51555-24-9Relevant academic research and scientific papers
Enantioselective hydrogenation of activated ketones in the presence of Pt-cinchona catalysts. Is the proton transfer concept valid?
Margitfalvi, József L.,Tálas, Emília
, p. 142 - 145 (2014)
Experimental evidences related to the proton transfer in the catalytic system Pt-cinchona alkaloids for enantioselective hydrogenation of activated ketones were collected and analyzed. Both new and earlier results indicate that in aprotic media direct transfer of proton from platinum to the substrate with the involvement of quinuclidine nitrogen as a general rule can be questioned.
Studies on structure-function relationships of acetolactate decarboxylase from: Enterobacter cloacae
Ji, Fangling,Feng, Yanbin,Li, Mingyang,Yang, Yongliang,Wang, Tianqi,Wang, Jingyun,Bao, Yongming,Xue, Song
, p. 39066 - 39073 (2018)
Acetoin is an important bio-based platform chemical with wide applications. Among all bacterial strains, Enterobacter cloacae is a well-known acetoin producer via α-acetolactate decarboxylase (ALDC), which converts α-acetolactate into acetoin and is identified as the key enzyme in the biosynthetic pathway of acetoin. In this work, the enzyme properties of Enterobacter cloacae ALDC (E.c.-ALDC) were characterized, revealing a Km value of 12.19 mM and a kcat value of 0.96 s-1. Meanwhile, the optimum pH of E.c.-ALDC was 6.5, and the activity of E.c.-ALDC was activated by Mn2+, Ba2+, Mg2+, Zn2+ and Ca2+, while Cu2+ and Fe2+ significantly inhibited ALDC activity. More importantly, we solved and reported the first crystal structure of E.c.-ALDC at 2.4 ? resolution. The active centre consists of a zinc ion coordinated by highly conserved histidines (199, 201 and 212) and glutamates (70 and 259). However, the conserved Arg150 in E.c.-ALDC orients away from the zinc ion in the active centre of the molecule, losing contact with the zinc ion. Molecular docking of the two enantiomers of α-acetolactate, (R)-acetolactate and (S)-acetolactate allows us to further investigate the interaction networks of E.c.-ALDC with the unique conformation of Arg150. In the models, no direct contacts are observed between Arg150 and the substrates, which is unlikely to maintain the stabilization function of Arg150 in the catalytic reaction. The structure of E.c.-ALDC provides valuable information about its function, allowing a deeper understanding of the catalytic mechanism of ALDCs.
Enhanced production of optical (: S)-acetoin by a recombinant Escherichia coli whole-cell biocatalyst with NADH regeneration
Li, Jian-Xiu,Huang, Yan-Yan,Chen, Xian-Rui,Du, Qi-Shi,Meng, Jian-Zong,Xie, Neng-Zhong,Huang, Ri-Bo
, p. 30512 - 30519 (2018)
Acetoin is an important platform chemical with a variety of applications in foods, cosmetics, chemical synthesis, and especially in the asymmetric synthesis of optically active pharmaceuticals. It is also a useful breath biomarker for early lung cancer diagnosis. In order to enhance production of optical (S)-acetoin and facilitate this building block for a series of chiral pharmaceuticals derivatives, we have developed a systematic approach using in situ-NADH regeneration systems and promising diacetyl reductase. Under optimal conditions, we have obtained 52.9 g L-1 of (S)-acetoin with an enantiomeric purity of 99.5% and a productivity of 6.2 g (L h)-1. The results reported in this study demonstrated that the production of (S)-acetoin could be effectively improved through the engineering of cofactor regeneration with promising diacetyl reductase. The systematic approach developed in this study could also be applied to synthesize other optically active α-hydroxy ketones, which may provide valuable benefits for the study of drug development.
