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Tytuł:
Ostatnie postępy w syntezie alkaloidów tropanowych i pochodnych tropanu
Recent advances in the synthesis of tropane alkaloids and other tropane derivatives
Autorzy:
Sidorowicz, K.
Kropiwnicki, K.
Łaźny, R.
Powiązania:
https://bibliotekanauki.pl/articles/171941.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
synteza
alkaloidy tropanowe
pochodne tropanów
synteza stereoselektywna
synthesis
tropane alkaloids
tropane derivatives
stereoselective synthesis
Opis:
Tropane alkaloids are a long-known class of compounds possessing an 8-azabicyclo[ 3.2.1]octane skeleton. Many tropane alkaloids posses biological activity (anticholinergic, anti-Parkinsonian, hypotensive), and as such had a significant influence on medicine and played a notable role in the development of organic chemistry [1]. The most known representatives of biologically active tropane alkaloids are: cocaine, atropine, scopolamine, ecgonine, and Bao Gong Teng A. A number of natural tropane alkaloids are chiral compounds, whose preparation in optically active forms is still a big challeng [2]. The biological activity of enantiomers often differs depending on their configurations. Alkaloids are a subject of an intensive research: scopus database contains nearly 200 thousand publications with the word „alkaloid”, and almost 4,500 publications with the phrase „tropane alkaloids” (about half of them have appeared in the last ten years). About 55 papers are devoted to stereoselective synthesis of tropane derivatives in 2000-2015. About half of this concernes stereoselective methods. The organic synthesis of alkaloids has a long history and numerous synthetic approaches to the tropane skeleton have been developed, from the classical synthesis of tropinone by Willstätter at the beginning of the XX century, to more recent developments dealing with asymmetric deprotonation of tropinone with chiral lithium amide bases for the enantioselective synthesis of a range of tropanes [3, 4]. Owing to extensiveness of the field, the current review presents the most interesting, from a synthetic point of view, approaches to tropane derivatives and tropane analogues. Most of the methods of synthesis are long (often several steps), time- and recourses-intensive, and often required elaborate and hardly available starting materials. But there are also notable exceptions, based on the asymmetric deprotonation approach; e.g., from the syntheses of cocaine described in this article, the most efficient one was reported by Lee in 2000 [5]. The concise synthesis (6 steps) gave the unnatural enantiomer of cocaine starting from commercially available tropinone in 78% overall yield. This approach allows to obtain both enantiomers and racemate, by changing type of one reactant only. However, most strategies provide only one enantiomer or racemic mixture of an alkaloid. As can be seen, despite of advances in chemicall science, there is no general way to synthesize majority of the representatives of this group of structurally related compounds.
Źródło:
Wiadomości Chemiczne; 2015, 69, 11-12; 1019-1045
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kwasy nukleinowe jako katalizatory reakcji chemicznych
Nucleic acids as catalysts in chemical reactions
Autorzy:
Bukowiecka-Matusiak, M.
Sobczak, M.
Powiązania:
https://bibliotekanauki.pl/articles/172466.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
DNA
kataliza
synteza asymetryczna
catalysis
asymmetric synthesis
Opis:
Nucleic acids, due to their specific structure, are effective and durable carriers of genetic information. They have also been used as catalysts in chemical reactions. The right-handed DNA double helix structure has become one of the icons of modern science, and its share in asymmetric catalysis is undeniable. In these reactions, DNA is a source of chirality and proximity between oligonucleotides and complexes of copper during catalysis, what allows a direct transfer of chirality from DNA to the reaction product. Almost complete regioselectivity and excellent enantioselectivity of the aforementioned reactions in water are the evidence of the potential of asymmetry based on DNA. Asymmetric catalysis used in organic synthesis, allows achieving high enantioselectivity. This strategy has been successfully used to create new C-C bonds in Diels- Alder cycloaddition, Friedel-Crafts alkylation and Michael addition using copper complexes with oligonucleotides as catalysts. The important factor to optimize the reaction of asymmetric catalysis in the presence of DNA constitutes its sequence. It has been shown that the use of the double helix DNA can provide the product with higher enantiomeric excess than using the single strand of DNA. In addition, the results of the study suggest that Friedel-Crafts alkylation is accelerated by DNA almost 30-fold. The same correlation is observed in Diels-Alder cycloaddition. Due to promising results, further testing directed at the possibility of using catalytic DNA is being conducted.
