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Effects of C-terminal amidation and heptapeptide ring on the biological activities and advanced structure of amurin-9KY, a novel antimicrobial peptide identified from the brown frog, Rana kunyuensis

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Zoological Research 2019年第3期40卷 198-204页

作者： Fen Zhang Zhi-Lai Guo Yan Chen Li Li Hai-Ning Yu Yi-Peng Wang Department of Pharmaceutical Sciences College of Pharmaceutical SciencesSoochow UniversitySuzhou Jiangsu 215123China Department of Bioscience and Biotechnology Dalian University of TechnologyDalian Liaoning 116023China School of Life Sciences Guizhou Normal UniversityGuiyang Guizhou 550001China

Rana kunyuensis is a species of brown frog that lives exclusively on Kunyu Mountain,Yantai,China.In the current study,a 279-bp cDNA sequence encoding a novel antimicrobial peptide (AMP),designated as amurin-9KY,was cloned from synthesized double-strand skin cDNA of R.kunyuensis.The amurin-9KY precursor was composed of 62 amino acid (aa) residues,whereas the mature peptide was composed of 14 aa and contained two cysteines forming a C-terminal heptapeptide ring (Rana box domain) and an amidated C-terminus.These structural characters represent a novel amphibian AMP family.Although amurin-9KY exhibited high similarity to the already identified amurin-9AM from R.amurensis,little is known about the structures and activities of amurin-9 family AMPs so far.Therefore,amurin-9KY and its three derivatives (amurin-9KY1-3) were designed and synthesized.The structures and activities were examined to evaluate the influence of C-terminal amidation and the heptapeptide ring on the activities and structure of amurin-9KY..Results indicated that C-terminal amidation was essential for antimicrobial activity,whereas both C-terminal amidation and the heptapeptide ring played roles in the low hemolytic activity.Circular dichroism (CD) spectra showed that the four peptides adopted an α-helical conformation in THF/H2O (v/v 1∶1) solution,but a random coil in aqueous solution.Elimination of the C-terminal heptapeptide ring generated two free cysteine residues with unpaired thiol groups,which greatly increased the concentration-dependent anti-oxidant activity.Scanning electron microscopy (SEM) was also performed to determine the possible bactericidal mechanisms.

关键词： Antimicrobial peptides Rana kunyuensis',Amurin-9KY Heptapeptide ring C-terminal amidation Structure activity relati on ship

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Cp^*Co(Ⅲ)-catalyzed C—H amidation of azines with dioxazolones

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Chinese Chemical Letters 2020年第12期31卷 3237-3240页

作者： Yanzhen Huang Chao Pi Zhen Tang Yangjie Wu Xiuling Cui Henan Key Laboratory of Chemical Biology and Organic Chemistry Key Laboratory of Applied Chemistry of Henan UniversitiesCollege of ChemistryGreen Catalysis CenterZhengzhou UniversityZhengzhou 450052China

Cp^*Co(Ⅲ)-catalyzed direct C—H amidation of azines has been developed.This co nversion could proceed smoothly in the absence of external oxidants,acids or bases,with excellent regioselectivity and broad functional group tolerance,CO2 was released as the sole byproduct,thus providing an environmentally benign amidation process.The products obtained are important intermediates in organic synthesis.

关键词： Cp^*Co(Ⅲ)-catalyzed Azines amidation Dioxazolone

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Rh-catalyzed Transient Directing Group Promoted C-H amidation of Benzaldehydes Utilizing Dioxazolones

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Chinese Journal of Chemistry 2018年第3期36卷 213-216页

作者： Xiaoyang Wang Song Song Ning Jiao State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical Sciences Peking University Xue Yuan Rd. 38 Beijing 200192 China State Key Laboratory of Organometallic Chemistry Chinese Academy of Sciences Shanghai 200032 China

Transition-metal catalyzed C--H functionalization of benzaldehydes is of great interest in organic synthesis. Herein, we developed a transient directing group assisted amidation of benzaldehydes catalyzed by rhodium catalyst. With the employment of 10 mol% of 4-trifluoromethyl aniline, the in situ generated imine groups as the directing group efficiently enable this transformation. By using this protocol, a wide range of benzaldehydes were efficiently converted into the corresponding N-（2-formylphenyl）benzamides utilizing dioxazolones as the nitrogen source.

关键词： amidation benzaldehydes rhodium C--H functionalization transient directing group

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Mn-Mediated Amide Synthesis via Transamidation of Tertiary Amides and amidation of Esters with Nitroarenes

Mn-Mediated Amide Synthesis via Transamidation of Tertiary A...

