固载化聚乙二醇树脂的合成及其接肽性能研究

聚乙二醇在浓氢氧化钠溶液中接枝到氯甲基化聚苯乙烯树脂上,制成了具有亲水性的固载化聚乙二醇树脂.讨论了各种反应条件对接枝反应产率的影响.用合成的树脂作载体,测定了合成多肽的反应动力学及缩合产率.与氯甲基化聚苯乙烯树脂相比,提高了合成多肽的反应速率及缩合产率.     

聚苯乙烯支载聚乙二醇二苯并-18-冠-6的合成及催化性能研究

叙述了几种聚苯乙烯支载聚乙二醇二苯并-18-冠-6高聚物冠醚的合成,并研究了它们对n-溴辛烷与碘化钾及苯酚钾盐取代反应时的相转移催化性能。     

聚乙二醇二丁二酸酯的合成

聚乙二醇在药物合成上有很广泛的用途,但其端羟基的活性相对较低,直接应用受到限制.若将羟基活化为羧基则可以扩大其应用范围;尤其是在合成二聚物时,将疏水链换成亲水的聚乙二醇二丁二酸酯链可以增加桥链的亲水性.为此,以聚乙二醇、丁二酸酐为反应物,以吡啶为溶剂,分别合成了一缩二乙二醇二丁二酸酯、二缩三乙二醇二丁二酸酯、三缩四乙二...     

Synthesis of a new hydrophilic poly(ethylene glycol)-ionic liquid and its application in peptide synthesis

The synthesis of a new hydrophilic ammonium-based poly(ethylene glycol)-ionic liquid (PEG-IL) is reported; the structure was assigned by NMR ((1)H, (13)C) and MALDI mass spectrometry. The viscosity and thermal stability were also studied, as well as its polarity. Its application as an alternative solvent in the synthesis of dipeptides under microwave irradiation is also described.     

聚苯乙烯支载聚氧乙烯季铵盐的合成及催化性能

本文合成了共聚苯乙烯-二乙烯基苯支载四聚乙二醇季铵盐以及共聚苯乙烯-二乙烯基苯支载聚乙二醇辛基苯基季铵盐, 并对它们在1-溴辛烷与碘化钾反应中的催化活性进行了研究。     

Identification and quantification of polyethylene glycol types in polyethylene glycol methyl ether and polyethylene glycol vinyl ether

Quantitative determination of polyethylene glycol (PEG) impurities in two monofunctional polyglycol types, PEG methyl ether (M-PEG) and PEG vinyl ether (V-PEG), has been carried out by reversed-phase liquid chromatography with evaporative light scattering detection (ELSD). In addition to optimizing the resolution between PEG and monofunctional PEG peaks, the major focus has been to determine the molecular weights of PEG impurities in M-PEG and V-PEG of diverse molecular weights. The latter is achieved by examining liquid chromatography–mass spectrometry (LC–MS) mass spectra of both monofunctional PEG and PEG in several cases, and matching peak retention times with those of available PEG standards for all M-PEG and V-PEG sample types. This information is helpful in selecting the appropriate PEG standard to determine PEG content in each sample type. ELSD response factors for various PEG standards have also been compared. It has been found that PEG standards with molecular weights from 1000 Da to 8000 Da show responses that are within 10% of each other. However, a low molecular weight PEG such as PEG 400, provides approximately 30% less response compared to its higher molecular weight counterparts.     

