- Fluorescing Isofunctional Ribonucleosides: Assessing Adenosine Deaminase Activity and Inhibition
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The enzymatic conversion of isothiazolo[4,3-d]pyrimidine-based adenosine (tzA) and 2-aminoadenosine (tz2-AA) analogues to the corresponding isothiazolo[4,3-d]pyrimidine-based inosine (tzI) and guanosine (tzG) derivatives is evaluated and compared to the conversion of native adenosine to inosine. Henri–Michaelis–Menten analyses provides the foundation for a high-throughput screening assay, and the efficacy of the assay is showcased by fluorescence-based analysis of tzA conversion to tzI in the presence of known and newly synthesized inhibitors.
- Ludford, Paul T.,Rovira, Alexander R.,Fin, Andrea,Tor, Yitzhak
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p. 718 - 726
(2019/03/05)
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- Atom-Specific Mutagenesis Reveals Structural and Catalytic Roles for an Active-Site Adenosine and Hydrated Mg2+ in Pistol Ribozymes
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The pistol RNA motif represents a new class of self-cleaving ribozymes of yet unknown biological function. Our recent crystal structure of a pre-catalytic state of this RNA shows guanosine G40 and adenosine A32 close to the G53–U54 cleavage site. While the N1 of G40 is within 3.4 ? of the modeled G53 2′-OH group that attacks the scissile phosphate, thus suggesting a direct role in general acid–base catalysis, the function of A32 is less clear. We present evidence from atom-specific mutagenesis that neither the N1 nor N3 base positions of A32 are involved in catalysis. By contrast, the ribose 2′-OH of A32 seems crucial for the proper positioning of G40 through a H-bond network that involves G42 as a bridging unit between A32 and G40. We also found that disruption of the inner-sphere coordination of the active-site Mg2+ cation to N7 of G33 makes the ribozyme drastically slower. A mechanistic proposal is suggested, with A32 playing a structural role and hydrated Mg2+ playing a catalytic role in cleavage.
- Neuner, Sandro,Falschlunger, Christoph,Fuchs, Elisabeth,Himmelstoss, Maximilian,Ren, Aiming,Patel, Dinshaw J.,Micura, Ronald
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supporting information
p. 15954 - 15958
(2017/11/21)
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- IMIDAZOPYRIDINE DERIVATIVES AS PI3 KINASE INHIBITORS
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This invention relates to the use of imidizopyridine derivatives for the modulation, notably the inhibition of the activity or function of the phosphoinositide 3' OH kinase family (hereinafter PI3 kinases), suitably, PI3Kα, PI3Kδ, PI3Kβ, and/or PI3Kγ. Suitably, the present invention relates to the use of imidizopyridines in the treatment of one or more disease states selected from: autoimmune disorders, inflammatory diseases, cardiovascular diseases, neurodegenerative diseases, allergy, asthma, pancreatitis, multiorgan failure, kidney diseases, platelet aggregation, cancer, sperm motility, transplantation rejection, graft rejection and lung injuries. More suitably, the present invention relates to PI3Kβ selective imidizopyridine compounds for treating cancer.
