5—甲基—2—巯基—1,3,4—噻二唑的合成

５－甲基－２－巯基－１，３，４－噻二唑的合成李占才李淑勉方少明侯守君聂晓兵林烨（郑州轻工业学院化工系郑州４５０００２）关键词５－甲基－２－巯基－１，３，４－噻二唑乙酰肼Ｎ－乙酰肼基二硫代甲酸钾中图分类号Ｏ６２６．２７５－甲基－２－巯基－１，３，４－噻...     

一种对异戊二烯立体控制聚合较敏感的稀土催化体系

发现了一种对异戊二烯聚合立体选择性较敏感的稀士催化体系：（β－ＣＨ＿３－ａｌｌｙｌ）＿２ＬｎＣｌ＿５Ｍｇ·２Ｔ的ＥＤ（Ｌｎ）－Ｒ＿３Ａｌ（Ａｌ）（Ｌｎ＝Ｎｄ、Ｃｅ和Ｌａ，Ｔ的ＥＤ：Ｎ，Ｎ，Ｎ′，Ｎ′－四甲基乙二胺；Ｒ＝Ｍｅ一，Ｅｔ一，ｉ－Ｂｕ一和Ｏｃｔ一）．该催化体系在改变聚合温度、聚合时间、Ａｌ／Ｌｎ摩尔比、溶剂等时，可使聚异戊二烯的立体现整度有较大的改变，其中顺式－１，４、反式－１，４和３，４－链节含量的变化范围分别为１９％～７９％、１７％～７８％和０％～３．５％，还可获得较低分子量的聚合物。     

(R)-N-酰基四氢噻唑-2-硫酮-4-羧酸在DCC存在下与胺的反应

由Ｎ－乙酰四氢噻唑－２－硫酮－４－羧酸（［α］２０Ｄ－１０９．８３°），及Ｎ－苯甲酰四氢噻唑－２－硫酮－４－羧酸（［α］２０Ｄ－１１２．２２°），在Ｎ，Ｎ′－二环己基二亚胺（ＤＣＣ）存在下分别与环己胺、苯胺反应得到光学活性产物（Ｒ）－Ｎ－乙酰四氢噻唑－２－硫酮－４－甲酰环己胺（［α］１７Ｄ－７４．５°），及（Ｒ）－Ｎ－苯甲酰四氢噻唑－２－硫酮－４－甲酰苯胺（［α］１９Ｄ－７．０４°）。用量子化学ＰＭ３方法研究了反应物和产物的电子结构。     

测定N—亚硝基化合物的分光光度法

利用Ｎ－亚硝基化合物的化学去亚硝基反应，建立了一种间接测定Ｎ－亚硝基化合物的分光光度法。实验结果表明，Ｎ－二苯基亚硝胺在０．２￣９．０ｍｇ／Ｌ浓度内呈线性关系。该法应用于香烟烟丝及侧流烟雾萃取液的分析，４次测定ＲＳＤ及回收率分别为１．８６％￣６．３２％，８６．２％￣９６．６％；３．０１％￣５．０３％，１０１．１％￣１０９．１％。     

OZONOLYSIS OF 4－ISOPROPYLIDENEPENTACYCLO（5．4．0．0~（2，6）．0~（3，10）．0~（5，9））UNDECANE－8，11－DIONE

ＯＺＯＮＯＬＹＳＩＳＯＦ４－ＩＳＯＰＲＯＰＹＬＩＤＥＮＥＰＥＮＴＡＣＹＣＬＯ（５．４．０．０￣（２，６）．０￣（３，１０）．０￣（５，９））ＵＮＤＥＣＡＮＥ－８，１１－ＤＩＯＮＥ￥ＪｉａｎＧｕａｎｇＳＵＮ；ＺｈｕａｎｇＳＵ；ＹｏｎｇＺｈｏｎｇＹＵ（Ｃ...     

