页
A novel series of diaryl biuret derivatives containing a tetrazole moiety was designed and synthesized.All the target compounds were evaluated for their in vitro antitumor activity against HT-29,HepG2,MCF-7 and A549 c... A novel series of diaryl biuret derivatives containing a tetrazole moiety was designed and synthesized.All the target compounds were evaluated for their in vitro antitumor activity against HT-29,HepG2,MCF-7 and A549 cells by MTT assay.Most of them exhibited obvious antitumor activity,and four of them(4a,4c,4h and 7a)were superior to sorafenib in general.Among them,Compound 4h displayed more potent activity than sorafenib in all tested cancer cells.Compound 4c exhibited the most outstanding activity in inhibition of growth of HepG2 cells(IC50=0.55 μmol/L).Further,they both revealed favorable metabolic stability in in vitro assay.Compounds 4c and 4h are promising candidates for further development. 展开更多
关键词 SORAFENIB DERIVATIVE TETRAZOLE MOIETY ANTITUMOR activity
Nucleoside diphosphate-linked moiety X-type motif 15 R139C genotypes impact 6-thioguanine nucleotide cut-off levels to predict thiopurine-induced leukopenia in Crohn’s disease patients 认领 被引量：1
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作者 Xia Zhu Kang Chao +7 位作者 Miao Li Wen Xie Hong Zheng Jin-Xin Zhang Pin-Jin Hu Min Huang Xiang Gao Xue-Ding Wang 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第38期5850-5861,共12页
BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants signif... BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants significantly improve the predictive sensitivity of TIL,more than 50%of cases of this toxicity cannot be predicted by this mutation.The potential use of the 6-thioguanine nucleotide(6TGN)level to predict TIL has been explored,but no decisive conclusion has been reached.Can we increase the predictive sensitivity based on 6TGN by subgrouping patients according to their NUDT15 R139C genotypes?AIM To determine the 6TGN cut-off levels after dividing patients into subgroups according to their NUDT15 R139C genotypes.METHODS Patients’clinical and epidemiological characteristics were collected from medical records from July 2014 to February 2017.NUDT15 R139C,thiopurine S methyltransferase,and 6TGN concentrations were measured.RESULTS A total of 411 Crohn’s disease patients were included.TIL was observed in 72 individuals with a median 6TGN level of 323.4 pmol/8×10^8 red blood cells(RBC),which was not different from that of patients without TIL(P=0.071).Then,we compared the 6TGN levels based on NUDT15 R139C.For CC(n=342)and CT(n=65)genotypes,the median 6TGN level in patients with TIL was significantly higher than that in patients without(474.8 vs 306.0 pmol/8×10^8 RBC,P=9.4×10-^5;291.7 vs 217.6 pmol/8×10^8 RBC,P=0.039,respectively).The four TT carriers developed TIL,with a median 6TGN concentration of 135.8 pmol/8×10^8 RBC.The 6TGN cut-off levels were 411.5 and 319.2 pmol/8×108 RBC for the CC and CT groups,respectively.CONCLUSION The predictive sensitivity of TIL based on 6TGN is dramatically increased after subgrouping according to NUDT15 R139C genotypes.Applying 6TGN cut-off levels to adjust thiopurine therapies based on NUDT15 is strongly recommended. 展开更多
关键词 Crohn’s disease Thioguanine NUCLEOTIDE levels NUCLEOSIDE diphosphatelinked MOIETY X-type MOTIF 15 Thiopurine-induced LEUKOPENIA
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Fe2N nanoparticles boosting FeNx moieties for highly efficient oxygen reduction reaction in Fe-N-C porous catalyst 认领 被引量：3
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作者 Xiao Liu Hong Liu +6 位作者 Chi Chen Liangliang Zou Yuan Li Qing Zhang Bo Yang Zhiqing Zou Hui Yang 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第7期1651-1657,共7页