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Page/Page column 32; 33
(2013/07/05)
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- Influence of the nucleobase and anchimeric assistance of the carboxyl acid groups in the hydrolysis of amino acid nucleoside phosphoramidates
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Nucleoside phosphoramidates (NPs) are a class of nucleotide analogues that has been developed as potential antiviral/antitumor prodrugs. Recently, we have shown that some amino acid nucleoside phosphoramidates (aaNPs) can act as substrates for viral polymerases like HIV-1 RT. Herein, we report the synthesis and hydrolysis of a series of new aaNPs, containing either natural or modified nucleobases to define the basis for their differential reactivity. Aqueous stability, kinetics, and hydrolysis pathways were studied by NMR spectroscopy at different solution pD values (5-7) and temperatures. It was observed that the kinetics and mechanism (P-N and/or P-O bond cleavage) of the hydrolysis reaction largely depend on the nature of the nucleobase and amino acid moieties. Aspartyl NPs were found to be more reactive than Gly or β-Ala NPs. For aspartyl NPs, the order of reactivity of the nucleobase was 1-deazaadenine>7- deazaadenine>adenine>thymine≥3-deazaadenine. Notably, neutral aqueous solutions of Asp-1-deaza-dAMP degraded spontaneously even at 4°C through exclusive P-O bond hydrolysis (a 50-fold reactivity difference for Asp-1-deaza-dAMP vs. Asp-3-deaza-dAMP at pD 5 and 70°C). Conformational studies by NMR spectroscopy and molecular modeling suggest the involvement of the protonated N3 atom in adenine and 1- and 7-deazaadenine in the intramolecular catalysis of the hydrolysis reaction through the rare syn conformation. Touching (nucleo)base: A dual intramolecular catalytic influence is demonstrated by the nucleobase and carboxyl groups in the chemical hydrolysis of amino acid nucleoside phosphoramidate prodrugs (see scheme). The replacement of the adenine N1 or N7 atoms instead of the N3 atom is shown to have a conformational role in which the protonated N3 is crucial in regulating the kinetics and mechanism of nucleotide (P-N pathway) versus nucleoside (P-O pathway) formation. Copyright
- Maiti, Munmun,Michielssens, Servaas,Dyubankova, Natalia,Maiti, Mohitosh,Lescrinier, Eveline,Ceulemans, Arnout,Herdewijn, Piet
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supporting information; experimental part
p. 857 - 868
(2012/03/26)
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- Synthesis and modulation properties of imidazo[4,5-b]pyridin-7-one and indazole-4,7-dione derivatives towards the Cryptosporidium parvum CpABC3 transporter
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The syntheses of new N-polysubstituted imidazo[4,5-b]pyridine-7-one (IP, 5 and 8a-8f) and indazole-4,7-dione (ID, 9 and 10) derivatives are described. The binding affinity of IP and ID towards the recombinant Nucleotide Binding Domain NBD1 of Cryptosporidium parvum CpABC3 was evaluated by intrinsic fluorescence quenching. IP induced a moderate quenching of the intrinsic fluorescence of H6-NBD1 whereas IDs 9 and 10 showed a binding affinity comparable to the ATP analogue TNP-ATP. In addition, 8d, 8e and 10 were shown to be competitive inhibitors of the ATPase activity, but with low affinity. These compounds could thus act like some flavonoid derivatives, which can partly overlap both the nucleotide-binding site and the adjacent hydrophobic steroid-binding region of mammalian P-glycoproteins.
- Zeinyeh, Wa?l,Xia, Hexue,Lawton, Philippe,Radix, Sylvie,Marminon, Christelle,Nebois, Pascal,Walchshofer, Nadia
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experimental part
p. 2480 - 2488
(2010/07/09)
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- Regioselective N-alkylation of imidazo[4,5-b]pyridine-4-oxide derivatives: an experimental and DFT study
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Regioselectivities were determined for N-alkylations of imidazo[4,5-b]pyridine-4-oxide and 2-methyl-imidazo[4,5-b]pyridine-4-oxide with benzyl bromide or benzyl iodide at RT using K2CO3 in DMF as a base. Experimental attempts have shown that N-1/N-3 ratios slightly varied according to the substitution on C-2 position. This was confirmed by DFT calculations in solvent phase. This computational study has shown first that this N-benzylation reaction passed through a SN2 mechanism. Moreover, regioselectivity of N-benzylation has appeared essentially governed by 'steric approach control'. It explained that opposite N-1/N-3 ratios were obtained with imidazo[4,5-b]pyridine-4-oxide and its 2-methyl-substituted analog. Finally, regioselectivities slightly varied with the nature of benzyl halide.
