- Amine Transaminase from Exophiala Xenobiotica - Crystal Structure and Engineering of a Fold IV Transaminase that Naturally Converts Biaryl Ketones
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Amine transaminases are frequently used for the production of chiral amines starting from prochiral ketones. These amines can be applied as active pharmaceutical ingredients or drug precursors. However, there are still limitations to the use of amine transaminases when it comes to bulky ketone substrates, such as biaryl ketones. Using data mining, an (R)-selective amine transaminase from Exophiala xenobiotica was identified which naturally converts biaryl ketone substrates to the corresponding amines with up to 85% conversion and excellent enantioselectivity (>99% ee). Its protein crystal structure was obtained with a resolution of 1.52 ?, which enabled us to explain this interesting substrate acceptance. Structure-guided protein engineering resulted in a quintuple variant with increased stability. Moreover, the amino acid exchange T273S increased the activity and broadened the substrate scope, enabling conversions of various biaryl ketones with up to >99%. A preparative biotransformation of 1-(4-(pyridin-3-yl)phenyl)ethenone at 75 mM (15 g/L) resulted in 96% of isolated yield of the respective amine.
- Telzerow, Aline,Paris, Juraj,H?kansson, Maria,González-Sabín, Javier,Ríos-Lombardía, Nicolás,Schürmann, Martin,Gr?ger, Harald,Morís, Francisco,Kourist, Robert,Schwab, Helmut,Steiner, Kerstin
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p. 1140 - 1148
(2019/01/21)
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- (R)- SELECTIVE AMINATION
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The present invention relates to a method for the enzymatic synthesis of enantiomerically enriched (R)-amines of general formula [1][c] from the corresponding ketones of the general formula [1][a] by using novel transaminases. These novel transaminases are selected from two different groups: either from a group of some 20 proteins with sequences as specified herein, or from a group of proteins having transaminase activity and isolated from a microorganism selected from the group of organisms consisting of Rahnella aquatilis, Ochrobactrum anthropi, Ochrobactrum tritici, Sinorhizobium morelense, Curtobacterium pusiffium, Paecilomyces lilacinus, Microbacterium ginsengisoli, Microbacterium trichothecenolyticum, Pseudomonas citronellolis, Yersinia kristensenii, Achromobacter spanius, Achromobacter insolitus, Mycobacterium fortuitum, Mycobacterium frederiksbergense, Mycobacterium sacrum, Mycobacterium fluoranthenivorans, Burkhoideria sp., Burkhoideria tropica, Cosmospora episphaeria, and Fusarium oxysporum.
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Paragraph 0120; 0121; 0122
(2016/03/22)
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- Asymmetric amination of tetralone and chromanone derivatives employing ω-transaminases
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Various (S)-selective and (R)-selective ω-transaminases were investigated for the amination of 1- and 2-tetralone and derivatives as well as of 3- and 4-chromanone. All ketones tested were aminated to give the corresponding enantiopure amines (ee > 99%) employing at least one of the enzymes investigated. In most of the cases the (S)- as well as the (R)-enantiomer was obtained in optically pure form. The amination of 3-chromanone was performed on a 100 mg scale leading to optically pure (R)-3-aminochromane (ee > 99%) with complete conversion and 78% isolated yield.
- Pressnitz, Desiree,Fuchs, Christine S.,Sattler, Johann H.,Knaus, Tanja,Macheroux, Peter,Mutti, Francesco G.,Kroutil, Wolfgang
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p. 555 - 559
(2013/06/05)
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- Investigation of one-enzyme systems in the ω-transaminase-catalyzed synthesis of chiral amines
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ω-Transaminase (TA) catalyzed asymmetric syntheses of amines were carried out in the one enzyme systems with wild-type enzymes (S)-TA from Pseudomonas aeruginosa, (S)-TA from Paracoccus denitrificans and (R)-TA from Aspergillus terreus. The scope of amine donors and aromatic carbonyl substrates was thoroughly explored. Among the range of potential amino donors, 2-propylamine, 2-butylamine and 1-phenylethylamine were found as promising candidates, which gave superior conversions in the amination reactions compared to other donors. Various prochiral aromatic ketones were accepted as substrates by the investigated enzymes. In most cases, good to excellent conversions (up to 98%) to the amine products with excellent e.e.-values (>99.9% for (S) or (R)) were obtained by the action of a single enzyme and an appropriate amino donor. (S)-TA from Paracoccus denitrificans was found to accept bulky ketones, e.g. 1-indanone, α- and β-tetralone or 2-acetonaphthone, in the asymmetric amination. In some cases the enantiomeric excesses in the amination reactions were dependent on the amino donor. More-over, the influence of the pH, temperature and cosolvents on the outcome of reactions was additionally investigated.
- Fesko, Kateryna,Steiner, Kerstin,Breinbauer, Rolf,Schwab, Helmut,Schuermann, Martin,Strohmeier, Gernot A.