Źródło:
Wiadomości Chemiczne; 2012, 66, 1-2; 119-137
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synteza modyfikowanych oligonukleotydów zawierających stereozdefiniowane internukleotydowe wiązania tiofosforanowe
Synthesis of modified oligonucleotides containing stereodefined internucleotide phosphorothioate bonds
Autorzy:
Radzikowska, E.
Kaczmarek, R.
Baraniak, J.
Powiązania:
https://bibliotekanauki.pl/articles/172219.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
oligonukleozydotiofosforany
oligonukleotydy antysensowe
synteza modyfikowanych oligonukleotydów
synteza stereospecyficzna
oligo(deoxy)ribonucleoside phosphorothioates
antisense oligonucleotides
synthesis of modified oligonucleotide
stereospecific synthesis
Opis:
Synthetic oligonucleotides constitute an important class of compounds which can exhibit biological activity. As potential drugs they could be employed in antisense strategy by acting on the pathogenic mRNA, causing inactivation of the target molecules during the translation process [1]. Ideal antisense agent (ASO) should be resistant to exo and/or endonucleases, exhibit a suitable pharmacological and pharmacokinetic profile and exhibits high binding affinity towards the target mRNA. To improve some properties of the ASO plethora of the chemical modifications introduced within the nucleobase, sugar unit and internucleotide linkage are investigated [3]. Among them, phosphorothioate oligonucleotides (PS-oligo), created by replacing one of the nonbridging oxygen atoms with a sulfur atom, are the major representatives of DNA analogs. PS-oligo display several attractive features like nuclease resistance, activation of RNase H, and good pharmacokinetic properties [1]. Replacement of one of two nonbridging oxygens at phosphorus by sulfur induces asymmetry at the phosphorus atom. Hence, the synthesized oligo(nucleoside phosphorothioate) is a mixture of 2n diastereomers (where n is the number of internucleotide phosphorothioate functions). Therefore the actual biological activity of the P-chiral oligonucleotide analogues, (e.g., interactions with proteins or nucleic acids) may depend on stereochemical factors [7]. One has to keep in mind that the phosphoramidite [5] and H-phosphonate [32] methodologies (commonly used to prepare PS-oligo) are nonstereospecific and give a mixture of 2n diastereomers. Thus, various methods have been elaborated to synthesize these P-chiral oligonucleotide analogs in a stereocontrolled manner [15, 17], among them the oxathiaphospholane method developed by Stec et al. [18], the method utilizing nucleoside 3’-O-(3-N-acyl)oxazaphospholidine derivatives as monomer units [19], and the method based on a stereoselective synthesis of nucleoside 3’-O-oxazaphospholidine monomers [21, 22] are the most significant.
Źródło:
Wiadomości Chemiczne; 2015, 69, 11-12; 957-981
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spaleniowa synteza nanoproszków wolframu, tantalu i molibdenu
Combustion synthesis of tungsten, tantalum, and molybdenum nanopowders
Autorzy:
Cudziło, S.
Czugała, M.
