20859-02-3Relevant articles and documents
Asymmetric Strecker synthesis using enantiopure sulfinimines and diethylaluminum cyanide: The alcohol effect
Davis, Franklin A.,Portonovo, Padma S.,Reddy, Rajarathnam E.,Chiu, Yu-Hung
, p. 440 - 441 (1996)
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Design of a self-sufficient hydride-shuttling cascade for concurrent bioproduction of 7,12-dioxolithocholate andl-tert-leucine
Chen, Qi,Han, Yu,Li, Chun-Xiu,Pan, Jiang,Qian, Xiao-Long,Xu, Jian-He,Yang, Bing-Yi,You, Zhi-Neng,Zhou, Ke
, p. 4125 - 4133 (2021)
Oxidoreductase-mediated biotransformation often requires consumption of a secondary sacrificial co-substrate and an additional auxiliary enzyme to drive the cofactor regeneration, which results in generation of unwanted by-product. Herein, we report a highly atom-economic self-sufficient hydride-shuttling cascade to concurrently obtain two pharmaceutically important building blocks (7,12-dioxo-lithocholic acid andl-tert-leucine) in which oxidation of cholic acid (CA) and reductive amination of trimethylpyruvic acid were integrated for redox self-recycling. In this cascade, the cofactor acts as a hydride shuttle that interconnects the two synthetically relevant reactions at the cost of only inorganic ammonium as the sacrificial agent and generates water as the greenest by-product. The preparative biotransformation using a whole-cell biocatalyst in the absence of any exogenous cofactor displayed a space-time yield of 768 g L?1d?1and a total turnover number (TTN) of 20?363 for NAD+recycling. This represents the highest cofactor TTN reported to date for the bio-oxidation of CA, indicating the great potential of this cofactor and redox self-sufficient bioprocess for cost-effective and sustainable biomanufacturing of high-value-added products.
SIMPLE OPTICAL RESOLUTION OF TERLEUCINE
Viret, Joelle,Patzelt, Heiko,Collet, Andre
, p. 5865 - 5868 (1986)
Underivatized terleucine (1) can be conveniently resolved into its L- and D-enantiomers by recrystallization of its diastereoisomeric 10-camphorsulphonate salts.
Cadmium sulfide net framework nanoparticles for photo-catalyzed cell redox
Chang, Zhaoyu,Dong, Wanyuan,Meng, Xiangqi,Ren, Yuhong,Wang, Hualei,Wei, Dongzhi,Zhang, Jian
, p. 37820 - 37825 (2020)
A strategy for synthesizing cadmium sulfide net framework (CdS-NF) nanoparticles was developed in a water-based system under mild reaction conditions. The CdS-NFs have not only the excellent photocatalytic properties of CdS, but also the large surface area and diverse porous structures of a metal-organic framework. An Escherichia coli-CdS-NF hybrid system was constructed using NADH regeneration to promote the conversion of trimethylpyruvate acid to l-tert-leucine. The E. coli-CdS-NF system showed higher NAD+ recycling efficiency and substrate conversion rate than CdS QDs under visible light illumination. This work demonstrates a novel method for developing a brilliant coenzyme recycling photocatalyst in bio-redox reactions.
Formate Dehydrogenase from Rhodococcus jostii (RjFDH) – A High-Performance Tool for NADH Regeneration
Boldt, Alexander,Ansorge-Schumacher, Marion B.
, p. 4109 - 4118 (2020)
The use of formate dehydrogenases (FDHs) for regeneration of the important cofactor NADH in enzyme-catalysed synthetic reactions has several advantages over alternative systems. However, a major bottleneck for broad industrial applications is the low specific activity of the currently used FDHs. In this study, we introduce a novel NAD-dependent formate dehydrogenase from Rhodococcus jostii (RjFDH) with both high specific activity and stability. The enzyme was identified in a targeted database research and recombinantly obtained from Escherichia coli. RjFDH is a homodimer with a monomeric molecular mass of 44.7 kDa. The homology model shows that all amino acid residues of the NAD-dependent formate dehydrogenases are usually concerned with catalytic activity, substrate acceptance, and cofactor binding. The only substrate oxidised by these enzymes is formate. RjFDH had a specific activity of 19.9 U mg?1 at 22 °C along with unimpaired activity and high stability over a broad pH range. The Km values for formate and NAD+ were 7.3 and 0.098 mmol L?1, respectively. The optimum temperature was found to be 50 °C, at which the enzyme activity increased to about 318%. Both activity and thermal stability were higher than those of the FDH from Candida boidinii (CbFDH), which is the standard enzyme currently in use for cofactor regeneration. Different solvents roughly had the same impact on the activity and stability of both RjFDH and CbFDH. The superior performance of RjFDH over CbFDH as a regeneration system for NADH was demonstrated for the synthesis of L-tert-leucine as well as (S)-1-phenylethanol. In both systems, the concentration of RjFDH used was only one-third of the concentration of CbFDH required to achieve comparable conversion rates. Rational designing provided a promising NADP-accepting variant. Thus, RjFDH has a great potential to serve as an alternative system for NADH regeneration in enzyme-catalysed synthetic reactions. (Figure presented.).
A Transient Directing Group Strategy Enables Enantioselective Multicomponent Organofluorine Synthesis
Engle, Keary M.,Gao, Yang,Li, Zi-Qi,Liu, Mingyu,Liu, Zhonglin,Oxtoby, Lucas J.,Tran, Van T.
supporting information, p. 8962 - 8969 (2021/07/01)
The vicinal fluorofunctionalization of alkenes represents an expedient strategy for converting feedstock olefins into valuable fluorinated molecules and as such has garnered significant attention from the synthetic community; however, current methods remain limited in terms of scope and selectivity. Here we report the site-selective palladium-catalyzed three-component coupling of alkenylbenzaldehydes, arylboronic acids, and N-fluoro-2,4,6-trimethylpyridinium hexafluorophosphate facilitated by a transient directing group. The synthetically enabling methodology constructs vicinal stereocenters with excellent regio-, diastereo-, and enantioselectivities, forging products that map onto bioactive compounds.
Method for preparing D-type or L-type tert-leucine
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Paragraph 0036; 0040-0042, (2020/06/16)
The invention discloses a method for preparing D-type or L-type tert-leucine, and belongs to the technical field of organic synthesis. The method comprises the following steps: 1, condensing glyoxylate serving as a raw material with chiral tert-butyl sulfinamide to obtain Schiff base; and 2, carrying out a reaction on the Schiff base with a tert-butyl Grignard reagent and a catalyst under a low-temperature condition, and hydrolyzing the reaction product under an acid/alkali condition to obtain D-type or L-type tert-leucine. The method is simple and convenient to operate and high in reaction yield, the purity and content of the obtained product are greater than 99%, the content of a single impurity is less than 0.2%, the chiral purity is greater than or equal to 98.5%, and the method has apotential process amplification prospect.