3976-69-0Relevant articles and documents
Durability enhancement of chirally modified metallic nickel catalysts for enantioselective hydrogenation
Osawa, Tsutomu,Kizawa, Tomoko,Lee, I-Yin Sandy,Ikeda, Shinji,Kitamura, Takayuki,Inoue, Yoshihisa,Borovkov, Victor
, p. 15 - 17 (2011)
Metallic Ni catalysts co-modified with (R,R)-tartaric acid and NaBr showed high enantioselectivity and durability upon hydrogenation of methyl acetoacetate to give methyl 3-hydroxybutyrate. The chirally modified catalyst prepared from 3-μm Ni powder was highly robust to maintain the hydrogenation activity and enantiodifferentiating ability for ca. 3 months under dry condition, which enables long-term storage and hence facilitates commercial distribution and industrial application.
Highly durable enantio-differentiating nickel catalyst for repeated use for the hydrogenation of methyl acetoacetate
Osawa, Tsutomu,Sakai, Saori,Harada, Tadao,Takayasu, Osamu
, p. 392 - 393 (2001)
The enantio-differentiating hydrogenation of methyl acetoacetate was repeated 30 times over a fine Ni powder catalyst while modifiers (optically active tartaric acid and NaBr) were directly added to the reaction media only in the first run. Over 80% optical yields were attained for the repeated runs. The addition of sodium 2-ethylhexanoate increased the optical yields in the subsequent runs. The very simple and highly durable enantio-differentiating nickel catalyst for repeated use was developed by an in situ modification.
Enhanced enantioselectivity achieved at low hydrogen pressure for the asymmetric hydrogenation of methyl acetoacetate over a tartaric acid NABR-modified Raney nickel catalyst: A kinetic study
Choliq, Azka Azkiya,Nakae, Rio,Watanabe, Mariko,Misaki, Tomonori,Fujita, Morifumi,Okamoto, Yasuaki,Sugimura, Takashi
, p. 1175 - 1180 (2019)
To ensure high enantiopurity of the product, enantio-differentiating hydrogenation of methyl acetoacetate over a (R,R)-tartaric acid-modified Raney nickel catalyst is normally performed under elevated H2-pressure (310 MPa). In this study, higher enantioselectivity than previously reported for methyl acetoacetate was achieved (92% ee) under low H2pressure of 0.42 MPa. Effects of reaction conditions on the enantioselectivity and hydrogenation rate were investigated using a low-pressure reaction system (2). It was found that impurities in the solvent greatly reduce the enantioselectivity of MAA. The low-pressure reaction system enabled a satisfactory kinetic approach. The reaction rate was well described by Langmuir-Hinshelwood formalism, verifying the previous assumption that the addition of adsorbed hydrogen to the substrate interacting with surface tartrate is a rate-determining step.
Configurationally Fixed α-Alkoxyorganocopper Reagents: 1,4-Addition of Cyclic Enantiopure Transferable Ligands with Complete Retention of Configuration
Lindermann, Russell J.,Griedel, Brian D.
, p. 5491 - 5493 (1991)
Optically active 4-lithio-1,3-dioxanes have been converted to the corresponding TMEDA-organocopper reagents and shown to undergo conjugate addition reactions to ethyl propiolate with complete retention of configuration.
Catalytic asymmetric hydrogenation of β-ketoesters using new BINAP complexes of ruthenium
Hoke, Jeffrey B.,Hollis, L. Steven,Stern, Eric W.
, p. 193 - 196 (1993)
Two new, air-stable BINAP complexes of ruthenium(II), (RCp)Ru(S-(-)-BINAP)Cl (R = H, CH3) have been prepared in good yield from the reaction of (RCp)Ru(PPh3)2Cl with S-(-)-BINAP in refluxing toluene.The structure of the methylcyclopentadienyl analog has been determined by X-ray crystallography.Both complexes have been found to be effective homogeneous catalysts for the enantioselective hydrogenation of β-ketoesters.
