共查询到20条相似文献,搜索用时 31 毫秒
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综述了核磁共振技术对映体纯度测定中的应用,它包括三个方面:(1)手性衍生剂法;(2)手性镧系位移试剂法;(3)手性溶剂法,对三种方法的测定机理和特点也做了讨论,全文共65篇参考文献。 相似文献
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Two 1H-2,3-dihydropyrrolizine derivatives bearing a nitro group at the 6 position have been synthesized and an improved method for nitrating pyrroles using potassium nitrate in trifluoroacetic acid was developed. An efficient, two-step synthesis of the butterfly pheromone, Danaidone, was also developed with an overall 33% yield. 相似文献
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Platinum(II)–Gadolinium(III) Complexes as Potential Single‐Molecular Theranostic Agents for Cancer Treatment
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Zhenzhu Zhu Prof. Dr. Xiaoyong Wang Dr. Tuanjie Li Prof. Dr. Silvio Aime Prof. Dr. Peter J. Sadler Prof. Dr. Zijian Guo 《Angewandte Chemie (International ed. in English)》2014,53(48):13225-13228
Theranostic agents are emerging multifunctional molecules capable of simultaneous therapy and diagnosis of diseases. We found that platinum(II)–gadolinium(III) complexes with the formula [{Pt(NH3)2Cl}2GdL](NO3)2 possess such properties. The Gd center is stable in solution and the cytoplasm, whereas the Pt centers undergo ligand substitution in cancer cells. The Pt units interact with DNA and significantly promote the cellular uptake of Gd complexes. The cytotoxicity of the Pt–Gd complexes is comparable to that of cisplatin at high concentrations (≥0.1 mM ), and their proton relaxivity is higher than that of the commercial magnetic resonance imaging (MRI) contrast agent Gd–DTPA. T1‐weighted MRI on B6 mice demonstrated that these complexes can reveal the accumulation of platinum drugs in vivo. Their cytotoxicity and imaging capabilities make the Pt–Gd complexes promising theranostic agents for cancer treatment. 相似文献
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金属纳米颗粒制备中的还原剂与修饰剂* 总被引:2,自引:0,他引:2
金属纳米颗粒由于其独特的光学、电学、化学性质以及各种潜在的应用价值,受到不少研究人员的广泛关注。实现金属纳米粒子尺寸、形貌可控,改善粒子分散性和稳定性,提高产率及纯度已成为具有挑战性的研究课题,不断发展和完善金属纳米粒子的合成方法则显得尤为重要。本文总结了目前制备金属纳米材料的几种化学方法:化学试剂还原法、电化学还原法、辐射还原法等,分类介绍了化学试剂还原法中常用的无机、有机还原剂,以及含氮、磷、羧基、巯基小分子有机化合物以及高分子聚合物等修饰剂并重点总结了其还原和修饰机理。 相似文献
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Scalia S 《Journal of chromatography. A》2000,870(1-2):199-205
A rapid supercritical fluid extraction (SFE) procedure for the isolation of five of the most common sunscreen agents (2-ethylhexyl-p-dimethylaminobenzoate, 2-hydroxy-4-methoxybenzophenone, 2-ethylhexyl-p-methoxycinnamate, 4-methylbenzylidene camphor and 4-tert.-butyl-4′-methoxydibenzoylmethane) from cosmetic products is described. Investigation of the factors affecting the extraction efficiency in SFE indicated that sunscreen recoveries were affected mainly by the supercritical CO2 pressure and by the trapping method. The sunscreens were analyzed by reversed-phase high-performance liquid chromatography after a 10-min extraction of the cosmetic product with CO2 at 250 bar and 40°C, using sequential glass surface and C18 sorbent as collection system. A quantitative comparison of SFE with a liquid extraction procedure was performed on commercial cosmetics. The SFE method yielded recoveries higher than 94.8% compared with conventional liquid extraction and exhibited a precision better than 5.3% relative standard deviation. Moreover, SFE minimized sample handling, reduced the consumption of harmful solvents and afforded a more effective purification of the cosmetic matrices. 相似文献
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《Electroanalysis》2003,15(3):157-167
This review discusses current development in electrochemical biosensors for detection of biological warfare agents. This could include bacteria, viruses and toxins that are aerosoled deliberately in air, food or water to spread terrorism and cause disease or death to humans, animals or plants. The rapid and unequivocal detection and identification of biological warfare agents is a major challenge for any government including military, health and other government agents. Reliable, specific characterization and identification of the microorganism from sampling location, either air, water, soil or others is required. This review will survey different types of electrochemical biosensors has been developed based on the following: i) Immunosensors ii) PCR (DNA base Sensor) iii) Bacteria or whole cell sensor and iv) Enzyme sensor. This article gives an overview of electrochemical biosensor for detection of biological warfare agents. Electrochemical biosensors have the advantages of sensitivity, selectivity, to operate in turbid media, and amenable to miniaturization. Recent developments in immunofiltration, flow injection, and flow‐through electrochemical biosensors for bacteria, viruses, and toxin detection are reviewed. The current research and development in biosensors for biological warfare agents detection is of interest to the public as well as to the defense is also discussed. 相似文献
