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Tytuł:
Zastosowanie związków kompleksowych platyny, palladu i kobaltu w medycynie. Cz. 1
Application of coordination compounds of platinum, palladium and cobalt in medicine. Part 1
Autorzy:
Pawlak, Marta
Drzeżdżon, Joanna
Jacewicz, Dagmara
Powiązania:
https://bibliotekanauki.pl/articles/1409835.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki kompleksowe platyny
związki kompleksowe palladu
związki kompleksowe kobaltu
leki przeciwnowotworowe
coordination compounds of platinum
coordination compounds of palladium
coordination compounds of cobalt
anticancer drugs
Opis:
The complex compounds containing metal ions are a group of compounds widely used in medicine. More and more metals are also being used to create cancer drugs or to help with other very serious diseases. Anticancer drugs are a particular use of complex compounds. Many thousands of platinum(II) compounds have been synthesized in cancer therapy, but only six of them have found use in the treatment of cancer. The most popular and the most commonly used compound is cisplatin, it has become the basis for the treatment of bladder, cervical, head, esophagus and many cancers occurring in children. The mechanism of action of platinum(II) and platinum(IV) compounds against cancer cells is to inhibit DNA replication, then RNA transcription and stop the G2 phase of the cell cycle and lead to programmed cell death or apoptosis. Coordination compounds containing more than one metal ion in their composition open new possibilities in the fight against cancer. Pt-DNA connections created by compounds containing at least two metal atoms are different from those formed by cisplatin. The basic dinuclear structure allows for great flexibility in forming DNA-DNA or DNA-protein bonds. The cobalt(III) complexes began to be used to image areas of hypoxia in cancer cells. It is believed, that cobalt(III) complexes undergo bioreduction, which leads to the release of the labile cobalt(II) complex and one or more bioactive ligands. Studies on nitro-Co(III) complexes containing acetylacetone and a nitrogen mustard ligand have shown that it is a particularly effective anti-cancer drug. Due to the fact that many people have cancer new effective anti-cancer drugs with low toxicity and no side effects are still being sought.
Źródło:
Wiadomości Chemiczne; 2020, 74, 11-12; 797-822
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anion alkoksyallenowy w syntezie związków naturalnych i ich analogów
Alkoxyallene anion in the synthesis of natural products and their analogues
Autorzy:
Busiak, B.
Utecht, G.
Jasiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/172377.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
alkoksyalleny
addycja nukleofilowa
synteza organiczna
związki naturalne
związki heterocykliczne
alkoxyallenes
nucleophilic addition
organic synthesis
natural products
heterocycles
Opis:
Among diverse systems containing multiple bonds, cumulenes are recognized as the most reactive derivatives towards both nucleophilic and electrophilic agents, and for this reason, they are considered as important class of substrates for organic synthesis. Over the last three decades alkoxyallenes have been demonstrated as highly useful C3-building blocks for the construction of numerous N-, O-, and S-containing heterocycles, including enantiomerically pure compounds. Special attention has been paid to lithiated alkoxyallenes as suitable nucleophiles for the reactions with alkyl halides, strained heterocycles, carbonyl compounds and their derivatives. The presence of the allene unit in the initially formed adducts opens up several possibilities in the preparation of more complex systems. In this review, selected applications of lithiated alkoxyallenes in the synthesis of natural products and their analogues are discussed.
