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Wyszukujesz frazę "1,3-dipolar cycloaddition" wg kryterium: Temat


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Tytuł:
Wykorzystanie reakcji 1,3-dipolarnej cykloaddycji Huisgena do modyfikacji nukleozydów i ligonukleotydów
An application of the Huisgen 1,3-dipolar cycloaddition to modify nukleosides and oligonucleotides
Autorzy:
Radzikowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/171872.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
1,3-dipolarna cykloaddycja
analogi nukleozydów
chemia click
synteza modyfikowanych oligonukleotydów
1,2,3-triazole
biokoniugaty
1,3-dipolar cycloaddition
analogues of nucleosides
click chemistry
synthesis of modified oligonucleotide
bioconjugates
Opis:
The 1,3-dipolar cycloaddition reaction between azides and terminal alkynes, known as the Huisgen reaction, constitutes a powerful tool for the synthesis of versatile molecules containing carbon – heteroatom bond. The use of a copper(I) salt in this reaction allowed Sharpless to develop the concept of „click chemistry” [1]. This strategy is based on reactions between small units characterized by mild reaction conditions, versatility, high yields and stereospecificity. The chemistry of nucleic acids and nucleoside analogues is undergoing rapid developments and numerous compounds from these classes of compounds are used in medicinal treatment. Analogues of nucleoside constitute a class of drugs that possesses either anticancer or/and antiviral activity (against HIV, HSV, VZV or HCV viruses) [3]. Many modified oligonucleotides show biological activity. As potential drugs oligonucleotides are employed in antisense, antigen and aptamer strategies. An antisense therapeutic agent acts on the pathogenic mRNA causing inactivation of the target whereas an antigen agent acts on DNA and aptamer on unwanted protein. It is not surprising that number of research groups are trying to join the concept of click chemistry with nucleic acids chemistry. In this way, it is possible to obtain new molecules like base- or sugar-modified nucleosides, nucleosides, bioconjugates and olignucleotides. The copper-catalyzed 1,3-dipolar cycloaddition CuAAC allows to functionalize DNA, for example by labelling it through attaching small molecules to DNA. Two general strategies have been developed for this purpose: presynthetic and postsynthetic labelling. In the presynthetic method nucleotide monomers are labelled before DNA synthesis and purification. In the postsynthetic strategy DNA containing small reactive groups is synthesized first and then it is conjugated with the desired molecules. CuAAC is also a convenient method for the synthesis of modified oligonucleotides in which phosphodiester linkage is replaced by 1,2,3- -triazole or for a solid phase synthesis. Such molecules appear to be useful in medicine, molecular diagnostic (e.g. fluorescent dyes) or mechanistic molecular model in the future.
Źródło:
Wiadomości Chemiczne; 2011, 65, 3-4; 207-234
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemia bioortogonalna : nowa perspektywa dla chemii organicznej
Bioorthogonal chemistry : new perspective for organic chemistry
Autorzy:
Miszczak, K.
Powiązania:
https://bibliotekanauki.pl/articles/172776.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
chemia bioortogonalna
bioortogonalna ligacja
ligacja Staudingera
1,3-dipolarna cykloaddycja
reakcja Dielsa-Aldera
bioorthogonal chemistry
bioorthogonal ligation
Staudinger ligation
1,3-dipolar cycloaddition
Diels-Alder reaction
Opis:
This work is about bioorthogonal chemistry as a chemistry of reactions taking place in the living, in particular human, organism environment. In the search for reactions that can occur under conditions, the focus is mainly on the reactions of molecules that do not occur naturally in the body. Then, to have any application, generally for the purpose of using this reactions to locate the accumulation spotes of the selected substance, one molekule is covalently bonded to the biomarker molecule, the second binds to the indicator molecule, which is frequently fluorescein. Among a numerous examples of reactions that were designed during the short history of bioorthogonal chemistry, there are mainly reactions involving organic azides, which are not naturalny present in the human body. An example of such a reaction is the Staudinger ligation. Subsequent modifications include mainly the 1,3-dipolar addition of azides to alkynes, catalyzed by copper(I) ions. The instability and toxicity of this catalyst has forced further innovations in bioorthogonal reactions. One of them is the use of alkynes with high angular stress, which causes a significant reduction in the activation energy of the process, that it is unnecessary to use a catalyst. Another example of the bioorthogonal reactions are Diels-Alder reactions. The interest in these reactions is not diminishing for several reasons. One of them is the fact that as a result of a simple reaction two new carbon-carbon bonds (or others, for the HDA reaction) occur. Furthermore, many of these reactions occur at standard temperature, without additional heating. Moreover, the possibility of numerous modifications of the skeleton and functional groups and the substituents of dienes and dienophils facilitates carrying out these reactions in the aquatic environment. At the end, the article presents examples of the application of cyclooaddition reactions in bioorthogonal chemistry.