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Zhang AH Jiang N Gu W Ma J Wang YR Song YC Tan RX 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(48):14479-14485
(-)-Alternarlactam [(-)-1], a new promising cytotoxin against two human cancer cell lines, was isolated from an endophyte culture and synthesized (along with (+)-1) from readily available starting materials. The absolute configuration, chirality-activity relevance and self-aggregation of (-)-1 were assigned by a combination of synthetic, spectroscopic and computational approaches. The full characterization of the new fungal cytotoxin may provide valuable information in the discovery of new antitumor agents. 相似文献
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《Journal of Coordination Chemistry》2012,65(1-4):187-200
Abstract The factors involved in the design of therapeutic chelating agents are outlined on the basis of the theoretical analyses of ligand design and experimental data obtained in animal studies. The starting point in such design must always be those factors which assure that a sufficiently high stability constant be achieved, and here the analyses presented by Martell and his co-workers furnish a general approach. If the removal of intracellular metal deposits is to be achieved, additional factors need to be considered to incorporate variables which govern the interaction of the chelating agent with the membrane systems of those organs within which the toxic metal is concentrated. For these, the QSAR (quantitative structure activity relationship) procedure of Hansch furnishes a useful guide. This allows the development of direct structure-efficacy correlations (DSEC) involving molecular parameters in addition to those which are directly involved in the determination of the stability constant. In several cases data are available which indicate how the relative efficacy of two chelating agents with essentially identical stability constant expectations is dependent upon structural features which govern the relative ease with which such molecules can gain access to intracellular deposits. The combination of these approaches allows the joint use of in vitro and in vivo data to design improved therapeutic chelating agents with an increased probability of success when tested in vivo. 相似文献
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Krutagn Patel Bhavesh Bharatiya Tulsi Mukherjee Tejal Soni Atindra Shukla B. N. Suhagia 《Journal of Dispersion Science and Technology》2017,38(5):626-631
The stability of silver nanoparticles is controlled mainly by two major factors, namely, aggregation and oxidation. In the present study, silver nanoparticles were synthesized by using different series of reducing agents like a strong reducing agent (sodium borohydride), a mild reducing agent (tri-sodium citrate), and a weak reducing agent (glucose) with different capping agents, namely, polyvinyl pyrrolidone (PVP K 30), starch, and sodium carboxyl methyl cellulose (NaCMC). The synthesized silver nanoparticles were characterized by UV-Visible absorption spectroscopy, dynamic light scattering (DLS), atomic force microscopy (AFM), and anti-microbial activity. The particle size of silver nanoparticles varies in the following order: sodium borohydride < tri-sodium citrate < glucose. Combination of sodium borohydride–polyvinyl pyrrolidone and tri-sodium citrate-polyvinyl pyrrolidone yields stable silver nanoparticles compared to other combinations of reducing agents and capping agents. The stability results confirmed that a refrigerated condition (8°C) was more suitable for storage of silver nanoparticles. Anti-microbial activity of silver nanoparticles synthesized in a sodium borohydride–polyvinyl pyrrolidone mixture shows a larger zone of inhibition compared to other silver nanoparticles. Anti-microbial results confirmed that the anti-microbial activity is better with smaller particle size. The size and stability of silver nanoparticles in the presence of different combinations of stabilizing and capping agents are reported. 相似文献