Źródło:
Wiadomości Chemiczne; 2016, 70, 1-2; 3-23
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biodegradacja związków fosfonowych przez grzyby
Biodegradation of phosphonates by fungi
Autorzy:
Wieczorek, Dorota
Lipok, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/172438.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki fosfonowe
biotransformacja
biodegradacja
grzyby
phosphonates
biotransformation
biodegradation
fungi
Opis:
Phosphonates are the group of organophosphorus compounds, which are characterized by the presence of covalent bond(s) between carbon and phosphorus atom in their structure. Both; the natural and synthetic phosphonic compounds, are encountered in various ecosystems, however because of their wide range of applications, the latter ones are considerably more frequently discussed. Regarding the broad spectrum of biological activity, capability to chelate metal cations and environmental stability of direct carbon to phosphorus bond under physiological conditions, phosphonic compounds found a variety of applications e.g. as pesticides, drugs, anticorrosive agents, additives to surfactants and flame resistant (partially)polymers. Such massive use of phosphonates, together with mentioned environmental stability of those compounds, results in their common presence as xenobiotic environmental pollutants. Scientific efforts dedicated to recognising the fate and biodegradation of phosphonic compounds in the environment had begun in 80’s last century. Currently it is known that many microorganisms, mainly bacteria, but also fungi, are able to decompose the C-P bond. Interestingly however, the number of known species of fungi that are able to biodegrade and/or to bio-transform the phosphonates, is relatively low. It seems to be surprising, because especially the fungi are known from their impressive skills to adaptation to various nutritional conditions. Such a thesis may be supported by the fact that the process of biodegradation of phosphonates may occur via several pathways. Enzymes which are known to catalyse this process are phosphonoacetaldehyde hydrolase, phosphonoacetate hydrolase, phosphonopyruvate hydrolase and C-P lyase complex. This article briefly presents the issue of degradation pathways of phosphonates, and the role of phosphonate- degrading fungi.
Źródło:
Wiadomości Chemiczne; 2020, 74, 1-2; 33-55
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktura i właściwości fizykochemiczne polimerów koordynacyjnych oraz materiałów typu MOF kadmu(II) i cynku(II)
Structure and physicochemical properties of coordination polymers and MOF materials based on cadmium(II) and zinc(II)
Autorzy:
Pobłocki, Kacper
Drzeżdżon, Joanna
Jacewicz, Dagmara
Powiązania:
https://bibliotekanauki.pl/articles/1413238.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
polimery koordynacyjne
sieci metaliczno-organiczne
związki kadmu(II)
związki cynku(II)
MOF
coordination polymer
metal organic framework
cadmium(II)
compounds
zinc(II) compounds
Opis:
In 1964, J.C. Bailat Jr. was one of the first scientists who use coordination polymers in his research. He established the rules of structure and the composition of compounds containing metal ions and organic ligands connected by coordination bonds to form layered or chain structures. He compared inorganic compounds belonging to polymeric species with organic polymers. The term Metal Organic Frameworks (MOF) was first used in the publication by О. M. Yaghia. Crystalline, microporous structures contain rigid organic ligands (used interchangeably: organic building blocks) that bind metal ions. This is called reticular synthesis. MOF surface area values usually range from 1000 to 10000 m2/g-1, thus exceeding the area values of traditional porous materials such as zeolites and carbons. Metal Organic Frameworks create porous three-dimensional structures, unlike coordination polymers. Inorganic minerals from the aluminosilicate group are used in the widespread heterogeneous catalysis and processes such as: adsorption and ion exchange, while compared to Metal Organic Frameworks, shows a lower potential than zeolites, moreover, the design of structures is less precise and rational due to the lack of shape, size and control functionalization of pores. To date, MOF are the most diverse and most numerous class of porous materials. All aspects have made them ideal structures for storing fuels such as hydrogen and methane. They are perfect for catalytic reactions and are good materials for capturing pollutants, e.g. CO2. The number of publications on coordination polymers (CP), Metal Organic Frameworks (MOF) or a group of hybrid compounds (organic-inorganic) increased tenfold at