- CO2-Assisted asymmetric hydrogenation of prochiral allylamines
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A new methodology for the asymmetric hydrogenation of allylamines takes advantage of a reversible reaction between amines and carbon dioxide (CO2) to suppress unwanted side reactions. The effects of various parameters (pressure, time, solvent, and base additives) on the enantioselectivity and conversion of the reaction were studied. The homogeneously-catalyzed asymmetric hydrogenation of 2-arylprop- 2-en-1-amine resulted in complete conversion and up to 82% enantiomeric excess (ee). Added base, if chosen carefully, improves the enantioselectivity and chemoselectivity of the overall reaction.
- Alridge, Christopher J.,De Winter, Tamara M.,Ho, Jaddie,Jessop, Philip G.
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p. 6755 - 6761
(2022/03/31)
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- Iron-Catalyzed Diastereoselective Synthesis of Disubstituted Morpholines via C-O or C-N Bond Formation
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The diastereoselective synthesis of 2,6- and 3,5-disubstituted morpholines was achieved from 1,2-amino ethers and 1,2-hydroxy amines substituted by an allylic alcohol using an iron(III) catalyst. The morpholines were obtained either by C-O or C-N bond formation. A plausible mechanism is suggested, involving a thermodynamic equilibrium to explain the formation of the cis diastereoisomer as the major product.
- Aubineau, Thomas,Dupas, Alexandre,Zeng, Tian,Cossy, Janine
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supporting information
p. 525 - 531
(2020/08/28)
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- Enantioselective Synthesis of β-Methyl Amines via Iridium-Catalyzed Asymmetric Hydrogenation of N-Sulfonyl Allyl Amines
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The iridium-catalyzed asymmetric hydrogenation of several N-sulfonyl allyl amines is reported. All substrates can be easily obtained by the Ir-catalyzed isomerization of N-tosylaziridines reported previously. The commercially available threonine-derived phosphinite (UbaPHOX) iridium complex has been found to be the best catalyst for this catalytic application, affording β-methyl amines with good to excellent ee values (up to 94%). The synthetic potential of this novel methodology was demonstrated by the formal synthesis of Lorcaserin and LY-404187. (Figure presented.).
- Cabré, Albert,Verdaguer, Xavier,Riera, Antoni
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p. 4196 - 4200
(2019/08/16)
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- Rhodium-catalyzed asymmetric hydrogenation of β-branched enamides for the synthesis of β-stereogenic amines
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Using a rhodium complex of a bisphosphine ligand (R)-SDP, β-branched simple enamides with a (Z)-configuration were hydrogenated to β-stereogenic amines in quantitative yields and with excellent enantioselectivities (88-96% ee).
- Zhang, Jian,Liu, Chong,Wang, Xingguang,Chen, Jianzhong,Zhang, Zhenfeng,Zhang, Wanbin
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supporting information
p. 6024 - 6027
(2018/06/18)
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- Biocatalytic Formal Anti-Markovnikov Hydroamination and Hydration of Aryl Alkenes
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Biocatalytic anti-Markovnikov alkene hydroamination and hydration were achieved based on two concepts involving enzyme cascades: epoxidation-isomerization-amination for hydroamination and epoxidation-isomerization-reduction for hydration. An Escherichia coli strain coexpressing styrene monooxygenase (SMO), styrene oxide isomerase (SOI), ω-transaminase (CvTA), and alanine dehydrogenase (AlaDH) catalyzed the hydroamination of 12 aryl alkenes to give the corresponding valuable terminal amines in high conversion (many ≥86%) and exclusive anti-Markovnikov selectivity (>99:1). Another E. coli strain coexpressing SMO, SOI, and phenylacetaldehyde reductase (PAR) catalyzed the hydration of 12 aryl alkenes to the corresponding useful terminal alcohols in high conversion (many ≥80%) and very high anti-Markovnikov selectivity (>99:1). Importantly, SOI was discovered for stereoselective isomerization of a chiral epoxide to a chiral aldehyde, providing some insights on enzymatic epoxide rearrangement. Harnessing this stereoselective rearrangement, highly enantioselective anti-Markovnikov hydroamination and hydration were demonstrated to convert α-methylstyrene to the corresponding (S)-amine and (S)-alcohol in 84-81% conversion with 97-92% ee, respectively. The biocatalytic anti-Markovnikov hydroamination and hydration of alkenes, utilizing cheap and nontoxic chemicals (O2, NH3, and glucose) and cells, provide an environmentally friendly, highly selective, and high-yielding synthesis of terminal amines and alcohols.
