排序方式: 共有71条查询结果,搜索用时 15 毫秒
21.
Dagmara Ziembicka Andrzej Olczak Katarzyna Gobis Izabela Korona-Głowniak Anna Pietrzak Ewa Augustynowicz-Kopeć Agnieszka Głogowska Marcin Zaborowski Małgorzata Szczesio 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(7):283-291
Three new 2,6-disubstituted thiosemicarbazone derivatives of pyridine, namely, 2-{amino[6-(pyrrolidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C13H20N6S, 2-{amino[6-(piperidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C14H22N6S, and 2-[amino(6-phenoxypyridin-2-yl)methylidene]-N,N-dimethylhydrazine-1-carbothioamide monohydrate, C15H17N5OS·H2O, have been synthesized and characterized by NMR spectroscopy and low-temperature single-crystal X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The ability of the tested compounds to inhibit bacterial growth was comparable to vancomycin as a reference drug. Compared to isoniazid (MIC 0.125 and 8 µg ml−1), the compounds showed the ability to inhibit the growth of Mycobacterium tuberculosis to a moderate degree for the standard strain and at the same level or higher (MIC 4–8 µg ml−1) for the resistant strain. All three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules. 相似文献
22.
Zuzana Vanovčanová Pavol Alexy Jozef Feranc Roderik Plavec Ján Bočkaj Leona Kaliňáková Katarína Tomanová Dagmara Perd’ochová Dávid Šariský Ivana Gálisová 《Chemical Papers》2016,70(10):1408-1415
Blends of biodegradable polymers polylactic acid/thermoplastic starch/polyhydroxybutyrate (PLA/TPS/PHB) were prepared using a twin-screw extruder. The TPS content was constant (50 %) and the PHB content in the blends was gradually changed from 0 mass % to 20 mass %. TPS was prepared by melting, where a mixture of native starch, water and glycerol was fed into the twinscrew extruder. Average temperature of extrusion was 180°C and the concentration of glycerol was 40 mass %. Influence of the PHB concentration in the blend and that of the processing technology on the mechanical and rheological properties of the PLA/PHB composition containing TPS were studied. Mechanical properties were measured 24 h after the film and monofilament preparation and also after the specific storage time to study the effect of storage on the properties. The results indicate that differences in morphology strongly influence the mechanical properties of the studied materials with identical material composition. 相似文献
23.
Structure,Physicochemical and Biological Properties of an Aqua (2,2′,2′′‐Nitrilotriacetato)‐oxidovanadium(IV) Salt with 4‐Methylpyridinium Cation
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Aleksandra Tesmar Dariusz Wyrzykowski Katarzyna Kazimierczuk Julia Kłak Szymon Kowalski Iwona Inkielewicz‐Stępniak Joanna Drzeżdżon Dagmara Jacewicz Lech Chmurzyński 《无机化学与普通化学杂志》2017,643(7):501-510
The crystal structure of a nitrilotriacetate (nta) oxidovanadium(IV) salt with 4‐methylpyridinium cation, [4‐Me(Py)H]+, of [4‐Me(Py)H][VO(nta)(H2O)] stoichiometry was determined. The complex comprises a discrete mononuclear [VO(nta)(H2O)]– coordination entity that can be rarely found among other known compounds containing nitrilotriacetate oxidovanadium(IV) moieties. The complex was characterized by spectroscopic (IR and EPR) methods, magnetic measurements, and thermogravimetry (TG‐FTIR). The stability of the title compound in aqueous solutions was investigated by using the potentiometric titration method. Furthermore, spectrophotometric (UV/Vis) studies have revealed that the compound is capable to scavenge the superoxide free radicals (O2 ? –) as well as stable organic radicals i.e. 2,2′‐azinobis(3‐ethylbenzothiazoline‐6 sulfonic acid) cation radical (ABTS+ ? ) and 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH ? ). Finally, biological properties of the complex studied were investigated in relation to its cytoprotective activity against the oxidative damage generated exogenously by using hydrogen peroxide in the HT22 hippocampal neuronal cell line (the MTT assay). Additionally, the biological action of the compound towards two human osteosarcoma HOS and MG‐63 cell lines (the MTT and BrdU tests) as well as the untransformed human osteoblast hFOB 1.19 cell line was tested. 相似文献
24.
