- Henry-Nef reaction: A practical and versatile chiral pool route to 2-substituted pyrrolidine and piperidine alkaloids
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The paper describes the synergistic protocol developed by combinatorial Henry and Nef reaction for the synthesis of 2-substituted pyrrolidine and piperidine alkaloids containing 1,3-aminoketone and 1,3-amino alcohol units. The utility of the protocol is demonstrated by asymmetric synthesis of 12 natural products of which asymmetric synthesis of (-)-N-methylpelletierine is presented for the first time. The one-carbon homologation described also provides an alternate route for the synthesis of key intermediates homoprolinol and homopipecolinol used as synthetic precursors for several alkaloids and construction of β-amino acids from α-amino acids.
- Bhat, Chinmay,Tilve, Santosh G.
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p. 6129 - 6143
(2013/07/27)
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- Non-nucleoside inhibitors of the measles virus RNA-dependent RNA polymerase: Synthesis, structure-activity relationships, and pharmacokinetics
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The measles virus (MeV), a member of the paramyxovirus family, is an important cause of pediatric morbidity and mortality worldwide. In an effort to provide therapeutic treatments for improved measles management, we previously identified a small, non-nucl
- Ndungu, J. Maina,Krumm, Stefanie A.,Yan, Dan,Arrendale, Richard F.,Reddy, G. Prabhakar,Evers, Taylor,Howard, Randy,Natchus, Michael G.,Saindane, Manohar T.,Liotta, Dennis C.,Plemper, Richard K.,Snyder, James P.,Sun, Aiming
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supporting information; experimental part
p. 4220 - 4230
(2012/06/30)
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- Enantioselective Synthesis of (+)-α-Conhydrine and (-)-Sedamine by L-ProlineCatalysed α-Aminooxylation
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An efficient organocatalytic approach to the enantioslective synthesis of two important piperidine alkaloids, namely (+)α-conhydrine (98% ee) and (-)-sedamine (95 % ee), by L-pro-line-catalysed α-aminooxylation of aldehydes has been developed. The strategy involves an intramolecular cyclization to construct the piperidine core.
- Shaikh, Tanveer Mahamadali,Sudalai, Arumugam
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experimental part
p. 3437 - 3444
(2010/08/20)
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- Improved protocol for asymmetric, intramolecular heteroatom Michael addition using organocatalysis: Enantioselective syntheses of homoproline, pelletierine, and homopipecolic acid
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(Chemical Equation Presented) An improved protocol for the construction of enantioenriched pyrrolidine, indoline, and piperidine rings using an organocatalyzed, intramolecular heteroatom Michael addition is described. Application to the enantioselective synthesis of homoproline, homopipecolic acid, and pelletierine has been accomplished.
- Carlson, Erik C.,Rathbone, Lauren K.,Yang, Hua,Collett, Nathan D.,Carter, Rich G.
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p. 5155 - 5158
(2008/09/21)
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- Enantioselective organocatalytic intramolecular aza-Michael reaction: A concise synthesis of (+)-sedamine, (+)-allosedamine, and (+)-coniine
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(Chemical Equation Presented) The intramolecular aza-Michael reaction of carbamates bearing remote α,β-unsaturated aldehydes under organocatalytic conditions took place with good yields and excellent ee's when Jorgensen catalyst IV was used in the process, giving rise to the enantioselective formation of several five- and six-membered heterocycles. The developed methodology was applied to the synthesis of three piperidine alkaloids.
- Fustero, Santos,Jimenez, Diego,Moscardo, Javier,Catalan, Silvia,Del Pozo, Carlos
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p. 5283 - 5286
(2008/09/18)
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- Design of selective thrombin inhibitors based on the (R)-Phe-Pro-Arg sequence
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Potent and selective inhibitors of thrombin were sought based on the (R)-Phe-Pro-Arg sequence. The objective was to generate similar binding interactions to those achieved by potent competitive inhibitors of the argatroban type, so eliminating the need for covalent interaction with the catalytic serine function, as utilized by aldehyde and boronic acid type inhibitors. Improving the S1 subsite interaction by substitution of arginine with a 4-alkoxybenzamidine residue provided potent lead 2 (Ki = 0.37 nM). Though an amide bond, which H-bonds to the active site, is lost, modeling indicated that a new H-bond is generated between the alkoxy oxygen atom and the catalytic Ser-195 hydroxyl group. Substitution of the benzamidine system by 1-amidinopiperidine then gave compound 4, which provided a further gain in selectivity over trypsin. However, previous work had shown that these compounds were likely to be too lipophilic (Log D +0.4 and +0.2, respectively) and to suffer rapid hepatic extraction, presumably via biliary elimination. Accordingly, both proved short-acting when administered intravenously to rats and showed poor activity when given intraduodenally. The aim was then to reduce lipophilicity below a log D of - 1.2, which in a previously reported series had been effective in preventing rapid clearance. It was anticipated that compounds of this type would rely on the cation selective paracellular route of absorption from the gastrointestinal tract. Potent polar analogues with selectivity >1000 over trypsin were obtained. The best in vivo activity was shown by compound 12. However, in the final analysis, its oral bioavilability proved poor, relative to analogues with similar physicochemical properties derived from argatroban, consistent with the hypothesis that molecular shape is an additional important determinant of paracellular absorption.
- Danilewicz, John C.,Abel, Stuart M.,Brown, Alan D.,Fish, Paul V.,Hawkeswood, Edward,Holland, Stephen J.,James, Keith,McElroy, Andrew B.,Overington, John,Powling, Michael J.,Rance, David J.
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p. 2432 - 2453
(2007/10/03)
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