the turn of 2005, which proves the growing interest in this field by scientists around the world. MOF diversity in terms of structure, size, geometry, functionality and flexibility of MOF has led to the study of over 20,000 different MOF’s over the past decade. The search for new materials consists of combining molecular building blocks with the desired physicochemical properties. To produce a solid, porous material that can be used in the construction of a "molecular scaffold", rigid organic moieties, which are described in the literature as rods, must be combined with multi-core, inelastic inorganic clusters that act as joints (also called SBU secondary building units). By design, multi-core cluster nodes are able to impart thermodynamic stability through strong covalent bonds and mechanical stability due to coordination bonds that can stabilize the position of metals in the molecule. This property contrasts with those of the unstable single coordination polymers. The size and most importantly the chemical environment of the resulting voids are determined by the length and functions of the organic unit. Therefore, adjusting the appropriate properties of the material is made by appropriate selection of the starting materials. The isoretical method made it possible to use MOF structures with large pores (98 Á and low densities (0.13 g/cm3). This method involves changing the size and nature of Metal Organic Frameworks without changing the topology of their substrate. Thanks to this, it was possible to include large molecules such as vitamins (e.g. B12) or proteins (e.g. green fluorescence protein) into their structure and use the pores as reaction vessels. The thermal and chemical stability of many MOFs has made them amenable to functionalization by post-synthetic covalent organic complexes with metals. These properties make it possible to significantly improve gas storage in MOF structures and have led to their extensive research into the catalysis of organic reactions, activation of small molecules such as hydrogen, methane and water, gas separation, biomedical imaging and conductivity. Currently, methods of producing nanocrystals and MOF super crystals for their incorporation into specialized devices are being developed. Crystalline structures of MOF’s are formed by creating strong bonds between inorganic and organic units. Careful selection of MOF components produces crystals of giant porosity, high thermal and chemical stability. These features allow the interior of the MOF to be chemically altered to separate and store gases. The uniqueness of MOF materials is that they are the only solids to modify and increase the particle size without changing the substrate topology.
Źródło:
Wiadomości Chemiczne; 2021, 75, 7-8; 1041-1073
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Areny jako proleki
Arenes as prodrugs
Autorzy:
Guzik, U.
Hupert-Kocurek, K.
Nieć, A.
Wojcieszyńska, D.
Powiązania:
https://bibliotekanauki.pl/articles/171928.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
prolek
związki aromatyczne
aktywacja proleku
prodrug
aromatic compounds
prodrugs activation
Opis:
Nowadays, improvement of physicochemical, biopharmaceutical and pharmacokinetic properties of pharmacologically active compounds is connected with development of prodrugs. Prodrugs are defined as pharmaceutical compounds inactive in their parent form and converted either chemically or enzymatically to the active derivative in the organism. A lot of prodrugs are aromatic compounds because of benzene ring reactivity. There are two main classes of prodrugs. In the carrier-linked prodrugs, the active drug is linked to a carrier through bioreversible covalent bond removed by enzymatic or chemical reactions. The second class comprises bioprecursor prodrugs that are modified in the body to induce the functional groups. Additionally, based on the site of prodrugs conversion into their active forms, they are classified into two groups: prodrugs metabolized intracellulary and prodrugs metabolized extracellulary. Chemical or enzymatic transformation of prodrugs may occur through their reduction, decarboxylation, oxidative deamination, cyclization, phosphorylation and/or hydrolysis. These reactions enable to overcome different barriers in drug delivery through changes in aqueous solubility, chemical instability and insufficient oral adsorption. It may also cause prolonged duration of drug action. Moreover, the prodrugs strategy allows achieving brain and tumor specific targeting. Summarizing, the designing of the prodrugs seems to be one of the most promising strategies to enhance the therapeutic effect of drugs and reduction of their negative side effects.
