- Characterization of nicotinamidases: Steady state kinetic parameters, classwide inhibition by nicotinaldehydes, and catalytic mechanism
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Nicotinamidases are metabolic enzymes that hydrolyze nicotinamide to nicotinic acid. These enzymes are widely distributed across biology, with examples found encoded in the genomes of Mycobacteria, Archaea, Eubacteria, Protozoa, yeast, and invertebrates, but there are none found in mammals. Although recent structural work has improved our understanding of these enzymes, their catalytic mechanism is still not well understood. Recent data show that nicotinamidases are required for the growth and virulence of several pathogenic microbes. The enzymes of Saccharomyces cerevisiae, Drosophila melanogaster, and Caenorhabditis elegans regulate life span in their respective organisms, consistent with proposed roles in the regulation of NAD+ metabolism and organismal aging. In this work, the steady state kinetic parameters of nicotinamidase enzymes from C. elegans, Sa. cerevisiae, Streptococcus pneumoniae (a pathogen responsible for human pneumonia), Borrelia burgdorferi (the pathogen that causes Lyme disease), and Plasmodium falciparum (responsible for most human malaria) are reported. Nicotinamidases are generally efficient catalysts with steady state kcat values typically exceeding 1 s -1. The Km values for nicotinamide are low and in the range of 2 -110 μM. Nicotinaldehyde was determined to be a potent competitive inhibitor of these enzymes, binding in the low micromolar to low nanomolar range for all nicotinamidases tested. A variety of nicotinaldehyde derivatives were synthesized and evaluated as inhibitors in kinetic assays. Inhibitions are consistent with reaction of the universally conserved catalytic Cys on each enzyme with the aldehyde carbonyl carbon to form a thiohemiacetal complex that is stabilized by a conserved oxyanion hole. The S. pneumoniae nicotinamidase can catalyze exchange of 18O into the carboxy oxygens of nicotinic acid with H218O. The collected data, along with kinetic analysis of several mutants, allowed us to propose a catalytic mechanism that explains nicotinamidase and nicotinic acid 18O exchange chemistry for the S. pneumoniae enzyme involving key catalytic residues, a catalytic transition metal ion, and the intermediacy of a thioester intermediate.
- French, Jarrod B.,Cen, Yana,Vrablik, Tracy L.,Xu, Ping,Allen, Eleanor,Hanna-Rose, Wendy,Sauve, Anthony A.
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- REACTIVITY OF METHYL DERIVATIVES OF NITROGENOUS HETEROCYCLES IN VAPOR-PHASE CATALYTIC OXIDATION
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A study has been made of the reactivity of methylpyridines, methylpyrazines, and methylquinolines in oxidation in the vapor phase in the presence of β-VO(PO3)2.Relationships have been found between the overall reaction rates of heterocyclic compounds and the charge on the ring nitrogen, and between the partial oxidation rate and the charge on the ring carbon atom adjacent to the methyl group.The partial oxidation rate of methylpyridines is given to a first approximation by the Hammett-type expression lnWa = -3.5 + 4.6 Σ?, with a correlation coefficient of 0.93.
- Leitis, L. Ya.,Skolmeistere, R. A.,Golender, L. O.,Yansone, D. P.,Meksh, P. A.,Shimanskaya, M. V.
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- HETEROCYCLIC AMIDES AS KINASE INHIBITORS
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Disclosed are compounds having the formula: (I) wherein R1, R2, and R3 are as defined herein, and methods of making and using the same.
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Page/Page column 74
(2016/12/07)
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- PYRAZOLOPYRIMIDINES AS INHIBITORS OF GLUCOCORTICOID RECEPTOR TRANSLOCATION
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Provided herein are compounds and pharmaceutical compositions comprising said compounds. The subject compounds and compositions are useful as modulators of Glucocorticoid Receptor (GR) translocation. Furthermore, the subject compounds and compositions are useful for the treatment of diseases involved in the hypothalamic-pituitary-adrenal (HPA) axis.
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Paragraph 00588
(2016/08/23)
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- Manganese oxide promoted liquid-phase aerobic oxidative amidation of methylarenes to monoamides using ammonia surrogates
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In the presence of amorphous MnO2, various methylarenes (even with two or more methyl groups) could be selectively converted into the corresponding primary monoamides in moderate to high yields. The observed catalysis was truly heterogeneous, and the retrieved amorphous MnO2 catalyst could be reused without an appreciable loss of its catalytic performance. Copyright
- Wang, Ye,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information; experimental part
p. 7250 - 7253
(2012/08/28)
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- SUBSTITUTED 4H-CHROMENE AND ANALOGS AS ACTIVATORS OF CASPASES AND INDUCERS OF APOPTOSIS AND THE USE THEREOF
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The present invention is directed to substituted 4H-chromene and analogs thereof, represented by the general Formula I: wherein A, B, X, Y, Z and R5 are defined herein. The present invention also relates to the discovery that compounds having Formula I are activators of caspases and inducers of apoptosis. Therefore, the activators of caspases and inducers of apoptosis of this invention can be used to induce cell death in a variety of clinical conditions in which uncontrolled growth and spread of abnormal cells occurs.