Polystyrene resins cross-linked with di- or tri(ethylene glycol) dimethacrylates as supports for solid-phase peptide synthesis

Polystyrene resins cross-linked with di(ethylene glycol) dimethacrylate (DEGDMA) and tri(ethylene glycol) dimethacrylate (TEGDMA), DEGDMA-PS and TEGDMA-PS, were synthesized by suspension copolymerization. Four functionalized resins, chloromethyl resin, 4-hydroxymethylphenoxymethyl resin (Wang resin), 4-methylbenzhydrylamine resin (MBHA resin) and 2-chlorotrityl chloride resin, were prepared from DEGDMA-PS and TEGDMA-PS. DEGDMA-PS and TEGDMA-PS showed high reactivity in the functionalization reactions in comparison with Merrifield resin (polystyrene cross-linked with divinylbenzene, DVB-PS). DEGDMA-PS-Wang resin and TEGDMA-PS-Wang resin were used as the solid-phase support for the synthesis of a difficult sequence, the fragment of acyl carrier protein 65-74. The yields of the crude peptide synthesized using DEGDMA-PS-Wang resin, TEGDMA-PS-Wang resin and DVB-PS-Wang resin were 92.3%, 91.6% and 78.8%, respectively. The purities of the crude peptides were 85.7%, 88.1% and 73.3%, respectively.     

聚苯乙烯固载NADH辅酶模型化合物的合成及应用

设计、合成了一类新型的高分子还原试剂--聚苯乙烯固载烟酰胺辅酶模型化合物1-苄基-1,4-二氢烟酰胺(BNAH)4.该还原剂可以在温和条件下有效的还原活化烯烃,而且可以循环再生,但循环再生后有效BNAH含量下降.     

Microwave-assisted lipase-catalyzed synthesis of polyethylene glycol stearate in a solvent-free system

Polyethylene glycol stearate, a condensation esterification product of stearic acid and polyethylene glycol 600, was widely applied in the biomedical and healthcare industries. The current work focuses on the enzymatic synthesis of PEG stearate using CALB_ex10000, a commercial Lipase enzyme in solvent-free conditions using microwave irradiation. The influence of various reaction parameters such as temperature, molar ratio of reactants, and enzyme loading was studied to obtain the highest conversion. Maximum conversion of 85% was attained under molar ratio 1:1 (PEG 600 to stearic acid using 0.7% (w/w) enzyme loading at 60 ​°C of temperature in 70 ​min of reaction time. Further, the thermodynamic parameters were analyzed and compared with the conventional and ultrasound-assisted synthesis of PEG stearate. The enzyme was recycled up to 5^th cycle giving more than 35% of the initial activity.     

Visualized investigation of yeast transformation induced with Li+ and polyethylene glycol

The effects of Li⁺ and polyethylene glycol (PEG) on the genetic transformation of Saccharomyces cerevisiae were investigated by using fluorescence microscopy (FM) to visualize the binding of plasmid DNA labeled with YOYO-1 to the surface of yeast cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) to image the change in surface topography of yeast cells, coupled with transformation frequency experiments. The results showed that under the same conditions, the transformation frequencies of yeast protoplasts were much higher than those of intact yeast cells. PEG was absolutely required for the binding of DNA to the surface of intact yeast cells or yeast protoplasts, and had no effect on the surface topography of intact yeast cells or yeast protoplasts. In the presence of PEG, Li⁺ could greatly enhance the binding of plasmid DNA to the surface of intact yeast cells, increase their transformation frequency, and affect their surface topography. On the other hand, no effect on the DNA binding to the surface of protoplasts and no increase in the number of transformants and no surface topography changes were found upon the treatment with Li⁺ to protoplasts. In the present work, the effects of Li⁺ and PEG on yeast genetic transformation were directly visualized, rather than those deduced from the results of transformation frequencies. These results indicate that cell wall might be a barrier for the uptake of plasmid DNA. Li⁺ could increase the permeability of yeast cell wall, then increase the exposed sites of DNA binding on intact yeast cells. The main role of PEG was to induce DNA binding to cell surface.     

Synthesis of polyethylenimine grafted with copolymers of polyethylene glycol and polycaprolactone and its potential for siRNA delivery

Copolymers mPEG-PCL were prepared and grafted onto polyethylenimine(PEI) to synthesize copolymers mPEG-PCL-g-PEI with low cytotoxicity.The mPEG-PCL-g-PEI could condense siRNA to form nanoparticles with positive zeta potential.These nanoparticles could delivery siRNA into cells to effectively inhibit the expression of target gene,which suggested that mPEG-PCL-g -PEI could serve as a highly efficient vector for siRNA delivery.     