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中国化学会·第十六届全国有机合成化学学术研讨会

作者：张志伟 Ni Shen Shao-Peng Wang Asim Ullah Xile Hu Jun-An Ma 天津大学 Department of Chemistry Tianjin Key Laboratory of Molecular Optoelectronic Sciences and Tianjin Collaborative Innovation Center of Chemical Science & Engineering Tianjin University Laboratory of Inorganic Synthesis and Catalysis Institute of Chemical Sciences and Engineering Ecole Polytechnique Federale de Lausanne (EPFL)

Amides are the ubiquitous compounds in pharmaceutical,agrochemical,and materials chemistry.The study of streamlined synthesis of amides is among the important research areas in organic synthesis.amidation of carboxylic acids with aryl amines in the presence of stoichiometric coupling reagents has long been used to synthesize N-aryl amides.This conventional method requires the prior reduction of nitroarenes to arylamines for subsequent amidation.On the other hand,nitroarenes are more stable,more readily available,and less expensive than arylamines.Thus,the direct use of nitroarenes for amide synthesis would be more step-economical and practical.To this end,we describe two alternative methods for direct amide synthesis using nitroarenes as nitrogen sources.In the presence of Mn powder and TMSI additive,reductive transamidation of tertiary amides with nitroarenes proceeded smoothly（Figure 1,top）.Based on this work,we found that Mn metal could also mediate the reductive amidation of esters with nitroarenes（Figure 1,bottom）.These two protocols allowed the utilization of a wide range of tertiary amides,esters,and nitroarenes as substrates.A myriad of N-aryl amides could also be synthesized,including several druglike molecules.

关键词： N-aryl amides nitroarenes transamidation amidation reductive coupling

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Arene C-H Bond amidation via Photocatalytic Hydrogen Evolution Cross-Coupling Reactions

Arene C-H Bond Amidation via Photocatalytic Hydrogen Evoluti...

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中国化学会第二届全国光功能材料青年学者研讨会

作者： Yi-Wen Zheng Stefano Crespi Bin Chen Burkhard K?nig Chen-Ho Tung Li-Zhu Wu Technical Institute of Physics and Chemistry Chinese Academy of Sciences University of Regensburg

In comparison to the well-established approaches, a straightforward and high atom economic methodology for N-aryl amides synthesis with liberation of H2 without preactivation and the use of any directing group has been challenging. Herein, a hydrogen evolution cross-coupling photocatalytic system consisting of a quinolinum ion photocatalyst and a cobaloxime catalyst is utilized for inter/intramolecular amidation of arene C-H with amide N-H bonds with concomitant evolution of H2. This dual catalytic system could be applied for quinazolinones synthesis via a regioselective amidation of simple benzamides. Although photocatalytic hydrogen evolution cross-coupling has been applied in a broad range of transformations, the mechanistic studies lag far behind.Therefore, mechanism for this dual catalytic system were also thoroughly investigated and discussed here by experimental and computational studies.

关键词： C-H functionalization dehydrogenation amidation photocatalysis

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Rhodium(Ⅲ)-Catalyzed Intermolecular Unactivated Secondary C(sp3)-H Bond amidation Assisted by 3,5-Dimethylpyrazole

Rhodium(Ⅲ)-Catalyzed Intermolecular Unactivated Secondary C...

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中国化学会·第十六届全国有机合成化学学术研讨会

作者：王衍伟 Hongxin Liu Bin Li Baiquan Wang 南开大学 State Key Laboratory of Elemento-Organic Chemistry College of ChemistryNankai University

Transition-metal-catalyzed amination of unactivated C(sp)-H bond has undergone a breakthrough in recent years. However,most of them focus on the primary C(sp)-H bond. Direct amination of intermolecular unactivated secondary C(sp)-H bond still remains highly challenge.Herein,Rh(Ⅲ)-catalyzed intermolecular unactivated secondary C(sp)-H bond amidation reactions via nitrene insertion assisted by 3,5-dimetlylpyrazole have been developed.This procedure tolerates a broad substrates scope including chain and cyclic N-alklyamides under mild conditions.Notably,the directing group 3,5-dimethylpyrazole of chain N-alkylamide substrates could be easily removed via cascade intermolecular amidation and intramolecular cyclization in one-pot affording the sulfonylureas by increasing the reaction temperature.

关键词： rhodium unactivated amidation sulfonylureas

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Ir(Ⅲ)-catalyzed site-selective amidation of azoxybenzenes and late-stage transformation

Ir(Ⅲ)-catalyzed site-selective amidation of azoxybenzenes a...

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中国化学会第十四届全国有机合成化学学术研讨会

作者： Wenge Zhang Hong Deng Hongji Li Lei Wang School of Chemistry and Materials Science Huaibei Normal University

The nitrogen-containing heterocycles are widely present in many natural products,pharmaceutical targets,and functional materials.For such an important structure,several representative powerful methods,such as Buchwald-Hartwig amination,Chan-Lam coupling and Ullmann-Goldberg coupling reactions and others have been established for C–N bond formation.Despite substantial progress in amination,the enhancement of atom-efficiency and step-economy did not get well improved until group-directed C-H activation was adopted in recent years.In fact,excellent selectivity in the C-N bond–forming process was also achieved by employing the same strategy. An efficient ortho C–H amidation of azoxybenzenes with 1,4,2-dioxazol-5-ones under Ir(III)-catalysis has been developed.This simple amidation reaction provides a new protocol for the diversification of azoxybenzenes,and affords the aminated products in moderate to good yields..

