- Regioselective Three-Component Reaction of Pyridine N-Oxides, Acyl Chlorides, and Cyclic Ethers
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A novel three-component reaction of pyridine N-oxides, acyl chlorides, and cyclic ethers is described. Treatment of an electron-deficient pyridine N-oxide with an acyl chloride in the presence of a cyclic ether at 25-50 °C leads to a substituted pyridine as a single regioisomer in up to 58% isolated yield. Isotopic-labeling experiments and substrate scope support the reaction proceeding through a carbene intermediate.
- Jones, D. Heulyn,Kay, Steven T.,McLellan, Jayde A.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
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supporting information
p. 3512 - 3515
(2017/07/17)
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- Catalyst-free and selective oxidation of pyridine derivatives and tertiary amines to corresponding N-oxides with 1,2-diphenyl-1,1,2,2-tetrahydroperoxyethane
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The catalyst-free oxidation of various pyridine derivatives and tertiary amines to their corresponding N-oxides with 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane as an efficient oxidant has been developed. The methodology proved to tolerate a number of functional groups. The reactions proceeded smoothly under solvent-free and mild conditions at room temperature. All the products were easily extracted from the reaction mixtures in excellent yields. Graphical abstract: The catalyst-free oxidation of various pyridine derivatives and tertiary amines to their corresponding N-oxides with 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane as an efficient oxidant has been developed. The methodology proved to tolerate a number of functional groups. The reactions proceeded smoothly under solvent-free and mild conditions at room temperature. All the products were easily extracted from the reaction mixtures in excellent yields.
- Azarifar, Davood,Mahmoudi, Boshra
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p. 645 - 651
(2016/02/19)
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- Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine: N -oxides
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A novel solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes easily accessible or commercially available pyridine N-oxides (PyO) and dialkylcyanamides. The observed C-H functionalization of PyO is suitable for the good-to-high yielding synthesis of a wide range of pyridine-2-yl substituted ureas featuring electron donating and electron withdrawing, sensitive, or even fugitive functional groups at any position of the pyridine ring (63-92%; 19 examples). In the cases of 3-substituted PyO, the C-H functionalization occurs regioselectively providing a route for facile generation of ureas bearing a 5-substituted pyridine-2-yl moiety.
- Rassadin, Valentin A.,Zimin, Dmitry P.,Raskil'dina, Gulnara Z.,Ivanov, Alexander Yu.,Boyarskiy, Vadim P.,Zlotskii, Semen S.,Kukushkin, Vadim Yu.
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supporting information
p. 6630 - 6636
(2018/03/01)
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- Base free regioselective synthesis of α-triazolylazine derivatives
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A regioselective α-heteroarylation followed by deoxygenation towards the synthesis of variety of azine triazole from simple azine N-oxides derivatives and N-tosyl-1,2,3-triazoles has been described. The reaction is metal free and base free with shorter reaction time, high yields and a broad substrate scope.
- Harisha, Mysore Bhyrappa,Nagaraj, Muthupandi,Muthusubramanian, Shanmugam,Bhuvanesh, Nattamai
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p. 58118 - 58124
(2016/07/06)
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- PYRIDINE COMPOUNDS AND THE USES THEREOF
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The invention relates to substituted pyridine compounds of Formula (I) and the pharmaceutically acceptable salts, prodrugs, and solvates thereof, wherein R1a, A1, A2, E, G, Z1, and Z2 are defined as set forth in the specification. The invention is also directed to the use of compounds of Formula I to treat a disorder responsive to the blockade of sodium channels. Compounds of the present invention are especially useful for treating pain.
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Page/Page column 204-205
(2012/04/04)
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- Synthesis of unsymmetrically substituted bipyridines by palladium-catalyzed direct C-H arylation of pyridine N -oxides
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Chemical equations presented. Substituted bipyridines were efficiently prepared by direct coupling between pyridine N-oxides and halopyridines using a palladium catalyst. Pyridine N-oxides with electron-withdrawing substitutents gave the best yields. This method allows the convenient preparation of 2,2′-, 2,3′-, and 2,4′-bipyridines which are useful as functionalized ligands for metal complexes or as building blocks for supramolecular architectures.