Simplified preparation of chirally modified nickel catalyst for enantioselective hydrogenation: A step forward to industrial use
Osawa, Tsutomu,Lee, I-Yin Sandy,Ikeda, Shinji,Kitamura, Takayuki,Inoue, Yoshihisa,Borovkov, Victor
, p. 269 - 273 (2012)
A chirally modified nickel catalyst for the enantio-differentiating hydrogenation of β-ketoesters is conventionally prepared by immersing the pre-activated metallic nickel into an aqueous solution of enantiopure tartaric acid (so called "modification step"). During the pre-activation step, nickel precursor is commonly treated with hydrogen gas at elevated temperatures of up to 473 K. The X-ray photoelectron spectral examinations of chirally modified nickel catalysts obtained under the different modification conditions revealed that the chiral modification process itself plays a major role in activating the nickel surface whilst the pre-activation procedure is a less important factor. The corresponding enantio-differentiating hydrogenations of methyl acetoacetate in the liquid phase using the prepared chiral catalysts unambiguously confirmed this conclusion, providing quantitative conversions and high enantioselectivities of up to 90%.
Efficient biocatalytic stereoselective reduction of methyl acetoacetate catalyzed by whole cells of engineered E. coli
Cui,Wei,Peng,Zong,Lou
, p. 9970 - 9978 (2018)
Asymmetric synthesis of chiral β-hydroxy esters, the key building blocks for many functional materials, is currently of great interest. In this study, the biocatalytic anti-Prelog reduction of methyl acetoacetate (MAA) to methyl-(R)-3-hydroxybutyrate ((R)-HBME) was successfully carried out with high enantioselectivity using the whole cell of engineered E. coli, which harbored an AcCR (carbonyl reductase) gene from Acetobacter sp. CCTCC M209061 and a GDH (glucose dehydrogenase) gene from Bacillus subtilis 168 for the in situ regeneration of the coenzyme. Compared with the corresponding wild strain, the engineered E. coli cells were proved to be more effective for the bio-reduction of MAA, and afforded much higher productivity. Under the optimized conditions, the product e.e. was >99.9% and the maximum yield was 85.3% after a reaction time of 10 h, which were much higher than those reported previously. In addition, the production of (R)-HBME increased significantly by using a fed-batch strategy of tuning pH, with a space-time yield of approximately 265 g L-1 d-1, thus the issue in previous research of relatively low substrate concentrations appears to be solved. Besides, the established bio-catalytic system was proved to be feasible up to a 150 mL scale with a large-scale relatively high substrate concentration and selectivity. For further industrial application, these results open a way to use of whole cells of engineered E. coli for challenging higher substrate concentrations of β-ketone esters enantioselective reduction reactions.
Catalytic enantiodifferentiating hydrogenation with commercial nickel powders chirally modified by tartaric acid and sodium bromide
Osawa, Tsutomu,Kizawa, Tomoko,Takano, Fumika,Ikeda, Shinji,Kitamura, Takayuki,Inoue, Yoshihisa,Borovkov, Victor
, p. 170 - 178 (2014)
The chirally modified nickel catalysts for the enantiodifferentiating hydrogenation of β-ketoesters are prepared conventionally by immersing hydrogen-activated metallic nickel into an aqueous solution of enantiopure tartaric acid, in which the preactivation of nickel is essential. Herein, we revealed that even commercially available nickel powders without any pretreatment can catalyze the enantiodifferentiating hydrogenation of β-ketoesters to give the corresponding β-hydroxyesters in quantitative yield and high enantioselectivity (up to 91 %) under optimized conditions. The immediate use of commercially available nickel powders and the reproducible high chemical and optical yields not only expand the scope of heterogeneous asymmetric catalysis but also pave the way for the practical application and industrial use of chirally modified nickel catalysts. Copyright
Heterogeneous enantioselective hydrogenation: PH dependence and interplay between catalytic efficacy and surface composition
Osawa, Tsutomu,Kizawa, Tomoko,Ikeda, Shinji,Kitamura, Takayuki,Inoue, Yoshihisa,Borovkov, Victor
, p. 1225 - 1226 (2013)
The performance of a catalytic system consisting of metallic Ni powder, tartaric acid (TA), and NaBr in the enantioselective hydrogenation of methyl acetoacetate was strongly influenced by the pH of TA solution upon chiral modification, which is attributable to the pH-induced change in the surface composition of Ni catalyst as unambiguously confirmed by X-ray photoelectron spectroscopy for the first time.
