- Tackling N-Alkyl Imines with 3d Metal Catalysis: Highly Enantioselective Iron-Catalyzed Synthesis of α-Chiral Amines
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A readily activated iron alkyl precatalyst effectively catalyzes the highly enantioselective hydroboration of N-alkyl imines. Employing a chiral bis(oxazolinylmethylidene)isoindoline pincer ligand, the asymmetric reduction of various acyclic N-alkyl imines provided the corresponding α-chiral amines in excellent yields and with up to >99 % ee. The applicability of this base metal catalytic system was further demonstrated with the synthesis of the pharmaceuticals Fendiline and Tecalcet.
- Blasius, Clemens K.,Gade, Lutz H.,Heinrich, Niklas F.,Vasilenko, Vladislav
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p. 15974 - 15977
(2020/07/04)
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- One-step asymmetric synthesis of (R)- and (S)-rasagiline by reductive amination applying imine reductases
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Imine reductases (IREDs) show great potential as catalysts for reductive amination of ketones to produce chiral secondary amines. In this work, we explored this potential and synthesized the pharmaceutically relevant (R)-rasagiline in high yields (up to 81%) and good enantiomeric excess (up to 90% ee) from the ketone precursor. This one-step approach in aqueous medium represents the shortest synthesis route from achiral starting materials. Furthermore, we demonstrate for the first time that tertiary amines also can be accessed by this route, which provides new opportunities for eco-friendly enzymatic asymmetric syntheses of these important molecules.
- Matzel,Gand,H?hne
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p. 385 - 389
(2017/08/14)
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- Photometric Characterization of the Reductive Amination Scope of the Imine Reductases from Streptomyces tsukubaensis and Streptomyces ipomoeae
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Imine reductases (IREDs) have emerged as promising enzymes for the asymmetric synthesis of secondary and tertiary amines starting from carbonyl substrates. Screening the substrate specificity of the reductive amination reaction is usually performed by time-consuming GC analytics. We found two highly active IREDs in our enzyme collection, IR-20 from Streptomyces tsukubaensis and IR-Sip from Streptomyces ipomoeae, that allowed a comprehensive substrate screening with a photometric NADPH assay. We screened 39 carbonyl substrates combined with 17 amines as nucleophiles. Activity data from 663 combinations provided a clear picture about substrate specificity and capabilities in the reductive amination of these enzymes. Besides aliphatic aldehydes, the IREDs accepted various cyclic (C4–C8) and acyclic ketones, preferentially with methylamine. IR-Sip also accepted a range of primary and secondary amines as nucleophiles. In biocatalytic reactions, IR-Sip converted (R)-3-methylcyclohexanone with dimethylamine or pyrrolidine with high diastereoselectivity (>94–96 % de). The nucleophile acceptor spectrum depended on the carbonyl substrate employed. The conversion of well-accepted substrates could also be detected if crude lysates were employed as the enzyme source.
- Matzel, Philipp,Krautschick, Lukas,H?hne, Matthias
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p. 2022 - 2027
(2017/10/07)
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- Disulfonimide-Catalyzed Asymmetric Reduction of N-Alkyl Imines
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A chiral disulfonimide (DSI)-catalyzed asymmetric reduction of N-alkyl imines with Hantzsch esters as a hydrogen source in the presence of Boc2O has been developed. The reaction delivers Boc-protected N-alkyl amines with excellent yields and enantioselectivity. The method tolerates a large variety of alkyl amines, thus illustrating potential for a general reductive cross-coupling of ketones with diverse amines, and it was applied in the synthesis of the pharmaceuticals (S)-Rivastigmine, NPS R-568 Hydrochloride, and (R)-Fendiline. A chiral disulfonimide (DSI)-catalyzed asymmetric reduction of N-alkyl imines with Hantzsch esters as a hydrogen source in the presence of Boc2O was developed. The reaction delivers Boc-protected N-alkyl amines with excellent yields and enantioselectivity. The method was successfully applied to the synthesis of the pharmaceuticals (S)-Rivastigmine, NPS R-568 Hydrochloride, and (R)-Fendiline.
- Wakchaure, Vijay N.,Kaib, Philip S. J.,Leutzsch, Markus,List, Benjamin
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supporting information
p. 11852 - 11856
(2015/10/05)
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- TACHYKININ RECEPTOR ANTAGONISTS
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The present invention relates to selective NK-1 receptor antagonists of Formula (I) or a pharmaceutically acceptable salt thereof, for the treatment of disorders associated with an excess of tachykinins.
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- 3-SUBSTITUTED-6-ARYL PYRIDINES
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3-substituted-6-aryl pyridines of Formula (I) are provided: Formula (I) wherein R1, R2, R3, R8, R9, A and Ar are defined herein. Such compounds are ligands of C5a receptors. Preferred compounds of Formula (I) bind to C5a receptors with high affinity and exhibit neutral antagonist or inverse agonist activity at C5a receptors. The present invention also relates to pharmaceutical compositions comprising such compounds, and to the use of such compounds in treating a variety of inflammatory, cardiovascular, and immune system disorders. In addition, the present invention provides labeled 3-substituted-6-aryl pyridines, which are useful as probes for the localization of C5a receptors.
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- Catalytic asymmetric and non-asymmetric reduction of times and oximes using metal catalysts
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A process is provided for catalytically reducing imines, oximes, hydrazones and related compounds. Moreover, there is provided a process for the catalytic asymmetric reduction of imines, oximes, hydrazones, and the like, using enantiomerically enriched catalysts, to provide chiral amine reaction products which are enriched in one enantiomer. Catalytic asymmetric reduction can also be carried out using an achiral precatalyst in combination with a The U.S. Government has rights in this invention pursuant to NIH Grant Number GM 34917.
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- Indane derivatives
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A compound of formula (I): or, where appropriate, a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, wherein, A represents >C=X, wherein, X represents oxygen or sulphur, or A represents a bond;, Y represents N or
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