Źródło:
Wiadomości Chemiczne; 2015, 69, 3-4; 255-269
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Właściwości katalityczne i biomedyczne związków zawierających jony rutenu (II) oraz Rutenu (III)
Catalytic and biomedical properties of compound containing ruthenium (II) and ruthenium (III) ions
Autorzy:
Pobłocki, Kacper
Pawlak, Marta
Walczak, Juliusz
Drzeżdżon, Joanna
Jacewicz, Dagmara Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/27310039.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki kompleksowe Ru(II)
związki kompleksowe Ru(III)
właściwości biomedyczne
właściwości katalityczne
Ru(II) complex compounds
Ru(III) complex compounds
biomedical properties
catalytic properties
Opis:
Ruthenium complexes appear in scientific publications mainly as catalysts in the olefins metathesis process. In this review, we want to indicate the research niche regarding the use of ruthenium(II) and ruthenium(III) complexes in other catalytic processes, i.e. polymerization or epoxidation of olefins and depolymerization. We would like to combine the catalytic properties of ruthenium(II,III) complex compounds with their biomedical activity due to the growing problem of drug resistance (including antibiotic resistance). Scientists have been designing new metallopharmaceuticals exhibiting biological activity for several years, therefore this requires a critical review of the literature. The main goal of designing new metallodrugs is to create compounds with new or stronger biological properties compared to free ligands. Ruthenium compounds are considered potential substitutes for known drugs. In particular, Ru(II) and Ru(III) based complexes have reduced toxicity and can be tolerated in vivo. In addition, a wide spectrum of ruthenium oxidation states, a different mechanism of action and the kinetics of ligand substitution increase the advantage over coordination complex compounds based on platinum. In conclusion, in this review, we will focus on the latest reports from the literature on the catalytic properties and biomedical activity of ruthenium(II) and ruthenium(III) chemical compounds.
Źródło:
Wiadomości Chemiczne; 2023, 77, 5-6; 569--595
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grzyby wielkoowocnikowe jako źródło substancji bioaktywnych
Macrofungi as a source of bioactive substances
Autorzy:
Jasicka-Misiak, Izabela
Powiązania:
https://bibliotekanauki.pl/articles/172536.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
grzyby wielkoowocnikowe
substancje bioaktywne
związki o niskiej masie cząsteczkowej
związki o wysokiej masie cząsteczkowej
macrofungi
bioactive molecules
low molecular weight compounds
high molecular weight compounds
Opis:
From ancient times medicine and natural products have been closely linked through the use of traditional medicines and natural toxins. Macrofungi have an established history of use especially in traditional oriental medicine. Nowadays, mushrooms comprise a vast and yet largely untapped source of powerful new pharmaceutical products. In particular, and most importantly for modern medicine, they are an unlimited source of compounds that exhibit multidirectional activity: antioxidant, immuno-enhancing, immunostimulatory, antibacterial, antiviral, anti- inflammatory, antidiabetic, antiallergenic and anticarcinogenic [1, 2, 5-8]. In the presented work, a substances with biological activity from mainly Basidiomycota were reviewed, including low-molecular-weight (terpenoids, polyphenols steroids, quinones, amines, cerebrosides) (Tab.1) and high-molecular- weight compounds (homo and heteroglucans, glycans, glycoproteins, glycopeptides, peptides, proteins) (Tab. 2). Selected species of toxic and hallucinogenic mushrooms were also included in the review. At present, mushrooms are considered to be functional food. Beneficial health effects may be achieved through the direct consumption of fruiting bodies or the use of dietary supplements in the form of ready-to-use preparations containing mushroom extracts. The last years is also a period of a flourishing new field of medicine - mycopharmacology. The scientific approach to compounds contained in mushrooms allowed the isolation and identification of many valuable active substances which are used in the prevention and treatment of lifestyle diseases.
