45972-74-5Relevant articles and documents
Continuous Flow Bioamination of Ketones in Organic Solvents at Controlled Water Activity using Immobilized ω-Transaminases
B?hmer, Wesley,Engelmark Cassimjee, Karim,Mutti, Francesco G.,Volkov, Alexey
, (2020)
Compared with biocatalysis in aqueous media, the use of enzymes in neat organic solvents enables increased solubility of hydrophobic substrates and can lead to more favorable thermodynamic equilibria, avoidance of possible hydrolytic side reactions and easier product recovery. ω-Transaminases from Arthrobacter sp. (AsR?ωTA) and Chromobacterium violaceum (Cv?ωTA) were immobilized on controlled porosity glass metal-ion affinity beads (EziG) and applied in neat organic solvents for the amination of 1-phenoxypropan-2-one with 2-propylamine. The reaction system was investigated in terms of type of carrier material, organic solvents and reaction temperature. Optimal conditions were found with more hydrophobic carrier materials and toluene as reaction solvent. The system's water activity (aw) was controlled via salt hydrate pairs during both the biocatalyst immobilization step and the progress of the reaction in different non-polar solvents. Notably, the two immobilized ωTAs displayed different optimal values of aw, namely 0.7 for EziG3?AsR?ωTA and 0.2 for EziG3?Cv?ωTA. In general, high catalytic activity was observed in various organic solvents even when a high substrate concentration (450–550 mM) and only one equivalent of 2-propylamine were applied. Under batch conditions, a chemical turnover (TTN) above 13000 was obtained over four subsequent reaction cycles with the same batch of EziG-immobilized ωTA. Finally, the applicability of the immobilized biocatalyst in neat organic solvents was further demonstrated in a continuous flow packed-bed reactor. The flow reactor showed excellent performance without observable loss of enzymatic catalytic activity over several days of operation. In general, ca. 70% conversion was obtained in 72 hours using a 1.82 mL flow reactor and toluene as flow solvent, thus affording a space-time yield of 1.99 g L?1 h?1. Conversion reached above 90% when the reaction was run up to 120 hours. (Figure presented.).
A Chemoenzymatic Cascade Combining a Hydration Catalyst with an Amine Dehydrogenase: Synthesis of Chiral Amines
Chang, Fengwei,Chen, Qipeng,Liu, Guohua,Wang, Chengyi,Zhang, Yongjin
supporting information, (2022/01/19)
The combination of biocatalysis and transition-metal catalysis can complement synthetic gaps only in a chemical or biological process. However, the intrinsic mutual deactivation between enzymatic and chemical species is a significant challenge in a single
GPhos Ligand Enables Production of Chiral N-Arylamines in a Telescoped Transaminase-Buchwald-Hartwig Amination Cascade in the Presence of Excess Amine Donor
Heckmann, Christian M.,Paradisi, Francesca
supporting information, p. 16616 - 16620 (2021/10/12)
The combination of biocatalysis and chemocatalysis can be more powerful than either technique alone. However, combining the two is challenging due to typically very different reaction conditions. Herein, chiral N-aryl amines, key features of many active pharmaceutical ingredients, are accessed in excellent enantioselectivity (typically>99.5 % ee) by combining transaminases with the Buchwald-Hartwig amination. By employing a bi-phasic buffer-toluene system as well as the ligand GPhos, the telescoped cascade proceeded with up to 89 % overall conversion in the presence of excess alanine. No coupling to alanine was observed.
Iterative Alanine Scanning Mutagenesis Confers Aromatic Ketone Specificity and Activity of L-Amine Dehydrogenases
Mu, Xiaoqing,Wu, Tao,Mao, Yong,Zhao, Yilei,Xu, Yan,Nie, Yao
, p. 5243 - 5253 (2021/11/16)
Direct reductive amination of prochiral ketones catalyzed by amine dehydrogenases is attractive in the synthesis of active pharmaceutical ingredients. Here, we report the protein engineering of L-Bacillus cereus amine dehydrogenase to allow reactivity on synthetically useful aromatic ketone substrates using an iterative, multiple-site alanine scanning mutagenesis approach. Mutagenesis libraries based on molecular docking, iterative alanine scanning, and double-proximity filter approach significantly expand the scope of active pharmaceutical ingredients relevant building blocks. The eventual quintuple mutant (A115G/T136A/L42A/V296A/V293A) showed reactivity toward aromatic ketones 12 a (5-phenyl-pentan-2-one) and 13 a (6-phenyl-hexan-2-one), which have not been reported to serve as targets of reductive amination by currently available amine dehydrogenases. Docking simulation and tunnel analysis provided valuable insights into the source of the acquired specificity and activity.
Parallel interconnected kinetic asymmetric transformation (PIKAT) with an immobilized ω-transaminase in neat organic solvent
B?hmer, Wesley,Koenekoop, Lucien,Mutti, Francesco G.,Simon, Timothée
, (2020/05/25)
Comprising approximately 40% of the commercially available optically active drugs, α-chiral amines are pivotal for pharmaceutical manufacture. In this context, the enzymatic asymmetric amination of ketones represents a more sustainable alternative than traditional chemical procedures for chiral amine synthesis. Notable advantages are higher atom-economy and selectivity, shorter synthesis routes, milder reaction conditions and the elimination of toxic catalysts. A parallel interconnected kinetic asymmetric transformation (PIKAT) is a cascade in which one or two enzymes use the same cofactor to convert two reagents into more useful products. Herein, we describe a PIKAT catalyzed by an immobilized ω-transaminase (ωTA) in neat toluene, which concurrently combines an asymmetric transamination of a ketone with an anti-parallel kinetic resolution of an amine racemate. The applicability of the PIKAT was tested on a set of prochiral ketones and racemic α-chiral amines in a 1:2 molar ratio, which yielded elevated conversions (up to >99%) and enantiomeric excess (ee, up to >99%) for the desired products. The progress of the conversion and ee was also monitored in a selected case. This is the first report of a PIKAT using an immobilized ωTA in a non-aqueous environment.
