- Synthetic applications of 2-aryl-4-piperidones. X. Synthesis of 3-aminopiperidines, potential substance P antagonists
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A general method is described for the synthesis of 3-aminopiperidines from 4-piperidones based on a KOEt treatment of the tosylate of the corresponding oximes (Neber rearrangement). The procedure is applied to the synthesis of N-benzyl-3-amino-4,4-diethoxypiperidine (13), (R)-N-(2-hydroxy-1-phenyl)ethyl analogues 18, and 2-phenyl derivatives 27-28. The methoxybenzylation of the primary amino group of these aminopiperidines leads to a series of potential substance P antagonists.
- Diez,Diez, Anna,Voldoire,Voldoire, Aline,Lopez,Lopez, Isabel,Rubiralta,Rubiralta, Mario,Segarra,Segarra, Victor,Pages,Pages, Lluis,Palacios,Palacios, Jose M.
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- Polymer-bound 4-benzylsulfonyl-1-triphenylphosphoranylidene-2-butanone as a tool for the solid-phase synthesis of substituted piperidin-4-one derivatives
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An efficient method for the construction of 2-substituted-piperidin-4- one derivatives on solid support has been developed using polymer-bound 4- benzylsulfonyl-1-triphenylphosphoranylidene-2-butanone as a convenient precursor for substituted divinyl ketones in the heterocyclization reaction with amines. The resin was released in a recyclable sulfinate form.
- Barco, Achille,Benetti, Simonetta,De Risi, Carmela,Marchetti, Paolo,Pollini, Gian P.,Zanirato, Vinicio
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- A two-step, formal [4 + 2] approach toward piperidin-4-ones via au catalysis
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(Chemical Equation Presented) An efficient, formal [4 + 2] synthesis of synthetically valuable piperidin-4-ones from secondary amines in two steps has been achieved via a key gold catalysis without the purification of tertiary amine intermediates. This reaction is selective toward the less-substituted alkyl group and shows moderate to excellent diastereoselectivities. Its synthetic potential in alkaloid synthesis is demonstratedin a highly diastereoselective synthesis of (±)-cermizine C.
- Cui, Li,Peng, Yu,Zhang, Liming
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supporting information; experimental part
p. 8394 - 8395
(2009/10/23)
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- Improved heteroatom nucleophilic addition to electron-poor alkenes promoted by CeCl3·7H2O/NaI system supported on alumina in solvent-free conditions
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(Chemical Equation Presented). Conjugate addition of heteroatom nucleophiles to carbon-carbon double bonds conjugated with a strong electron-withdrawing group is one of the most important new bond-forming strategies in synthetic organic chemistry. Among the methods for these Michael additions, Lewis acids have shown the best promoter activity, and in particular, the use of reagents impregnated over inorganic supports is rapidly increased. With the increase of environmental consciousness in chemical research, the solvent-free Michael addition has attracted our attention. In continuation of our ongoing program to develop synthetic protocols utilizing cerium trichloride, we report an extension of the CeCl3·7H2O/NaI combination supported under solvent-free conditions to promote heteroatom Michael addition. Using neutral alumina (Al2O3) as solid support permits us to circumvent some of the problems associated with the procedure where the inorganic support is silica gel. The CeCl 3· 7H2O/NaI/Al2O3 system works well for hetero-Michael additions utilizing weakly nucleophiles such as imidazoles and carbamates, and also the reaction proceeds with good yields in the case of Michael acceptors different from α,β-unsaturated carbonyl compounds. An important synthetic application of this our methodology is the intramolecular aza-Michael reaction in producing 4-piperidinone derivatives, which are of interest as synthetic intermediates toward important classes of heterocycles.
- Bartoli, Giuseppe,Bartolacci, Massimo,Giuliani, Arianna,Marcantoni, Enrico,Massaccesi, Massimo,Torregiani, Elisabetta
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p. 169 - 174
(2007/10/03)
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- Combinatorial synthesis of dihydropyridone libraries and their derivatives
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Polymer-supported quench methodology has been used for parallel purification of combinatorial libraries of dihydropyridones and their derivatives. The dihydropyridone scaffold was assembled via a solution phase Lewis acid catalyzed, hetero-Diels-Alder reaction. Further modifications allow for the rapid generation of subsequent aminopiperidine and acylaminopiperidine libraries utilizing a library from library approach.
- Creswell, Mark W.,Bolton, Gary L.,Hodges, John C.,Meppen, Malte
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p. 3983 - 3998
(2007/10/03)
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