Wyniki wyszukiwania - BazTech

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Kompleks mocznikowo-wodoronadtlenkowy jako efektywny i ekologiczny czynnik utleniający w syntezie organicznej

Podraza A., Pielichowski J.

Przemysł Chemiczny

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2013

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T. 92, nr 2

158-164

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Zastosowanie chemii kombinatorycznej i metod high-throughput w syntezie i badaniach materiałów polimerowych

Paturej M., El Fray M.

Polimery

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2009

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T. 54, nr 3

179-188

PL

Artykuł stanowi przegląd literaturowy dotyczący - wykorzystujących podejście chemii kombinatorycznej (CombiChem) - metod syntezy materiałów polimerowych, ze szczególnym uwzględnieniem polikondensacji, polimeryzacji rodnikowej, kontrolowanej polimeryzacji rodnikowej oraz polimeryzacji z otwarciem pierścienia ROP. Omówiono urządzenia stosowane w procesach CombiChem, tj. reaktory konwencjonalne i mikrofalowe, opisano proces tworzenia wirtualnych bibliotek polimerowych, metody oczyszczania oraz sposoby analizy i charakterystyki tak otrzymywanych produktów. Oceniono obecny stopień wykorzystania CombiChem w projektowaniu i pozyskiwaniu nowych biodegradowalnych materiałów polimerowych.

EN

The paper is a literature review of the methods, applying the combinatorial chemistry (CombiChem) approach, concerning the polymer materials syntheses, especially polycondensation (Table 1), radical polymerization, controlled radical polymerization and ring opening polymerization ROP. The equipment used in CombiChem processes, i.e. conventional and microwave reactors (Table 2, Fig. 1) were discussed. The process of formation of virtual polymer libraries and the methods of purification, analyses and characterization of the products obtained were described. The present degree of CombiChem application in design and preparation of novel biodegradable polymer materials was evaluated.

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Narzędzia chemii kombinatorycznej. Cz. 4. Synteza asymetryczna na fazie stałej

Łaźny R., Nodzewska A., Żabicka B.

Wiadomości Chemiczne

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2006

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[Z] 60, 3-4

191-255

EN

Solid Phase Asymmetric Synthesis (SPOS) is a recently introduced term embracing all methods of asymmetric synthesis involving use of solid supported substrates and reagents. This review presents basic definitions of asymmetric synthesis and currently used concepts for enatioselective and diastereoselective transformations involving supported synthesis. The concepts of chiral auxiliary, chiral catalyst and chiral reagent are illustrated with selected but fairly comprehensive overview of methods published till January 2005. In particular use of chiral auxiliaries such as oxazolidine derivatives, amines, hydrazines, sulfoxides, sulfinyl amides, sulfoxy imines, carbohydrates and alcohols is covered. Applications of immobilized chiral catalysts to synthesis of carbon-carbon bonds, carbon-hydrogen bonds, carbon--heteroatom bonds and in phase-transfer catalysis is presented with selected reactions due to huge volume of literature in this field. Moreover applications of chiral catalysts and chiral reagents in reactions of immobilized substrates and use of chiral immobilized reagents is also reviewed. The literature review shows that the most popular methods of supported asymmetric synthesis are the alkylation of enolates, aldol reactions, Grignard reactions, cycloadditions, reduetion of ketones, epoxida-tions, olefin dihydroxylation, and phase-transfer catalyzed reactions. There are numerous applications of immobilized chiral catalysts and a substantial number of applications of immobilized chiral auxiliaries. On the other hand there are only scarce reports of applications of chiral reagents and chiral catalysts to the reactions of achiral immobilized substrates.

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Narzędzia chemii kombinatorycznej. Cz 3. Reakcje w syntezie organicznej na fazie stałej

Łaźny R., Łapińska M., Sienkiewicz M.