Źródło:
Wiadomości Chemiczne; 2020, 74, 1-2; 71-87
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Związki wanadu i chromu jako potencjalne insulino-mime tyki wykorzystywane w leczeniu cukrzycy
Vanadium and chromium compounds as the potential insulin-mimetics used in the treatment of diabetes
Autorzy:
Drzeżdżon, Joanna
Malinowski, Jacek
Zych, Dominika
Jacewicz, Dagmara
Powiązania:
https://bibliotekanauki.pl/articles/972299.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki wanadu
związki chromu
działanie insulino-naśladowcze
właściwości przeciwcukrzycowe
leczenie cukrzycy u ludzi
vanadium derivatives
chromium derivatives
insulin mimetic action
antidiabetic properties
human diabetic treatment
Opis:
The report focuses on the antidiabetic, also termed insulin-like, effect of various vanadium and chromium derivatives, proposed mechanisms of their activity, their use in in vivo and in vitro studies, as well as in diabetic patients, their toxicity and effectiveness in controlling clinical signs of diabetes. Studies indicate that compounds of vanadium and chromium is necessary for regulation of carbohydrate and lipid metabolism mainly due to increasing the number of insulin receptors and its activation by phosphorylation. Some authors believe that compounds of chromium(III) deficiency can lead to glucose intolerance and symptoms of type 2 diabetes. However, due to methodological limitations of many clinical studies, the statements of major diabetes associations concerning recommendation of various vanadium and chromium derivatives supplementation in individuals with diabetes and obesity still remains negative. Additional studies are urgently needed to elucidate the mechanism of action of chromium and vanadium compounds and its role in the prevention and control of diabetes.
Źródło:
Wiadomości Chemiczne; 2019, 73, 11-12; 753-775
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adam Bartecki (1920-2010) - szkic o życiu i twórczości
Adam Bartecki (1920-2010) - an essay on his life and work
Autorzy:
Cieślak-Golonka, M.
Starosta, J.
Powiązania:
https://bibliotekanauki.pl/articles/172023.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki chromu
spektroskopia
widma elektronowe
analiza komputerowa
biografia naukowa
Bartecki Adam
Źródło:
Wiadomości Chemiczne; 2011, 65, 7-8; 533-556
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Glony na zdrowie
Algae and human health
Autorzy:
Godlewska, K.
Michalak, I.
Chojnacka, K.
Powiązania:
https://bibliotekanauki.pl/articles/172057.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
makroglony
związki biologicznie czynne
medycyna
kosmetyka
macroalgae
biologically active compounds
medicine
cosmetics
Opis:
Marine algae are rich in a variety of biologically and pharmacologically active substances. They are considered as a resource that has been used by humans to some extent [6]. Nowadays, algal biomass is a renewable source of many valuable bioactive substances, having a wide array of applications in many industries, such as food, chemical, agricultural, pharmaceutical, cosmetic, medical. The present work focuses on the impact of algae on the human body. The potential use of algae and algal extracts in medicine and cosmetic industry is discussed. Due to the antibacterial, antiviral, antifungal, anti-inflammatory properties, algae can be used in the curing of many types of diseases [7, 8]. These properties result from the biologically active compounds present in the biomass of algae. The components of the algae that may help in the treatment tumor diseases are: polyphenols [37], polysaccharides [38], carrageenan [33–35], fucoidan [24, 30–32], fucoxanthin [25], diterpenes [27–29] or monoterpenes [36]. Substances extracted from algae with anti-inflammatory, antipyretic and analgesic include: fucosterol [48], porphyrins [52], lactones, phenols, carbohydrates [40], polysaccharides [51, 53, 54], fucoidan [46], galactan [49], fucan [45]. Fucoxanthin [64–68], fucoidan [58], triacyloglycerols [69], polyphenols [71] or phlorotannin [63] can be used as anti-obesity agents. Overreaction of the immune system to harmless environmental substances can be minimized by the use of antiallergic substances, which include mainly phlorotannins [73, 77, 78] and fatty acids [79, 80]. The components of algae, such as polysaccharides [99–101], diterpenes [91], bromophenol [90], carbohydrates [102], fucans [96, 97], galactans [98], carrageenan [94], fucoidan [92] or galactofucan [93] could be successfully utilized against various types of viruses. It has been proved that algae show dermatological and cosmetic properties: anti-inflammatory and bactericidal action (due to the presence of zinc) [8, 9, 19, 113], increase of the flexibility of the skin (peptides and vitamins) [13, 104, 105], improve blood circulation of the skin and thanks to the alginic acid they treat erythema [13, 103]. They influence on of inhibition of sebum secretion and on other problems of oily skin. Algae are used in many cosmetics to tone up the skin, lighten stretch marks [104, 111, 112]. Compresses made of algae slenderize and eliminate cellulite. A field of skin cosmetics called Thalassotherapy is a form of therapy that uses marine climate, sea water, mud, algae, sand and other substances derived from the sea as a therapeutic agents [13, 103].
