Combined Imine Reductase and Amine Oxidase Catalyzed Deracemization of Nitrogen Heterocycles
A novel amine oxidase (AO)/imine reductase (IRED) system was developed for the deracemization of racemic amines. By combining (R)-6-hydroxy-d-nicotine oxidase (6-HDNO) with an (R)-IRED, a panel of racemic 2-substituted piperidines and pyrrolidines were deracemized to yield the (S)-amines in high yields and enantiomeric excess values. Other N-heterocycles were deracemized with monoamine oxidase (MAO-N) or 6-HDNO in combination with ammonia borane, which allowed comparison of the two enzyme deracemization approaches with that involving a chemical reducing agent.
Heath, Rachel S.,Pontini, Marta,Hussain, Shahed,Turner, Nicholas J.
p. 117 - 120
(2016/01/26)
An (R)-imine reductase biocatalyst for the asymmetric reduction of cyclic imines
Although the range of biocatalysts available for the synthesis of enantiomerically pure chiral amines continues to expand, few existing methods provide access to secondary amines. To address this shortcoming, we have over-expressed the gene for an (R)-imine reductase [(R)-IRED] from Streptomyces sp. GF3587 in Escherichia coli to create a recombinant whole-cell biocatalyst for the asymmetric reduction of prochiral imines. The (R)-IRED was screened against a panel of cyclic imines and two iminium ions and was shown to possess high catalytic activity and enantioselectivity. Preparative-scale synthesis of the alkaloid (R)-coniine (90 % yield; 99 % ee) from the imine precursor was performed on a gram-scale. A homology model of the enzyme active site, based on the structure of a closely related (R)-IRED from Streptomyces kanamyceticus, was constructed and used to identify potential amino acids as targets for
Hussain, Shahed,Leipold, Friedemann,Man, Henry,Wells, Elizabeth,France, Scott P.,Mulholland, Keith R.,Grogan, Gideon,Turner, Nicholas J.
p. 579 - 583
(2015/03/05)
Aromatic organozinc reagents as nucleophiles in the α-arylation of piperidine and tetrahydropyran
The arylation at the α-position of piperidine derivatives is achieved in good yield using aromatic organozinc reagents and either 2-methoxylated or α-cyanated piperidine. Oxygen-containing heterocycles such as 2-methoxy-tetrahydropyran reacts in a same manner to yield efficiently 2-arylated tetrahydropyran.
Le Gall, Erwan,Gosmini, Corinne,Troupel, Michel
p. 455 - 458
(2007/10/03)
A One-Pot Process for the Enantioselective Synthesis of Amines via Reductive Amination under Transfer Hydrogenation Conditions
(Equation presented) Cyclic amines may be prepared via a sequence of deprotection followed by intramolecular reductive amination of t-Boc-protected amino ketones under asymmetric transfer hydrogenation conditions. In cases where the corresponding imine reaction proceeds with high enantioselectivity, this is reflected in the one-step process.
Williams, Glynn D.,Pike, Richard A.,Wade, Charles E.,Wills, Martin
p. 4227 - 4230
(2007/10/03)
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