Wiadomości Chemiczne

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2005

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[Z] 59, 11-12

881--952

EN

Solid Phase Organic Synthesis (SPOS) is a dynamically growing branch of organic synthesis encompusing methods for synthesis of both small molecules and oligomers on solid supports. Synthetically useful organic reactions of substrates immobilized on solid supports constitute a central part of the methodology of solid phase synthesis. This review article presents a representative and fairly comprehensive overview of reactions of supported substrates published till January 2005. The reactions are classified in synthetic terms into functional group interconvertions (FG1, according to type of functional group reacting and prepared) and C-C bond forming reactions (according to reaction type; usually name reaction). Fn particular preparations of halogens, alcohols, ethers, thiols, aldehydes, ketones, acids, esters, amides, phosphines, amines, poliamines, peptides, peptoids, oligonucleotides, and oligosaccharides is covered. Oxidation reactions of alcohols, aldehydes and ketones as well as reduction reactions of aldehydes, ketones, esters, acids, nitro and nitroso compounds are also presented. Only the selected reactions used for preparation of oligonucleotides, oligosaccharides, and polypeptides are covered due to the large volume of literaturę on this topie. The important C-C bond forming reactions such as Mannich, Michael, aldol, Heck, Suzuki, Stille, Sonogashira, Wittig, Horner-Wad-sworth-Emmons, metathesis, carbonyl compound alkylation and acylation reactions are illustrated with examples. Moreover the multicomponent reactions such as Ugi reaction, Hantzsch reaction and Baylis-Hillman reaction are also included in the review. The literature review shows a spectrum of synthetic organic reactions which can be performed on the immobilized substrates and suggests that in principle every reaction could be performed on solid phase. Howeverthe literature review indicates that reactions of polar organometallic reagents, radical reactions, and enantioselective reactions of achiral immobilized substrates are rather rarely used in SPOS.

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Narzędzia chemii kombinatorycznej : nośniki stosowane w syntezie organicznej związków nisko- i wysokocząsteczkowych

Łaźny R., Nodzewska A.

Wiadomości Chemiczne

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2003

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[Z] 57, 7-8

587--625

EN

Progress in combinatorial chemistry is largely determined by development of specific synthetic organic chemistry tools such as solid supports, linkers, polymer supported reactions and methods of analysis, screening and deconvolution of combinatorial libraries. This review article presents basic terms related to polymer supported synthesis, enumerates major advantages of supported reactions, and gives a comprehensive, up to date, overview of support matrices used for immobilization of small and large molecules. The review covers the literature up to September 2002. The supports reviewed include (i) polymeric gels (Merrifield gel, TentaGel, ArgoGelTM, JandaJelTM, PEGA, PEG-PS, PEG-POP, SPOCC, PS-TTEGDA, CLEAR, DendroGel, Pepsyn, and Sucholeiki paramagnetic gel), (ii) soluble polymers (LPS, PEG, ROMP-polymer, PAMAM-dendrymer, Boltron), (iii) macroporous supports (CPG, Pepsyn K, PolyHIPE, ArgoPoreTM) and other developments including SMART reactors, MicroTubeTM, membranes, pins, and cellulose. For most of the supports reviewed basic characteristics such as swelling in different solvents, solvent usability, typical loading, typical anchoring groups, preparation, and recent applications are given or cited. The reviewed literature suggests that the supports most often used for synthesis of small molecules and peptides are based on gel matrices. The variety of available supports, many of which were introduced in the last years, shows that this area of synthetic methodology may grow dynamically in the future.

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Narzędzia chemii kombinatorycznej. Cz.2. Łączniki stosowane w syntezie organicznej na fazie stałej

Łaźny R., Michalak M.