Źródło:
Wiadomości Chemiczne; 2014, 68, 9-10; 834-852
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enancjoselektywna enzymatyczna desymetryzacja katalizowana lipazami. Część II, Optymalizacja warunków reakcji. Związki mezo
Enantioselectve enzymatic desymmetrization catalyzed in the presence of lipase. Part II, Optymalization of reaction conditions. Meso compounds
Autorzy:
Karczmarska-Wódzka, A.
Kołodziejska, R.
Tafelska-Kaczmarek, A.
Przybyła, T.
Dramiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/172192.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki mezo
desymetryzacja
transestryfikacja
hydroliza
lipaza
meso compounds
desymmetrization
transesterification
hydrolysis
lipase
Opis:
In the enzymatic asymmetric synthesis, the enzyme allows the desymmetrization of achiral compounds resulting in chiral compounds of high optical purity. Meso compounds (bearing a plane of symmetry) are very important group of compounds used in EEDs (Scheme 1) [1–4]. Similarly to prochiral compounds, selective acylation or hydrolysis of meso substrates leads to optically active products. Most lipases preferentially convert the same enantiomers in the above mentioned types of reaction. This allows the preparation of the both enantiomers of the product in high chemical and optical yield (Scheme 3–20) [35–58]. An effective enzymatic catalysis should be performed under conditions optimal for a biocatalyst performance. Hence, it is essential to select an appropriate reaction medium, the pH, and temperature [6–34]. Optimization of the reaction conditions in terms of an appropriate solvent selection is effective and most frequently the simplest way to modify the enzyme selectivity. One of the most important criteria for the solvent selection is its nature [25]. The enzyme selectivity is conditioned by its conformational rigidity, which increases in more hydrophobic medium (typical hydrophobic solvents, scCO2). A hydrophobic solvent decreases biocatalyst lability, which does not allow the connection between the structurally mismatched substrate and the active side of an enzyme [10, 26–31]. Ionic liquids are a separate group of solvents which, despite their high hydrophobicity (logP << 0) and polarity, can constitute an ideal medium for the biotransformation reactions [18–23].
Źródło:
Wiadomości Chemiczne; 2013, 67, 9-10; 819-841
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymetryczne przeniesienie wodoru do ketonów katalizowane związkami Rutenu(II) i Rodu(III)
Asymmetric transfer hydrogenation of ketones catalyzed by Ruthenium(II) and Rhodium(III) complexes
Autorzy:
Karczmarska-Wódzka, A.
Kołodziejska, R.
Studzińska, R.
Wróblewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/172550.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
transfer wodoru asymetryczny
związki kompleksowe Ru(II) i Rh(III)
chiralne ligandy
prochiralne związki karbonylowe
asymmetric transfer hydrogenation
Ru(II) and Rh(III) complexes
chiral ligands
prochiral carbonyl compounds
Opis:
Asymmetric hydrogen transfer (ATH) is one of the methods of stereoselective reduction of prochiral carbonyl compounds (Scheme 6). Complexes of the platinum group metals (Noyori catalysts) are the most common catalysts for AT H reactions. The specific structure of the Noyori catalyst allows to activate two hydrogen atoms. These atoms are transferred from donor to acceptor in the form of hydride ion and proton (Scheme 1). Depending on the used catalyst the transfer hydrogenation of ketons can proceed by direct and indirect transfer mechanism. The direct hydride transfer from a donor to an acceptor proceeds via a six-membered transition state (3) (Scheme 2). The indirect hydride transfer proceeds through the formation of an intermediate metal hydride. A monohydride (HLnMH) and or a dihydride (LnMH2) can be formed depending on the catalyst that is used (Scheme 3). In the monohydride route, the reduction proceeds in the inner sphere of the metal (four-membered transition state (4)) or in the outer sphere of the metal (six-membered transition state (5)) (Scheme 4). The proposed reduction of carbonyl compounds in the AT H reaction by Noyori catalysts uses the mechanism of the hydride ion and proton transfer from the donor to the catalyst and the formation of the monohydride. In the indirect transfer hydrogenation the hydride ion and proton are transferred from the monohydride to the acceptor (Scheme 5, 7). AT H reactions that lead to chiral alcohols are conducted in organic solvents or in water. Hydrogen donors most often used in organic solvent reactions are propan-2-ol or an azeotropic mixture of formic acid and triethylamine (Tab. 1, 6). Sodium formate is usually used as hydrogen donor in the reactions conducted in water. Yield and enantioselectivity of the reaction depend on many factors the most important of which are: the structure of a substrate, hydrogen donor and solvent that were used, the reaction time, substrate concentration, and the S/C ratio [2]. In the case of asymmetric reduction conducted in water the solvent pH is also of great importance [3, 7, 8]. An optimal pH range depends on the type of a catalyst [7, 8]. AT H reactions conducted in water are distinguished by a shorter reaction time and higher enantioselectivity than the reactions conducted in organic solvents. In addition, catalysts used in the AT H reactions are more stable in water allowing reuse of the catalyst without loss of its activity. This paper presented examples of the use of specific catalysts in asymmetric reactions of hydrogen transfer. In particular, I drew attention to the reactions running in the aquatic environment due to the above-mentioned advantages of this solvent. The authors focused specifically on bifunctional catalysts based on Ru(II) and Rh(III) on the account of wide usage of the catalysts of that type in AT H reactions in water and their good performance [8, 9, 15, 16, 17, 19, 20, 21, 22]. p-Cymene is the most common aromatic ligand in catalysts based on Ru(II) while in the case of catalysts with Rh(III) the most common is anionic pentamethylcyclopentadienyl ligand. In both cases the second most common ligands are diamines or amino alcohols (Scheme 8). There are better performance and enantioselectivity when diamines are used as ligands. Attempts to replace diamines and amino alcohols by Schiff bases (Scheme 13) in the catalysts containing Rh(III) proved poor results due to a very low enantioselectivity of conducted reactions (Tab. 7).
Źródło:
Wiadomości Chemiczne; 2012, 66, 3-4; 273-295
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enancjoselektywna enzymatyczna desymetryzacja katalizowana lipazami. Część 1, Związki prochiralne
Enantioselectve enzymatic desymmetrization catalyzed in the presence of lipase. Part 1, Prochiral compounds
Autorzy:
Kołodziejska, R.
Karczmarska-Wódzka, A.
Tafelska-Kaczmarek, A.
Studzińska, R.
Dramiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/171684.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki prochiralne
desymetryzacja
transestryfikacja
hydroliza
lipazy
prochiral compounds
desymmetrization
transesterification
hydrolysis
lipase
Opis:
In the enzymatic asymmetric synthesis, the enzyme allows the desymmetrization of achiral compounds resulting in chiral compounds of high optical purity. Therefore, this type of biotransformation is known as enantioselective enzymatic desymmetrization (EED) [1–11]. This method is related to the generation of an asymmetry (loss of symmetry elements) in prochiral molecules (most often an sp3 or sp2 hybridized carbon atom), in meso synthones, and centrosymmetric compounds. An achiral center of the tetrahedral system is defined as a prochiral one if it becomes chiral as a result of one of the two substituents replacement which, when separated from the particles, are indistinguishable (Scheme 1, 2) [1–4, 9, 12]. Asymmetric synthesis is enantioselective when one of the enantiotopic groups or faces of an optically inactive compound is biotransformed faster than the other (Scheme 3–5) [1, 10, 11, 13–15]. Lipases are enzymes of highest importance in stereoselective organic synthesis, mainly due to their exceptionally broad substrate tolerance, stability, activity in unphysiological systems, and relatively low price [9, 14]. The mechanism of enzymatic hydrolysis catalysed by hydrolases is similar to that observed in the chemical hydrolysis with the use of base. The selectivity of enzymatic catalysis depends on the substrate orientation in the enzyme active site (Scheme 6, 7) [25–29]. Lipases were successfully used for the desymmetrization of different prochiral diesters, alcohols and amines. Most lipases preferentially convert the same prochiral groups in the above mentioned types of reaction. This allows the preparation of the both enantiomers of the product in high chemical and optical yield (Scheme 9–13) [9, 13, 32–56].
