Imidazole synthesis on a solid support

Imidazole synthesis has been demonstrated using polymer supported O-carboxamido -5-aminoimidazole and hypoxanthine.     

Solvent resistance of a polymer chain chemically linked onto a solid surface

Polystyrene or polystyrene–polyisoprene copolymers have been grafted onto silica by an anionic procedure. The solvent resistance of the grafts has been examined. Linear relationships between the extractable amount of polymer and the solvent extraction temperatures are observed. The extrapolation of these lines leads to temperatures that are in close agreement with the ceiling temperatures of the grafted polymers.     

Formation of lysozyme fibrils on a solid support

The formation of lysozyme fibrils on a solid support was studied with a FemtoScan? atomic force microscope. It is found that, at room temperature and pH 3, when aggregation in solution is absent, the fibrils can be formed on the surface. It is shown that the proximity of lysozyme molecules to the surface favors their aggregation. The physical sorption of lysozyme on the gold surface does not result in aggregation, and the chemical grafting of lysozyme to the gold surface is favorable for the fibril formation. The force of interaction of lysozyme molecules immobilized on the gold surface of a cantilever was measured on an Atomic Balance?.     

Angeli-Rimini's reaction on solid support: a new approach to hydroxamic acids

Angeli-Rimini's reaction has been performed for the first time on solid phase. A convenient one-step procedure for the synthesis of hydroxamic acids starting from aldehydes and solid-supported N-hydroxybenzenesulfonamide is reported. The hydroxamates are isolated in good to high yields and purities by simple evaporation of the volatile solvents, after treatment of the crude reaction mixture with sequestering agents.     

Preparative manipulation of gold nanoparticles by reversible binding to a polymeric solid support

A preparative scheme is presented for controlled modification of gold nanoparticles (NPs) by using reversible binding to a polymeric solid support through boronic acid chemistry. Octanethiol-capped Au NPs were bound to a boronic acid functionalized resin by custom-synthesized bifunctional linker molecules. The NPs were chemically released from the resin to the solution, with one (or a few) linker molecules embedded in their capping layer. This was confirmed by rebinding the linker-derivatized NPs to a boronic resin, exploiting the reversibility of the boronic acid/diol chemistry. The same scheme was employed to demonstrate a new method for affinity separation of NPs by means of a solid-phase reaction. The use of boronic acid provides versatility and chemical reversibility, while the polymeric solid support affords the separation and preparative aspects. The method presented here may be useful in various facets of NP handling, manipulation, and separation.     

Catalytic test determination of copper on a solid support

A test procedure was developed for the determination of 5 × 10^?7?1 × 10^?3 M copper with the use of the copper-catalyzed reaction of the reduction of molybdophosphoric acid by thiourea on a solid support (paper). The conditions of the indicator reaction and the technique for its conduction were optimized; the pH range in which the acidity of the solution does not affect the time of the reaction was revealed. The calibration plot for the determination of copper was constructed in reaction time-pCu coordinates. The effect of different components on the rate of the indicator reaction was studied. The procedure was approved in the analysis of real and model solutions.     

Preparation of novel polythioether dendrons on a solid support

A synthetic scheme for the solid-phase synthesis of unprecedented polythioether dendrons has been established, the dendrons prepared up to the fourth generation, and the applicability of the dendronized resins for supported catalysis has been demonstrated.     

Enzymatic optical resolution via acylation-hydrolysis on a solid support

By taking advantage of the reversibility of the thermolysin-catalysed amide synthesis-hydrolysis reaction on a solid support, both L,L and L,D diastereoisomers of dipeptides and L-amino acids are accessible in good yields starting from enantiomeric mixtures of amino acids.     

Supramolecular self-assembly on a solid support: metal-directed complementarity

Resin immobilised (poly)-2,2'-bipyridines have been prepared and used as templates for the copper(II)-mediated assembly of alkene-functionalised 2,2'ratio6',2'-terpyridines which undergo subsequent templated metathesis to form complementary poly-2,2'ratio6',2'-terpyridine strands.     

Synthesis of polypyrrolinones on solid support

[reaction: see text] An efficient, three-step iterative synthesis of polypyrrolinones has been achieved on solid support, setting the stage for the construction of a wide variety of libraries based on the pyrrolinone scaffold. Central to the approach is an effective end-game sequence featuring pyrrolinone ring construction with traceless release from the solid support.     

Exploiting site-site interactions on solid support to generate dimeric molecules

[structure: see text]. "Intra-site" olefin cross-metathesis on solid support leads to nearly quantitative yields of dimeric molecules.     

Use of olefin cross-metathesis to release azide-containing sugars from solid support

[reaction: see text] The octenediol linker used during automated oligosaccharide assembly is cleaved by olefin cross-metathesis. Until now, this linker could not be applied to sugars containing azides. A detailed study of the cleavage reaction served as basis for the development of a new protocol using the [(H(2)Imes)(3-Br-py)(2)(Cl)(2)Ru=CHPh] catalyst and 1-pentene. Efficient release of azide-protected carbohydrates from solid support can be readily achieved.     

Oriented immobilization of chymotrypsin by use of suitable antibodies coupled to a nonporous solid support.

In order to eliminate the kinetic limitation of chymotryptic hydrolysis of proteins due to diffusion, nonporous hydroxyalkyl methacrylate solid support was developed and used for oriented immobilization of chymotrypsin by means of suitable polyclonal antibodies. Nonporous microspheres were prepared by dispersion copolymerization of 2-hydroxyethyl methacrylate and ethylene dimethacrylate in an alcohol-toluene mixture stabilized with cellulose acetate butyrate. The resulting particles were 1.2 microm in diameter and possessed narrow size distribution. After modification with adipic acid dihydrazide they contained 2 micromol of reactive groups available for coupling of anti-chymotrypsin antibodies. Prepared immunosorbent adsorbed 166.7 microg of chymotrypsin per 1 g of dry carrier. Immobilized chymotrypsin retained practically 100% of its native proteolytic activity. Kinetic parameters of catalysis by chymotrypsin immobilized via this way were improved due to the good steric accessibility of the enzyme active site for high-molecular-mass substrates, when digestion of proteins in batch experiments was used.     

Efficient synthesis of antisense phosphorothioate oligonucleotides using a universal solid support

It is demonstrated that solid support containing a novel universal linker could be efficiently used to synthesize both phosphorothioate oligodeoxyribonucleotides and second-generation 2′-O-methoxyethyloligoribonucleotides with high yield and quality as judged by ion-pair-liquid chromatography-electrospray mass spectroscopy, ³¹P NMR and reversed phase HPLC. Analysis of oligonucleotides shows quality being superior to that produced with standard succinyl-linker solid supports, without contamination of materials resulting from linker or support backbone decomposition.     

Synthesis of a new troponoid liquid crystalline library on solid support

Five types of troponoids including 40 molecules were prepared by means of palladium(0)-catalyzed carbonylation and successive acylation or benzoylation after immobilization of 2-methoxy-5-trifluoromethylsulfonyloxytropone on solid support. Four types of them showed mesophases. The final products have enough purity to detect their mesomorphic properties.