An Ammonium-Formate-Driven Trienzymatic Cascade for ω-Transaminase-Catalyzed (R)-Selective Amination
Chen, Fei-Fei,Liu, Lei,Wu, Jian-Ping,Xu, Jian-He,Zhang, Yu-Hui,Zhang, Zhi-Jun,Zheng, Gao-Wei
, p. 14987 - 14993 (2019/12/02)
(R)-Amination mediated by (R)-specific ω-transaminases generally requires costly d-alanine in excess to obtain the desired chiral amines in high yield. Herein, a one-pot, trienzymatic cascade comprising an (R)-specific ω-transaminase, an amine dehydrogenase, and a formate dehydrogenase was developed for the economical and eco-friendly synthesis of (R)-chiral amines. Using inexpensive ammonium formate as the sole sacrificial agent, the established cascade system enabled efficient ω-transaminase-mediated (R)-amination of various ketones, with high conversions and excellent ee (>99%); water and CO2 were the only waste products.
Upgraded Bioelectrocatalytic N2 Fixation: From N2 to Chiral Amine Intermediates
Chen, Hui,Cai, Rong,Patel, Janki,Dong, Fangyuan,Chen, Hsiaonung,Minteer, Shelley D.
, p. 4963 - 4971 (2019/03/26)
Enantiomerically pure chiral amines are of increasing value in the preparation of bioactive compounds, pharmaceuticals, and agrochemicals. ω-Transaminase (ω-TA) is an ideal catalyst for asymmetric amination because of its excellent enantioselectivity and wide substrate scope. To shift the equilibrium of reactions catalyzed by ω-TA to the side of the amine product, an upgraded N2 fixation system based on bioelectrocatalysis was developed to realize the conversion from N2 to chiral amine intermediates. The produced NH3 was in situ reacted with l-alanine dehydrogenase to generate alanine with NADH as a coenzyme. ω-TA transferred the amino group from alanine to ketone substrates and finally produced the desired chiral amine intermediates. The cathode of the upgraded N2 fixation system supplied enough reducing power to synchronously realize the regeneration of reduced methyl viologen (MV?+) and NADH for the nitrogenase and l-alanine dehydrogenase. The coproduct, pyruvate, was consumed by l-alanine dehydrogenase to regenerate alanine and push the equilibrium to the side of amine. After 10 h of reaction, the concentration of 1-methyl-3-phenylpropylamine achieved 0.54 mM with the 27.6% highest faradaic efficiency and >99% enantiomeric excess (eep). Because of the wide substrate scope and excellent enantioselectivity of ω-TA, the upgraded N2 fixation system has great potential to produce a variety of chiral amine intermediates for pharmaceuticals and other applications.
n-Butylamine as an alternative amine donor for the stereoselective biocatalytic transamination of ketones
Slabu, Iustina,Galman, James L.,Iglesias, Cesar,Weise, Nicholas J.,Lloyd, Richard C.,Turner, Nicholas J.
, p. 96 - 101 (2017/09/30)
Formal reductive amination has been a main focus of biocatalysis research in recent times. Among the enzymes able to perform this transformation, pyridoxal-5′-phosphate-dependent transaminases have shown the greatest promise in terms of extensive substrate scope and industrial application. Despite concerted research efforts in this area, there exist relatively few options regarding efficient amino donor co-substrates capable of allowing high conversion and atom efficiency with stable enzyme systems. Herein we describe the implementation of the recently described spuC gene, coding for a putrescine transaminase, exploiting its unusual amine donor tolerance to allow use of inexpensive and readily-available n-butylamine as an alternative to traditional methods. Via the integration of SpuC homologues with tandem co-product removal and cofactor regeneration enzymes, high conversion could be achieved with just 1.5 equivalents of the amine with products displaying excellent enantiopurity.
Biocatalytic transamination with near-stoichiometric inexpensive amine donors mediated by bifunctional mono- and di-amine transaminases
Galman, James L.,Slabu, Iustina,Weise, Nicholas J.,Iglesias, Cesar,Parmeggiani, Fabio,Lloyd, Richard C.,Turner, Nicholas J.
supporting information, p. 361 - 366 (2017/08/14)
The discovery and characterisation of enzymes with both monoamine and diamine transaminase activity is reported, allowing conversion of a wide range of target ketone substrates with just a small excess of amine donor. The diamine co-substrates (putrescine, cadaverine or spermidine) are bio-derived and the enzyme system results in very little waste, making it a greener strategy for the production of valuable amine fine chemicals and pharmaceuticals.
Vicinal Diamines as Smart Cosubstrates in the Transaminase-Catalyzed Asymmetric Amination of Ketones
Payer, Stefan E.,Schrittwieser, Joerg H.,Kroutil, Wolfgang
supporting information, p. 2553 - 2559 (2017/05/12)
Transaminases (TAs) have recently been established as catalysts for the asymmetric, reductive amination of prochiral ketones. Depending on the ketone substrate and the amine donor (the cosubstrate), equilibrium constants may limit high conversions; thus, methods to overcome this limitation are required. Removal of the co-product from the reaction equilibrium through spontaneous, intramolecular reactions has provided a successful solution to this problem; therefore, these amine donors have been named “smart cosubstrates”. Here, we present a comparison of various bifunctional amine donors including vicinal diamines as potential structural cosubstrate motifs. Upon TA-catalyzed deamination of 1,2-diamines, spontaneous dimerization of the resulting α-aminoketones and oxidation gave heteroaromatic pyrazines.
