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Wyświetlanie 1-2 z 2
Tytuł:
1’-homonukleoz(t)ydy : synteza i aktywność biologiczna
1’-homonucleos(t)ides : synthesis and biological activity
Autorzy:
Gotkowska, J.
Piotrowska, D. G.
Powiązania:
https://bibliotekanauki.pl/articles/171503.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
analogi nukleozydów
1’-homonukleoztydy
podstawione tetrahydrofurany
modyfikowane monosacharydy
aktywność biologiczna
nucleoside analogues
1’-homonucleostides
substituted tetrahydrofurans
modified monosaccharides
biological activity
Opis:
Long-lasting interest in the synthesis of nucleos(t)ide analogues is dictated by hope to obtain compounds possessing antibacterial, antiviral and antitumor activities [1, 2]. Introduction of a methylene linker between an anomeric carbon and the nucleobase nitrogen atom produces a new class of compounds called 1’-homonucleos(t)ides as potentially active analogues. Although a sugar ring in nucleosides can be replaced by several cyclic or even acyclic moieties we focus attention on compounds containing the tetrahydrofuran ring. Since methods of attachment of nucleobases are limited to their alkylation with appropriate compounds and the de novo synthesis we discussed various synthetic approaches to substituted tetrahydrofuranes in racemic or optically pure forms. Various pentose and hexose derivatives were employed as starting materials and their transformations into the final sugar frameworks were detailed, thus revealing the importance of these class of compounds. To prepare deoxysugars Barton-McCombie reaction sequence was applied. A significant number of final 1’-homonucleos(t)ides were screened for antiviral and cytotoxic activity to identify a few very potent compounds. Thus, phosphonates trans- and cis-138a were as active against HCMV as ganciclovir. In addition trans- -138a inhibited the proliferation of several murine and human cancer cell lines with IC50s in the μM range. 1’-Homonucleosides 64b and 66b exhibited selective antiviral activity against HSV-1 TK– and HSV-2 TK– (MIC = 8–12 μg/mL). Compound 129 was found active against HCV (EC = 6.31 μM) and reduced growth of CCRF-CEM cells with IC50 = 5.73 μM. Despite limited activity observed so far for the known 1’-homonucleos( t)ides and their analogues, they deserve further interest both from the synthetic point of view and biological potential inherent in molecules having nucleobase scaffolds.
Źródło:
Wiadomości Chemiczne; 2016, 70, 5-6; 319-351
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metody określania struktury polisacharydów
Methods for determining polysaccharides structure
Autorzy:
Samaszko-Fiertek, J.
Kuźma, M.
Dmochowska, B.
Ślusarz, R.
Madaj, J.
Powiązania:
https://bibliotekanauki.pl/articles/172410.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
polisacharydy
monosacharydy
degradacja oksydacyjna
analiza metylacyjna
acetoliza
NMR
magnetyczny rezonans jądrowy
MS
polysaccharides
monosaccharides
oxidative degradation
methylation analysis
acetolysis
nuclear magnetic resonance (NMR)
Opis:
Sequencing of polysaccharides is difficult to achieve because of the heterogeneous nature of the polysaccharide structure, high molecular weight (the size of a polysaccharide varies between approximately 16,000 and 16,000,000 daltons (Da)), and polydispersity of the polymer chains. The following information is essential to determine the primary structure of a polysaccharide: • monosaccharide composition: nature and molar ratios of the monosaccharide building blocks; • relative configuration of monosaccharides: d or l; • anomeric configuration: α- or β-configuration of the glycosidic linkage; • ring size: presence and distinction of furanosidic and pyranosidic rings; • linkage patterns: linkage positions between the monosugars and branches; • sequences of monosaccharide residues in the repeating units; • substitutions: position and nature of OH–modifications, such as O–phosphorylation, acetylation, O-sulfation, etc.; • molecular weight and molecular weight distribution. A polysaccharide extracted from plant materials or food products is usually purified before being subjected to structural analysis. The first step of characterizing a polysaccharide is the determination of its purity, which is reflected by its chemical composition, including total sugar content, level of uronic acids, proteins, ash, and moisture of the preparation. The second step is the determination of monosaccharide composition, which will unveil structural information such as the number of monosaccharides present in the polysaccharide and how many of each sugar unit. NMR spectroscopy has become the most powerful and noninvasive physicochemical technique for determining polysaccharide structures. It can provide detailed structural information of carbohydrates, including identification of monosaccharide composition, elucidation of α- or β-anomeric configurations, establishment of linkage patterns, and sequences of the sugar units in oligosaccharides and/or polysaccharides. Monosaccharide composition can be determined also by analysis of totally acid hydrolyzed polysacharide using high performance liquid chromatography (HPLC) or gas chromatography (GC). The ring size and glycosidic linkage positions of sugar units in a polysaccharide could be established by methylation analysis and/or cleavage reduction. The anomeric configuration is conventionally determined by oxidation, and this method can be combined with mass spectrometry to obtain more structural information.
Źródło:
Wiadomości Chemiczne; 2016, 70, 5-6; 299-318
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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