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Ali MM Woods M Caravan P Opina AC Spiller M Fettinger JC Sherry AD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(24):7250-7258
The design of effective pH responsive MRI contrast agents is a key goal in the development of new diagnostic methods for conditions such as kidney disease and cancer. A key factor determining the effectiveness of an agent is the difference between the relaxivity of the "on" state compared to that of the "off" state. In this paper, we demonstrate that it is possible to improve the pH-responsive action of a low molecular weight agent by conjugating it to a macromolecular construct. The synthesis of a bifunctional pH responsive agent is reported. As part of that synthetic pathway we examine the Ing-Manske reaction, identifying an undesirable by-product and establishing effective conditions for promoting a clean and effective reaction. Reaction of the bifunctional pH responsive agent with a G5-PAMAM dendrimer yielded a product with an average of 96 chelates per dendrimer. The relaxivity of the dendrimer conjugate rises from 10.8 mM(-1) s(-1) (pH 9) to 24.0 mM(-1) s(-1) (pH 6) per Gd(3+) ion. This more than doubles the relaxivity pH response, Deltar(1), of our agent from just 51 % for the original low molecular weight chelate to 122 % for the dendrimer. 相似文献
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Perspectives in nonsteroidal anti-inflammatory agents 总被引:1,自引:0,他引:1
T Y Shen 《Angewandte Chemie (International ed. in English)》1972,11(6):460-472
Among numerous nonsteroidal anti-imflammatory agents synthesized in the past few years, various analogs of indomethacin, phenylacetic acid and heteroarylacetic acid have reached the stage of clinical evaluation. Their biochemical mechanisms of action are exemplified by the broad activity profile of indomethacin which includes inhibition of mediators and enzymes, effects on cell membranes, and, most recently, inhibition of prostaglandin biosynthesis. The importance of pharmacodynamic properties to clinical efficacy was clearly demonstrated in some cases. Several candidates were eliminated because of their side-effects. A group of α-methylarylacetic acids showed a high degree of stereospecificity in their potency and metabolisms in vivo, as well as inhibition of prostaglandin synthetase and albumin binding in vitro. Extrinsic Cotton effect provides a sensitive technique in the study of interactions of these drugs with biopolymers. Competitive binding and antagonistic interactions between nonsteroidal drugs, particularly salicylate, were observed in vitro and in vivo. Progress in salicylate research was marked by the synthesis of flufenisal as a new derivative with enhanced potency and longer duration of action. Several fenamate analogs and new chemical types have shown promise in preliminary clinical trials. Various immunological approaches are under investigation for the treatment of rheumatoid arthritis. Newer concepts are still needed to achieve more effective control of arthritic disorders. 相似文献
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The analysis of chemical warfare agents and their degradation products is an important component of verification of compliance with the Chemical Weapons Convention. Gas and liquid chromatography, particularly combined with mass spectrometry, are the major techniques used to detect and identify chemicals of concern to the Convention. The more polar analytes, and some of the more reactive or highly volatile agents, are usually derivatised to facilitate chromatography, and to impart properties beneficial for detection. This review focuses on derivatisation reactions used in the chromatographic analysis of chemical warfare agents, their degradation products and metabolites. 相似文献
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Elena Calatrava-Pérez Luke A. Marchetti Gavin J. McManus Dylan M. Lynch Robert B. P. Elmes D. Clive Williams Thorfinnur Gunnlaugsson Eoin M. Scanlan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(3):e202103858