Influence of Synthesis Conditions on the Structure of Nickel Nanoparticles and their Reactivity in Selective Asymmetric Hydrogenation
Arrigo, Rosa,Gallarati, Simone,Schuster, Manfred E.,Seymour, Jake M.,Gianolio, Diego,da Silva, Ivan,Callison, June,Feng, Haosheng,Proctor, John E.,Ferrer, Pilar,Venturini, Federica,Grinter, David,Held, Georg
, p. 1491 - 1503 (2020)
Unsupported and SiO2-supported Ni nanoparticles (NPs) were synthesised via hot-injection colloidal route using oleylamine (OAm) and trioctylphosphine (TOP) as reducing and protective agents, respectively. By adopting a multi-length scale structural characterization, it was found that by changing equivalents of OAm and TOP not only the size of the nanoparticles is affected but also the Ni electronic structure. The synthetized NPs were modified with (R,R)-tartaric acid (TA) and investigated in the asymmetric hydrogenation of methyl acetoacetate to chiral methyl-3-hydroxy butyrate. The comparative analysis of structure and catalytic performance for the synthetized catalysts has enabled us to identify a Ni metallic active surface, whereby the activity increases with the size of the metallic domains. Conversely, at the high conversion obtained for the unsupported NPs there was no impact of particle size on the selectivity. (R)-selectivity was very high only on catalysts containing positively charged Ni species such as over the SiO2-supported NiO NPs. This work shows that the chiral modification of metallic Ni NPs with TA is insufficient to maintain high selectivity towards the (R)-enantiomer at long reaction times and provides guidance for the engineering of long-term stable enantioselective catalysts.
Occurrence of a High Concentration of Spider Pheromones in the Ascomycete Fungus Hypoxylon truncatum
Quang, Dang Ngoc,Hashimoto, Toshihiro,Toyota, Masao,Asakawa, Yoshinori
, p. 1613 - 1614 (2003)
A large amount of sex pheromones of the European spider Linyphia triangularis, 3R-hydroxybutyric acid (1), its dimer 3R-(3R-hydroxybutyryloxy)butyric acid (2), and trimer 3R-[3R-(3R-hydroxybutyryloxy)-butyryloxy]butyric acid (3) were isolated from the EtOAc extract of the Japanese inedible mushroom Hypoxylon truncatum.
Nectrianolins A, B, and C, new metabolites produced by endophytic fungus Nectria pseudotrichia 120-1NP
Ariefta, Nanang Rudianto,Kristiana, Priska,Nurjanto, Handojo Hadi,Momma, Hiroyuki,Kwon, Eunsang,Ashitani, Tatsuya,Tawaraya, Keitaro,Murayama, Tetsuya,Koseki, Takuya,Furuno, Hiroshi,Usukhbayar, Narandulam,Kimura, Ken-ichi,Shiono, Yoshihito
, p. 4082 - 4086 (2017)
Two sesquiterpene-epoxycyclohexenone conjugates, nectrianolins A (1) and B (2), together with a sesquiterpene, nectrianolin C (3), were isolated from the brown rice culture of Nectria pseudotrichia 120-1NP, an endophytic fungus isolated from Gliricidia sepium. Their structures were determined on the basis of 1D-/2D-NMR spectroscopy and HRESIMS data analyses in combination with chemical means. Nectrianolins A–C (1–3) exhibited cytotoxic activity against both HL60 and HeLa cells.
A C-GLUCOSYLATED 5-METHYLCHROMONE FROM KENYA ALOE
Speranza, Giovanna,Dada, Giuseppe,Lunazzi, Ludovico,Gramatica, Paola,Manitto, Paolo
, p. 2219 - 2222 (1986)
Key Word Index - Aloe ferox; Liliaceae; Kenya aloe; 5-methylchromones; C-glucoside; aloeresin D. A new bitter C-glucoside, aloeresin D, was isolated from a commercial sample of Kenya aloe.Its structure was assigned as 8-C-β-D-glucopyranosyl -2-propyl-7-methoxy-5-methyl-chromone by spectral data and chemical transformations.
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.
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.