毛细管电泳对微生物代谢中硫酸根和硫代硫酸根的分离与测定

建立了微生物代谢中硫酸根和硫代硫酸根的毛细管电泳分析方法．在选定实验条件下，各种阴离子（Ｓ２Ｏ２－３、ＳＯ２－４、ＣＩ－、ＮＯ－３、ＰＯ３－４）在４ ｍｉｎ内达到完全分离，其中 Ｓ２Ｏ２－３和ＳＯ２－４迁移时间的相对标准偏差小于１％，峰面积的相对标准偏差小于５％．测定了４种菌株分别在两种培养基中的Ｓ２Ｏ２－３和ＳＯ２－４浓度随培养时间的变化．结果表明，其中一菌株在ＳＫ基中对Ｓ２Ｏ２－３有明显的氧化作用．     

测定N-亚硝基化合物的分光光度法

利用Ｎ－亚硝基化合物的化学去亚硝基反应，建立了一种间接测定Ｎ－亚硝基化合物的分光光度法。实验结果表明，Ｎ－二苯基亚硝胺在 ０ ２～ ９．０ ｍｇ／Ｌ浓度范围内呈线性关系。该法应用于香烟烟丝及侧流烟雾卒取液的分析，４次测定ＲＳＤ及回收率分别为１．８６％～６．３２％，８６．２％～９６．６％；３．０１％～５．０３％，１０１．１％～１０９．１％。     

金属键有机化合物的研究──非对称型η~5－取代环戊二烯基三羰基钼（钨）金属单键化合物的合成及表征

通过η５－Ｒ~１Ｃ＿５Ｈ＿４（ＣＯ）＿３ＭＮａ与η~５－Ｒ~２Ｃ＿５Ｈ＿４（ＣＯ）＿３ＭＮａ（Ｍ＝Ｍｏ，Ｗ）以及η~５－Ｒ~１Ｃ＿５Ｈ＿４（ＣＯ）＿３ＭｏＮａ与η~５－Ｒ~２Ｃ＿５Ｈ＿４（ＣＯ）＿３ＷＮａ在Ｆｅ＿２（ＳＯ＿４）＿３醋酸水溶液作用下的交叉氧化偶联反应，合成了７个新的非对称型金属单键化合物η~５－Ｒ~１Ｃ＿５Ｈ＿４（ＣＯ）－３Ｍｏ─Ｍｏ（ＣＯ）＿３Ｃ＿５Ｈ＿４Ｒ~２－η~５（Ｒ~１，Ｒ~２：Ｃ（Ｏ）Ｍｅ，ＣＯ２Ｅｔ），η５－Ｒ１Ｃ５Ｎ４（ＣＯ）３Ｗ─Ｗ（ＣＯ）３Ｃ５Ｈ４Ｒ２－η５（Ｒ１，Ｒ２：Ｃ（Ｏ）Ｍｅ，ＣＯ２Ｅｔ；Ｈ，ＣＯ２Ｅｔ）和η５－Ｒ１Ｃ５Ｈ４（ＣＯ）３Ｍｏ─Ｗ（ＣＯ）３Ｃ５Ｈ４Ｒ２－η５（Ｒ１，Ｒ２：Ｃ（Ｏ）Ｍｅ，Ｈ；Ｅｔ，Ｃ（Ｏ）Ｍｅ；Ｃ（Ｏ）Ｍｅ，ｎ－Ｂｕ；ＣＯ２Ｍｅ，ｎ－Ｂｕ）．用Ｃ／Ｎ分析、ＩＲ、１ＨＮＭＲ和ＭＳ表征了它们的结构，并对该氧化偶联反应的特点进行了讨论．     

3—羟基异恶唑的O—和N—酰化及其区域选择性研究 Ⅱ.3—羟基—5—甲基…

本文研究了不同反应条件下３－羟基－５－甲基异恶唑（１）与３－甲基－２－对氯苯基丁酰氯（２ａ）的反应，提出了区域选择性合成Ｏ－和Ｎ－酰化产物的方法。在三乙胺存在下，乙腈为溶剂，１和２ａ～２ｅ反应得到含量为８８～９６％的Ｏ－酰化产物３ａ～３ｅ；而若将１转化为相应的异恶唑硅醚４，再与２ａ～２ｉ反应，则得到含量为８６～９７％的Ｎ－酰化产物５ａ～５ｉ。试验表明，在ＤＭＡＰ催化下，３ａ和５ａ可发生Ｏ－／Ｎ－酰     

（3—苄基—4—芳酰基—1,2,4—三唑—5—基）（5—苯基—1,3,4—E…

通过３－苄基－４－芳酰基－１，２，４－三唑－５－巯基负离子在２－甲磺酰基－５－苯基－１，３，４－Ｅ二唑环２－位上的亲核取代反应，制得１３个新的（３－苄基－４－芳酰基－１，２，４－三唑－５－基）（５－苯基－１，３，４－Ｅ二唑－２－基）硫醚衍生物。经元素分析、ＩＲ、＾１Ｈ ＮＭＲ和ＭＳ裂解碎片分析确认结构。初步观察了它们在０．０１％浓度时对大肠杆菌繁殖的抑制作用。     