- Wu, Shuke,Liu, Ji,Li, Zhi
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p. 5225 - 5233
(2017/08/17)
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- Enantioselective Hydroaminomethylation of Olefins Enabled by Rh/Br?nsted Acid Relay Catalysis
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Herein, by employing a rhodium catalyst with a commercial ligand and a phosphoric acid catalyst, highly chemo-, regio-, and enantioselective hydroaminomethylation of olefins is realized through a relay catalytic hydroformylation/dynamic kinetic reductive amination process. The method features mild conditions (1 bar of syngas, room temperature in most cases), high yields (up to 99%), and high enantioselectivities (up to >99.5:0.5 er). Besides styrenes, acrylamides also provided the products with high yields and enantioselectivities. Aliphatic alkenes and vinyl esters are also applicable for the current method, albeit lower yields and enantioselectivities were obtained.
- Meng, Jing,Li, Xing-Han,Han, Zhi-Yong
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supporting information
p. 1076 - 1079
(2017/03/15)
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- Dynamic kinetic resolution of 2-phenylpropanal derivatives to yield β-chiral primary amines via bioamination
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The amination of racemic α-chiral aldehydes, 2-phenylpropanal derivatives, was investigated employing ω-transaminases. By medium and substrate engineering the optical purity of the resulting β-chiral chiral amine could be enhanced to reach optical purities up to 99% ee. Using enantiocomplementary ω-transaminases allowed us to access the (R)- as well as the (S)-enantiomer in most cases. It is important to note that the stereopreference of the ω-transaminases found for α-chiral aldehydes did not correlate with the stereopreference previously observed for the amination of methyl ketones. In one case the stereopreference switched even upon exchanging a methyl substituent to a methoxy group.
- Fuchs, Christine S.,Hollauf, Manuel,Meissner, Maximilian,Simon, Robert C.,Besset, Tatiana,Reek, Joost N. H.,Riethorst, Waander,Zepeck, Ferdinand,Kroutil, Wolfgang
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p. 2257 - 2265
(2014/07/21)
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- Resolution of (±)-β-methylphenylethylamine by a novel chiral stationary phase for Pirkle-type column chromatography
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In this study, a new Pirkle-type chiral column stationary phase for resolution of β-methylphenylethyl amine was described by using activated Sepharose 4B as a matrix, L-tyrosine as a spacer arm, and an aromatic amine derivative of L-glutamic acid as a ligand. The binding capacities of the stationary phase were determined at different pH values (pH = 6, 7, and 8) using buffer solutions as mobile phase, and enantiomeric excess (ee) was determined by HPLC equipped with chiral column. The ee was found to be 47%.
- Yilmaz, Hayrullah,Topal, Giray,Cakmak, Resit,Hosgoren, Halil
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experimental part
p. 252 - 257
(2010/12/18)
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- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
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Page/Page column 45-49; 62
(2010/12/31)
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- AMPA RECEPTOR POTENTIATORS
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The present invention relates to a compound of Formula (I) or a pharmaceutically acceptable salt thereof which is useful for the treatment of conditions associated with glutamate hypofunction, such as psychiatric and neurological disorders.
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Page/Page column 7-8
(2008/12/06)
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- Lipase-catalyzed enantioselective reaction of amines with carboxylic acids under reduced pressure in non-solvent system and in ionic liquids
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Lipase-catalyzed enantioselective acylation of 1-phenylethylamine and 2-phenyl-1-propylamine was performed by reacting the amines with carboxylic acids in a non-solvent system or in ionic liquids as reaction media. The reaction equilibrium was shifted toward amide synthesis by the removal of formed water under reduced pressure.
- Irimescu, Roxana,Kato, Katsuya
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p. 523 - 525
(2007/10/03)
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- Heterocyclic sulfonamide derivatives
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The present invention provides certain heterocyclic sulfonamide derivatives of formula (I): useful for potentiating glutamate receptor function in a patient and therefore, useful for treating a wide variety of conditions, such as psychiatric and neurological disorders.
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- Sulfonamide derivatives
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The present invention relates to a compound of formula (I) or a pharmaceutically acceptable salt thereof which is useful for the treatment of conditions associated with glutamate hypofunction, such as psychiatric and neurological disorders.
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- Combination therapy for treatment of depression
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The present invention provides a method for treating depression, comprising administering to a patient an effective amount of a first component which is a suitable antidepressant, in combination with an effective amount of a second component which is a suitable AMPA receptor potentiator.
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- Sulfonamide derivatives
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The present invention relates to a compound of formula (Ia) or a pharmaceutically acceptable salt thereof which is useful for the treatment of conditions associated with glutamate hypofunction, such as psychiatric and neurological disorders. 1
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- Catalytic Enantioselective Conjugate Reduction of β,β -Disubstituted Nitroalkenes
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Efficient addition: Bisphosphane-CuI complexes catalyze the enantioselective reduction of β,β-disubstituted nitroalkenes, giving chiral β,β-disubstituted nitroalkanes in useful yields and selectivities (see scheme). The reaction can be carried out with as little as 0.1 mol % of complex, rendering the process among one of the more efficient methods for conjugate addition chemistry.
- Czekelius, Constantin,Carreira, Erick M.