Immobilized stationary phase on the basis of polyethylene glycol cross-linked with pluriisocyanates of the Desmodur type

Summary The preparation of an immobilized stationary phase based on Carbowax 20M is described. The stationary phase cross-linking was carried out with Desmodur N 75 or Desmodur L 75, pluriisocyanates. The properties of the prepared stationary phases are compared.     

一种重金属离子吸附捕集剂的合成及性能研究

在较温和的温度条件下合成了N,N-双(二硫代羧基)二乙烯三胺乙基聚合物,并对NaOH的加入次序及加入量、二硫化碳加入次序、二乙烯三胺的用量、反应温度、反应时间等进行了研究。论文通过红外光谱、紫外光谱和熔点测定对聚合物进行表征。研究了聚合物吸附捕集部分重金属离子的性能,结果表明,合成的聚合物能稳定地吸附捕集某些重金属离子,对Ag 、Cu2 、Zn2 等离子有较高的吸附量;吸附效果在pH值为5左右时最好。     

Synthesis of dityrosine cross-linked peptide dimers using the Miyaura-Suzuki reaction

[reaction: see text] Since peroxidase-catalyzed dityrosine formation is inefficient for peptides, we have developed alternative conditions for intermolecular dityrosine formation using the Miyaura-Suzuki reaction. A one-pot reaction is effective for cross-linking short peptides, but longer peptides inhibit the Suzuki step, mandating a traditional two-step procedure using potassium acetate for the Miyaura reaction and potassium carbonate for the Suzuki coupling. These palladium-based methods are complementary to the well-established peroxidase-catalyzed oxidative phenolic coupling of full-length proteins.     

Uncatalyzed synthesis of thiomorpholide using polyethylene glycol as green reaction media

Abstract

Polyethylene glycol-600 was used as an efficient and recyclable solvent for the one-pot three component condensation reactions of aryl alkyl ketones, sulfur, and morpholine to produce the corresponding thiomorpholide. This protocol has advantages of high yields, short reaction times, mild reaction conditions, minimal environmental pollution, and simple work up procedure.     

Pyrene-1-carboxylic acid polyethylene glycol esters: synthesis and photophysical studies

Russian Chemical Bulletin - Monoesters of tri- and tetraglycol and 1-pyrenecarboxylic acid were characterized for the first time by NMR spectroscopy and elemental analysis. The photophysical...     

Synthesis of functionalised polyethylene glycol derivatives of naproxen for biomedical applications

The preparation of a series of mono-naproxen functionalised polyethylene glycol derivatives have been achieved. These compounds feature several different terminal functional groups, the identities of which have been chosen to facilitate conjugation of these hybrid molecules to nanomaterials.     

Molecular association in polyethylene glycol

Summary Existence of intra and intermolecular hydrogen bonds has been confirmed in the literature. Present reduced viscosity studies of PEG solution in urea and thiourea also confirm the view of the presence of the molecular association of PEG in water by intermolecular hydrogen bonding as well as of the existence of intramolecular hydrogen bonding in PEG molecules. The existence of intramolecular hydrogen bonding is more appreciated in the case of PEG solution in relatively smaller concentration of urea and thiourea. The presence of urea and thiourea is responsible for the breaking of hydrogen bonds which result in the change of molecular size and conformation.

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Zusammenfassung Das Auftreten von intra- und intermolekularen Wasserstoff bindungen bei Polymeren wird in der Literatur schon bestätigt. Wir zeigten an Polyäthylenglycollösungen in Wasser mit und ohne Harnstoff und Thioharnstoff, daß sich die Existenz von solchen Wasserstoffbrücken in vorliegendem Falle ebenfalls bestätigen läßt.

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