86728-85-0Relevant articles and documents
Method for continuously preparing (R)-4-halo-3-hydroxy-butyrate by using micro-reaction system
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Paragraph 0071-0093, (2021/02/10)
The invention belongs to the technical field of chemical engineering, and particularly relates to a method for continuously preparing (R)-4-halo-3-hydroxy-butyrate by using a micro-reaction system. Asubstrate solution containing halogenated acetoacetate and a biological catalytic solution are continuously subjected to an enzyme-catalyzed asymmetric reduction reaction in the micro-reaction systemcomposed of a micro-mixer, a micro-channel reactor and a pH regulator so as to obtain the (R)-4-halo-3-hydroxy-butyrate. Compared with the prior art, the method has the advantages that: the reaction time is only a few minutes, the yield of the product (R)-4-halo-3-hydroxy-butyrate is more than 95 percent, the process is continuous, the automation degree is high, the efficiency is high, the technological process is simple and convenient to operate, and the industrial production is easy.
Single-Point Mutant Inverts the Stereoselectivity of a Carbonyl Reductase toward β-Ketoesters with Enhanced Activity
Li, Aipeng,Wang, Ting,Tian, Qing,Yang, Xiaohong,Yin, Dongming,Qin, Yong,Zhang, Lianbing
, p. 6283 - 6294 (2021/03/16)
Enzyme stereoselectivity control is still a major challenge. To gain insight into the molecular basis of enzyme stereo-recognition and expand the source of antiPrelog carbonyl reductase toward β-ketoesters, rational enzyme design aiming at stereoselectivity inversion was performed. The designed variant Q139G switched the enzyme stereoselectivity toward β-ketoesters from Prelog to antiPrelog, providing corresponding alcohols in high enantiomeric purity (89.1–99.1 % ee). More importantly, the well-known trade-off between stereoselectivity and activity was not found. Q139G exhibited higher catalytic activity than the wildtype enzyme, the enhancement of the catalytic efficiency (kcat/Km) varied from 1.1- to 27.1-fold. Interestingly, the mutant Q139G did not lead to reversed stereoselectivity toward aromatic ketones. Analysis of enzyme–substrate complexes showed that the structural flexibility of β-ketoesters and a newly formed cave together facilitated the formation of the antiPrelog-preferred conformation. In contrast, the relatively large and rigid structure of the aromatic ketones prevents them from forming the antiPrelog-preferred conformation.
Method for preparing 3 -hydroxy -4 -chlorobutyric acid ethyl ester
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Paragraph 0010-0012, (2021/08/25)
The invention discloses a method for preparing 3 -hydroxy -4 -chlorobutyric acid ethyl ester. The method comprises 4 - chloroacetoacetate as a raw material, methanol as a solvent and sodium borohydride as a reducing agent. The methanol is concentrated to recycle after the reaction is finished. The residue is added with methanol, hydrogen chloride gas is introduced to pH=2 - 3 filtration desalination, and the hydrogen chloride - methanol system is recycled. The residue was distilled under reduced pressure to give ethyl 3 -hydroxy -4 -chlorobutyric acid ethyl ester. The sodium borohydride is low in use amount, no by-product peak occurs, and the yield reaches 83 - 87%. The methanol and hydrogen chloride - methanol two solvent systems are separately recycled, so that the use of a low-boiling-point solvent is avoided. The synthetic process is low in cost, high in yield and environmentally friendly, and can be used for industrial large-scale production.
Deep Eutectic Solvents as Media in Alcohol Dehydrogenase-Catalyzed Reductions of Halogenated Ketones
Ibn Majdoub Hassani, Fatima Zohra,Amzazi, Saaid,Kreit, Joseph,Lavandera, Iván
, p. 832 - 836 (2019/12/24)
The application of deep eutectic solvents (DESs) in biotechnological processes has gained an outstanding relevance, as they can be used as greener media to obtain higher productivities and selectivities. In the present contribution, an eutectic mixture composed of choline chloride (ChCl): glycerol (1 : 2 mol/mol) has been used as a reaction medium in combination with Tris?SO4 50 mM buffer pH 7.5, applied to the alcohol dehydrogenase (ADH)-catalyzed reduction of various carbonyl precursors of chiral halohydrins. These alcohols are key intermediates of biologically active compounds, and hence they are of industrial interest. In the presence of up to 50 % v/v of DES, these biotransformations were achieved up to 300–400 mM of the α-halogenated ketone substrate, getting access to the final compounds with excellent conversions (usually >90 %) and enantiomeric excess (ee >99 %). Among the different ADHs tested, two stereocomplementary enzymes (Lactobacillus brevis ADH and Rhodococcus ruber ADH) afforded the best results, so both alcohol enantiomers could be obtained in all the studied examples. Selected bioreductions were scaled up to 250 mg and 1 g, demonstrating the potential that DESs can offer as media in redox processes for substrates with low solubility in water.