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p. 4793 - 4795
(2007/10/03)
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- The stereoselectivity of inhibition of rat liver mitochondrial MAO-A and MAO-B by the enantiomers of 2-phenylpropylamine and their derivatives
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As part of a study of the stereoselectivity of inhibition of the different forms of monoamine oxidase (MAO-A and MAO-B), the enantiomers of 2- phenylpropylamine, N-methyl-2-phenylpropylamine and N-methyl-N-propargyl-2- phenylpropylamine have been prepared. The K(i) values for each enantiomer when competitively inhibiting both MAO-A and MAO-B are reported. The enantiomers of N-methyl-N-propargyl-2-phenylpropylamine were also evaluated as irreversible inhibitors (first order rate constant [k2] for formation of the covalent adduct). These compounds represent a series of enantiomers in which asymmetry is due to the presence of a hydrophobic (-CH3) substituent at the carbon atom β to the amino function. The results are discussed in comparison to previous studies of similar enantiomeric compounds in which the asymmetry was present at the carbon atom α to the amino function.
- Bocchinfuso, Ronald,Robinson, J. Barry
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p. 293 - 300
(2007/10/03)
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- Enantioselective synthesis of β-substituted primary and secondary amines by alkylation of (R)-phenylglycinol amide enolates
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General and convenient syntheses of optically active β-substituted secondary or primary amines 4 and 8 are described. The method is based on diastereoselective alkylation of amides 1 and 5 derived from R-(-)-phenylglycinol followed by reduction and removal of the chiral appendage. This procedure has also been applied to the preparation of 1,4-amino alcohols 12 and γ-amino esters 14.
- Jullian, Valérie,Quirion, Jean-Charles,Husson, Henri-Philippe
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p. 1091 - 1097
(2007/10/03)
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- Die Isocyanid-Cyanid-Umlagerung - Mechanismus und praeparative Anwendung
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Bis vor kurzem war die Isocyanid-Cyanid-Umlagerung hauptsaechlich als Beispiel fuer eine unimolekular verlaufende Gasphasenreaktion bekannt und nur fuer einfache Systeme kinetisch untersucht.Kinetikstudien in Loesung wurden erst moeglich, als man eine ueberlagerte, zum gleichen Produkt fuehrende Radikalkette erkannte und diese inhibieren konnte.Die Geschwindigkeit der Isomerisierung erwies sich als kaum von der Struktur und von Substituenten abhaengig.Allenfalls starke sterische Hinderung in drei Dimensionen wie in tris-α-substituierten Triptylcylisocyaniden fuehrt zu einer deutlichen Erhoehung der Aktivierungsenthalpie.Die Ergebnisse lassen sich mit einem rein sigmatropen Mechanismus deuten und sind damit in Einklang mit Voraussagen aus ab-initio-Rechnungen.Auch praeparativ laesst sich diese Umlagerung inzwischen nutzen.Bei der Blitzpyrolyse sind die Ausbeuten an Cyanid nahezu quantitativ.Allylisocyanide reagieren ohne Allylisomerisierung und optisch aktive Isocyanide unter vollstaendiger Retention.Die Umlagerung kann sowohl Bestandteil wirtschaftlich interessanter Synthesen, z.B. der Entzuendungshemmer Ibuprofen und (S)-Naproxen, sein als auch beim Aufbau optisch aktiver β-Acyloxycyanide, die nuetzliche Synthesebausteine sind, aus optisch aktiven α-Aminosaeuren helfen.
- Ruechardt, Christoph,Meier, Michael,Haaf, Klaus,Pakusch, Joachim,Wolber, Erwin K. A.,Mueller, Barbara
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p. 907 - 915
(2007/10/02)
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- Asymmetric Hydrogenation of 2-Aryl-1-nitropropenes by Fermenting Bakers'Yeast
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2-Aryl-1-nitropropenes were enantioselectively hydrogenated on C=C double bonds by incubation with fermenting bakers' yeast to afford optically active 2-aryl-1-nitopropanes.
- Ohta, Hiromichi,Ozaki, Kazuhiko,Tsuchihashi, Gen-ichi
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p. 191 - 192
(2007/10/02)
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- Stereochemistry of Aliphatic Carbocations, 15. Rearrangements in 2-Arylalkyl Systems
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Phenyl shifts from secondary to primary carbon proceed with virtually complete inversion at the migration origin, regardless whether they are induced by solvolysis of the aryl sulfonate 25 or by deamination of the amines 12, 17, 26, and 43.Sequential rearrangements (Ph, CH3 and Ph, H) are likewise stereo- and regiospecific.These results strongly support the intervention of phenonium ions.In contrast, the competitive alkyl shifts (deamination only) from benzylic to primary carbon produce but a small excess of inversion (Me 27percent, Et 13percent, iPr 20percent, tBu 3percent).Obviously, benzyl cations are the predominant intermediates.
- Kirmse, Wolfgang,Guenther, Bernd-Rainer,Loosen, Karin
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p. 2140 - 2153
(2007/10/02)
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