National Repository of Grey Literature 32 records found  beginprevious13 - 22next  jump to record: Search took 0.01 seconds. 
Novel conformationally locked nucleosides and nucleotides based on bicyclo[3.2.1]octane scaffold as a pseudosugar moiety
Šála, Michal ; Dejmek, Milan ; Procházková, Eliška ; Hřebabecký, Hubert ; Rybáček, Jiří ; Dračínský, Martin ; Novák, Pavel ; Rosenbergová, Šárka ; Fukal, J. ; Sychrovský, Vladimír ; Rosenberg, Ivan ; Nencka, Radim
A route to a series of novel carbocyclic nucleosides locked in North conformation with bicyclo[3.2.1]octane scaffold was developed. Prepared nucleosides served as a starting material for the synthesis of modified oligomers [d(GCATATCAC), r(GCAUAUCAC), and A9]. Biological effects of the prepared nucleosides as well as the hybridization properties of the appropriate duplexes were evaluated.
Enzymatic decomposition of a locked nucleoside phosphoramidate monitored by 31P NMR spectroscopy
Procházková, Eliška ; Hřebabecký, Hubert ; Nencka, Radim ; Dračínský, Martin
Phosphoramidate derivatives are often used as prodrugs of modified nucleosides. The crucial step for the biologically active compound release in cells is then enzymatic hydrolysis of the phosphoramidate derivative. The enzymatic decomposition of a nucleoside prodrug 1 was monitored using 31P NMR spectroscopy and the structure of the reaction products was determined by 1D and 2D (COSY, HSQC, HMBC) NMR experiments and compared with the products obtained with non-enzymatic hydrolysis of the prodrug.
Synthesis and biological properties of polysubstituted 5-nitrosopyrimidines
Janeba, Zlatko ; Čechová, Lucie ; Žurek, Jiří ; Procházková, Eliška ; Dračínský, Martin
2,4,6-Triamino-5-nitrosopyrimidines have been reported to contain a strong intramolecular hydrogen bond between the 5-nitroso and 4- or 6-amino groups, thus forming an additional pseudoring. Such analogues were speculated to be good mimics of fused bicyclic derivatives, e.g. purines. A series of novel polysubstituted 2-amino-5-nitrosopyrimidines, as potential structural mimics of modifi ed purine nucleos(t)ides well-known for their important biological properties, has been designed and synthesized. The physicochemical and biological properties of the prepared polysubstituted 2-amino-5-nitrosopyrimidines are being evaluated.
Switchable intramolecular hydrogen bond in polysubstituted 5-nitrosopyrimidines
Procházková, Eliška ; Čechová, Lucie ; Žurek, Jiří ; Janeba, Zlatko ; Dračínský, Martin
The formation of strong intramolecular hydrogen bonds was observed in a series of 2-amino-5-nitrosopyrimidines with alkylamino and arylamino substituents in the positions 4 and 6. Mixtures of two rotamers differing in the orientation of the nitroso group were observed in the NMR spectra of the compounds where two distinct intramolecular hydrogen bonds could be formed. In several cases, we were able to isolate and characterize the two hydrogen bond isomers (two conformers) by column chromatography. The ratio of the two rotamers in equilibrium depends strongly on the character of the substituents in the positions 4 and 6 and can be finely tuned in a broad range of conformation ratios. The experimental results were supported by DFT calculations.
New amphiphilic prodrugs of adefovir and cidofovir
Tichý, Tomáš ; Andrei, G. ; Dračínský, Martin ; Holý, Antonín ; Balzarini, J. ; Snoeck, R. ; Krečmerová, Marcela
New adefovir (PMEA) prodrugs with a pro-moiety consisting of decyl(oxyethyl) chain bearing hydroxyl function(s), hexaethyleneglycol or a (5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl unit were prepared from the tetrabutylammonium salt of the phosphonate drug and an appropriate alkyl bromide or tosylate. Analogously, two esters of Cidofovir [(S)-HPMPC] bearing a hexaethyleneglycol moiety were prepared. The antiviral activity of the prodrugs was evaluated in vitro. A loss in the antiviral activities of the hydroxylated decyl(oxyethyl) esters and hexaethyleneglycol esters of PMEA against HIV and herpesviruses. (S)-HPMPC prodrugs exhibited anticytomegalovirus activities in the same range as the parent drug, whereas the anti-HSV and anti-VZV activities were one- to seven-fold lower than that of Cidofovir.
The mechanism of isotopic exchange reaction of hydrogen H-5 of uracil derivatives in water and in non-protic solvents
Dračínský, Martin ; Jansa, Petr ; Chocholoušová, Jana ; Vacek, Jaroslav ; Kovačková, Soňa ; Holý, Antonín
The mechanism of isotopic exchange reaction of hydrogen H-5 of uracil and its methyl-derivatives in water and in organic solvents was studied. The key intermediate of the reaction is a C-5 tautomer of uracil. We have used 1H NMR spectroscopy to follow the kinetics of the hydrogen-to-deuterium exchange reaction. In aqueous media, a general base catalysis was observed and in organic solvents we propose a reaction mechanism with participation of the solvent molecules. These findings could be effectively used for the tritium labeling of pyrimidine nucleic acid bases.
Nucleosides containing 8-aza-7,9-dedeazaxanthine
Mařák, David ; Otmar, Miroslav ; Dračínský, Martin ; Krečmerová, Marcela
8-aza-7,9-dideazaxanthine nucleosides were prepared from 5-nitrouracil employing a Barton-Zard reaction.
9-[2-hydroxy-3-(phosphonomethoxy)propyl] ("iso-HPMP")derivatives of purine bases and their side-chain modified analogues: synthesis and antimalarial activity
Krečmerová, Marcela ; Holý, Antonín ; Hocková, Dana ; Dračínský, Martin ; Keough, D. T. ; Guddat, L. W.
Hypoxanthine and guanine iso-HPMP derivatives substsituted in 2´-position were prepared and studied as potential inhibitors of a key enzyme of the malarial parasite Plasmodium falciparum HGXPRT.
Piperidine nucleoside phosphonic acid derivatives
Kovačková, Soňa ; Dračínský, Martin ; Rejman, Dominik
A series of novel phosphonic acid derivatives of piperidine nucleosides was prepared, whereby synthesis of both enantiomeric and diastereomeric derivatives was discussed. Preparation of diphosphate analogs of phosphonic acids derivatives is also described. The prepared nucleotide analogs were tested for their potential biological properties.
3-Fluoro-2-(phosphonomethoxy)propyl hypoxanthine and guanine derivatives as inhibitors of plasmodial hypoxanthine-guanine-xanthine phosphoribosyltransferases
Baszczyňski, Ondřej ; Jansa, Petr ; Hocková, Dana ; Janeba, Zlatko ; Dračínský, Martin ; Holý, Antonín ; Keough, D. T. ; de Jersey, J. ; Guddat, L. W.
A new methodology for the synthesis of ANPs containing 9-[2-(phosphonoethoxy)ethyl] (PEE) moiety has been developed. FPEP compound containing guanine moiety exhibited inhibition activity against the enzyme in micromolar range without any signs of toxicity.

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