Synthesis of ethyl (R)-4-chloro-3-hydroxybutyrate by immobilized cells using amino acid-modified magnetic nanoparticles
Dai, Hongqian,Lu, Yuan,Ou, Zhimin,Shi, Hanbing,Sun, Xingyuan,Tang, Lan
, p. 9 - 20 (2020/09/01)
Fe3O4-Arg was selected as the optimal carrier due to its high activity recovery of immobilized cells in the preparation of Fe3O4-Arg-Cells. The optimal immobilization conditions for the preparation of Fe3O4-Arg-Cells were 30 °C, 4 h, pH 7, and 3 g dry yeast. The activity recovery of immobilized cells reached 76.8 percent. For a batch reduction in a shaker in an alternating magnetic field, Fe3O4-Arg-Cells were used as a catalyst to gain ethyl (R)-4-chloro-3-hydroxybutyrate ((R)-CHBE). For further improvement in reduction productivity, a continuous reduction in the magnetic fluidized bed reactor system (MFBRS) was completed. Under their optimal transformation conditions, it took 24 h for Fe3O4-Arg-Cells to complete the conversion of ethyl 4-chloro-3-oxobutanoate (COBE) (0.8553 mol/L) in the shaker and only 8 h for the batch reduction in an alternating magnetic field. Continuous reduction in MFBRS provided new ideas for the efficient production of (R)-CHBE; 1.5882 mol/L (10 mL) of COBE can be completely converted in 6 h. The conversion and enantiomeric excess (e.e.) of (R)-CHBE were 100 percent and above 99.9 percent respectively, in the three reaction systems mentioned above.
Efficient Nicotinamide Adenine Dinucleotide Phosphate [NADP(H)] Recycling in Closed-Loop Continuous Flow Biocatalysis
Baumer, Benedikt,Classen, Thomas,Pohl, Martina,Pietruszka, J?rg
, p. 2894 - 2901 (2020/04/15)
Biocatalytic redox reactions regularly depend on expensive cofactors that require recycling. For continuous conversions in flow chemistry, this is often an obstacle since the cofactor is washed away. Here, we present a quasi-stationary recycling system for nicotinamide adenine dinucleotide phosphate utilizing an immobilized alcohol dehydrogenase. Four model substrates were reduced with high enantioselectivity as a proof of concept. The two-phase system enables continuous production as well as quick substrate changes. This setup may serve as a general cofactor regeneration module for continuous biocatalytic devices employing (co-)substrates being miscible in organic solvent. The system resulted in space-time yields up to 117 g L?1 h?1 and total turnover numbers for nicotinamide adenine dinucleotide phosphate higher than 12,000 mol/mol are possible. (Figure presented.).
Efficient Asymmetric Synthesis of Ethyl (S)-4-Chloro-3-hydroxybutyrate Using Alcohol Dehydrogenase SmADH31 with High Tolerance of Substrate and Product in a Monophasic Aqueous System
Chen, Rong,Liu, Qinghai,Wang, Hualei,Wei, Dongzhi,Xie, Youyu,Yang, Zeyu,Ye, Wenjie
, p. 1068 - 1076 (2020/07/06)
Bioreductions catalyzed by alcohol dehydrogenases (ADHs) play an important role in the synthesis of chiral alcohols. However, the synthesis of ethyl (S)-4-chloro-3-hydroxybutyrate [(S)-CHBE], an important drug intermediate, has significant challenges concerning high substrate or product inhibition toward ADHs, which complicates its production. Herein, we evaluated a novel ADH, SmADH31, obtained from the Stenotrophomonas maltophilia genome, which can tolerate extremely high concentrations (6 M) of both substrate and product. The coexpression of SmADH31 and glucose dehydrogenase from Bacillus subtilis in Escherichia coli meant that as much as 660 g L-1 (4.0 M) ethyl 4-chloroacetoacetate was completely converted into (S)-CHBE in a monophasic aqueous system with a >99.9% ee value and a high space-time yield (2664 g L-1 d-1). Molecular dynamics simulation shed light on the high activity and stereoselectivity of SmADH31. Moreover, five other optically pure chiral alcohols were synthesized at high concentrations (100-462 g L-1) as a result of the broad substrate spectrum of SmADH31. All these compounds act as important drug intermediates, demonstrating the industrial potential of SmADH31-mediated bioreductions.