Real-time tracking of prodrug uptake, delivery and activation in vivo represents a major challenge for prodrug development. Herein, we demonstrate the use of novel glycosylated theranostics of the cancer pharmacophore Amonafide in highly-selective, enzymatic triggered release. We show that the use of endogenous enzymes for activated release of the therapeutic component can be observed, in real time, and monitored using one and two-photon bioimaging, offering unique insight into the prodrug pharmacokinetic profile. Furthermore, we demonstrate that the potent cytotoxicity of Amonafide is preserved using this targeted approach. 相似文献
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Lucia Veselovská Natálie Kudlová Dr. Soňa Gurská Dr. Barbora Lišková Martina Medvedíková Dr. Ondřej Hodek Eva Tloušťová Nemanja Milisavljevic Dr. Michal Tichý Dr. Pavla Perlíková Dr. Helena Mertlíková-Kaiserová Jana Trylčová Dr. Radek Pohl Dr. Blanka Klepetářová Dr. Petr Džubák Prof. Dr. Marián Hajdúch Prof. Dr. Michal Hocek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(57):13002-13015
All four isomeric series of novel 4-substituted pyrido-fused 7-deazapurine ribonucleosides possessing the pyridine nitrogen atom at different positions were designed and synthesized. The total synthesis of each isomeric fused heterocycle through multistep heterocyclization was followed by glycosylation and derivatization at position 4 by cross-coupling reactions or nucleophilic substitutions. All compounds were tested for cytostatic and antiviral activity. The most active were pyrido[4′,3′:4,5]pyrimidine nucleosides bearing MeO, NH2, MeS, or CH3 groups at position 4, which showed submicromolar cytotoxic effects and good selectivity for cancer cells. The mechanism involved activation by phosphorylation and incorporation to DNA where the presence of the modified ribonucleosides causes double-strand breaks and apoptosis. 相似文献
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In Situ Proteome Profiling and Bioimaging Applications of Small‐Molecule Affinity‐Based Probes Derived From DOT1L Inhibitors
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Biwei Zhu Dr. Hailong Zhang Sijun Pan Chenyu Wang Dr. Jingyan Ge Prof. Dr. Jun‐Seok Lee Prof. Dr. Shao Q. Yao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7824-7836
DOT1L is the sole protein methyltransferase that methylates histone H3 on lysine 79 (H3K79), and is a promising drug target against cancers. Small‐molecule inhibitors of DOT1L such as FED1 are potential anti‐cancer agents and useful tools to investigate the biological roles of DOT1L in human diseases. FED1 showed excellent in vitro inhibitory activity against DOT1L, but its cellular effect was relatively poor. In this study, we designed and synthesized photo‐reactive and “clickable” affinity‐based probes (AfBPs), P1 and P2 , which were cell‐permeable and structural mimics of FED1 . The binding and inhibitory effects of these two probes against DOT1L protein were extensively investigated in vitro and in live mammalian cells (in situ). The cellular uptake and sub‐cellular localization properties of the probes were subsequently studied in live‐cell imaging experiments, and our results revealed that, whereas both P1 and P2 readily entered mammalian cells, most of them were not able to reach the cell nucleus where functional DOT1L resides. This offers a plausible explanation for the poor cellular activity of FED1 . Finally with P1 / P2 , large‐scale cell‐based proteome profiling, followed by quantitative LC‐MS/MS, was carried out to identify potential cellular off‐targets of FED1 . Amongst the more than 100 candidate off‐targets identified, NOP2 (a putative ribosomal RNA methyltransferase) was further confirmed to be likely a genuine off‐target of FED1 by preliminary validation experiments including pull‐down/Western blotting (PD/WB) and cellular thermal shift assay (CETSA). 相似文献
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Chemotherapy of virus diseases. 总被引:1,自引:0,他引:1
The purpose of this review is to provide an overview of current screening methodology and major advances in the area of viral chemotherapy. This presentation will be limited to those drugs which are currently in use and those which having shown activity against major human pathogenic viruses are now being evaluated in man. 相似文献