- Asymmetric Dearomative Cascade Multiple Functionalizations of Activated N-Alkylpyridinium and N-Alkylquinolinium Salts
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An enantioselective cascade reaction of N-alkylpyridinium and -quinolinium salts with o-hydroxybenzylideneacetones to access fused polyheterocycles through cross dienamine-mediated addition followed by trapping of the dearomatized enamine-type intermediates and aminal formation has been developed. A cascade assembly of N-benzyl-4-methylpyridinium salt and cyclic 2,4-dienones is further disclosed to give bridged frameworks via repetitive dearomatization and aromatization activation.
- Chen, Ying-Chun,Du, Wei,Song, Xue,Yan, Ru-Jie
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supporting information
p. 7617 - 7621
(2020/10/09)
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- Straightforward Regeneration of Reduced Flavin Adenine Dinucleotide Required for Enzymatic Tryptophan Halogenation
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Flavin-dependent halogenases are known to regioselectively introduce halide substituents into aromatic moieties, for example, the indole ring of tryptophan. The process requires halide salts and oxygen instead of molecular halogen in the chemical halogena
- Ismail, Mohamed,Schroeder, Lea,Frese, Marcel,Kottke, Tilman,Hollmann, Frank,Paul, Caroline E.,Sewald, Norbert
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p. 1389 - 1395
(2019/02/10)
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- Nucleophilic Dearomatization of Pyridines under Enamine Catalysis: Regio-, Diastereo-, and Enantioselective Addition of Aldehydes to Activated N-Alkylpyridinium Salts
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Catalytic addition of chiral enamines to azinium salts is a powerful tool for the synthesis of enantioenriched heterocycles. An unprecedented asymmetric dearomative addition of aldehydes to activated N-alkylpyridinium salts is presented. The process exhibits complete C-4 regioselectivity along with high levels of diastereo- and enantiocontrol, achieving a high-yielding synthesis of a broad range of optically active 1,4-dihydropyridines. Moreover, the presented methodology enables the synthesis of functionalized octahydropyrrolo[2,3-c]pyridines, the core structure of anticancer peptidomimetics.
- Bertuzzi, Giulio,Sinisi, Alessandro,Pecorari, Daniel,Caruana, Lorenzo,Mazzanti, Andrea,Bernardi, Luca,Fochi, Mariafrancesca
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supporting information
p. 834 - 837
(2017/02/26)
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- Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts
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The cyclization of cyclohexane-1,3-diones with various substituted pyridinium salts afforded functionalized 8-oxa-10-aza-tricyclo[7.3.1.0 2,7]trideca-2(7),11-dienes. The reaction proceeds by regioselective attack of the central carbon atom of t
- Kiamehr, Mostafa,Moghaddam, Firouz Matloubi,Mkrtchyan, Satenik,Semeniuchenko, Volodymyr,Supe, Linda,Villinger, Alexander,Langer, Peter,Laroshenko, Viktor O.
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supporting information
p. 1119 - 1126
(2013/07/19)
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- Pyridinium salts - Versatile reagents for the regioselective synthesis of functionalized thiazocino[2,3-b]indoles by tandem dinucleophilic reactions of thiooxindoles
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The reaction of thiooxindoles with various 2- and 3-substituted pyridinium salts afforded a variety of functionalized thiazocinoindoles. The products have been prepared in good to excellent yields by regioselective dinucleophilic C/S-cyclocondensation of
- Kiamehr, Mostafa,Gormay, Pavel V.,Villinger, Alexander,Langer, Peter,Iaroshenko, Viktor O.,Moghaddam, Firouz Matloubi,Semeniuchenko, Volodymyr
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supporting information
p. 9685 - 9693,9
(2020/08/20)
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- Structure Sensitivity of the Marcus λ for Hydride Transfer between NAD+ Analogues
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Thirty-five rate constants, kij, for transfer of hydride between various pyridinium, quinilinium, acridinium, and phenantridinium ions spanning a range of over 10E11 in their equilibrium constants Kij and over 10E6 in kij
- Kreevoy, Maurice M.,Ostovic, Drazen,Lee, In-Sook Han,Binder, David A.,King, Gary W.
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p. 524 - 530
(2007/10/02)
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- Marcus Theory of Hydride Transfer from an Anionic reduced Deazaflavin to NAD+ Analogues
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Eighteen rate constants, kij for hydride transfer from the conjugate base of 1,5-dihydro-3,10-dimethyl-5-diazaisoalloxazine to a variety of pyridinium, quinolinium, phenanthridinium, and acridinium ions have been determined. (All the oxidizing agents can be regarded as analogues of NAD+.) The kij values span 7 powers of 10 and the corresponding equilibrium constants, Kij, span more than 13 powers of 10.For reactions with ΔG0 near zero, the kij values are close to those given by modified Marcus theory (ref 10).However, with more negative ΔG0 values, the observed kij increase more strogly than the calculated values.Agreement can be produced by making the standard free energy of precursor complex formation, symbolized WT +- here, to indicate that it applies to reactants of opposite charge, a linear function of ΔG0, and treating the slope and interrcept of the linear relation as adjustable parameters.The best fit is obtained with WT+-(in kJ*mol-1)=-9.4+0.11ΔG0.An avarage discrepancy between calculated and observed ln kij values of 0.5 is achieved, which is a good as the overall fit achieved for hydride transfer from neutral NADH analogues to NAD+ analogues (ref 10).The form and the parameterization of Wf are shown to be a physically reasonable approximation for reactions with ΔG00.These results strengthen the conclusion (ref 10) that a wide range of hydride transfer rates can be quantitavely understood without introducing high-energy metastable intermediates (radicals and radical ions).
- Lee, In-Sook Han,Ostovic, Drazen,Kreevoy, Maurice
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p. 3989 - 3993
(2007/10/02)
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- Kinetics of the reduction of nicotinonitrile cations by 1,4-dihydronicotinamides
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The rates of reduction of a series of 1-(Z-benzyl)nicotinonitrile cations by a series of 1-(X-benzyl)-1,4-dihydronicotinamides have been studied at 25 deg C in 20percent CH3CN - 80percent H2O (pH 7.0 (5 mM phosphate), ionic strength 1.0 (KCl)).Spectral st
- Bunting, John W.,Brewer, John C.
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p. 1245 - 1249
(2007/10/02)
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- MUTUAL EFFECTS OF THE STRUCTURE IN THE REACTIONS OF BENZYL BROMIDES WITH PYRIDINES
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The rate of the reactions of benzyl bromides with pyridines in nitrobenzene at 40 deg C was measured.The nonadditivity of the joint action of the electronic effects of substituents in the molecules of the reagents on the reactivity of the benzyl bromide-p
- Shpan'ko, I. V.,Korostylev, A. P.,Shved, E. N.,Litvinenko, L. M.
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p. 1562 - 1565
(2007/10/02)
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