4-异丙基苯硼酸的合成与表征

利用格氏试剂法合成了4-异丙基苯硼酸,得出了较佳的工艺路线:先制得格氏试剂(产率98.1%),然后与硼酸三丁酯在-10℃下亲核取代,快速升至室温,经酸性水解得产品,分离后总产率56.6%,对产品进行了核磁共振和质谱表征。     

Diversity‐Oriented Synthesis of Diol‐Based Peptidomimetics as Potential HIV Protease Inhibitors and Antitumor Agents

Peptidomimetic HIV protease inhibitors are an important class of drugs used in the treatment of AIDS. The synthesis of a new type of diol‐based peptidomimetics is described. Our route is flexible, uses d ‐glucal as an inexpensive starting material, and makes minimal use of protection/deprotection cycles. Binding affinities from molecular docking simulations suggest that these compounds are potential inhibitors of HIV protease. Moreover, the antiproliferative activities of compounds 33 a , 35 a , and 35 b on HT‐29, M21, and MCF7 cancer cell lines are in the low micromolar range. The results provide a platform that could facilitate the development of medically relevant asymmetrical diol‐based peptidomimetics.     

Synthesis,post‐modification and characterization of linear polystyrene‐based supports for interaction with immobilized biocatalysts

A series of linear polystyrene‐based supports has been synthesized using conventional or controlled (reversible addition fragmentation chain transfer or nitroxide‐mediated) free radical polymerizations, in order to modulate their molecular weight characteristics. Polymer post‐modification via esterification of the primary hydroxyl alcohol functionalities, pendant from the polymer backbone, with a mandelic acid derivative introduces efficiently (>85% yield) racemic, enzyme‐cleavable moieties. A study of the interactions of these polymeric substrates with immobilized penicillin G acylase, in mixed organic/aqueous buffer solvent systems, results in a modest enantioselectivity (comparable with that of racemic mandelic acid methyl ester), but reveals that the biocatalytically active moieties on the linear polymers can be cleaved with first‐order rate kinetics, as observed with small molecules in solution; the reaction rates (which can differ by more than one order of magnitude) are influenced both by the synthetic polymer length and by the polymer structure resulting from the method of polymerization used. Copyright © 2012 Society of Chemical Industry     

导电聚苯胺的合成与表征

采用微乳液聚合法,以苯胺为单体、十二烷基苯磺酸(DBSA)/盐酸(HCl)复合酸掺杂制备了导电聚苯胺,通过红外光谱对其结构进行了表征,考察了合成工艺条件对聚苯胺导电性能的影响,探讨了有机无机复合酸体系对聚苯胺热稳定性的影响。在复合酸十二烷基苯磺酸与盐酸物质的量比为3∶2、复合酸与单体物质的量比为2.0∶1、聚合温度为20℃、聚合时间为10h的优化条件下,所得到的掺杂态聚苯胺导电性能最佳。适当配比的有机无机复合酸掺杂后,导电聚苯胺的热稳定性显著提高。     

Glucose 1‐Phosphate Thymidylyltransferase in the Synthesis of Uridine 5′‐Diphosphate Galactose and its Application in the Synthesis of N‐Acetyllactosamine

In this study, we describe the direct synthesis of uridine 5′‐diphosphate galactose (UDP‐Gal) by a wild‐type bacterial thymidylyltransferase (RmlA), which is used to synthesize thymidine 5′‐diphosphate glucose (TDP‐glucose) in nature. By using magnesium (Mg²⁺) as a cofactor and a reaction temperature of 55 °C, a one hundred milligram‐scale synthesis of UDP‐Gal was achieved by RmlA. In addition, RmlA was site‐specifically and covalently immobilized on magnetic nanoparticles (MNPa) The resulting RmlA‐MNP complex retained almost 95% of its activity after reuse in ten consecutive enzyme assays. Furthermore, β‐1,4‐galactosyltransferase (GalT) from Neisseria meningitides was successfully overexpressed and purified by using an intein‐mediated protein expression system. GalT was relatively stable at 25 °C, and its activity was enhanced in the presence of DTT and BSA. Thus, it was feasible to synthesize N‐acetyllactosamine (LacNAc) using RmlA and GalT in a sequential addition of enzyme and adjustment of thereaction temperature. These results demonstrate the potential applications of bacterial RmlA in carbohydrate synthesis.     