Mucin Adsorption to Hydrophobic Surfaces

The adsorption isotherm of bovine submaxillary gland mucin (BSM) onto a hydrophobic polystyrene surface was determined by using the solution depletion method, in which mucin concentrations were analyzed by amino acid analysis. Adsorption and desorption kinetics of BSM onto hydrophobic polystyrene surfaces were also studied by the solution depletion method, in which mucin solution concentrations were determined by measuring UV absorbance at a wavelength of 280 nm and by a BCA colorimetric assay with final calibration by amino acid analysis. From the adsorption isotherm, we found that the saturated surface concentration (Gamma(max)) was 2.3 mg/m(2), and the adsorption constant (K) was calculated as 0.099 (ml/mg). By using a Langmuir adsorption model and nonlinear fitting, kinetics parameters, k(on) and k(off), were found to be 8.13x10(-3) cm(3) mg(-1) s(-1) and 5.67x10(-4) s(-1), respectively. The coating was found to be very stable with very limited desorption (less than 2%) from a long-term observation (28 h). The mucin coating layer thickness was investigated by several analytical techniques: flow field-flow-fractionation, photon correlation spectroscopy, scanning electron microscopy, and atomic force microscopy. The thickness was measured as 4-5 nm, from which a monolayer coating was concluded. Finally, the weight average molecular weight of purified bovine submaxillary gland mucin (BSM) was determined as 1.6x10(6) Da by using static light scattering. Copyright 2000 Academic Press.     

Rapid analysis of amino sugars by microchip electrophoresis with laser-induced fluorescence detection.

Microchip electrophoresis for the short-time analysis of amino sugars is described. D-Glucosamine, D-galactosamine and their reduced forms were labeled with 4-nitro-2,1,3-benzoxadiazole 7-fluoride (NBD-F) at pH 6.0 and the fluorescent derivatives were purified on an octadecyl silica (ODS) gel plate. The derivatives were analyzed by electrophoresis on a microfabricated chip with a 33 mm long separation channel with argon laser-induced fluorescence detection. Under the established conditions, these amino sugarderivatives were well separated from each other within 60 s. Amino sugars of as small an amount as 0.5 fmol could be detected with a signal-to-noise (S/N) ratio of 3, and peak response showed good linearity between at least 0.8 and 8 fmol of samples with a relative standard deviation (RSD) of ca. 4%. This method was also applied to the analysis of amino sugar composition of O-linked glycans released from bovine submaxillary mucin with alkali in the presence of borohydride. The result of amino sugar composition analysis for individual O-glycans fractionated by high-performance liquid chromatography was quite useful for their identification.     

Measurement of neutral sugars in glycoproteins as dansyl derivatives by automated high-performance liquid chromatography

Automated high-performance liquid chromatography was used to analyse dansylhydrazine derivatives of neutral sugars in unfractionated acid hydrolysates of four well-characterized glycoproteins: fetuin, ovalbumin, alpha-1-acid glycoprotein and bovine submaxillary mucin. After a simple single-step derivatization at 65 degrees C the sugar derivatives in protein hydrolysates chromatographed as single peaks on reversed-phase C18 columns. The isocratic solvent consisted of 20% (v/v) aqueous acetonitrile containing 0.01 M formic acid, 0.04 M acetic acid and 0.001 M triethylamine. The triethylamine significantly increases the sugar peak height at 254 nm. Repeated automatic sample injection without deterioration of column performance or interference from dansyl hydrazine is not possible with published methods, but was achieved by cleaning the column between each analysis with a solvent of 20% (v/v) acetonitrile and 80% (v/v) methanol. Hydrolysis with 2 M trifluoroacetic acid is superior to 2 M hydrochloric acid for both sugar recovery and convenience but must continue for 6-8 h at 105 degrees C to ensure complete sugar release. We confirmed that mannose is present in most preparations of human high-molecular-weight salivary glycoproteins, and also examined purified bovine skin proteodermatan sulphate. p-Nitrophenylhydrazine derivatives of neutral sugars are readily produced, but do not chromatograph as successfully as the dansyl derivatives while phenylhydrazine derivatives are not easily produced at 65 degrees C. Further development of the method should be possible by producing other hydrazine derivatives of neutral sugars.     

