26150-05-0

We report on the stereoselective synthesis of both molecular granny and square knots through the use of lanthanide-complexed overhand knots of specific handedness as three-crossing "entanglement synthons". The composite knots are assembled by combining two entanglement synthons (of the same chirality for a granny knot; of opposite handedness for a square knot) in three synthetic steps: first, a CuAAC reaction joins together one end of each overhand knot. Ring-closing olefin metathesis (RCM) then affords the closed-loop knot, locking the topology. This allows the lanthanide ions necessary for stabilizing the entangled conformation of the synthons to subsequently be removed. The composite knots were characterized by 1H and 13C NMR spectroscopy and mass spectrometry and the chirality of the knot stereoisomers compared by circular dichroism. The synthetic strategy of combining building blocks of defined stereochemistry (here overhand knots of λ- or Δ-handed entanglement) is reminiscent of the chiron approach of using minimalist chiral synthons in the stereoselective synthesis of molecules with multiple asymmetric centers.

This work relates to the use of organic functionalized heteropolytungstates (HPTs) as protein-specific electron microscopy labels.The objective is the development of a polycationic ligand that prevents the nonspecific precipitation reaction observed between certain polycationic biomolecules and polianionic heteropolytungstates.Simple tetra- and pentaammonium salts between Keggin HPT 1b or Dawson HPT 2b and amines 3-6 or quaternary ammonium compounds 8 and 9 were all of low aqueous solubility as were salts derived from the oxygenated partners 7, 11, 12, and 15-18.However, tetrakis quaternary salt 23a, which is made up of several highly oxygenated alkyl groups, effectively prevents precipitation between Dawson HPT 2b and the exemplary basic proteins lysozyme and poly-L-lysine as well as the lectin concanavalin A.

(Matrix presented) The synthesis of a ruthenium[2]catenane is described. One ring includes two 1,10-phenanthroline moieties, the other a bipyridinic unit. The interlocking ring system was formed by using a double ring closing metathesis reaction. Under ir

The invention discloses a single mercapto double-cetyl [...] glycol [...] glycolipid synthesis method, characterized in that the 2, 3, 4, 6 - O - acetyl - α - D - pyran mannose the heat stability of the polyurethane in the [...][...] benzoic acid with thr

Controlling the helix-coil transition of polypeptides under physiological conditions is an attractive way toward smart functional materials. Here, we report the synthesis of a series of tertiary amine-functionalized ethylene glycol (EGx)-linked polypeptide electrolytes with their secondary structures tunable under physiological conditions. The resultant polymers, denoted as P(EGxDMA-Glu) (x = 1, 2, and 3), show excellent aqueous solubility (>20 mg/mL) regardless of their charge states. Unlike poly-l-lysine that can form a helix only at pH above 10, P(EGxDMA-Glu) undergo a pH-dependent helix-coil switch with their transition points within the physiological range (pH ～5.3-6.5). Meanwhile, P(EGxDMA-Glu) exhibit an unusual salt-induced helical conformation presumably owing to the unique properties of EGx linkers. Together, the current work highlights the importance of fine-tuning the linker chemistry in achieving conformation-switchable polypeptides and represents a facile approach toward stimuli-responsive biopolymers for advanced biological applications.

The present invention relates to a novel triazine compound represented by chemical formula 1, an all-solid-state polymer electrolyte composition comprising the same as a cross-linking agent and uses thereof. More specifically, the triazine compound effectively inhibits crystallization of a plasticizer at a low temperature (room temperature) to show significantly improved ion conductivity, and can realize significantly improved electrochemical stability and excellent battery properties, thereby being usefully used as an all-solid-state polymer electrolyte composition such as a lithium-polymer secondary battery, a dye-sensitized solar cell, etc.COPYRIGHT KIPO 2018

Herein, the preparation of neoglycoconjugates bearing mannose-6-phosphate analogues is described by: (a) synthesis of a cyclic sulfate precursor to access the carbohydrate head-group by nucleophilic displacement with an appropriate nucleophile; (b) introduction of spacers on the mannose-6-phosphate analogues via Huisgen's cycloaddition, the Julia reaction, or the thiol-ene reaction under ultrasound activation. With the resulting compounds in hand, gold nanoparticles could be functionalized with various carbohydrate derivatives (glycoconjugates) and then tested for angiogenic activity. It was observed that the length and flexibility of the spacer separating the sugar analogue from the nanoparticle have little influence on the biological response. One particular nanoparticle system substantially inhibits blood vessel growth in contrast to activation by the corresponding monomeric glycoconjugate, thereby demonstrating the importance of multivalency in angiogenic activity.