Powiązania:
https://bibliotekanauki.pl/articles/172471.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
synteza spaleniowa
SACR
nanoproszki metali
combustion synthesis
metal nanopowders
Opis:
Refractory metal nanopowders have recently been of interest as starting materials for preparation of heavy alloys with exceptionally good mechanical properties resulting from their structure homogeneity at a nanoscopic level. In the light of recently published papers, the combustion synthesis seems to be a promising technique for the large-scale production of metal nanopowders. In this method, the self-sustaining internal combustion of energetic composites is used to produce useful materials. The energy released in the combustion wave, propagating through a pressed sample of the green mixture, causes a rapid increase in temperature which in turns enables the processes and reactions with high activation barriers to proceed. Unbalanced conditions and high time and space variability of temperature in combustion wave are conducive to the creation of compounds and structures that are difficult to produce using other methods. Thanks to this combustion synthesis there is a source of simple and complex metal oxides, ceramic materials, metals and intermetallic compounds as well as various composites of the substances, both in powdery and compact forms. The product form and its microstructure depends on the synthesis conditions, especially on the size and morphology of substrate particles, reactants ratio, the initial density, the presence and concentration of additives, temperature and external pressure [1–6]. Metal powders are typically produced by reduction of relevant oxides. Aluminum, magnesium, zinc, calcium, zirconium, titanium, silicon, carbon and their mixtures or compounds are used as reducers [11]. If the combustion temperature is excessively high (above 2000°C) coarse metal powders are usually produced. The initially formed crystallites are irregular in shape, they melt on the surface and agglomerate giving even bigger particles. To overcome this problem, alkali metal halide is included as an additional reactant in the system. The additive melts in the combustion wave, reduces the combustion temperature, aids in transportation of the main reactant species, which positively affects the size and shape of combustion product particles. In addition, molten salt prevents grain growth by forming a protective layer around the particles. The current paper reviews recently published works (mainly by H.H. Nersisyan et al. [7, 12–23]) on molten salt assisted combustion synthesis (SACR ) of tungsten, tantalum and molybdenum nanopowders. A detailed description of the synthesis method including its specific features, the experimental procedure, combustion parameters and macro-kinetic aspects of chemical reactions in the combustion wave, and characterization of the metal nanopowders are presented.
Źródło:
Wiadomości Chemiczne; 2012, 66, 3-4; 249-272
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Glikozydy nasercowe : nowe trendy w chemii medycznej saponin i sapogenin
Cardiac glycosides : new trends in medicinal chemistry of saponins and their genins
Autorzy:
Grynkiewicz, G.
Szeja, W.
Powiązania:
https://bibliotekanauki.pl/articles/171696.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
glikozydy nasercowe
digitoksyna
synteza digitoksozy
cardiac glycosides
digitoxin
digitoxose synthesis
Opis:
Plant secondary metabolites – ubiquitous low molecular weight chemicals which are not essentials for the host existence and reproduction but serve many auxiliary functions, are frequently occurring as glycosides, for which particularly abundant examples exist in antibiotic, saponins and flavonoid categories. Cardiac glycosides (CG), originally isolated from Digitalis plants, also known as cardiotonic steroids, have particularly extensive record of ethnopharmacological and medicinal use. Although their application in treatment of dropsy is documented since 1875, long time has elapsed before their chemical structure were determined and mechanisms of their toxicity and cardiotonic action were recognized as inhibition of Na+ / K+ ATP-ase pump. Contemporary molecular pharmacology has revealed that cardiac glycosides are endogenous compounds in variety of animals, where they function as toxins or hormones. Besides, numerous recent studies confirmed anticancer activity of CGs at very low concentrations. These findings have been possible due to advances in ultrasensitive analytical techniques and also due to progress in organic synthesis, particularly total enantioselective syntheses of carbohydrates, which secured availability of individual CG and their analogs for medicinal chemistry studies.
Źródło:
Wiadomości Chemiczne; 2015, 69, 11-12; 1047-1065
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prolina : pospolity aminokwas wyjątkowy katalizator. Część IV, Reakcja Michaela
Proline as a common amino acid and an exceptional catalyst. Part IV, Michael reaction
Autorzy:
Karczmarska-Wódzka, A.
Studzińska, R.
Kołodziejska, R.
Wróblewski, M.
Dramiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/171840.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
prolina
reakcja Michaela
synteza asymetryczna
proline
Michael reaction
asymmetric synthesis
Opis:
In recent years there has been a dynamic development of asymmetric synthesis. Groups of researchers, particularly the one led by Benjamin List and Carlos Barbas, carried out a number of reactions and showed the effectiveness of the use of small organic molecules such as proline as catalysts. Michael addition catalyzed with proline is a particularly interesting reaction because it can be carried out in two aminocatalytic pathways. The analysis of Michael reaction reveals potential for both forms of aminocatalysis: enamine and iminium catalysis (Scheme 1) [1–14]. Presumably Michael reaction proceeds mainly according to enamine mechanism. The use of proline in Michael reaction with imine activated acceptor is slightly effective. So far the researches have shown that the modification of proline molecule or addition of other catalyst is necessary for condensation to appear. Enamine catalysis concerns the activation of carbonyl compound in situ being a donor. There is no need for enolase anion to be created earlier [2, 15–17]. When, as a result of the reaction of a,b-unsaturated carbonyl compound with proline, Michael acceptor activation appears it means that it is enamine mechanism reaction (Scheme 1) [2, 24]. One of the first examples of direct Michael reaction proceeding through enamine transition state is the reaction of cyclopentanone with nitrostyrene (Scheme 6) [20–23]. Other examples of Michael addition of ketone with nitro olefin catalysed by proline are shown in table 2 and 3 [10, 23, 30]. Nitroketones obtained in that way are useful as precursors for different organic compounds [33], also pyrrolidines [34]. Pyrrolidines are pharmacologically active and they selectively block presynaptic dopamine receptors [34] (Scheme 7). Except for Michael intermolecular reaction, intramolecular condensation adducts were also obtained. Michael intramolecular proline-catalyzed condensation in which inactive ketones transform into α,β-unsaturated carbonyl compounds was described (Scheme 9) [35, 36]. These reactions require a stoichiometric amount of a catalyst and a long time of reaction and they give as a result a little enantiomeric excess [11, 24, 35]. In 1991, Yamaguchi and co-workers carried out malonates Michael addition to α, β-unsaturated aldehydes catalyzed by L-proline [24, 39]. The reaction proceeded according to enamine mechanism, for example dimethyl malonate was reacted with hex- 2-enal in the presence of proline to give Michael adduct in 44% yield. To improve the yield an attempt of a slight modification of a proline molecule was made transforming it into proper salt. Proline lithium salt enabled to obtain the condensation product in 93% yield (Tab. 4). Regardless of a used catalyst the products in the form of racemates were obtained. In order to improve enantioselective properties of a catalyst, Michael addition of diisopropyl malonate to cycloheptenone was carried out in chloroform in the presence of different proline salts. Optimal enantioselectivity and yield was obtained by using rubidium salt (Tab. 5–7) [40, 41]. Rubidium prolinate-catalyzed Michael additions are used in industry e.g. for enantioselective synthesis of the selective serotonine reuptake inhibitior (SSRI) (–)-paroxetine (antidepressant) (Scheme 12) [24].
Źródło:
Wiadomości Chemiczne; 2014, 68, 1-2; 49-65
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Syntezy i aktywność biologiczna wybranych zasad Mannicha
Synthesis and biological activity of selected Mannich bases
Autorzy:
Nawrocka, W. P.
Nowicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/172259.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
zasada Mannicha
aktywność biologiczna
syntezy
Mannich bases
biological activity
synthesis
Opis:
The Mannich reaction is important for the synthesis and modification of biologically active compounds. Mannich bases – substituted products containing different heterocyclic system in their structures seem to be suitable candidates for further chemical modifications and might be of interest as pharmacologically active compounds. The main goal of this article is to present synthesis and biological activity of selected Mannich bases. Based on a review of the chemical literature, Mannich bases showed a multipharmacological effects. The Mannich bases, containing various heterocyclic systems were identified as potent anticancer agents. Presented compounds exhibit cytotoxic, antiproliferate in vitro, anticonvulsant, antioxidative, antiinflaminatory and analgesic activity. Some of them can be used in a treatment of diabetes and hypertension.
Źródło:
Wiadomości Chemiczne; 2014, 68, 11-12; 981-1008
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prolina : pospolity aminokwas wyjątkowy katalizator. Część III, Reakcja Mannicha
Proline as a common amino acid and an exceptional catalyst. Part III, Mannich reaction
Autorzy:
Studzińska, R.
Karczmarska-Wódzka, A.
Wróblewski, M.
Kołodziejska, R.
Dramiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/172649.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
prolina
reakcja Mannicha
synteza asymetryczna
proline
Mannich reaction
asymmetric synthesis
Opis:
Mannich reaction occuring among ketone, aldehyde, and amine is one of the ways of a synthesis of biologically active compounds. Reactions of this type were carried out in the presence of different catalysts [3–10], however in recent years a lot of attention has been paid to enantioselective Mannich reaction catalyzed with proline. Such reactions were carried out with the use of different compounds containing carbonyl group and the most frequently used amine was p-anisidine. The advantage of the use of p-anisidine is a possibility of conducting the direct Mannich reaction (Scheme 3). In this way β-amino ketones (Tab. 1, 2, 4) [15, 18–20, 23, 24], α-hydroxy-β-amino ketones (Tab. 3) [15, 22], and β-amino alcohols (Tab. 5, 6) [25, 26] were obtained. A possibility of syntheses of β-amino sugars and α-amino acids with their derivatives (Tab. 7) [28, 29] is worth noticing. In a great number of described reactions, the products were obtained with satisfactory yield and enantiomeric excess. Taking into consideration the difficulty of a removal of p-hydroxyphenyl group which protects amine group in the resulting products, the attempts of using different amine compounds in Mannich reactions catalyzed with proline were undertaken. The use of amines blocked by tert-butoxycarbonyl group (Boc) enabled to obtain the products with high yield and ee values (Tab. 12–15) [35–38]. However in the case of the use of Boc the reaction must be carried out in an indirect way (it is necessary to prepare imine blocked by Boc earlier).
Źródło:
Wiadomości Chemiczne; 2014, 68, 1-2; 21-48
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polimery z pamięcią kształtu i ich otrzymywanie
Shape-memory polymers and their preparation
Autorzy:
Andrzejewski, Kewin
Czyżów, Wiktor
Jacewicz, Dagmara
Drzeżdżon, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/2086740.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
polimery
synteza
katalizatory
zielona chemia
polymers
synthesis
catalysts
green chemistry
Opis:
SMP (shape-memory polymers) is an innovative class of programmable materials responsive to various stimuli. They are attracting increasing attention regarding possible new inventions, industrial use, and overall polymer research. After a brief introduction, this article examines the conventional shape-memory effect, methods of fabrication of shape memory polymers, and molecular and structural requirements for SMP to function. The shape memory behavior of such polymers is thoroughly presented, with the focus being on the thermo- and photo-induced SME. The uses in biomedical and industrial areas are also discussed.
Źródło:
Wiadomości Chemiczne; 2022, 76, 3-4; 183--205
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Katalizatory wykorzystywane w syntezie biodiesla
Catalysts used in biodiesel synthesis
Autorzy:
Pobłocki, Kacper
Walczak, Juliusz
Drzeżdżon, Joanna
Jacewicz, Dagmara Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/2200588.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
katalizator
biodiesel
synteza
biopaliwa
energia odnawialna
catalyst
synthesis
biofuels
renewable energy
Opis:
Rising prices of electricity, conventional fuels and heating require decisive steps in the further development of technologies based on renewable energy sources. These include geothermal- ; hydrothermal- ; aerothermal- ; and solar energy. Due to the fact that the petrochemical industry is one of the fastest growing branches of the economy, we would like to expand on the topic related to biofuels. Biodiesel is an alternative fuel similar to conventional diesel. It is usually made from animal fat, vegetable oil and waste cooking oil. Its biodegradability, nontoxicity and lack of sulfur and aroma content make it superior to conventional gasoline and diesel. During fuel consumption, it emits fewer air pollutants and greenhouse gases other than nitrogen oxides. In this literature review, we will discuss the latest trends in the world related to catalysts used in biodiesel synthesis.
Źródło:
Wiadomości Chemiczne; 2022, 76, 3-4; 129--144
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Syntezy pochodnych 2,7-naftyrydyny
Synthesis of 2,7-naphthyridine derivatives
Autorzy:
Wójcicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/171682.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
pochodne 2,7-naftyrydyny
synteza
cyklokondensacja
2,7-naphthyridine derivatives
synthesis
cyclocondensation
Opis:
2,7-Naphthyridines have been the least known from all of the six structural isomers of pyridopyridines. The broad spectrum of biological activity of 2,7-naphthyridine derivatives [1] is the main of reason for obtaining of the new compounds containing this scaffold (Fig. 1). Gabriel and Colman were the first to obtain isomer 2,7-naphthyridine in 1902 and they called it ‘copiryne’ (Fig. 2) [2]. The goal of this study is the presentation of various methods for the preparation of 2,7-naphthyridine derivatives. Compounds containing copyrine scaffold can be obtained from a different substrates, but that synthesis may be classified into three main categories: from pyridine derivatives, from quinoline derivatives and from other compounds. Most of 2,7-naphthyridines have been synthesized by cyclocondensation (Scheme 5, 7–10, 13–14, 16–18, 20, 28–29, 32, 35–36) or intramolecular cyclization (Scheme 1–4, 6, 11–12, 15, 19, 21–25, 30–31, 33–34, 38) of pyridine derivatives by annulation of the other pyridine ring [3–24, 27–31]. Intramolecular rearrangement of pyrrolo [3,4-c] pyridines (Scheme 26–27) and pyrano [3,4-c] pyridine or thiopyrano [3,4-c] pyridine (Scheme 35–37) also gave the 2,7-naphthyridine scaffold [32-34]. There are also many syntheses of benzo[c][2,7]naphthyridine, benzo [f] [2,7] naphthyridine or benzo [ c,f] [2,7] naphthyridine scaffolds, in which the substrates are quinoline derivatives (Scheme 39–48) [35–43]. 2,7-naphthyridines have been least often obtained by cyclocondensation of non-cyclic substrates (Scheme 49–53) [44–49].