Efficient (3S)-acetoin and (2S, 3S)-2, 3-butanediol production from meso-2, 3-butanediol using whole-cell biocatalysis
He, Yuanzhi,Chen, Feixue,Sun, Meijing,Gao, Huifang,Guo, Zewang,Lin, Hui,Chen, Jiebo,Jin, Wensong,Yang, Yunlong,Zhang, Liaoyuan,Yuan, Jun
, (2018)
(3S)-Acetoin and (2S, 3S)-2, 3-butanediol are important platform chemicals widely applied in the asymmetric synthesis of valuable chiral chemicals. However, their production by fermentative methods is difficult to perform. This study aimed to develop a whole-cell biocatalysis strategy for the production of (3S)-acetoin and (2S, 3S)-2, 3-butanediol from meso-2, 3-butanediol. First, E. coli co-expressing (2R, 3R)-2, 3-butanediol dehydrogenase, NADH oxidase and Vitreoscilla hemoglobin was developed for (3S)-acetoin production from meso-2, 3-butanediol. Maximum (3S)-acetoin concentration of 72.38 g/L with the stereoisomeric purity of 94.65% was achieved at 24 h under optimal conditions. Subsequently, we developed another biocatalyst co-expressing (2S, 3S)-2, 3-butanediol dehydrogenase and formate dehydrogenase for (2S, 3S)-2, 3-butanediol production from (3S)-acetoin. Synchronous catalysis together with two biocatalysts afforded 38.41 g/L of (2S, 3S)-butanediol with stereoisomeric purity of 98.03% from 40 g/L meso-2, 3-butanediol. These results exhibited the potential for (3S)-acetoin and (2S, 3S)-butanediol production from meso-2, 3-butanediol as a substrate via whole-cell biocatalysis.
Enantioselective enzymatic synthesis of the α-hydroxy ketone (R)-acetoin from meso-2,3-butanediol
Kochius, Svenja,Paetzold, Melanie,Scholz, Alexander,Merkens, Hedda,Vogel, Andreas,Ansorge-Schumacher, Marion,Hollmann, Frank,Schrader, Jens,Holtmann, Dirk
, p. 61 - 66 (2014)
Acetoin (3-hydroxy-2-butanone) is an important flavour compound and is applied in cosmetics, pharmacy and chemical synthesis. In contrast to chemical syntheses or fermentations an enzymatic route facilitates enantioselective acetoin production. The discovery of a (S)-selective alcohol dehydrogenase enables a novel production process of (R)-acetoin from meso-2,3-butanediol. It was shown that the regeneration of oxidised nicotinamide adenine dinucleotide is a key point in preparative application of dehydrogenases for the oxidative route. An electrochemical regeneration system was successful combined with the ADH catalysed reaction. Up to 48 mM (R)-acetoin was produced in the reaction system while productivities up to 2 mM h-1 were reached. The possibility to apply an electrochemical system in a semi-preparative synthesis will stimulate further research of electroenzymatic processes with oxidoreductases.
Elucidation of the enantioselective cyclohexane-1,2-dione hydrolase catalyzed formation of (S)-acetoin
Loschonsky, Sabrina,Waltzer, Simon,Brecht, Volker,Mueller, Michael
, p. 969 - 972 (2014)
Thiamine diphosphate (ThDP) dependent enzymes catalyze the formation of acetoin (3-hydroxybutan-2-one) through one of three different pathways: homocoupling of pyruvate, homocoupling of acetaldehyde, or cross-coupling of acetaldehyde (as acceptor) and pyruvate (as donor). The enantioselectivity of the resulting acetoin is highly dependent on the particular enzyme. We established that ThDP-dependent cyclohexane-1,2-dione hydrolase (CDH) is able to form (S)-acetoin with particularly high enantioselectivity (up to 95 % ee) by all three pathways. Mechanistic studies utilizing 13C-labeled substrates revealed an unprecedented non-acetolactate pathway for the homocoupling of pyruvate, which explains the high enantioselectivity in the CDH-catalyzed formation of (S)-acetoin. Differentiating hydrolases: Investigating thiamine diphosphate dependent cyclohexane-1,2-dione hydrolase (CDH) catalyzed homocoupling of 13C-labeled [1,2]-13C-pyruvate to (S)-[2,3]-13C-acetoin reveals a non-acetolactate pathway, which explains the high enantioselectivity of this reaction (up to 93 % ee). CDH also catalyzes the formation of (S)-acetoin by the cross-coupling of pyruvate and acetaldehyde and the homocoupling of acetaldehyde.