- Duric, Sasa,Tzschucke, C. Christoph
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supporting information; experimental part
p. 2310 - 2313
(2011/06/28)
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- Ruthenium catalyzed oxidation of tertiary nitrogen compounds with molecular oxygen: An easy access to N-oxides under mild conditions
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A variety of tertiary nitrogen compounds have been efficiently oxidized to their corresponding N-oxides in excellent yields with molecular oxygen as a sole oxidant and ruthenium trichloride as catalyst.
- Jain, Suman L.,Sain, Bir
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p. 1040 - 1041
(2007/10/03)
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- Oxidation of tertiary nitrogen compounds to N-oxides by molecular oxygen-aldehyde system in the absence of metal catalyst
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A variety of tertiary nitrogen compounds have been oxidized to corresponding N-oxides in near quantitative yields by molecular oxygen/2-methylpropanal system in the absence of metal catalyst.
- Dongre,Venkateshwar Rao,Sharma,Sain,Bhatia
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p. 167 - 172
(2007/10/03)
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- An efficient synthesis of heterocyclic N-oxides over molecular sieve catalyst
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Heterocyclic N-oxides have been synthesized in very high yields over redox molecular sieve catalysts in the presence of H2O2.
- Prasad, M. Ramakrishna,Kamalakar, G.,Madhavi, G.,Kulkarni, S. J.,Raghavan, K. V.
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p. 1577 - 1578
(2007/10/03)
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- Tertiary amine oxidation using HOF-CH3CN: A novel synthesis of N-oxides
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HOF·CH3CN, probably the best oxygen transfer agent organic chemistry has to offer, is easily made by bubbling diluted fluorine (10-15%) through aqueous acetonitrile solution. Used as formed without any isolation or purification, it reacts with various tertiary amines such as pyridine derivatives, polyaromatic nitrogen containing compounds and aliphatic and alicyclic ones to form the corresponding N-oxides. When two nitrogen atoms are present it is possible to make both the N-monoxides and the N,N-dioxides. The reaction times are short (a few minutes), conditions are very mild (0-25 °C) and the yields range from good to excellent (70-95%).
- Dayan, Sharon,Moshe, Kol,Rozen, Shlomo
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p. 1427 - 1430
(2007/10/03)
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- A simple and efficient method for the preparation of pyridine-N-oxides II
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Oxidation of pyridines with bis(trimethylsilyl)peroxide in the presence of catalytic amounts of inorganic rhenium derivatives gives high yields of their analytically pure N-oxides by simple work-ups, typically a filtration or a Kugelrohr distillation.
- Coperet, Christophe,Adolfsson, Hans,Chiang, Jay P.,Yudin, Andrei K.,Sharpless, K. Barry
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p. 761 - 764
(2007/10/03)
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- ELUCIDATION OF THE REACTION PATH FOR THE NITROSATION OF 2- AND 4-METHYLPYRIDINE 1-OXIDES WITH ALKYL NITRITE IN LIQUID AMMONIA
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The reaction path for the nitrosation of 2- and 4-methylpyridine 1-oxides with alkyl nitrite in the presence of NaNH2 in liquid NH3 was elucidated experimentally, and theoretically by the use of a semiempirical molecular orbital method (PM3 method).In the case of the nitrosation of 4-methylpyridine 1-oxide at room temperature, only 4-pyridinecarboxamide 1-oxide was obtained, while at -33 deg C a thermodynamically unstable aldoxime, (Z)-4-pyridinecarbaldehyde 1-oxide oxime, which was easily transformed into E-form by heating, was obtained.On the other hand, the nitrosation of 2-methylpyridine 1-oxide gave only a thermodynamically stable aldoxime, (E)-2-pyridinecarbaldehyde 1-oxide oxime, both at room temperature and at -33 deg C.These results were reasonably explained by PM3 method.
- Tagawa, Yoshinobu,Togashi, Hideo,Goto, Yoshinobu
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p. 327 - 336
(2007/10/02)
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