Źródło:
Wiadomości Chemiczne; 2013, 67, 7-8; 751-772
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aminy biogenne w aspekcie ich roli w organizmach żywych
Biogenic amines in their role in living systems
Autorzy:
Jastrząb, R.
Tylkowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/171885.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
poliaminy
aminy biogenne
związki kompleksowe
nowotwory
polyamines
biogenic amines
coordination compounds
tumors
Opis:
Although polyamines (PA) belong to relatively simple aliphatic substances, their role in life processes of animals and plants is of key importance [1–5]. The group of the most important amines, called biogenic ones includes: Spermine (Spm): H2N(CH2)3NH(CH2)4NH(CH2)3NH2 Spermidine (Spd): H2N(CH2)3NH(CH2)4NH2 Putrescine (Put): H2N(CH2)4NH2. Of secondary importance are homologues of biogenic amines, occurring in lower contents in living organisms [2, 6–8]: 1,3-diaminopropan: H2N(CH2)3NH2 Cadaverine: H2N(CH2)5NH2 Homospermidine: H2N(CH2)4NH(CH2)4NH2 Norspermine (3,3,3-tet): H2N(CH2)3NH(CH2)3NH(CH2)3NH2 Thermospermine: H2N(CH2)3NH(CH2)4NH(CH2)4NH2 Caldopentamine: H2N(CH2)3NH(CH2)3NH(CH2)3NH(CH2)3NH2. The first polyamine discovered in a living organism was tetramine, a spermine crystallised out of sperm in 1678 by Van Leewenkeuk [9]. Putrescine was discovered in the end of the 19th century in microbes and then triamine: spermidine was discovered in the beginning of the 20th century [2]. Later studies have shown that in animal cells spermidine and spermine occur at elevated levels, while in prokaryotes spermidine and putrescine contents are dominant. Putrescine, spermidine, 1,3-diaminopropan, homospermidine, norspermidine, and norspermine have been found in many gramnegative bacteria and algae [7, 10, 11]. Total concentration of PA in living organisms is on the order of millimols, however, the concentration of free polyamines is much lower. A low level of free amines follows from the fact that they are involved in noncovalent interactions with biomolecules occurring in living organisms such as nucleic acids, proteins, or phospholipids. High concentrations of non-bonded polyamines have been detected first of all in young molecules in the process of growth, in particular in rapidly proliferating cancer cells [6, 12]. Elevated levels of free polyamines have been observed, e.g. in breast, colon, lung, prostate, and skin tumours, accompanied by changed levels of enzymes responsible for biosynthesis and catabolism of polyamines. Because of the increased level of free polyamines and a tendency of their interaction with nucleic acids and other bioligands, these compounds have become objects of intense study [1, 13–19]. There is no doubt that the regulation of biosynthesis of polyamines and catabolism is one of the most important pathways in the search strategy for chemoprevention and chemotherapeutic drugs [14, 15, 20–36]. The present state of knowledge of these processes, their significance in biological systems, and their application in medicine are presented in subsequent sections of this chapter.
Źródło:
Wiadomości Chemiczne; 2016, 70, 1-2; 57-79
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
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