- Zeinyeh, Wael,Pilmé, Julien,Radix, Sylvie,Walchshofer, Nadia
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scheme or table
p. 1828 - 1833
(2009/07/17)
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- HETEROCYCLIC COMPOUNDS AND THEIR USES
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Substituted bicyclic heteroaryls and compositions containing them, for the treatment of general inflammation, arthritis, rheumatic diseases, osteoarthritis, inflammatory bowel disorders, inflammatory eye disorders, inflammatory or unstable bladder disorders, psoriasis, skin complaints with inflammatory components, chronic inflammatory conditions, including but not restricted to autoimmune diseases such as systemic lupus erythematosis (SLE), myestenia gravis, rheumatoid arthritis, acute disseminated encephalomyelitis, idiopathic thrombocytopenic purpura, multiples sclerosis, Sjoegren's syndrome and autoimmune hemolytic anemia, allergic conditions including all forms of hypersensitivity. The present invention also enables methods for treating cancers that are mediated, dependent on, or associated with p110 activity, including but not restricted to leukemias, such as acute myeloid leukaemia (AML), myelo-dysplastic syndrome (MDS), myelo-proliferative diseases (MPD), chronic myeloid leukemia (CML), T-cell acute lymphoblastic leukaemia (T-ALL), B-cell acute lymphoblastic leukaemia (B-ALL), non Hodgkins lymphoma (NHL), B-cell lymphoma and solid tumors, such as breast cancer.
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Page/Page column 123
(2008/12/04)
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- 2,6,8-Trisubstituted 1-deazapurines as adenosine receptor antagonists
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In this study we developed a refined pharmacophore model for antagonists of the human adenosine A1 receptor, based on features of known pyrimidine and purine derivatives. The adoption of these updated criteria assisted us in synthesizing a series of 1-deazapurines with consistently high affinity as inverse agonists for the adenosine A1 receptor. These 1-deazapurines (otherwise known as 3H-imidazo[4,5-b]pyridines) were substituted at their 2- and 6-positions, yielding a series with five of the derivatives displaying Ki values in the subnanomolar range. The most potent of these, compound 10 (LUF 5978), displayed an affinity of 0.55 nM at the human adenosine A1 receptor with > 300-fold and 45-fold selectivity toward A2A and A3 receptors, respectively. Compound 14 (LUF 5981, Ki = 0.90 nM) appeared to have the best overall selectivity with respect to adenosine A2A (> 200-fold) and A 3 (700-fold) receptors.
- Chang, Lisa C. W.,Von Frijtag Drabbe Künzel, Jacobien K.,Mulder-Krieger, Thea,Westerhout, Joost,Spangenberg, Thomas,Brussee, Johannes,Ijzerman, Adriaan P.
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p. 828 - 834
(2007/10/03)
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- New (1-deaza)purine derivatives via efficient C-2 nitration of the (1-deaza)purine ring
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Nitration of substituted (1-deaza)purines using a mixture of tetrabutylammonium nitrate (TBAN) and trifluoracetic acid anhydride (TFAA) was applied to prepare nitrosubstituted (1-deaza)purines at low temperature. The nitro group influences the system twofold: 1) it activates other substituents towards nucleophilic aromatic substitution and 2) it can be substituted itself leading to a variety of di-substituted (1-deaza)purines, also via solid phase syntheses. Several of the molecules obtained were studied for their antiprotozoal activity and for interactions with the different human adenosine receptors.
- Wanner,Rodenko,Koch,Koomen
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p. 1313 - 1320
(2007/10/03)
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- Structure-based design, synthesis, and antimicrobial activity of purine derived SAH/MTA nucleosidase inhibitors
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The structure-based design, synthesis, and biological activity of novel inhibitors of S-adenosyl homocysteine/methylthioadenosine (SAH/MTA) nucleosidase are described. Using 6-substituted purine and deaza purines as the core scaffolds, a systematic and structure guided series of modifications provided low nM inhibitors with broad-spectrum antimicrobial activity.
- Tedder, Martina E.,Nie, Zhe,Margosiak, Stephen,Chu, Shaosong,Feher, Victoria A.,Almassy, Robert,Appelt, Krzysztof,Yager, Kraig M.
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p. 3165 - 3168
(2007/10/03)
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- Methyltrioxorhenium (MeReO3) catalyzed selective oxidation of purine and related compounds into their N-oxides
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A convenient method for the selective N-oxidation of purine, 6-methylpurine, 1H-imidazo[4,5-c]pyridine, 1H-imidazo[4,5-b]pyridine, 6-chloropurine, 6-bromopurine, and 7-azaindole by H2O2 catalyzed by methyltrioxorhenium is reported.
- Jiao,Yu
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