Synthesis and Characterization of Polystyrene‐Encapsulated Laponite Composites via Miniemulsion Polymerization

Summary: A novel polystyrene‐encapsulated laponite composite system has been developed via a miniemulsion polymerization approach. The encapsulation mechanism and process parameters have been examined in detail using light‐scattering, sedimentation analysis, wide‐angle X‐ray diffraction (WXRD), and transmission electron microscopy (TEM). The laponite was encapsulated through a miniemulsion polymerization process in which laponite was predispersed in the monomer phase. The stability of both the miniemulsion and the latex depends on initiation loci, premixing procedures, intensity and time of ultrasonification and the surfactants and co‐stabilizer used. Hydrophobicity of the laponite clay played a vital role in both the encapsulation of the clay and the stability of the latex. A quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), was mixed with the clay in the monomer phase prior to emulsification. As a result, the clay particles were hydrophobically modified and were intercalated. The hydrophobicity not only favored the clay dispersion in the oil droplets but also aided the entry of the monomer into the clay's intergalleries during polymerization. Meanwhile, CTAB helped stabilize the system when it was used in conjunction with the nonionic surfactant polyoxyethylene (40) isooctylphenyl ether (TX‐405). In this way, the laponite is effectively encapsulated within a polystyrene shell in a stable latex form. More importantly, the polymerization initiated in the intergalleries of the clay effectively expands the clay's platelet array to form an exfoliated structure.

     

Synthesis of poly‐N‐(thiazol‐2‐yl)methacrylamide: Characterization,complexation, and bioactivity

Cu(II) complexes with N‐(thiazol‐2‐yl)methacrylamide (NTM) and its polymer PNTM have been synthesized. The ligands (NTM and PNTM) and their Cu(II) complexes have been characterized by FTIR and ¹H‐NMR. EDX was performed to know the elemental composition and X‐ray powder diffractometry (XRD) analysis was applied to detect the crystallinity of the complexes. The morphology of these complexes was investigated with scanning electron microscopy (SEM) and proves that the monomer complexes have a strongly crystalline structure compared with the polymer complexes, which show that it is only weakly crystalline. These results from SEM are in agreement with results obtained from XRD. Thermal properties of the ligands and their complexes have been studied by thermogravimetric analysis and differential scanning calorimetry. The activity of the ligands and their complexes has been screened against S. aureus, E. coli, Pseudomonas, and Candida albicans. The synthesized compounds have shown good affinity as antibacterial and antifungal agents, which increased on complexation with Cu(II) ion. The results of these studies show the Cu(II) complexes to be more thermal stable as compared with NTM and PNTM. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

沉淀聚合法制备对氨基苯甲酸印迹聚合物及其表征

以对氨基苯甲酸为模板分子,采用沉淀聚合法制备了分子印迹聚合物微球,优化了聚合反应条件,静态平衡吸附实验结果表明,该微球对模板分子存在一种均匀的结合位点,最大表观结合量为49.298μmol/g。应用此微球制备的色谱填充柱能够分离对氨基苯甲酸及其位置异构体邻氨基苯甲酸,分离度为1.42。     

2‐Hydroxypropylmethacrylate based mono‐ and bifunctional gel beads prepared by suspension polymerization

Spherical and swellable gel beads in the size range 35–200 µm were prepared by suspension polymerization of 2‐hydroxypropylmethacrylate (HPMA). In the proposed method, a mixture of cyclohexanol and octanol was used as a diluent phase dispersed in an aqueous medium including poly(vinyl pyrrolidone) (PVP) as the stabilizer. The polymerization was initiated within the organic phase including the monomer and the crosslinker (ethylene glycol dimethacrylate) by an oil soluble initiator benzoyl peroxide. Spherical and swellable gel beads carrying both hydroxyl and carboxyl functional groups were also prepared by suspension copolymerization of HPMA and a water soluble comonomer (methacrylic acid). For this purpose, the suspension polymerization method proposed for HPMA was modified by using poly(vinyl alcohol) as a stabilizer instead of PVP. The effect of initiator concentration, polymerization temperature, monomer/diluent ratio, crosslinker concentration, stirring rate on yield, average size, size distribution, and carboxyl content of the HPMA based gel beads, were investigated. The swelling characteristics of the gel beads were defined. © 2000 Society of Chemical Industry     