The formation of interlocked lanthanide-based catenanes using Eu(iii)-directed synthesis is described (catenation being achieved via a ring-closing metathesis reaction); the self-assembly formation of the supramolecular structures was analysed by HRMS, NM

The present invention relates to linker molecules that readily conjugate cellular recognition ligand at one end and drug payload at the other, and are useful in treating or preventing cancer, an autoimmune disease, an inflammatory condition, a central nervous system disorder or an infection. The linker inker molecules of the invention are represented by Formula I, II and III; Linker-Drug compounds represented by Formula IV, V and VI; and Ligand-Linker-Drug conjugates represented by Formula VII, VIII and IX:

With the aim of connecting atorvastatin lactone 9 to a linker for affinity-based target fishing, a concise route to the pyrrolecarboxylic acid 8 was developed. Key features of the synthesis of the diol-containing side-chain were a catalytic enantioselecti

An acoustic wave biosensor comprising a surface of a mixed self-assembling monolayer for receiving a probe-biomolecule is described herein. The biosensor surface may comprise a piezoelectric quartz crystal,—for detection purposes with the electromagnetic piezoelectric acoustic sensor (EMPAS)—upon which a mixed self-assembling monolayer is formed, which includes at least one linker, such as 2,2,2-trifluoroethyl-13-trichlorosilyl-tridecanoate (TTTA); its oligoethylene glycol (OEG) analog OEGylated TTTA (OEG-TTTA); S-(2-(2-(2-(3-trichlorosilyl-propyloxy)-ethoxy)-ethoxy)-ethyl)-benzenethiosulfonate (OEG-TU BTS). Linker/diluent systems for attaching a functionalizing entity to the surface of a biosensor are described, as well as methods for preparing a biosensor surface with an oligoethylene glycol linker.

A catenated anion receptor 7 comprising two indolocarbazole units was prepared by olefin ring-closing metathesis using Grubbs' catalyst. Receptor 7 possesses a cage-like cavity where anions are encapsulated by forming four hydrogen bonds in the order of C

The thermodynamic and kinetic stability of three structurally related monolayer-protected gold clusters have been systematically investigated, revealing that the nanoparticles display significantly different stability against thermo- and cyanide-induced decomposition and external thiol agents. The Royal Society of Chemistry.

We describe the synthesis of a hybrid DNA/organic macrocycle that is prepared by formation of an amide linkage across one full turn of DNA. Formation of a catenane proved that the linkage crossed a turn rather than running along the phosphodiester backbone contour. The product, a doubly tailed catenane, contains 5′- and 3′-termini that can be functionalized further or used to incorporate the catenane structure into other DNA assemblies. Copyright

The present invention relates to a cyclic siloxane-based compound and a solid polymer electrolyte composition containing the same as a crosslinking agent, more particularly to a cyclic siloxane-based compound having a novel structure in which polyalkylene oxide acrylate groups are introduced into a cyclic siloxane compound and a solid polymer electrolyte composition containing the cyclic siloxane-based compound as a crosslinking agent along with other electrolyte components such as a plasticizer, lithium salt and a curing initiator. Since the solid polymer electrolyte composition of the present invention improves ion conductivity and electrochemical stability at room temperature, it can be useful as polymer electrolyte for electrolyte films, small-sized to high-capacity lithium-polymer secondary batteries, etc. Also, physical properties of the polymer electrolyte can be controlled easily by controlling the length of the polyalkylene oxide group in the cyclic siloxane-based crosslinking agent.

