24915-95-5Relevant articles and documents
The effect of absorbing resins on substrate concentration and enantiomeric excess in yeast reduction
D'Arrigo, Paola,Fantoni, Giuseppe Pedrocchi,Servi, Stefano,Strini, Alberto
, p. 2375 - 2379 (1997)
The correlation between the enantiomeric excess (e.e.) of the (S)-(+)-ethyl-3-hydroxybutanoate 2, obtained in the baker's yeast reduction of ethyl acetoacetate 1, and the concentration of the substrates in the fermentation mixture has been studied by the use of two different techniques (absorbing resins and organic solvents) The presence of resins undoubtedly influences the enantiomeric excess of the product.
BEHAVIOR OF SKELETAL COPPER-PALLADIUM CATALYSTS IN ENANTIOSELECTIVE HYDROGENATION
Vedenyapin, A. A.,Kuznetsova, T. I.,Klabunovskii, E. I.,Akimov, V. M.,Gorina, N. B.,et al.
, p. 1990 - 1994 (1983)
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The use of liquefied petroleum gas (LPG) as a solvent for yeast reactions
Johns, Melanie K.,Smallridge, Andrew J.,Trewhella, Maurie A.
, p. 4261 - 4262 (2001)
The yeast mediated reduction of ethyl acetoacetate to ethyl (S)-3-hydroxy butyrate proceeds with good yield and high enantioselectivity in liquefied petroleum gas (LPG). It was found that slightly more water (2 ml/g yeast) and more yeast (1.6 g/mmol substrate) were required to effect complete conversion than was the case with more conventional organic solvents, such as petroleum spirit.
Enantio-differentiating hydrogenation of alkyl 3-oxobutanoates over tartaric acid-modified Ni catalyst: Enthalpy-entropy compensation effect as a tool for elucidating mechanistic features
Osawa, Tsutomu,Wakasugi, Masahiro,Kizawa, Tomoko,Borovkov, Victor,Inoue, Yoshihisa
, p. 131 - 136 (2018)
The enantio-differentiating hydrogenations of a series of alkyl 3-oxobutanoates were carried out at the temperatures ranging from 333 to 393 K over the (R,R)-tartaric acid-modified Ni catalyst prepared from commercially available Ni powder to achieve high enantiomeric excesses of 91-94%. It was demonstrated that the enantio-selectivity was not a simple function of the reaction temperature, being enhanced in the low temperature region to reach a maximum at 363–373 K and then decreased at higher temperatures. Nevertheless, all the differential enthalpies and entropies of activation calculated from the enantiomer ratios in the low and high temperature regions compensated with each other, indicating the same enantio-differentiation mechanism over the entire temperature range. A plausible enantio-differentiation mechanism explaining the effects of hydrogenation temperature on the enantio-selectivity is proposed.
LnNi5-xCux HYDRIDES MODIFIED BY R,R-(+)-TARTARIC ACID AS CATALYSTS FOR ETHYL ACETOACETATE HYDROGENATION
Starodubtseva, E. V.,Konenko, I. R.,Klabunovskii, E. I.,Savitskii, E. M.,Mordovich, V. P.,Savost'yanova, T. P.
, p. 696 - 700 (1984)
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SYNERGISM OF THE ASYMMETRIZING ACTION OF BIMETALLIC HYDROGENATION CATALYSTS
Vedenyapin, A. A.,Kuznetsova, T. I.,Klabunovskii, E. I.
, p. 1326 (1983)
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Formation of the (R)- and (S)-Enantiomers of Ethyl 3-Hydroxybutanoate and of 1-(1,3-Dithian-2-yl)-2-hydroxypropane by Microbial Reduction
Bernardi, Rosanna,Cardillo, Rosanna,Ghiringhelli, Dario
, p. 460 - 461 (1984)
The (R) and (S) enantiomers of 3-hydroxybutanoate and 1-(1,3-dithian-2-yl)-2-hydroxypropane are obtained from ethyl 3-oxobutanoate (1a) and 1-(1,3-dithian-2-yl)-2-oxopropane (1b), respectively, using growing cultures from different strains of Geotrichum candidum and Aspergillus niger.