High-performance size-exclusion chromatography of porcine colonic mucins. Comparison of Bio-Gel TSK 40XL and Sepharose 4B columns

A high-performance size-exclusion chromatography (HPSEC) method was developed for the separation of porcine colonic mucins using a Bio-Gel TSK 40XL HPSEC column (300 mm x 75 mm). In addition, porcine gastric and bovine submaxillary mucin preparations were used to describe more fully the separation characteristics of the HPSEC column. For comparison, the same preparations were also separated using a Sepharose 4B column (100 cm x 2.6 cm). The colonic and gastric mucins eluted in the void volume (V0) of both columns. Bovine submaxillary mucin was in the elution volume (Ve) of both columns. Analytical HPSEC of fractions (V0 and Ve) of the various preparations obtained by Sepharose 4B chromatography exhibited retention times identical to those for fractions obtained by HPSEC. After separation by both methods, purified mucins were obtained by CsCl2 density gradient ultracentrifugation; analytical HPSEC profiles, protein contents, and monosaccharide compositions of both gastric and colonic mucins from either column were similar. The HPSEC method, however, is ideally suited to separate microgram to milligram quantities of colonic mucin preparations quickly: 2 to 4 h, compared with 24 to 30 h for the Sepharose 4B method.     

Effects of mucin addition on the stability of oil–water emulsions

In this work, bovine submaxillary gland mucin (BSM) was used as an emulsifier to stabilize oil–water emulsion systems. Prior to use, commercial BSM was purified by jacalin affinity chromatography. Emulsions consisting of 5% mineral oil in phosphate buffered saline (PBS) were prepared through the addition of different amounts of purified mucin followed by sonication using either of two methods: (1) low energy input for a long time (2 h), or (2) high energy input for a short time (20 s). The surfactancy property of mucin was investigated by surface tension measurements, which showed the BSM to greatly reduce the surface tension of PBS. Compared to several synthetic surfactants of the Pluronic® type, mucin showed comparable or better surface activity than F68, F88 and F108 products in dilute solutions. The formed emulsions had a mean droplet size that decreased monotonically with increasing concentration of mucin until a plateau was reached at concentrations around 0.1% by weight. The stability of these emulsions was evaluated by monitoring their average droplet size during a 33-day period. Emulsions with more than 0.25% mucin showed a constant mean size throughout the period. Specifically, an emulsion produced with 0.95% mucin showed a stable mean droplet size of about 300 nm. The stability of the mucin-emulsified systems was also evaluated by measuring turbidity changes with time, which allowed a comparison with similar emulsions stabilized by the Pluronic® surfactants in the same concentration. Thus, mucin showed its ability to establish more stable and more efficient oil–water emulsion systems. Since mucin is a glycoprotein, and hence biodegradable, our results suggest that mucin might serve as an ideal biological surfactant for the stabilization of emulsion systems intended for biomedical and pharmaceutical applications.     

Adsorption and viscoelastic properties of fractionated mucin (BSM) and bovine serum albumin (BSA) studied with quartz crystal microbalance (QCM-D)

The adsorption profile and viscoelastic properties of bovine submaxillary gland mucin (BSM) and bovine serum albumin (BSA), extracted from a commercial mucin preparation, adsorbing to polystyrene surfaces has been studied using quartz crystal microbalance with dissipation monitoring (QCM-D). A significant difference in the adsorption properties of the different proteins was detected; with the BSA adsorbing in a flat rigid layer whilst the mucin adsorbed in a diffuse, highly viscoelastic layer. Subsequent addition of BSA to the preadsorbed mucin layer resulted in stiffening of the protein layer which was attributed to complexation of the mucin by BSA. In contrast, a preadsorbed layer of BSA prevented mucin adsorption altogether. Combined mixtures of mucin and BSA in well defined ratios revealed intermediate properties between the two separate protein species which varied systematically with the protein ratios. The results shed light on the synergistic effects of complexation of lower molecular weight biomolecular species with mucin. The possibility to selectively control protein uptake and tailor the physical properties of the adsorbed layer makes mucin an attractive option for application in biomaterial coatings.     