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- Discovery of 4-aryl-4H-chromenes as a new series of apoptosis inducers using a cell- and caspase-based high-throughput screening assay. 1. Structure-activity relationships of the 4-aryl group
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By applying a novel cell- and caspase-based HTS assay, 2-amino-3-cyano-7- (dimethylamino)-4-(3-methoxy-4,5-methylenedioxyphenyl)-4H-chromene (1a) has been identified as a potent apoptosis inducer. Compound 1a was found to induce nuclear fragmentation and PARP cleavage, as well as to arrest cells at the G2/M stage and to induce apoptosis as determined by the flow cytometry analysis assay in multiple human cell lines (e.g. Jurkat, T47D). Through structure-activity relationship (SAR) studies of the 4-aryl group, a 4- and 7-fold increase in potency was obtained from the screening hit 1a to the lead compounds 2-amino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-7-(dimethylamino) -4H-chromene (1c) and 2-amino-3-cyano-7-(dimethylamino)-4-(5-methyl-3-pyridyl)- 4H-chromene (4e), with an EC50 of 19 and 11 nM in the caspase activation assay in T47D breast cancer cells, respectively. The 2-amino-4-aryl-3-cyano-7-(dimethylamino)-4H-chromenes also were found to be highly active in the growth inhibition MTT assay, with GI50 values in the low nanomolar range for compound 1c. Significantly, compound 1c was found to have a GI50 value of 2 nM in the paclitaxel resistant, p-glycoprotein overexpressed, MESSA/DX5 tumor cells. Functionally, compound 1c was found to be a potent inhibitor of tubulin polymerization and to effectively inhibit the binding of colchicine to tubulin. These results confirm that the cell-based caspase activation assay is a powerful tool for the discovery of potent apoptosis inducers and suggest that the 4-aryl-4H-chromenes have the potential to be developed into future anticancer agents.
- Kemnitzer, William,Drewe, John,Jiang, Songchun,Zhang, Hong,Wang, Yan,Zhao, Jianghong,Jia, Shaojuan,Herich, John,Labreque, Denis,Storer, Richard,Meerovitch, Karen,Bouffard, David,Rej, Rabindra,Denis, Real,Blais, Charles,Lamothe, Serge,Attardo, Giorgio,Gourdeau, Henriette,Tseng, Ben,Kasibhatla, Shailaja,Cai, Sui Xiong
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p. 6299 - 6310
(2007/10/03)
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- A General Synthesis of Substituted Fluorenones and Azafluorenones
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Twenty-one variously substituted fluorenones and azafluorenones have been synthesized via photochemical Pschorr cyclizations of 2-diazoniodiaryl ketones as the key ring-forming step.Direct, (bipy)3RuII-, or (bipy)3RuII/CuII-photosensitized conditions were used, depending on the system to be cyclized.Where selectivities were possible in the ring closure, the isomer ratios obtained were in accord with an aryl radical as the reactive intermediate.The precursor aminodiaryl ketones were obtained from the sequence ortho lithiation of an arylpivalamide, reaction withan aryl aldehyde to give a 2-pivalamidodiarylcarbinol, oxidation to give a 2-pivalamidodiaryl ketone, and hydrolysis to give the 2-aminodiaryl ketone.
- Kyba, Evan P.,Liu, Shiuh-Tzung,Chockalingam, Kannappan,Reddy, B. Raghava
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p. 3513 - 3521
(2007/10/02)
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- SYNTHESIS OF SUBSTITUTED 3-PYRIDINECARBOXALDEHYDES
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Treatment of 3-substituted 1-(phenoxycarbonyl)-1,2-dihydropyridines with Vilsmeier reagent (POCl3/DMF) gave 3-substituted 5-formyl-1-(phenoxycarbonyl)-1,2-dihydropyridines, which were aromatized with hot sulfur to provide 5-substituted 3-pyridinecarboxaldehydes. The formylation of 4-substituted 1-(phenoxycarbonyl)-1,4-dihydropyridines and subsequent aromatization gave 4-substituted 3-pyridinecarboxaldehydes.
- Comins, Daniel L.,Herrick, James J.
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p. 2159 - 2164
(2007/10/02)
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