Dariusz Wyrzykowski Michał Wera Artur Sikorski Dagmara Jacewicz Lech Chmurzyński 《Central European Journal of Chemistry》2011,9(6):1096-1101
The crystal structure of 2-methylpyridinium tetrachloroferrate(III) was determined. The iron cation is tetracoordinated by
chloride anions, and it adopts a slightly distorted tetrahedral coordination with three angles smaller, two almost equal and
one larger than the tetrahedral. The compound is isostructural with its 3-, and 4-methylpyridinium analogues. The thermal
properties of 2-, 3- and 4-methylpyridinium tetrachloroferrates(III) have been studied using TG and DSC techniques. The compounds
exhibit a high stability in the melt.
相似文献
25.
Du Y Derewacz DK Deguire SM Teske J Ravel J Sulikowski GA Bachmann BO 《Tetrahedron》2011,67(35):6568-6575
The apoptolidins are 20/21-membered macrolides produced by Nocardiopsis sp. FU40. Several members of this family are potent and remarkably selective inducers of apoptosis in cancer cell lines, likely via a distinct mitochondria associated target. To investigate the biosynthesis of this natural product, the complete genome of the apoptolidin producer Nocardiopsis sp. FU40 was sequenced and a 116 kb region was identified containing a putative apoptolidin biosynthetic gene cluster. The apoptolidin gene cluster comprises a type I polyketide synthase, with 13 homologating modules, apparently initiated in an unprecedented fashion via transfer from a methoxymalonyl-acyl carrier protein loading module. Spanning approximately 39 open reading frames, the gene cluster was cloned into a series of overlapping cosmids and functionally validated by targeted gene disruption experiments in the producing organism. Disruption of putative PKS and P450 genes delineated the roles of these genes in apoptolidin biosynthesis and chemical complementation studies demonstrated intact biosynthesis peripheral to the disrupted genes. This work provides insight into details of the biosynthesis of this biologically significant natural product and provides a basis for future mutasynthetic methods for the generation of non-natural apoptolidins. 相似文献
26.
Monika M. Karpińska Joanna Matysiak Andrzej Niewiadomy Joanna Wietrzyk Dagmara K?opotowska 《Monatshefte für Chemie / Chemical Monthly》2012,34(10):269-276
Abstract
A one-pot synthesis of new biologically active 4- and 6-(1-alkyl/aryl-1H-benzimidazol-2-yl)benzene-1,3-diols has been developed. The compounds were obtained by the reaction of aryl-modified sulfinylbis[(2,4-dihydroxyphenyl)methanethione] with N-substituted benzene-1,2-diamines. Elemental analysis, IR, 1H NMR, 13C NMR, and mass spectral data were used to elucidate their structures. The developed method offers short reaction times, easy and quick isolation of the products, and good yields. The antiproliferative properties of the synthesized compounds were investigated against a panel of human cancer cell lines. Some of the tested compounds showed significant cytotoxic activity. 相似文献27.
Mateusz uny Dagmara Kaczanowska Barbara Gawdzik Alicja Wzorek Aleksandra Pawlak Boena Obmiska-Mrukowicz Monika Dymarska Ewa Kozowska Edyta Kostrzewa-Susow Tomasz Janeczko 《Molecules (Basel, Switzerland)》2022,27(12)
This research aimed to select yeast strains capable of the biotransformation of selected 2′-hydroxybromochalcones. Small-scale biotransformations were carried out using four substrates obtained by chemical synthesis (2′-hydroxy-2″-bromochalcone, 2′-hydroxy-3″-bromochalcone, 2′-hydroxy-4″-bromochalcone and 2′-hydroxy-5′-bromochalcone) and eight strains of non-conventional yeasts. Screening allowed for the determination of the substrate specificity of selected microorganisms and the selection of biocatalysts that carried out the hydrogenation of tested compounds in the most effective way. It was found that the position of the bromine atom has a crucial influence on the degree of substrate conversion by the tested yeast strains. As a result of the biotransformation of the 2′-hydroxybromochalcones, the corresponding 2′-hydroxybromodihydrochalcones were obtained. The products obtained belong to the group of compounds with high potential as precursors of sweet substances. 相似文献
28.