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p. 103 - 110
(2013/10/22)
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- N-octanoyldimethylglycine trifluoroethyl ester, an acyl donor leading to highly enantioselective protease-catalysed kinetic resolution of amines
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The use of N-octanoyldimethylglycine trifluoroethyl ester as acyl donor in the kinetic resolution of aliphatic amines catalysed by proteases led to enantiomeric ratios >200 in most cases. The resolutions mediated by Protex 6L were shown to be much faster
- Queyroy, Severine,Vanthuyne, Nicolas,Gastaldi, Stephane,Bertrand, Michele P.,Gil, Gerard
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supporting information; experimental part
p. 1759 - 1764
(2012/08/08)
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- Chemoenzymatic dynamic kinetic resolution of primary amines catalyzed by CAL-B at 38-40°c
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The (R)-selective chemoenzymatic dynamic kinetic resolution of primary amines was performed at 38-40 °C in MTBE, in good to high yields and with high enantiomeric excesses. These reactions associating CAL-B to octanethiol as radical racemizing agent were carried out in the presence of methyl β-methoxy propanoate as acyl donor, under photochemical irradiation at 350 nm in glassware.
- Poulhes, Florent,Vanthuyne, Nicolas,Bertrand, Michele P.,Gastaldi, Stephane,Gil, Gerard
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experimental part
p. 7281 - 7286
(2011/10/10)
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- Indirect and direct catalytic asymmetric reductive amination of 2-tetralone
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Herein we report a one-pot catalytic asymmetric reductive amination of 2-tetralone. High-throughput screening of a small library of chiral ligands allowed us to perform the enantioselective hydrogenation of the intermediate enamine with up to 60% ee and a one-pot reaction with up to 47% enantiomeric excess of the desired amine.
- Bondarev, Oleg,Bruneau, Christian
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experimental part
p. 1350 - 1354
(2010/10/21)
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- Asymmetric catalytic aziridination of dihydronaphthalenes for the preparation of substituted 2-aminotetralins
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An enantioselective synthesis of substituted 2-aminotetralins from dihydronaphthalenes in four steps is described. The key step is the Jacobsen's (diimine)copper-catalyzed asymmetric aziridination of dihydronaphthalenes to the respective aziridines in 33-82% yields and 60-87% enantiomeric excess. The enantioselectivity and the yield were dependent on the properties of the nitrene precursor. pTsNIPh appeared in general to give better results than pNsNIPh. Aziridines were ring-opened in the benzylic position by catalytic hydrogenolysis in quantitative yields, and deprotected in two steps to the respective 2-aminotetralins in 66-85% yields. The synthesis of (S)-2-aminotetralin (>98% ee) and (S)-2-amino-7-methoxytetralin (56% ee) were accomplished in 30 and 52% overall yields, respectively.
- Aaseng, Jon Erik,Melnes, Silje,Reian, Gard,Gautun, Odd R.
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experimental part
p. 9790 - 9797
(2011/02/22)
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- A chemoenzymatic synthesis of (2R)-8-substituted-2-aminotetralins
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(2R)-2-Amino-8-methoxy-1,2,3,4-tetrahydronaphthalene, a useful precursor of the 5-hydroxytryptamine receptor agonist 8-OH-DPAT ((2R)-2-(dipropylamino)-8-hydroxytetrahydronaphthalene), has been synthesized from 1-methoxynaphthalene through a chemoenzymatic protocol. The same protocol has been subsequently applied to the synthesis of other (2R)-2-amino-1,2,3,4-tetrahydronaphthalenes.
- Orsini, Fulvia,Sello, Guido,Travaini, Elena,Di Gennaro, Patrizia
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p. 253 - 259
(2007/10/03)
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- A novel asymmetric route to 2-amino-1,2,3,4-tetrahydronaphthalenes
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A novel asymmetric route to 2-amino-1,2,3,4-tetrahydronaphthalenes has been demonstrated starting from phthalimidovinylglycinol (PVG). Functionalisation of PVG via Heck reaction, olefin hydrogenation and cyclisation provides the title products. (C) 2000 Elsevier Science Ltd.
- Harris, Michael C. J.,Jackson, Mark,Lennon, Ian C.,Ramsden, James A.,Samuel, Helen
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p. 3187 - 3191
(2007/10/03)
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- Asymmetric synthesis of β-aminotetralins by electrophilic amination
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An effective synthesis of β-aminotetralins (6) including an asymmetric electrophlic amination by di-t-butyl azodicarboxylate is reported. Depending on the chiral auxiliaries (S)-7a-d, the central intermediates 9 and 10 could be isolated in 62-80% de. Subsequent hydrolysis and reductive degradation resulted in the nonracemic final products 6 (57-84% ee). Separation of the diastereomeric intermediates by chromatography makes possible the synthesis of optically pure products. An induction model for the asymmetric amination is provided.
- Gmeiner, Peter,Bollinger, Bernd
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p. 10909 - 10922
(2007/10/02)
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- Asymmetric Synthesis Using Chirally Modified Borohydrides. Part 3. Enantioselective Reduction of Ketones and Oxime Ethers with Reagents Prepared from Borane and Chiral Amino Alcohols
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The asymmetric reduction of aromatic and aliphatic ketones, halogeno ketones, keto esters, and ketone oxime ethers with reagents prepared from borane and chiral amino alcohols has been investigated.When α,α-diphenyl-β-amino alcohols, such as (2S,3R)-(-)-2-amino-3-methyl-1,1-diphenylpentanol (2d), were used as a chiral auxiliary, very high enantioselectivities (ca. 90percent e.e.) were obtained in the reduction of various ketones and oxime ethers.
- Itsuno, Shinichi,Nakano, Michio,Miyazaki, Koji,Masuda, Hirofumi,Ito, Koichi,et al.
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p. 2039 - 2044
(2007/10/02)
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