Replacing Pt-based electrocatalysts for the oxygen reduction reaction (ORR) with high performance and low-cost non-precious metal catalysts is crucial for the commercialization of fuel cells.Herein,we present a highly... Replacing Pt-based electrocatalysts for the oxygen reduction reaction (ORR) with high performance and low-cost non-precious metal catalysts is crucial for the commercialization of fuel cells.Herein,we present a highly efficient Fe-N-C porous ORR electrocatalyst with FeNx moieties promoted by Fe2N nanoparticles derived from Fe-doped zeolitic imidazolate framework.The best-performing Fe-N-C/HPC-NH3 catalyst exhibits a superior ORR activity with an onset (E0) and half-wave (E1/2) potential of 0.945 and 0.803 V (RHE),respectively,which is comparable to those of the commercial Pt/C in acidic media.Probing and acid-leaching experiments prove that FeNx moieties play an important role in the ORR and the Fe2N can further improve the ORR activity.Density functional theory calculation reveals a synergistic effect that the existence of Fe2N weakens the adsorption of ORR intermediates on active sites and lowers the reaction free energy of the potential limiting step,thus facilitating the ORR.Both experimental evidence and theoretical analysis for the enhancement of ORR activity by Fe2N decoration in Fe-N-C catalyst might inspire a new strategy for rational design of high performance non-precious metal catalysts. 展开更多
关键词 non-precious metal oxygen reduction reaction Fe2N NANOPARTICLE FeNx MOIETY PROTON exchange membrane fuel cell
Synthetic Approach for Novel Fluorine Substituted <i>α</i>-Aminophosphonic Acids Containing 1,2,4-Triazin-5-One Moiety as Antioxidant Agents 认领
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作者 Mohammed S. T. Makki Reda M. Abdel-Rahman Abdulrahman S. Alharbi 《有机化学国际期刊(英文)》 2018年第1期1-15,共15页
Novel fluorine substituted α-amino phosphonic acids containing 1,2,4-triazin- 5-one (6a-f) have been obtained from fluoroacylation of 6-(2&prime;-amino-5&prime;-nitrophenyl)-3-thioxo-1,2,4-triazin-5(4H)-one (... Novel fluorine substituted α-amino phosphonic acids containing 1,2,4-triazin- 5-one (6a-f) have been obtained from fluoroacylation of 6-(2&prime;-amino-5&prime;-nitrophenyl)-3-thioxo-1,2,4-triazin-5(4H)-one (1) followed by ammonilysis to give the corresponding 3-amino-derivative 3. Condensation of compound 3 with nitro/halogenated aromatic aldehydes yielded the Schiff bases 4. The simple addition of diethyl phosphonate to compound 4 produced the α-amino phosphonates 5. Acidic hydrolysis of compound 5 produced the fluorine substituted α-amino acids derivatives 6. Structures of the new compounds have been established with the help of elemental analysis and spectral measurements. Also, the products evaluated as antioxidants, where the fluorinated α-amino phosphonic acids 6 are more active than the other synthesized systems. 展开更多
关键词 Synthetic FLUORINE α-Amino Acids 1 2 4-Triazin-5-One MOIETY ANTIOXIDANTS Activity
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Substrate specificity of the cypemycin decarboxylase CypD 认领
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作者 Wei Ding Tianlu Mo +1 位作者 Dhanaraju Mandalapu Qi Zhang 《合成和系统生物技术》 SCIE 2018年第3期159-162,共4页
The linaridin antibiotic cypemycin is a ribosomal synthesized and post-translationally modified peptide(RiPP)that possesses potent activity against mouse leukemia cells.This peptide natural product contains an S-[(Z)-... The linaridin antibiotic cypemycin is a ribosomal synthesized and post-translationally modified peptide(RiPP)that possesses potent activity against mouse leukemia cells.This peptide natural product contains an S-[(Z)-2-aminovinyl]-D-cysteine(AviCys)moiety in the C-terminus.Formation of AviCys moiety requires an oxidative decarboxylation of the C-terminal Cys of the precursor peptide CypA,and this process is catalyzed by a flavin-containing protein CypD.In this work,we tested CypD substrate specificity with a series