The effect of water on the enantioselective hydrogenation of ethyl pyruvate and butane-2,3-dione using cinchona-modified Pt/Al2O3
Wells, Richard P. K.,McGuire, Neil R.,Li, Xiaobao,Jenkins, Robert L.,Collier, Paul J.,Whyman, Robin,Hutchings, Graham J.
, p. 2839 - 2845 (2002)
A detailed study of Pt/alumina modified with cinchona alkaloids for the catalytic enantioselective hydrogenation of ethyl pyruvate to ethyl lactate and of butane-2,3-dione to 3-hydroxybutan-2-one is reported. Catalytic and 1H NMR spectroscopic studies have been carried out on both systems to investigate the influence of water on modifier conformation and enantioselectivity. Interestingly, the presence of small amounts of water has been shown to result in an increase the proportion of the open 3 conformer of cinchonidine when it is present in dilute solutions. Increased enantioselectivity, coupled with an increase in the proportion of the open 3 conformation of cinchonidine, is observed after pretreatment of the pyruvate ester with the modifier prior to admission to the reaction vessel. In contrast, no analogous effects are observed with butane-2,3-dione. It is proposed that the enhancements in enantioselectivity are a consequence of hydrolysis of ethyl pyruvate by a process that is catalysed by the basic cinchona modifier. The pyruvic acid formed during the hydrolysis interacts with the modifier and this leads to a further enhancement in the concentration of open 3 conformer present. The results contribute to an understanding of the widely variable enantioselectivities reported in the literature for this reaction.
N-PEGylated Thiazolium Salt: A Green and Reusable Homogenous Organocatalyst for the Synthesis of Benzoins and Acyloins
Haghighi, Ali Javaheri,Mokhtari, Javad,Karimian, Khashayar
, p. 1646 - 1652 (2020/10/19)
N-PEGylated-thiazolium salt is used as efficient catalyst for the benzoin condensation. The catalyst was synthesized by reaction of activated polyethylene glycol 10,000 (PEG-10000) with 4-methyl-5-thiazoleethanol (sulfurol). Reaction mixture undergoes temperature-assisted phase transition and catalyst separated by simple filtration. After reaction course, catalyst can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. Synthesized benzoins and acyloins by this method have been characterized on the basis of melting point and 1H-NMR spectral studies. Graphic Abstract: [Figure not available: see fulltext.]
carba Nicotinamide Adenine Dinucleotide Phosphate: Robust Cofactor for Redox Biocatalysis
D?ring, Manuel,Sieber, Volker,Simon, Robert C.,Tafertshofer, Georg,Zachos, Ioannis
supporting information, p. 14701 - 14706 (2021/05/13)
Here we report a new robust nicotinamide dinucleotide phosphate cofactor analog (carba-NADP+) and its acceptance by many enzymes in the class of oxidoreductases. Replacing one ribose oxygen with a methylene group of the natural NADP+ was found to enhance stability dramatically. Decomposition experiments at moderate and high temperatures with the cofactors showed a drastic increase in half-life time at elevated temperatures since it significantly disfavors hydrolysis of the pyridinium-N?glycoside bond. Overall, more than 27 different oxidoreductases were successfully tested, and a thorough analytical characterization and comparison is given. The cofactor carba-NADP+ opens up the field of redox-biocatalysis under harsh conditions.
Sol-gel synthesis of ceria-zirconia-based high-entropy oxides as high-promotion catalysts for the synthesis of 1,2-diketones from aldehyde
Dinjar, Kristijan,Djerdj, Igor,Koj?inovi?, Jelena,Kukovecz, ákos,Markovi?, Berislav,Mileti?, Aleksandar,Nagy, Sándor Balázs,Sapi, Andras,Stenzel, David,Széchenyi, Aleksandar,Szenti, Imre,Tang, Yushu,Tatar, Dalibor,Varga, Gábor,Ziegenheim, Szilveszter
, (2021/10/20)
Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.