关键词： azoxybenzenes amidation Ir-catalysis C-H activation

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Molecular modulating of cobalt phthalocyanines on aminofunctionalized carbon nanotubes for enhanced electrocatalytic CO_(2)conversion

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Nano Research 2023年第3期16卷 3649-3657页

作者： Huajian Xu Huizhu Cai Linxia Cui Limei Yu Rui Gao Chuan Shi State Key Laboratory of Fine Chemicals College of Chemical EngineeringDalian University of TechnologyDalian 116024China College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

Metal porphyrins and metal phthalocyanines(Pc)constitute a promising class of metal molecular catalysts(MMCs)for efficient CO_(2)-to-CO electrocatalytic conversion due to their well-defined molecular structures.How to adjust the local coordination and electronic environment of the metal center and enhance the molecular-level dispersion of the active components remains as great challenges for further improving the performance.Herein,a cobalt(II)Pc(CoPc)-COOH/carbon nanotube(CNT)-NH_(2)hybrid catalyst was rationally designed by clicking the CoPc-COOH molecules onto the surface of CNT-NH_(2)through amidation reaction.This novel hybrid catalyst exhibited the enhanced current density of 22.4 mA/cm2 and CO selectivity of 91%at−0.88 V vs.reversible hydrogen electrode(RHE)in the CO_(2)electroreduction,as compared with CoPc-COOH/CNT and CoPc/CNT samples.The superior activity was ascribed to the charge transfer induced by introduction of-COOH and-NH_(2)functional groups to CoPc and CNT,respectively,facilitating the active centers of CoI being generated at lower potentials,and leading to the highest turnover frequency(TOF)being obtained over the CoPc-COOH/CNT-NH_(2)hybrid catalyst.The inherent directivity and saturability of covalent bonds formed via the amidation reaction ensure not only a higher density of Co active centers,but also an improved stability for CO_(2)reduction reaction(CO_(2)RR).The present study represents an effective strategy for improving MMCs performance by molecular modulating of metal phthalocyanines on functionalized carbon substrates directed by click confinement chemistry.

关键词： electrocatalytic CO_(2)reduction cobalt tetracarboxylphthalocyanine amino functionalized carbon nanotubes amidation

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Adsorption Behavior of Reducing End-Modified Cellulose Nanocrystals:A Kinetic Study Using Quartz Crystal Microbalance

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Journal of Renewable Materials 2020年第1期8卷 29-43页

作者： Maud Chemin Céline Moreau Bernard Cathala Ana Villares INRAE UR BIAF-44316NantesFrance

In this work,we studied the adsorption of modified cellulose nanocrystals onto solid surfaces by quartz crystal microbalance with dissipation monitoring(QCM-D).Cellulose nanocrystals obtained from tunicate(CNC)were modified at reducing end by amidation reactions.Two different functionalities were investigated:a polyamine dendrimer(CNC-NH_(2)),which interacts with gold surface by the amine groups;and a biotin moiety(CNC-Biot),which has a strong affinity for the protein streptavidin(SAV).QCM-D results revealed different adsorption behaviors between modified and unmodified CNCs.Hence,unmodified CNCs covered almost all the surface forming a rigid and flat layer whereas reducing end modified CNCs remained rather upright forming a hydrated and viscoelastic layer with lower surface coverage.The analysis of adsorption kinetics allowed the calculation of an apparent collision rate factor,which resulted 10-fold higher for unmodified CNCs compared to reducing end modified CNCs,therefore,demonstrating the different adsorption behavior.

关键词： Cellulose nanocrystals amidation reducing-end modification Voight model collision rate efficiency factor rate constant

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Construction of [1]rotaxanes with pillar[5]arene as the wheel and terpyridine as the stopper

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Chinese Chemical Letters 2020年第1期31卷 81-83页

作者： Ling-Ling Zhao Ying Han Chao-Guo Yan College of Chemistry & Chemical Engineering Yangzhou University

The condensation reaction ofω-aminoalkyleneamide-functionalized pillar[5]arenes with 2-(4-([2,2’:6’,2〃-terpyridin]-4’-yl)phenoxy)acetic acid or 4-(4-([2,2’:6’,2"-terpyridin]-4’-yl)phenoxy)butanoic acid in dry chloroform at room temperature under the catalysis of HOBT/EDCl resulted in novel pillar[5]arene diamido-bridged terpyridine derivatives.~1 H NMR and 2 D NOESY spectra clearly indicated that the interesting[1]rotaxanes were formed by longer alkylene such as propylene,butylene and hexylenediamido chains threading into the cavity of the pillar[5]arene and with larger terpyridine acting as the stopper.However,the shorter ethylenediamido chain only exists outer of cavity of pillar[5]arene and the molecule exist on free form.

关键词： Pillararene TerpyridineRotaxane amidation Interlocked molecule

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