Готові списки джерел за темами / Chemoenzymatic catalysis

Добірка наукової літератури з теми "Chemoenzymatic catalysis"

Автор: Grafiati

Опубліковано: 5 березня 2024

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Статті в журналах з теми "Chemoenzymatic catalysis":

Pauly, Jan, Harald Gröger, and Anant V. Patel. "Developing Multicompartment Biopolymer Hydrogel Beads for Tandem Chemoenzymatic One-Pot Process." Catalysts 9, no. 6 (June 18, 2019): 547. http://dx.doi.org/10.3390/catal9060547.

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Chemoenzymatic processes have been gaining interest to implement sustainable reaction steps or even create new synthetic routes. In this study, we combined Grubbs’ second-generation catalyst with pig liver esterase and conducted a chemoenzymatic one-pot process in a tandem mode. To address sustainability, we encapsulated the catalysts in biopolymer hydrogel beads and conducted the reaction cascade in an aqueous medium. Unfortunately, conducting the process in tandem led to increased side product formation. We then created core-shell beads with catalysts located in different compartments, which notably enhanced the selectivity towards the desired product compared to homogeneously distributing both catalysts within the matrix. Finally, we designed a specific large-sized bead with a diameter of 13.5 mm to increase the diffusion route of the Grubbs’ catalyst-containing shell. This design forced the ring-closing metathesis to occur first before the substrate could diffuse into the pig liver esterase-containing core, thus enhancing the selectivity to 75%. This study contributes to addressing reaction-related issues by designing specific immobilisates for chemoenzymatic processes.

Xu, Yuanfeng, Meng Wang, Bo Feng, Ziyang Li, Yuanhua Li, Hexing Li, and Hui Li. "Dynamic kinetic resolution of aromatic sec-alcohols by using a heterogeneous palladium racemization catalyst and lipase." Catalysis Science & Technology 7, no. 24 (2017): 5838–42. http://dx.doi.org/10.1039/c7cy01954h.

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Mertens, M. A. Stephanie, Daniel F. Sauer, Ulrich Markel, Johannes Schiffels, Jun Okuda, and Ulrich Schwaneberg. "Chemoenzymatic cascade for stilbene production from cinnamic acid catalyzed by ferulic acid decarboxylase and an artificial metathease." Catalysis Science & Technology 9, no. 20 (2019): 5572–76. http://dx.doi.org/10.1039/c9cy01412h.

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Kadokawa, Jun-ichi. "Enzymatic preparation of functional polysaccharide hydrogels by phosphorylase catalysis." Pure and Applied Chemistry 90, no. 6 (June 27, 2018): 1045–54. http://dx.doi.org/10.1515/pac-2017-0802.

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Abstract This article reviews enzymatic preparation of functional polysaccharide hydrogels by means of phosphorylase-catalyzed enzymatic polymerization. A first topic of this review deals with the synthesis of amylose-grafted polymeric materials and their formation of hydrogels, composed of abundant natural polymeric main-chains, such as chitosan, cellulose, xantham gum, carboxymethyl cellulose, and poly(γ-glutamic acid). Such synthesis was achieved by combining the phosphorylase-catalyzed enzymatic polymerization forming amylose with the appropriate chemical reaction (chemoenzymatic method). An amylose-grafted chitin nanofiber hyrogel was also prepared by the chemoenzymatic approach. As a second topic, the preparation of glycogen hydrogels by the phosphorylase-catalyzed enzymatic reactions was described. When the phosphorylase-catalyzed enzymatic polymerization from glycogen as a polymeric primer was carried out, followed by standing the reaction mixture at room temperature, a hydrogel was obtained. pH-Responsive amphoteric glycogen hydrogels were also fabricated by means of the successive phosphorylase-catalyzed enzymatic reactions.

Horvat, Melissa, Victoria Weilch, Robert Rädisch, Sebastian Hecko, Astrid Schiefer, Florian Rudroff, Birgit Wilding, et al. "Chemoenzymatic one-pot reaction from carboxylic acid to nitrile via oxime." Catalysis Science & Technology 12, no. 1 (2022): 62–66. http://dx.doi.org/10.1039/d1cy01694f.

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We report a new chemoenzymatic cascade starting with aldehyde synthesis by carboxylic acid reductase (CAR) followed by chemical in situ oxime formation and enzymatic dehydration by aldoxime dehydratase (Oxd).