Efficient asymmetric synthesis of chiral alcohols using high 2-propanol tolerance alcohol dehydrogenase: Sm ADH2 via an environmentally friendly TBCR system
Yang, Zeyu,Fu, Hengwei,Ye, Wenjie,Xie, Youyu,Liu, Qinghai,Wang, Hualei,Wei, Dongzhi
, p. 70 - 78 (2020/01/21)
Alcohol dehydrogenases (ADHs) together with the economical substrate-coupled cofactor regeneration system play a pivotal role in the asymmetric synthesis of chiral alcohols; however, severe challenges concerning the poor tolerance of enzymes to 2-propanol and the adverse effects of the by-product, acetone, limit its applications, causing this strategy to lapse. Herein, a novel ADH gene smadh2 was identified from Stenotrophomonas maltophilia by traditional genome mining technology. The gene was cloned into Escherichia coli cells and then expressed to yield SmADH2. SmADH2 has a broad substrate spectrum and exhibits excellent tolerance and superb activity to 2-propanol even at 10.5 M (80%, v/v) concentration. Moreover, a new thermostatic bubble column reactor (TBCR) system is successfully designed to alleviate the inhibition of the by-product acetone by gas flow and continuously supplement 2-propanol. The organic waste can be simultaneously recovered for the purpose of green synthesis. In the sustainable system, structurally diverse chiral alcohols are synthesised at a high substrate loading (>150 g L-1) without adding external coenzymes. Among these, about 780 g L-1 (6 M) ethyl acetoacetate is completely converted into ethyl (R)-3-hydroxybutyrate in only 2.5 h with 99.9% ee and 7488 g L-1 d-1 space-time yield. Molecular dynamics simulation results shed light on the high catalytic activity toward the substrate. Therefore, the high 2-propanol tolerance SmADH2 with the TBCR system proves to be a potent biocatalytic strategy for the synthesis of chiral alcohols on an industrial scale.
Method for preparing chiral beta-hydroxycarboxylate compound
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Paragraph 0075-0081, (2019/08/20)
The invention provides a method for preparing a chiral beta-hydroxycarboxylate compound, comprising the following steps: dissolving [Ir(COD)Cl]2, a ligand and an alkaline additive in a solvent, stirring at room temperature, carrying out in-situ synthesis of a catalyst, dissolving a substrate beta-hydroxycarboxylate compound in a solvent, adding the prepared catalyst, and introducing hydrogen to carry out an asymmetric catalytic hydrogenation reaction on the substrate beta-hydroxycarboxylate compound. The reaction conditions are as follows: pressure is 10-100 atmospheres, the reaction temperature is 0-200 DEG C, and the reaction time is 12-48 hours. The reaction activity and selectivity are high, and the hydrogenation reaction conditions are mild. The method is suitable for various beta-hydroxycarboxylate compounds; the substrate application range is wide; and the reaction process causes little environmental pollution.
Cobalt-Catalyzed Alkoxycarbonylation of Epoxides to β-Hydroxyesters
Xu, Jian-Xing,Wu, Xiao-Feng
, p. 9907 - 9912 (2019/08/26)
Herein, we developed a new and practical catalytic system for the carbonylative synthesis of β-hydroxyesters. By using simple, cheap, and air-stable cobalt(II) bromide as the catalyst, combined with pyrazole and catalytic amount of manganese, active cobalt complex can be generated in situ and can catalyze various epoxides to give the corresponding β-hydroxyesters in moderate to excellent yields. Mechanism studies indicate that pyrazole plays a crucial role in this reaction. Moreover, with the addition of the catalytic amount of manganese, the active cobalt catalyst can be regenerated, which provides a possibility for reusing the cobalt catalyst.