Synthesis and modification of epoxy‐ and hydroxy‐functional microspheres

This article describes the synthesis and surface modification of epoxy‐ and hydroxy‐functional polymeric microspheres. The functionalized microspheres were synthesized using aqueous and nonaqueous cationic suspension photopolymerizations using multifunctional silicon‐containing epoxy monomers with iodonium salt photoinitiators. Although generally solid microspheres were obtained using these techniques, macroporous spheres could be obtained though the use of porogens. Various rapid and facile acid‐ and base‐catalyzed ring‐opening addition reactions were performed on the epoxy‐functional microspheres. These reactions include the additions of mercaptans, acid chlorides, isocyanates, amines, sodium azide, water, and alcohols. Similar functionalization reactions were performed on the hydroxy‐functional microspheres. The particle size and size distribution were determined using scanning electron microscopy. Fourier transform infrared spectroscopy was used to monitor the functionalization reactions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1574–1585, 2005     

Innovative Carbon Dioxide‐Capturing Organic Solvent: Reaction Mechanism and Kinetics

The reaction rates of CO₂ with an innovative CO₂‐capturing organic solvent (CO₂COS), consisting of blends of 2‐tert‐butyl‐1,1,3,3‐tetramethylguanidine (BTMG) and 1‐propanol, were obtained as function of BTMG concentration and temperature. A stopped‐flow apparatus with conductivity detection was used. The reaction was modeled by means of a modified termolecular reaction mechanism which resulted in a second‐order rate constant, and activation energies were calculated for a defined temperature range. Quantum chemical calculations at the B3LYP/6‐31G(d) level also produced the activation energy of this reaction system which strongly supports the experimental findings.     

Synthesis of chiral stationary phase via surface‐initiated atom transfer radical polymerization of vinylated cellulose 3,5‐dimethylphenylcarbamate

A polysaccharide‐immobilized chiral stationary phase (CSP) was prepared by the surface‐initiated atom transfer radical polymerization (SI‐ATRP), in pyridine, of cellulose 2,3‐bis(3,5‐dimethylphenylcarbamate), having a polymerizable vinyl group, on the surface of SiO₂ support. The successful preparation of the CSP was confirmed via Fourier transform infrared spectroscopy, field‐emission scanning electron microscopy, X‐ray photoelectron spectroscopy, elemental analysis and thermal analysis. The chiral recognition ability of the prepared CSP was evaluated with high‐performance liquid chromatography using 10 racemates with various mobile phases of hexane/alcohol, hexane/tetrahydrofuran and hexane/chloroform. As a result, this CSP prepared using SI‐ATRP can be used in tetrahydrofuran and chloroform solutions as eluents. Copyright © 2011 Society of Chemical Industry     

Synthesis and characterization of highly porous poly(methacrylic‐co‐triethylene glycol dimethacrylate) by suspension polymerization

Porous poly(methacrylic‐co‐triethyleneglycol dimethacrylate) (MAA‐3G) was prepared by suspension polymerization using benzoyl peroxide as an initiator, poly(vinyl alcohol) as a protective colloid, and n‐hexane as a porogenic agent. The prepared polymer was base hydrolysed using hydroxyl amine and sodium methoxide into the corresponding polyhydroxamic acid (HYOX). The metal binding behavior of polyhydroxamic acid with various metal ions, the effect of pH on the metal ion capturing, and the selectivity of the resin towards the different metal ions were also examined by means of atomic absorption spectrophotometer. The thermal stability of the prepared base‐hydrolysed polymer and the metal polymer complex was examined by thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC). The prepared porous polymer methacrylic‐co‐triethyleneglycol dimethacrylate and its different modulated forms were characterized by means of FTIR specroscopy and scanning electron microscope. The hydroxamic acid content was also examined by elemental analysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 149–159, 1999     

Synthesis of plant sterol esters catalyzed by heteropolyacid in a solvent‐free system

