- Development, Scope, and Applications of Titanium(III)-Catalyzed Cyclizations to Aminated N-Heterocycles
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The exceptionally mild conditions of a titanium(III)-catalyzed cyclization reaction paired with a convenient acid/base extraction have enabled the straightforward synthesis, isolation, and direct N-functionalization of amino heterocycles such as 3-aminoindoles and -pyrroles. The unprotected heterocycles are ideal building blocks for the installation of aminated indoles and pyrroles into target molecules, but their sensitivity has previously impeded their synthesis by modern catalytic methods. This full paper presents the development and extended scope of the new cyclization methodology. The transformation of the products into fused bis-indoles is also demonstrated along with the discovery of an unusual palladium-catalyzed reductive biphenyl coupling reaction. The titanium(III)-catalyzed cyclization has also been applied to the synthesis of substituted 3-iminoindolines, which are of potential interest for applications in natural product synthesis and exhibit tunable blue-to-green fluorescence properties.
- Leijendekker, Leonardus H.,Weweler, Jens,Leuther, Tobias M.,Kratzert, Daniel,Streuff, Jan
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p. 3382 - 3390
(2019/02/14)
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- Synthesis and monoamine transporter binding properties of 2,3-cyclo analogues of 3β-(4′-aminophenyl)-2β-tropanemethanol
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A series of cyclo-3β-(4-aminophenyl)-2β-tropanemethanol analogues (5a-m) possessing varying linker groups between the 2- and 3-position on the tropane ring were synthesized and evaluated for their monoamine transporter binding properties. The results show that binding to the dopamine and serotonin transporters (DAT and 5-HTT) is highly dependent on the specific linker used. Cyclo-3β-(4-aminophenyl)-2β-tropanemethanol pimelic acid ester/amide (5b) had an IC50 of 3.8 nM at the DAT. Cyclo-3β-(4-aminophenyl)- 2β-tropanemethanol sebacic acid ester/amide (5e) had a Ki of 1.9 nM at the 5-HTT and was 68- and 737-fold selective for the 5-HTT relative to the DAT and NET. Small changes to the size as well as the electrostatic and hydrophobic properties of the 2,3-linker in 5b or 5e led to much less potent analogues at all three transporters. These results suggest that the high affinity for 5b and 5e at the DAT and 5-HTT may be due to their specific conformational properties.
- Carroll, F. Ivy,Blough, Bruce E.,Huang, Xiaodong,Nie, Zhe,Mascarella, S. Wayne,Deschamps, Jeffrey,Navarro, Hernán A.
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p. 4589 - 4594
(2007/10/03)
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- Polynuclear branched tetrazole systems. 2*. New 2-(5-tetrazolyl) ethyl podands and their NH-acidity
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Nine new polynuclear 2-(5-tetrazolyl)ethyl podands have been obtained by the azidation of the corresponding nitriles. Using Bjerrum distribution functions, the values of pKa1, pKa 2, pKa3, and pKa4 have been determined by a potentiometric method for 14 polynuclear tetrazoles in aqueous and aqueous methanolic solution. The found values lie in the range from 3.5 to 7.5 pH units. The overall rules and the sequence of the ionization of the spatially separated tetrazole fragments in these podand systems are discussed.
- Zubarev,Bezklubnaya,Pyartman,Trifonov,Ostrovskii
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p. 1317 - 1325
(2007/10/03)
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- UTILISATION DE MEMBRANES ECHANGEUSES D'IONS EN ELECTROSYNTHESE ORGANIQUE.
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The addition of carbon acids to acrylonitrile or methyl acrylate can be initiated by means of bases electrogenerated in aprotic media in the absence of supporting-electrolyte, at the interface between a porous cathode and a solid polymer electrolyte.The consumption of electricity is below 1E-2 faraday per mole.Putting to the test donors with decreasing acidity (2-nitropropane, malononitrile, diethyl malonate, ethyl cyanacetate, 2-methylcyclohexanone, fluorene) allows to estimate the basicity level that can be reached at such an interface.The influence of differentfactors (such as the nature of the ion exchange membrane, the basicity of the second side of the membrane, the presence of a probase) on the rates and yields of the reactions has been investigated.
- Raoult, Eugene,Sarrazin, Jean,Tallec, Andre
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p. 5299 - 5306
(2007/10/02)
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