Źródło:
Wiadomości Chemiczne; 2017, 71, 5-6; 349-379
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Peptydoglikan : budowa, rola biologiczna oraz synteza
Peptidoglycan : structure, biological activity and chemical synthesis
Autorzy:
Samaszko-Fiertek, J.
Dmochowska, B.
Madaj, J.
Powiązania:
https://bibliotekanauki.pl/articles/171802.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
peptydoglikan
synteza chemiczna
biosynteza
aktywność biologiczna
peptidoglycan
chemical synthesis
biosynthesis
biological activity
Opis:
The most important component of bacterial cell walls especially Gram-positive bacteria is peptidoglycan, called also murein, PGN. The first time this synonym was used in 1964 by Weidel and Pelzer [1]. Peptidoglycan is present in the outer layer of the cytoplasmic membrane and its structure. The structure of peptidoglycan depends on the bacteria strain. It is estimated that in Gram-negative bacteria, it occupies only about 10–20% of the total area of the cell wall, when in Gram-positive bacteria it is 50 and up to 90% of all space. Problems with isolation with high purity of biological material shows the need for developing techniques for chemical synthesis of peptidoglycan fragments and their analogs. In past few years there has been a growing interest within the synthesis of compounds glycoprotein (glycopeptides, peptidoglycan, etc.). As a basis for the construction of cell walls of many bacteria. Despite intensive research and gain significant knowledge of the physical and biological, chemical synthesis or biosynthesis (Fig. 5 and 6) of peptidoglycan, not so far failed to unambiguously determine its three-dimensional structure. The works of Kelman and Rogers [15] and Dimitriev [20] nearer picture of its structure. However, the time to develop in vivo visualization of cell structure it will be difficult to identify correctly peptidoglycan three-dimensional structure. Due to the important biological roles of murein, many research centers have taken to attempt their chemical synthesis. For biological research began to use chemically synthesized peptidoglycan fragments which guaranteed both uniform and a certain structure. An important roles in the development of methods of chemical synthesis of peptidoglycan had H. Chowdhury work, Fig. 8 [35], Hesek, Fig. 9 and 10 [36, 37], Dziarskiego [38] and Boneca [39] and Inamury [34, 40].
Źródło:
Wiadomości Chemiczne; 2015, 69, 7-8; 513-540
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metody chemicznej ligacji w syntezie peptydów i białek. Część 2
Chemical ligation methods in the synthesis of peptides and proteins. Part 2
Autorzy:
Jędrzejewska, K.
Kropidłowska, M.
Wieczerzak, E.