Dagmara Jacewicz Aleksandra Dąbrowska Izabela Kolisz Lech Chmurzyński Bogdan Banecki Michał Woźniak 《Transition Metal Chemistry》2005,30(2):209-216
The mechanism and kinetics of the reaction between an aqueous solution of CO2 and coordinate ions, cis-[Cr(C2O4)(L–L)(OH2)2]+, where L–L denotes histamine (hm) or pyridoxamine (pm), were investigated using the stopped-flow technique. The studies were carried out at 5 to 25 °C over the pH range 6.04–8.15 at a fixed ionic strength solution (1 M NaClO4). The results enabled determination of the number of steps of the reactions studied. Based on the kinetic equations, rate constants were determined for each step. Finally, thermodynamic activation parameter values H, were calculated for the reaction studied from temperature relationships. 相似文献
29.
Dagmara Jacewicz Agnieszka Łapińska Aleksandra Dąbrowska Lech Chmurzyński Michał Woźniak 《Transition Metal Chemistry》2006,31(8):1045-1051
A stopped-flow method was used to investigate the kinetics of the acid hydrolysis of a newly synthesised coordination ion
of the cis-[Cr(C2O4)(AaraNH2)(O2CO)]− type, where AaraNH2 stands for methyl 3-amino-2,3-dideoxy-α -d-arabino-hexapyranoside, over a range of hydrogen ion concentrations 0.01 < [H+] < 2.7 M and temperatures 5 < T < 25°C. Initiated by perchloric acid (HClO4), the hydrolysis (decarboxylation) of the chromium(III) ion complexed with a bicoordinately linked carbonate ligand turned
out to be a two-step process. The kinetic parameters k
1, k
2 were determined of both steps of the hydrolysis of the cis-[Cr(C2O4)(AaraNH2)(O2CO)]− ion, as was the equilibrium constant K of the protonation of this ion, which precedes the actual two-step hydrolysis. From an analysis of the values of the constants
obtained, a mechanism is proposed for the acid hydrolysis of the cis-[Cr(C2O4)(AaraNH2)(O2CO)]− coordination ion. 相似文献
30.
Podkoscielny D Philip I Gibb CL Gibb BC Kaifer AE 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(15):4704-4710
In aqueous media the deep-cavity cavitand octaacid 1 forms stable dimeric molecular capsules 1(2), which are stabilized by hydrophobic effects. In this work we investigate the binding interactions in aqueous solution between these capsules and the redox active guests, ferrocene (Fc) and three 4,4'-bipyridinium (viologen) dications: methyl viologen (MV(2+)), ethyl viologen (EV(2+)), and butyl viologen (BV(2+)). Using NMR spectroscopic and electrochemical techniques we clearly show that the hydrophobic Fc guest is encapsulated inside 1(2). An interesting effect of this encapsulation is that the reversible voltammetric response of Fc is completely eliminated when it resides inside the 1(2) capsular assembly, a finding that is attributed to very slow electrochemical kinetics for the oxidation of Fc@1(2). Diffusion coefficient measurements (PGSE NMR spectroscopy) reveal that all three viologen guests are strongly bound to the dimeric capsules. However, the (1)H NMR spectroscopic data are not consistent with encapsulation and the measured diffusion coefficients indicate that two viologen guests can strongly associate with a single dimeric capsule. Furthermore, the (V(2+))(2)*1(2) complex is capable of encapsulating ferrocene, clearly suggesting that the viologen guests are bound externally, via coulombic interactions, to the anionic polar ends of the capsule. The electrochemical kinetic rate constants for the reduction of the viologen residue in the V(2+)*1(2) complexes were measured and found to be substantially lower than those for the free viologen guests. 相似文献