β-Ketoester reduction by baker's yeast immobilized in calcium alginate: An examination of pH effects on enantiospecificity
Bhalerao,Chandraprakash,Babu,Fadnavis
, p. 1201 - 1208 (1993)
Enantiospecificity of the reduction process and product yields in the reduction of ethyl benzoylacetate by baker's yeast immobilized in calcium aliginate beads depend strongly on the pH of the medium, and under optimum conditions products with high yields (80-85%) and high optical purity (e.e. 90-99%) can be obtained.
ELECTROHYDROGENATION OF ETHYL ACETOACETATE ON A MODIFIED NICKEL CATALYST
Baturova, M. D.,Kuznetsova, T. I.,Vedenyapin, A. A.,Klabunovskii, E. I.
, p. 2478 - 2480 (1987)
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Triptycene-Based Chiral and meso-N-Heterocyclic Carbene Ligands and Metal Complexes
Savka, Roman,Bergmann, Marvin,Kanai, Yuki,Foro, Sabine,Plenio, Herbert
, p. 9667 - 9675 (2016)
Based on 1-amino-4-hydroxy-triptycene, new saturated and unsaturated triptycene-NHC (N-heterocyclic carbene) ligands were synthesized from glyoxal-derived diimines. The respective carbenes were converted into metal complexes [(NHC)MX] (M=Cu, Ag, Au; X=Cl, Br) and [(NHC)MCl(cod)] (M=Rh, Ir; cod=1,5-cyclooctadiene) in good yields. The new azolium salts and metal complexes suffer from limited solubility in common organic solvents. Consequently, the introduction of solubilizing groups (such as 2-ethylhexyl or 1-hexyl by O-alkylation) is essential to render the complexes soluble. The triptycene unit infers special steric properties onto the metal complexes that enable the steric shielding of selected areas close to the metal center. Next, chiral and meso-triptycene based N-heterocyclic carbene ligands were prepared. The key step in the synthesis of the chiral ligand is the Buchwald–Hartwig amination of 1-bromo-4-butoxy-triptycene with (1S,2S)-1,2-diphenyl-1,2-diaminoethane, followed by cyclization to the azolinium salt with HC(OEt)3. The analogous reaction with meso-1,2-diphenyl-1,2-diaminoethane provides the respective meso-azolinium salt. Both the chiral and meso-azolinium salts were converted into metal complexes including [(NHC)AuCl], [(NHC)RhCl(cod)], [(NHC)IrCl(cod)], and [(NHC)PdCl(allyl)]. An in situ prepared chiral copper complex was tested in the enantioselective borylation of α,β-unsaturated esters and found to give an excellent enantiomeric ratio (er close to 90:10).
HETEROGENEOUS NICKEL-COBALT CATALYSTS IN THE ENANTIOSELECTIVE HYDROGENATION OF ETHYL ACETOACETATE
Zubareva, N. D.,Klabunovskii, E. I.
, p. 1031 - 1033 (1988)
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INHIBITION OF ENANTIOSELECTIVE HYDROGENATION OF ETHYL ACETOACETATE
Chernysheva, V. V.,Murina, I. P.,Klabunovskii, E. I.
, p. 689 - 692 (1983)
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Synthesis of BINAP ligands with imidazole tags for highly enantioselective Ru-catalyzed asymmetric hydrogenation of β-keto esters in ionic liquid systems
Jin, Xin,Kong, Fang-Fang,Yang, Zhi-Qiang,Cui, Fei-Fei
, p. 22 - 26 (2013)
The imidazole-tagged BINAP ligands were synthesized and used for Ru-catalyzed asymmetric hydrogenation of β-keto esters in ionic liquid (IL) systems. The Ru-BINAP catalysts with the imidazolium tags show high catalytic activity and enantioselectivity, which closely parallel the performance of unmodified BINAP. The catalyst recycling experiments using [bmim]Tf 2N/MeOH system demonstrated that introducing imidazolium moieties to the BINAP backbone can effectively enhance the affinity of the Ru-catalysts to the IL, reduce Ru leaching and improve catalysts stability, and after several cycles no significant loss of activity and enantioselectivity was observed.