of synthetic oligopeptides.We show that most of the N-terminal sequence of CypA is not required for CypD activity,and the Cterminal three residues serve as the minimal structural element for enzyme recognition.We also show that CypD tolerates various substrates with modified C-termini,allowing for the generation of four novel cypemycin variants with modified AviCys moiety by site direct mutagenesis of the precursor peptide CypA.Our study demonstrates the relaxed substrate specificity of CypD and lays a foundation for future bioengineering of AviCys-containing natural products. 展开更多
关键词 MOIETY OXIDATIVE relaxed
新型含七氟异丙基结构的吡唑酰胺类化合物的合成与杀虫活性研究 认领 被引量：4
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作者 洪宇 戴红 +6 位作者 叶林玉 仲苏林 曹雄飞 石玉军 李春建 石健 施磊 《有机化学》 CSCD 北大核心 2017年第11期3006-3012,共7页
为了寻找具有较好生物活性的吡唑类化合物,通过活性亚结构拼接的方法,设计并合成了一系列未见文献报道的新型含七氟异丙基结构的吡唑酰胺类衍生物.利用~1H NMR、~（13）C NMR和元素分析等手段确证了目标化合物的结构.初步的生物活性测... 为了寻找具有较好生物活性的吡唑类化合物,通过活性亚结构拼接的方法,设计并合成了一系列未见文献报道的新型含七氟异丙基结构的吡唑酰胺类衍生物.利用~1H NMR、~（13）C NMR和元素分析等手段确证了目标化合物的结构.初步的生物活性测试结果显示,部分目标化合物表现出较好的杀虫活性.在测试浓度为500μg/m L时,有11个化合物对粘虫的杀灭活性可达60%~100%.当测试浓度降为100μg/m L时,3个化合物对粘虫的杀死率可达60%~70%,优于对照药剂唑虫酰胺的药效. 展开更多
关键词 七氟异丙基 吡唑 合成 杀虫活性
Factors predicting aggressiveness of non-hypervascularhepatic nodules detected on hepatobiliary phase ofgadolinium ethoxybenzyl diethylene-triamine-pentaacetic-acidmagnetic resonance imaging 认领
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《世界胃肠病学杂志：英文版（电子版）》 SCIE CAS 2015年第15期4583-4591,共9页
AIM： To establish a prognostic formula that distinguishesnon-hypervascular hepatic nodules （NHNs） with higheraggressiveness from less hazardous one.METHODS： Seventy-three NHNs were detected ingadolinium ethoxybenz... AIM： To establish a prognostic formula that distinguishesnon-hypervascular hepatic nodules （NHNs） with higheraggressiveness from less hazardous one.METHODS： Seventy-three NHNs were detected ingadolinium ethoxybenzyl diethylene-triamine-pentaaceticacidmagnetic resonance imaging （Gd-EOB-DTPA-MRI）study and confirmed to change 2 mm or more in size and/or to gain hypervascularity. All images were interpretedindependently by an experienced, board-certifiedabdominal radiologist and hepatologist; both knew that the patients were at risk for hepatocellular carcinomadevelopment but were blinded to the clinical information.A formula predicting NHN destiny was developedusing a generalized estimating equation model withthirteen explanatory variables： age, gender, backgroundliver diseases, Child-Pugh class, NHN diameter, T1-weighted imaging/T2-weighted imaging detectability, fatdeposition, lower signal intensity in arterial phase, lowersignal intensity in equilibrium phase, α-fetoprotein, des-γ-carboxy prothrombin, α-fetoprotein-L3, and coexistenceof classical hepatocellular carcinoma. The accuracy of theformula was validated in bootstrap samples that werecreated by resampling of 1000 iterations.RESULTS： During a median follow-up period of 504 d,73 NHNs with a median diameter of 9 mm （interquartilerange： 8-12 mm） grew or shrank by 68.5% （fiftynodules） or 20.5% （fifteen nodules）, respectively,whereas hypervascularity developed in 38.4% （twentyeight nodules）. In the fifteen shrank nodules, twelvenodules disappeared, while 11.0% （eight nodules） werestable in size but acquired vascularity. A generalizedestimating equation analysis selected five explanatoriesfrom the thirteen variables as significant factors topredict NHN progression. The estimated regressioncoefficients were 0.36 for age, 6.51 for lower signalintensity in arterial phase, 8.70 or 6.03 for positivityof hepatitis B virus or hepatitis C virus, 9.37 for des-γ-carboxy prothrombin, and -4.05 for fat deposition.A formula incorpora 展开更多
关键词 Hepatocellular carcinoma Magnetic resonanceimaging Ethoxybenzyl MOIETY Non-hypervascular hepaticnodule Fate prediction
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