Fluorous osmium tetraoxide (OsO4): a recoverable and reusable catalyst for dihydroxylation of olefins

A fluorous osmium catalyst was firstly developed. It had been effectively used as recoverable and reusable catalyst in the dihydroxylation of olefins.     

Hydroformylation in fluorous solvents

The hydroformylation of long chain alkenes under fluorous biphase conditions and in neat perfluorocarbon solvents is reviewed. Special emphasis is placed upon the authors' evaluation of the steric and electronic influence of perfluoroalkylation on catalyst activity, regioselectivity and retention in the fluorocarbon phase.     

亲和标记-基质辅助激光解吸电离飞行时间质谱用于蛋白质相对定量方法的研究

将亲和标记技术和基质辅助激光解吸电离飞行时间串联质谱联用,建立了蛋白质相对定量方法,以牛血清白蛋白为实验对象,考察了该方法的准确度、重现性等指标;又以数种标准蛋白混合物为研究对象,考察了该方法的动态范围及相应的标准偏差,为实际生物样品中差异蛋白质分析奠定了基础。     

Fluorescence detection and quantitation of recombinant proteins containing oligohistidine tag sequences directly in sodium dodecyl sulfate-polyacrylamide gels

Two fluorophore-nitrilotriacetic acid conjugates, Pro-Q Sapphire 365 and Pro-Q Sapphire 488 oligohistidine gel stains, have been developed for the fluorescence detection of fusion proteins containing oligohistidine tags directly in sodium dodecyl sulfate polyacrylamide gels, without the requirement for electroblotting, reporter enzymes or secondary detection reagents. Pro-Q Sapphire 365 oligohistidine gel stain exhibits bright-blue fluorescence (emission maximum = 450 nm) when illuminated with UV-A or UV-B light from a standard ultraviolet transilluminator. Pro-Q Sapphire 488 oligohistidine gel stain exhibits bright-green fluorescence (emission maximum = 515 nm) when illuminated with visible light from a laser-based gel scanner equipped with a 470 nm second-harmonic generation (SHG) or 488 nm argon-ion laser source. Typically, 25-65 ng of oligohistidine-tagged fusion protein in whole cell lysates is detectable using either stain. After documenting the fluorescence signal from the Pro-Q Sapphire dyes, gels may be post-stained with the red-fluorescent SYPRO Ruby protein gel stain in order to reveal the total protein pattern.     

Self-assembled luminescent CdSe-ZnS quantum dot bioconjugates prepared using engineered poly-histidine terminated proteins

We report a simple and versatile approach for the conjugation of luminescent CdSe-ZnS core-shell quantum dots (QDs) to proteins through coordination of engineered C-terminal oligohistidine sequences. Several histidine tail containing proteins were self-assembled onto the QD surface using this method. A recombinant antibody specific for the high explosive 2,4,6-trinitrotoluene (TNT) was conjugated to QDs through a carboxy terminal histidine tail and the bioconjugate used to detect TNT by competitive immunoassay. TNT was detected over the range of 10 μg/ml down to 41 ng/ml using the scFv conjugated to QDs. These results open up the possibility to conjugate luminescent QDs to a whole range of proteins to form QD bioconjugates that can be effectively used in bio-oriented applications, such as sensing, imaging, immunoassay and other diagnostics.     

Synthesis and properties of fluorous arenes and triaryl phosphorus compounds with branched fluoroalkyl moieties (“split pony tails”)

Most compounds designed for immobilization in fluorous media feature linear pony tails of the formula (CH₂)_m(CF₂)_n−1CF₃ [(CH₂)_mR_fn]. This paper presents a first-generation approach to compounds with branched or “split” pony tails of the formula (CH₂)_lCH[(CH₂)_mR_fn]₂. Allyl tri(n-butyl)tin is reacted twice with perfluorooctyl iodide (R_f8I; first, photochemical, 78-81%; second, thermal with radical initiator, 71%; 13-18 g scales) to give the secondary alkyl iodide ICH(CH₂R_f8)₂ (3). A subsequent Ni(Cl)₂(PPh₃)₂-catalyzed reaction with allyl tri(n-butyl)tin yields the branched alkene H₂CCHCH₂CH(CH₂R_f8)₂ (74%). A palladium-catalyzed Heck coupling with OP(p-C₆H₄Br)₃ gives the fluorous phosphine oxide OP(p-C₆H₄CHCHCH₂CH(CH₂R_f8)₂)₃ (84%), and Pd/C-catalyzed hydrogenation affords OP(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃ (>99%). Reduction with SiHCl₃ gives P(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃, which is protected as the air-stable borane adduct H₃B·P(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃ (9, 64%). The CF₃C₆F₁₁/toluene partition coefficient of 9 is much higher than that of the analog with p-(CH₂)₃R_f8 groups (96.6:3.4 versus 37.3:62.7). The iodide 3 is unreactive towards PAr₃ at 175-250 °C. However, a CuBr-catalyzed reaction with C₆H₅MgBr gives C₆H₅CH(CH₂R_f8)₂, which also exhibits a high partition coefficient (97.9:2.1).     

The synthesis and application of fluorous boronates without perfluorinated solvents

The synthesis of a fluorous diol 4 bearing a perfluorodecyl chain was described. A series of boronic acid were attached to 4 by esterification. The purification of the products was fulfilled by facile filtration instead of expensive and environmental troublesome fluorous liquid-liquid extraction. The Suzuki cross-coupling reactions of the formed fluorous boronates 5 underwent smoothly and the fluorous diol 4 was recycled in good yields.     

Redox Polymerization of Methyl Methacrylate in the Fluorous Triphasic System

Fluorous-phase chemistry is currently a topic of considerable interest1-6. Since fluoroustriphasic reactions were first described by the Curran and co-workers7, this triphasicsystem has been widely used for detagging7,8 and phase-vanishing reactions9-11. …     

Fluorous Synthesis of Biaryl-Substituted Proline Analogs by 1,3-Dipolar Cycloaddition and Suzuki Coupling Reactions

A solution-phase synthesis of bicyclic prolines containing four points of diversity has been developed by a two-step synthesis involving 1,3-dipolar cycloaddition of perfluoroalkylsulfonyl-protected hydroxybenzaldehydes followed by Pd-catalyzed Suzuki coupling reaction of fluorous sulfonates with boronic acids. Both reactions are conducted under microwave irradiation and reaction mixtures are purified by solid-phase extractions without performing chromatography.