Study on effects of modification conditions of powdered nickel-cobalt catalysts on enantioselectivity of hydrogenation of ethyl acetoacetate
Zubareva,Dorokhin,Klabunovskii
, p. 499 - 501 (2009)
An effect of modification conditions of powdered nickel-cobalt catalysts on enantioselectivity of hydrogenation of ethyl acetoacetate has been studied. Addition of NaBr to the modifying solution of RR-(+)-tartaric acid does not improve enantioselectivity of the catalyst. When the Ni-Co catalysts are modified with amino acids, the best results are obtained with L-β-plienylalanine (17% ee).
Enantioselective catalytic asymmetric hydrogenation of ethyl acetoacetate in room temperature ionic liquids
Berthod, Mikael,Joerger, Jean-Michel,Mignani, Gerard,Vaultier, Michel,Lemaire, Marc
, p. 2219 - 2221 (2004)
Ethyl acetoacetate was chosen to evaluate the efficiency of hydrosoluble derivatives of 4,4′- and 5,5′-diamBINAP in enantioselective catalytic asymmetric hydrogenation in various room temperature ionic liquids (RTILs). Complete conversion and good selectivity were obtained. Recycling by simple extraction with pentane was also possible.
ENANTIOSELECTIVE HYDROGENATION OF ETHYL ACETOACETATE ON ASYMMETRIC RANEY Ni CATALYST
Zubareva, N. D.,Chernysheva, V. V.,Grigor'ev, Yu. A.,Klabunovskii, E. I.
, p. 476 - 478 (1987)
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ENHANCED OPTICAL PURITY OF 3-HYDROXYESTERS OBTAINED BY BAKER'S YEAST REDUCTION OF 3-KETOESTERS
Spiliotis, Vassilis,Papahatjis, Demetris,Ragoussis, Nikitas
, p. 1615 - 1616 (1990)
Fermenting Baker's yeast, enclosed in a dialysis tube, reduces efficiently 3-ketoesters added to the surrounding subtonic solution, to the corresponding 3-hydroxyesters in good yield (45-55percent) and enhanced optical purity (ee 96-97percent)
107. Preparative Asymmetric Reduction of 3-Ketobutyrate and -valerate by Suspended Cells of Thermophilic Bacteria (Thermoanaerobium brockii) in Ordinary Laboratory Equipment
Seebach, Dieter,Giovannini, Fabio,Lamatsch, Bernd
, p. 958 - 960 (1985)
The thermophilic and anaerobic bacteria specified in the title are isolated on a 0.8 kg scale by tangential flow filtration and centrifugation from a 300-l bioreactor.The microorganisms are stored in a freezer (-20 deg) and used, analogously to baker's yeast, for asymmetric reductions.Thus, ethyl 3-ketovalerate (4.3 g/l (H2O) is converted in 40 percent yield to (S)-3-hydroxyvalerate (6), with an enantiomeric excess of 93 percent (24 h at 72 deg).
SORPTION AND CATALYTIC PROPERTIES OF LaNi3 AND LaNi5-xCuX INTERMETALLIC COMPOUNDS AND THEIR HYDRIDES
Konenko, I. R.,Starodubtseva, E. V.,Fedorovskaya, E. A.,Klabunovskii, E. I.,Savitskii, E. M.,Mordovin, V. P.
, p. 692 - 696 (1984)
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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.
SYNTHESIS OF 3-HYDROXYBUTYRYL 3-HYDROXYBUTYRATE AND RELATED COMPOUNDS
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Paragraph 0308; 0317, (2021/04/02)
In various embodiments methods of preparing hydroxybutyryl 3-hydroxybutyrate and related compounds are provided along with methods of use thereof.