Mucin coating on polymeric material surfaces to suppress bacterial adhesion

Mucin, a group of large glycoproteins, constitutes one of the major components of mucous which covers the lumenal surfaces of epithelial organs and serves as a physical barrier between the extracellular milieu and the plasma membrane. The molecules have a generic structure consisting of a thread-like peptide backbone with densely packed carbohydrate side chains. Protein and carbohydrate contents are about 30 and 50%, respectively. On hydrophobic materials in aqueous environments the naked parts of mucin’s protein backbone will adhere due to their hydrophobicity, while the carbohydrate side chains are thought to orient themselves away from the surface. This gives the mucin molecules their unique properties as surfactants, i.e. they tend to adsorb to hydrophobic surfaces via protein-surface interactions while they hold water molecules via their hydrophilic oligosaccharide clusters. In the present work, bovine submaxillary gland mucin (BSM) is purified by SEC and subsequently characterized with PAGE. Four polymeric materials, PMMA, silicone, Tecoflex® polyurethane and polystyrene, are selected as coating targets. Contact angle measurements show significant changes in these materials after coating with BSM. Surface concentrations of adsorbed BSM are determined by amino acid analysis and found to correlate well with observed reductions in contact angle. Both Staphylococcus aureus and CNS S. epidermidis are used to contaminate uncoated and BSM coated surfaces of all four materials, demonstrating a correlation between suppression of bacterial adhesion and surface concentration of BSM. Thus, bacterial counts on the coated PMMA, PS, PU and silicone specimens amount to ≈3, 10, 8 and 30% of the counts found on their uncoated counterparts. These results suggest that mucin coatings could profitably be employed to reduce the risk of microbial infections on polymeric biomaterials.     

Mucin Interactions with Functionalized Polystyrene Latexes

The interactions of pig gastric mucin and bovine submaxillary mucin with carboxylate (PCM) and amino (PAM) polystyrene latexes with 750 and 1000 nm diameters have been studied in vitro. The mucin interaction increased when the pH decreased from 7.4 to 3.0 and when the electrolyte concentration increased from 86 to 205 mM. The driving force of the interaction was very probably nonionic. Under certain conditions, electrostatic attraction also was important for PAM. Under all experimental conditions tested, the mucins interacted less with PAM than with PCM. The functional groups of the latexes directed the conformation of the adsorbed mucins at the interface. At low pH, the mucins probably were adsorbed in multilayers.     

Purification of Two Novel Sugar Acid-binding Lectins from <Emphasis Type="Italic">Haplomitrium Mnioides</Emphasis> (bryophyte,Plantae) and their Preliminary Characterization

Two novel sugar acid-binding lectins were purified from Haplomitrium mnioides (Lindb.) Schust. using a procedure consisting of ammonium sulfate precipitation, G-50 gel filtration, hydroxyapatite chromatography, and HW-50 gel filtration. We reported their partial physicochemical properties: molecular weight, affinity for carbohydrates and organic acids, pH stability, and dependence of their hemagglutination activity on metal ions. We also determined their N-terminal amino acid sequences. H. mnioides lectins (HMLs) were monomers (one with a molecular weight of approximately 27 kDa, and the other with a molecular weight of approximately 105 kDa) under both nonreducing and reducing conditions. They were named HML27 and HML105, respectively. Both HMLs had an affinity for N-acetylneuraminic acid, d-glucuronic acid, d-glucaric acid, bovine submaxillary mucin, heparin, and organic acids, such as citrate, 2-oxoglutaric acid, and d-2-hydroxyglutarate. Furthermore, HML27 had an affinity for α-d-galacturonic acid, d-malate, l-malate, and pyruvate, while HML105 had an affinity for d-gluconic acid. HML27 and HML105 are novel plant lectins: they have an affinity for sugar acids and organic acids and specifically recognize the carboxyl group, and there is no homology between their N-terminal amino acid sequences and those of the previously described lectins and agglutinins.     

Synergistic Properties of Arabinogalactan (AG) and Hyaluronic Acid (HA) Sodium Salt Mixtures

The properties of mixtures of two polysaccharides, arabinogalactan (AG) and hyaluronic acid (HA), were investigated in solution by the measurement of diffusion coefficients D of water protons by DOSY (Diffusion Ordered SpectroscopY), by the determination of viscosity and by the investigation of the affinity of a small molecule molecular probe versus AG/HA mixtures in the presence of bovine submaxillary mucin (BSM) by ¹HNMR spectroscopy. Enhanced mucoadhesive properties, decreased mobility of water and decreased viscosity were observed at the increase of AG/HA ratio and of total concentration of AG. This unusual combination of properties can lead to more effective and long-lasting hydration of certain tissues (inflamed skin, dry eye corneal surface, etc.) and can be useful in the preparation of new formulations of cosmetics and of drug release systems, with the advantage of reducing the viscosity of the solutions.