Powiązania:
https://bibliotekanauki.pl/articles/172242.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
natywna chemiczna ligacja
synteza peptydów
tioester
native chemical ligation
peptide synthesis
thioester
Opis:
Proteins are synthesized only by living organisms. Today, we are able to receive them by recombinant protein expression in bacterial cells. This technique is very useful and gives satisfactory amount of desirable material but it precludes the possibility of introduction of some chemical modifications that are often obligatory. For this reason, chemical synthesis of longer peptide chains is still important and is the object of scientists attention. Over the last century, notion of peptide synthesis took a new meaning. Nowadays, we know a number of innovative methods and also automated devices which help us to make progress in this area. Nevertheless, the synthesis of longer, more complicated peptide chains and proteins still constitutes a problem. Native chemical ligation (NCL) has facilitated the synthesis of numerous complex peptide and protein targets. Expansion of ligation techniques has allowed the entry of peptides into the world of therapeutic drugs [1]. NCL reactions are carried out in aqueous solution and give good yields. Due to mild conditions, NCL overcomes racemic and solubility problems encountered in classical peptide synthesis using protected fragments. The challenge is to synthesize the C-terminal thioester-containing peptide necessary for the transesterification reaction, which is the first step of linking the peptide fragments [2]. In this review we discuss the evolution, advantages and potential applications of chemical ligation reactions. In the first part of this article we described the utility of native chemical ligation approach to non-cysteine containing peptides. This part details a number of important approaches to the synthesis of peptides bearing a C-terminal thioester. Contemporary applications of these techniques to the total chemical synthesis of proteins are also presented.
Źródło:
Wiadomości Chemiczne; 2017, 71, 9-10; 747-761
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sililujące sprzęganie : użyteczne narzędzie selektywnej syntezy organicznej
Silylative coupling : a useful tool for selective organic synthesis
Autorzy:
Pawluć, Piotr
Zaranek, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/1413309.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
sililujące sprzęganie
zastosowanie w syntezie organicznej
silylative coupling
application in organic synthesis
Opis:
The design and development of highly selective methods for the synthesis of functionalized olefins based on sequential catalytic reactions using organosilicon reagents have been the subject of extensive study because of their versatile application in organic and organometallic synthesis. The ruthenium-catalyzed silylative coupling of olefins with vinyl-substituted organosilicon compounds (discovered by professor Bogdan Marciniec and co-workers in Poznań) represents one of the most efficient methods for the synthesis of stereodefined alkenylsilanes and isomeric bis(silyl)alkenes, which are particularly attractive scaffolds for further transformations including palladium-catalyzed cross-coupling with organic halides (Hiyama coupling) or substitution with organic and inorganic electrophiles. The unique feature of these methodologies is that the stereochemistry of the overall processes can be controlled during the initial step as the subsequent desilylation usually proceeds with retention of the configuration at the carbon atom and allows the formation of stereodefined products. The sequential silylative coupling - Hiyama coupling has been successfully used for stereoselective synthesis of (E)-stilbenes, bis-(E)-styrylarenes, stilbenoid dendrimers and poly(arylene-vinylene)s. On the other hand, the combination of silylative coupling with electrophilic halodesilylation reaction has been applied for the selective preparation of synthetically useful alkenyl halides (e.g. (E)-styryl halides, (E)-N-2-iodovinylcarbazole, (E)-N-2-iodovinylamides) - versatile coupling partners in palladium-catalyzed Suzuki and Sonogashira couplings, leading to vide variety of stereodefined ß-substituted (E)-enimides, (E,E)-dienimides and (E)- enynimides as well as related л-conjugated derivatives of N-substituted carbazole. The discovery of sequential silylative coupling and rhodium- or iridium-catalyzed acylation reactions is of great importance in the synthesis of (E)-α,ß-unsaturated ketones. The article highlights recent developments and covers literature mainly from the last decade in the sequential (also one-pot) synthetic strategies including ruthenium-catalyzed silylative coupling followed by desilylative cross-coupling, acylation and halogenation, leading to stereodefined я-conjugated organic derivatives which are widely applied as fine chemicals, functional materials or building blocks in organic synthesis.
Źródło:
Wiadomości Chemiczne; 2021, 75, 1-2; 93-110
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Donorowo-akceptorowe struktury oligopirolowe : projektowanie, synteza i właściwości
Donor-acceptor oligopyrroles : design, synthesis, and properties
Autorzy:
Stępień, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/1409858.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
pirol
układy donorowo-akceptorowe
chromofory
synteza
pyrrole
donor-acceptor systems
chromophores
organic synthesis
Opis:
The review summarizes one decade of research carried out in the Stępień Laboratory at the University of Wrocław. We focus on the group’s contributions to pyrrole chemistry, notably the development of donor-acceptor pyrrole hybrids and their use as building blocks in the synthesis of porphyrins, small-molecule dyes, and nanographene analogues.
Źródło:
Wiadomości Chemiczne; 2021, 75, 5-6; 593-602
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł

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