Źródło:
Wiadomości Chemiczne; 2018, 72, 9-10; 703-722
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Izoksazolidynowe analogi nukleozydów
Isoxazolidine analogues of nucleosides
Autorzy:
Kokosza, K.
Piotrowska, D. G.
Powiązania:
https://bibliotekanauki.pl/articles/171674.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
1,3-dipolarna cykloaddycja
nitrony
izoksazolidyny
analogi nukleozydów
nukleozasady
C-nukleozydy
homonukleozydy
nukleozydy
fosfonylowane nukleozydy
psiko-nukleozydy
aktywność przeciwwirusowa
aktywność przeciwnowotworowa
1,3-dipolar cycloaddition
nitrones
isoxazolidines
nucleoside analogues
nucleobases
C-nucleosides
homonucleosides
nucleosides
phosphonylated nucleosides
psico-nucleosides
antiviral activity
anticancer activity
Opis:
Compounds having isoxazolidine moiety are of special interest since they show a broad spectrum of biological activity, including anticancer [1–5], antiviral [6], antibacterial [7–9] and antifungal activities [9–12]. Extensive studies on isoxazolidine moiety containing compounds resulted in discovery of several potentially antiviral and anticancer drugs (e.g. pyridemine-A 1 [2, 3], as well as isoxazolidines substituted with thymine and 5-fluorouracil 52a (AdT) [38–40] and 59 [(–)-AdFU] [41–43], respectively). In this review the most spectacular examples of the synthesis of isoxazolidine analogues of nucleosides are discussed and their biological activity is emphasized.
Źródło:
Wiadomości Chemiczne; 2012, 66, 11-12; 1041-1070
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation on Curing Properties and Kinetics of Isophthalonitrile Oxide
Autorzy:
Fan, Y.
Tang, C.
Hu, Q.
Lei, Y.
Huo, J.
Powiązania:
https://bibliotekanauki.pl/articles/780045.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
N,N-dihydroxybenzene-1,3-dicarboximidoyl dichloride
kinetics
elastomer
synthesis
1,3-dipolar cycloaddition
Opis:
N,N-dihydroxybenzene-1,3-dicarboximidoyl dichloride was synthesized from benzene-1,3-dicarboxaldehyde and characterized by fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance  1H and 13C NMR). The elastomer was prepared through the 1,3-dipolar cycloaddition of reaction between liquid polybutadiene (LPB) and isophthalonitrile oxide in this work. The tensile strength of different elastomer was enhanced from 0.14 MPa to 0.33 MPa as the elongation at break decreased from 145% to 73%, and the modulus increased from 0.09 kPa to 0.47 kPa. The parameters of kinetic indicated that the curing reaction was first order reaction and the apparent activation energy of each curing system was less than 10.10 kJ/mol when the content of N,N-dihydroxybenzene-1,3- dicarboximidoyl dichloride was increased from 7% to 12%. These results suggested that nitrile oxides achieved curing of polymer binders at room temperature and this work had definite guiding significance for the application of nitrile oxides in polymer binders.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 3; 37-46
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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