- Selective Chemical Functionalization at N6-Methyladenosine Residues in DNA Enabled by Visible-Light-Mediated Photoredox Catalysis
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Selective chemistry that modifies the structure of DNA and RNA is essential to understanding the role of epigenetic modifications. We report a visible-light-activated photocatalytic process that introduces a covalent modification at a C(sp3)-H bond in the methyl group of N6-methyl deoxyadenosine and N6-methyl adenosine, epigenetic modifications of emerging importance. A carefully orchestrated reaction combines reduction of a nitropyridine to form a nitrosopyridine spin-trapping reagent and an exquisitely selective tertiary amine-mediated hydrogen-atom abstraction at the N6-methyl group to form an α-amino radical. Cross-coupling of the putative α-amino radical with nitrosopyridine leads to a stable conjugate, installing a label at N6-methyl-adenosine. We show that N6-methyl deoxyadenosine-containing oligonucleotides can be enriched from complex mixtures, paving the way for applications to identify this modification in genomic DNA and RNA.
- Nappi, Manuel,Hofer, Alexandre,Balasubramanian, Shankar,Gaunt, Matthew J.
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supporting information
p. 21484 - 21492
(2021/01/11)
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- GSK-3 INHIBITORS
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The disclosure generally relates to compounds of formula (I), including their salts, as well as compositions and methods of using the compounds to treat disorders associated with GSK-3.
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Page/Page column 84; 85
(2018/06/12)
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- Photocontrol over cooperative porphyrin self-assembly with phenylazopyridine ligands
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The cooperative self-assembly of chiral zinc porphyrins is regulated by a photoresponsive phenylazopyridine ligand (1; see picture). Porphyrin stacks depolymerize into dimers upon axial ligation and the strength of the coordination is regulated by its pho
- Hirose, Takashi,Helmich, Floris,Meijer
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supporting information
p. 304 - 309
(2013/02/23)
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- C-H arylation of pyridines: High regioselectivity as a consequence of the electronic character of C-H bonds and heteroarene ring
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We report a new catalytic protocol for highly selective C-H arylation of pyridines containing common and synthetically versatile electron-withdrawing substituents (NO2, CN, F and Cl). The new protocol expands the scope of catalytic azine functi
- Guo, Pengfei,Joo, Jung Min,Rakshit, Souvik,Sames, Dalibor
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supporting information; experimental part
p. 16338 - 16341
(2011/11/29)
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- Cross coupling strategies towards the synthesis of the streptonigrin CD moiety
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An efficient route to an appropriate model of the streptonigrin 4- phenylpyridine CD moiety is reported. 4-Chloro-3-nitropyridine was found to be the key precursor and its reactivity in cross coupling reactions was further investigated.
- Crous, Renier,Dwyer, Catherine,Holzapfel, Cedric W.
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p. 721 - 726
(2007/10/03)
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- The synthesis of β-nitropyridine compounds
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Pyridine and a number of substituted pyridines have been nitrated by reaction with N2O5 followed by reaction with an aqueous solution of SO2xH2O or NaHSO3. The dependence of the yields on the pH of the aqueous reaction medium, on the concentration of SO2xH2O-HSO3-, on addition of methanol to the aqueous phase, and on the reaction temperature were investigated. The yields obtained with NaHSO3 were: 3-nitropyridine 77%, 2-methyl-5-nitro-pyridine 36%, 3-methyl-5-nitropyridinc 24%, 3-acetyl-5-nitropyridine 18%, 5-nitropyridine-3-carboxylic acid 15%, 3-chloro-5-nitropyridine 11%, 4-methyl-3-nitropyridine 39%, 4-acetyl-3-nitropyridine 67%, 4-cyano-3-nitropyridine 45%, 4-phenyl-3-nitropyridine 68%, 4-formyl-3-nitropyridine 62% (from reaction in liquid SO2), 3-nitropyridine-4-carboxylic acid 48%, methyl 3-nitropyridine-4-carboxylate 75%, 2,3-dimethyl-5-nitropyridine 37%, 2,4-dimethyl-5-nitropyridine 64%, 3-nitroquinoline 10% and 4-nitroisoquinoline 42%.
- Bakke, Jan M.,Ranes, Eli,Riha, Jaroslav,Svensen, Harald
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p. 141 - 144
(2007/10/03)
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- Nitration of Aromatic and Heteroaromatic Compounds by Dinitrogen Pentaoxide
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Nitration of benzene and monosubstituted benzenes in liquid SO2 by dinitrogen pentaoxide at - 11 deg C gave the corresponding nitroarenes with substitution patterns similar to those obtained by nitrations with HNO3-H2SO4.For acetophenone an o/m ratio of 0.94 was obtained.The yields were dependent on the substituents.With a 1:1 ratio of arene: N2O5 the yields varied from 73percent for toluene to 0.4percent for nitrobenzene as substrates.From competition experiments and the nitration of bibenzyl it was concluded that the reaction was faster than the macroscopic rate of mixing.The qualitative order of reactivity for PhX was X = OCH3>CH3>H>Cl>CH3CO>NO2.Nitration with N2O5 in liquid CO2 gave similar results.Nitration of pyrimidine, pyrrole, imidazole and indole with N2O5-SO2 gave no nitrated products.With thiophene, 2- (34percent) and 3-nitrothiophene (5percent) together with 2,4-(16percent) and 2,5-dinitrothiophene (8percent) were obtained.With pyridine, mono- and di-methylpyridines, quinoline, isoquinoline and 4-phenylpyridine nitration of the pyridine ring was obtained.The yields varied from ca. 70percent to 16percent, except for 3,5-, 2,5- and 2,6-dimethylpyridine for which only traces of nitro-dimethylpyridines were obtained.The reaction with the pyridines appears to be intramolecular both in the SO2 phase and in the water phase used for quenching the reaction.The reaction was proposed to proceed by a complex formed in liquid SO2:
- Bakke, Jan M.,Hegbom, Ingrid,Oevreeide, Elin,Aaby, Kjersti
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p. 1001 - 1006
(2007/10/02)
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