A general method to prepare macroheterocycles is reported in which a rigid symmetric platinated tris-pincer tricationic complex (3) is used as a template. The system uses bisolefin functionalized pyridine ligands (1, 2) which selectively bind to the three platinum centers of the template resulting in pre-organization of the olefinic tails. By subjecting these pre-organized complexes (4) to olefin metathesis reaction conditions, the olefinic tails were interconnected affording several macroheterocycles of different compositions and sizes. Various pyridines with different substitution patterns (2,6- and 3,5-disubstituted) and different olefinic tails (aliphatic, polyether, and styryl) were synthesized and used in the cyclization reactions, showing the diversity of this method. It was found that only the use of 2,6-disubstituted pyridines resulted in the formation of the desired macrocycles while 3,5-difunctionalized pyridines gave only pyridinophane formation. Furthermore, the length of the olefinic tails needs to be at least eleven atoms (C or O) in order to suppress oligomerization in favor of macrocycle formation. Yields of up to 70% of the macrocycles were obtained using the first-generation [Cl 2(Cy3P)2Ru=CHPh] or second-generation [Cl 2(Cy3P)(IMeS)Ru=CHPh] Grubbs' catalysts. Reactions of the platinated pincer pyridines with Schrock Mo-based metathesis catalysts results in exclusive olefin isomerization and no productive metathesis. The generated macrocycles (hosts) could effectively be separated from the template by addition of aqueous sodium chloride and reattached to the (recycled) template (guest). The X-ray structure determination of host-guest complex 10 is the definite proof for this reattachment and the perfect cyclic structure of the macrocycle.

Purpose. Angiogenesis is a key event in tumor growth and metastasis, chronic inflammatory disease, and cardiovascular disease. It is controlled by positive and negative regulators, which include vascular endothelial growth factor (VEGF) as the most active

A convenient approach to the synthesis of oligo(ethylene glycols) under phase transfer conditions is described. Oligo(ethylene glycols) (x = 7-12) are obtained in excellent yields and high purity via modular, bi-directional elongation of readily available ethylene glycol bis-tosylates.

New single ion conductors were synthesized by grafting the allyl group-containing lithium salt, lithium bis(allylmalonato)borate (LiBAMB), onto allyl group-containing comb-branch polyacrylate or polymethacrylate ethers by means of hydrosilylation. The highest ambient temperature conductivity of 3.5 × 10-7 S cm-1 was obtained for a polyacrylate ether-based single ion conductor containing eight EO units in the side chain and five EO units in the cross-linking side chain, to which the anion was fixed with a salt concentration of EO/Li = 20. For polyacrylate ether-based single ion conductors, an increase of chain length in both side chains and cross-linking anion chains favors an increase of ionic conductivity. The addition of 50 wt % EC/DMC (1/1, wt/wt) increased the ionic conductivity by more than 2 orders of magnitude due to both the increase in ionic mobility from the liquid phase and the increase in the concentration of free ions from the high dielectric constant of the solvent. The preliminary Li/Li cycling profiles of dry polyacrylate- and polymethacrylate ether-based single ion conductors are encouraging as almost no concentration polarization or relaxation was observed. The observed increase in cell potential with cycling is apparently due to an increase in the interfacial impedance associated with the SEI layer, and the cell failure is accompanied by the decomposition of the ester bond of the polyacrylate backbone.

Catalytic reactions of diazoacetates tethered through zero, one, two, and three ethylene glycol units to an allyl group have been investigated for chemoselectivity, diastereoselectivity, and enantioselectivity. Results from cyclopropanation, carbon-hydrogen insertion, and oxonium ylide generation are compared from reactions of achiral and chiral catalysts of copper(I) and dirhodium(II) carboxylates and carboxamidates. Relative to results from intermolecular reactions of ethyl diazoacetate with allyl ethyl ether, intermolecular reactions show a diversity of selectivities including preference for the opposite configurational arrangement from the one preferred in corresponding intermolecular cyclopropanation reactions. Enantioselectivities for cyclopropanation are dependent on the catalyst ligands in a manner that reflects divergent trajectories of the carbon-carbon double bond to the reacting carbene center. Enantioselectivity increases as a function of ring size with chiral copper catalysts, but the reverse occurs with chiral dirhodium(II) carboxamidates. Mechanistic implications, including those related to the conformation of the reacting metal carbene, offer a new dimension to understanding of enantioselectivity in catalytic asymmetric cyclopropanation reactions.

Approaches to water-soluble phosphines are described which involve conversion of ethylene glycol derivatives and sugar diacetonides into monoallyl ethers, and hydrophosphorylation of the latter.In the case of the sugars, water-solubility is conferred by a subsequent hydrolysis.