The synthesis of phytosteryl esters is of importance due to their recent recognition and application as cholesterol‐lowering agents in the food and nutraceutical industries. In this study, a synthetic route potentially useful for the large‐scale production of food‐grade phytosteryl esters with high yield and purity in a solvent‐free system was investigated. To examine the feasibility of replacing sodium methylate by heteropolyacid, four heteropolyacids, tungstosilicic acid, tungstophosphoric acid, molybdosilicic acid and molybdophosphoric acid, were evaluated to determine the best catalyst and the optimum conditions for the esterification reaction between various fatty acids and phytosterols. The results suggested that tungstosilicic acid was more selective towards butyric acid and caprylic acid than towards lauric acid, palmitic acid, and oleic acid. However, there was no significant discrimination in terms of the tungstosilicic acid catalyst's selectivity to stearic acid, oleic acid, linoleic acid and alpha‐linolenic acid, all with C18 chains, in the esterification reaction. The yield of phytosteryl ester was higher than 90% when the esterification reaction was carried out at 150 °C, with phytosterols and fatty acids in a molar ratio of 1 : 1.5, and catalyzed by 0.2% tungstosilicic acid in silica gel. The catalysts recovery experiments suggested that the immobilized tungstosilicic acid did not significantly lose its activity in six operation runs. As a result, the immobilized tungstosilicic acid would be a promising catalyst for replacing sodium methylate, to synthesize phytosteryl esters with fatty acids and phytosterols as the starting materials in a commercial production.     

马来海松酸烯丙酯的合成、表征及性能分析

以马来海松酸为原料,先合成马来海松酸酰氯,然后和烯丙醇进行酯化反应,合成马来海松酸烯丙酯,得率为 70 %,质量分数 99.2 %。采用FT-IR、GC-MS、 ¹³C NMR 和DSC对其结构和性能进行分析。研究结果表明,马来海松酸烯丙酯是一种含有酸酐基团的烯丙基类单体,加热到熔点以上可以发生聚合反应,均聚物玻璃化转变温度约为 98 ℃,可作为环氧树脂和不饱和树脂前聚体。     

Synthesis of D‐Galactofuranose‐Containing Molecules: Design of Galactofuranosyl Acceptors

D ‐Galactofuranose (D ‐Galf) is present in glycoconjugates of several pathogenic microorganisms but is absent in mammals, so it is a good target for the development of chemotherapeutic agents for the treatment of microbial infections. This fact has increased interest in the synthesis of D ‐Galf‐containing molecules for corresponding glycobiological studies. The synthesis of oligosaccharides, glycoconjugates, and mimetics of D ‐Galf requires specific methods for the preparation of galactose derivatives in the furanosic configuration, the synthesis of appropriate acceptors, and efficient glycosylation methods for the construction of α‐ and β‐D ‐Galf linkages. This review summarizes the different strategies developed for the preparation of partially protected derivatives of D ‐Galf, suitable as acceptors for the construction of (1→2), (1→3), (1→5), and (1→6) link‐ ages, and describes recent applications.     

Characterization of acrylic acid‐grafted PP membranes prepared by plasma‐induced graft polymerization

Acrylic acid (AA)‐g‐polypropylene (PP) membranes were prepared by grafting AA on to a microporous PP membrane via plasma‐induced graft polymerization. The grafting of AA to the PP membrane was investigated using Fourier transform infrared spectroscopy (FTIR). Pore‐filling of the membranes was confirmed by field emission‐scanning electron microscopy (FESEM) and energy dispersing X‐ray (EDX). Ion exchange capacity (IEC), membrane electric resistance, transport number and water content were measured and analyzed as a function of grafting reaction time. The prepared AA‐g‐PP membranes showed moderate electrochemical properties as a cation‐exchange membrane. In particular, membranes with a degree of grafting of 155% showed good electrical properties, with an IEC of 2.77 mmol/g dry membrane, an electric resistance of 0.4 Ω cm² and a transport number of 0.96. Chronopotentiometric measurements indicated that AA‐g‐PP membranes, with a high IEC had a sufficient conducting region in the membrane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Characterization of Candida rugosa Lipase Immobilized on Poly(N‐methylolacrylamide) and Its Application in Butyl Butyrate Synthesis

Candida rugosa lipase was immobilized on poly(N‐methylolacrylamide) by physical adsorption. The biocatalyst performance (immobilized lipase) was evaluated in both aqueous (hydrolysis) and organic (butyl butyrate synthesis) media. In the first case, a comparative study between free and immobilized derivatives was provided in terms of pH, temperature and thermal stability following the olive oil hydrolysis, establishing new optimum values. In the second case, the influence of temperature, biocatalyst concentration and acid/alcohol molar ratio was simultaneously studied according to a 2³ full experimental design. The highest molar conversion (96 %), volumetric productivity (1.73 g L^–1 h^–1) and specific esterification activity (1.00 μM mg^–1 min^–1) were obtained when working at the lowest level of temperature and butyric acid in excess. Under these conditions, repeated batch use of the immobilized enzyme was performed and half‐life time (t_1/2) was found to be 145 h.