Wiadomości Chemiczne

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2003

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[Z] 57, 11-12

1061--1091

EN

Linkers constitute fundamental tools of polymer supported synthesis and combinatorial chemistry. Synthesis of any compound on solid support requires an efficient method for binding substrate molecules to solid phase and methods for cleavage of product molecules from the support after completion of the synthetic sequence. This review article presents role of linkers in solid-phase synthesis, analogy between linkers and protecting groups, and properties of linkers that need to be considered when planning synthesis of a particular compound on solid support. Basic concepts of linker methodology are presented and illustrated with selected examples. In addition the role of the linker as protection or activation of functional group of the substrate and an element controlling regio- or chemoselectivity is mentioned. The selected, representative examples of classical and recently elaborated linkers are classified according to the condition of cleavage. These include acid sensitive, base or nucleophile sensitive, photolabile, safety catch linkers, traceless linkers and cyclative cleavage linkers.

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Selekcja kwasów nukleinowych in vitro

Nawrot B.

Wiadomości Chemiczne

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2000

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[Z] 54, 7-8

615-636

EN

In vitro selection of nucleic acids (Systematic Evolution of Ligands by Exponential Enrichment - SELEX) is the selection technique which, from the library of randomised or degenerated RNA or DNA molecules, allows the isolation of nucleic acids with expected biochemical properties. Repeated cycles of selection and amplification have been used to isolate sequences of nucleic acids (aptamers) that bind with high affinity specific molecular targets - proteins or low molecular weight ligands. This method allows also to isolate a number of nucleic acids with catalytic activity and thus to generate new ribozymes and deoxyribozymes. SELEX is an useful tool of molecular biology and bioorganic chemistry for developing new therapeutic agents, as well for the insight in function of RNA in molecular evolution and RNA World hypothesis.

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Wybrane problemy projektowania substancji biologicznie aktywnych

Polański J.

Wiadomości Chemiczne

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1999

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[Z] 53, 1-2

1-16

EN

Although most of the drugs have been discovered serendipitously the rational design of the molecules has been attempted from years. However, only the recent years brought a variety of new techniques providing unquestionably efficient procedures. In particular, the methodology of 2D and 3D quantitative structure activity relationships (QSAR) and combinatorial chemistry should be mentioned. In this review the basic methodology of the classical Hansch QSAR aproach has been briefly discussed. In general, classical two-dimensional QSAR fails to distinguish between stereoisomers. This fact inspired the development of the idea of 3D QSAR. Just the last year brought the concept of 4D QSAR covering quantitative description of conformational effects. On the other hand, the comparative molecular field analysis CoMFA, which is the most common 3D QSAR scheme, demands perfect alignment of the series of molecules analyzed. Moreover, the results critically depend upon the way of overlaying the molecules. The CoMFA and 4D QSAR analyses base on the statistical techniques of the partial least square (PLS) and cross-validation procedure. Both from the theoretical and practical points of view more flexible procedures for the alignment of molecules are needed. A comparative technique of self-organizing neutral network provides one of alternatives allowing for such more flexible visualization and quantitative analysis of molecular similarity. The problem of the molecules alignment can also be solved by the use of a new 2D QSAR technique, the so-called holographic QSAR (HQSAR) which uses fragmental coding of the molecule. Combinatorial chemistry is a method that puts together the randomness of screening and the rationality of design. The idea of combinatorial synthesis consists in the parallel synthesis of the set (combinatorial library) of compounds obtained simultaneously. Depending upon the technique used such libraries can be obtained as complex mixtures of the products of the defined composition or separate compounds. Although it is the diversity of molecular library created by combinatorial procedure that allows for increasing the probability of finding active analogs, combinatorial methods are far from brute randomness. The new methods for the description of the similarity of such libraries have been proposed. The newest trend represented by in vitro nucleic acid selection which is designed to mimic the Nature's evolutionary processes is probably one of the most interesting ideas in drug desing. Just recently this idea has been expanded to small organic molecules.

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Notatki chaotyczne. Cz. 18. O chemii kombinatorycznej

Siemion I.Z.

Wiadomości Chemiczne

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1998

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[Z] 52, 3-4

311--318