Reymond, Jean-Louis, and Jérémy Boilevin. "Synthesis of Lipid-Linked Oligosaccharides (LLOs) and Their Phosphonate Analogues as Probes To Study Protein Glycosylation Enzymes." Synthesis 50, no. 14 (June 26, 2018): 2631–54. http://dx.doi.org/10.1055/s-0037-1609735.

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Here we review chemical and chemoenzymatic methods for the synthesis of lipid-linked oligosaccharides (LLOs) and their phosphonate analogues, which serve as substrates and inhibitors to investigate the structure and mechanism of protein N-glycosylation enzymes. We emphasize how to overcome the challenges pertaining to the instability and difficult physicochemical properties of this class of compounds.1 Introduction2 LLO Syntheses2.1 Glycosyl Phosphate Syntheses2.2 Glycosyl Phosphonates2.3 Lipid Elongation2.4 Lipid Phosphates2.5 Coupling Reaction Strategies3 Chemoenzymatic Synthesis of Elongated LLOs4 Biological Properties of Synthetic LLOs5 Conclusion

Kuska, Justyna, Freya Taday, Kathryn Yeow, James Ryan, and Elaine O'Reilly. "An in vitro–in vivo sequential cascade for the synthesis of iminosugars from aldoses." Catalysis Science & Technology 11, no. 13 (2021): 4327–31. http://dx.doi.org/10.1039/d1cy00698c.

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Here, we report a chemoenzymatic approach for the preparation of a small panel of biologically important iminosugars from readily available aldoses, employing a transaminase in combination with Gluconobacter oxydans whole cells.

Gao, Liya, Zihan Wang, Yunting Liu, Pengbo Liu, Shiqi Gao, Jing Gao, and Yanjun Jiang. "Co-immobilization of metal and enzyme into hydrophobic nanopores for highly improved chemoenzymatic asymmetric synthesis." Chemical Communications 56, no. 88 (2020): 13547–50. http://dx.doi.org/10.1039/d0cc06431a.

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Wu, Yuqi, Jiawei Shen, Dong Yang, Daozhu Xu, Menghan Huang, and Yucai He. "Production of Furfuryl Alcohol from Corncob Catalyzed By CCZU-KF Cell Via Chemoenzymatic Approach." Academic Journal of Science and Technology 6, no. 1 (June 2, 2023): 132–38. http://dx.doi.org/10.54097/ajst.v6i1.9022.

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In this work, the hybrid route of chemo-catalysis and bio-catalysis were used to chemoenzymatically catalyze corncob to produce furfuryl alcohol via sequential conversion with solid acid catalyst at 180 ℃ for 10 min, and E. coli CCZU-KF whole-cell biocatalyst at 35 ℃ for 72 h in 10 vol% choline chloride system. The yield of furfuryl alcohol was 97.7%. This work successfully demonstrated the green and efficient synthesis of furfuryl alcohol production from biomass via chemoenzymatic approach.

Gadler, P., S. M. Glueck, W. Kroutil, B. M. Nestl, B. Larissegger-Schnell, B. T. Ueberbacher, S. R. Wallner, and K. Faber. "Biocatalytic approaches for the quantitative production of single stereoisomers from racemates." Biochemical Society Transactions 34, no. 2 (March 20, 2006): 296–300. http://dx.doi.org/10.1042/bst0340296.

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Strategies for the chemoenzymatic transformation of a racemate into a single stereoisomeric product in quantitative yield have been developed. A range of industrially relevant α-hydroxycarboxylic acids was deracemized in a stepwise fashion via lipase-catalysed enantioselective O-acylation, followed by mandelate racemase-catalysed racemization of the remaining non-reacted substrate enantiomer. Alternatively, aliphatic α-hydroxycarboxylic acids were enzymatically isomerized using whole resting cells of Lactobacillus spp. Enantioselective hydrolysis of rac-sec-alkyl sulphate esters was accomplished using novel alkyl sulphatases of microbial origin. The stereochemical path of catalysis could be controlled by choice of the biocatalyst. Whereas Rhodococcus ruber DSM 44541 and Sulfolobus acidocaldarius DSM 639 act through inversion of configuration, stereo-complementary retaining sulphatase activity was detected in the marine planctomycete Rhodopirellula baltica DSM 10527.

Більше джерел

Дисертації з теми "Chemoenzymatic catalysis":

Horrobin, Tina M. "The chemoenzymatic synthesis of oligosaccharides." Thesis, University of Warwick, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307318.

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Luo, Yunfei. "Chemoenzymatic synthesis of C2 symmetric chiral dienes for asymmetric catalysis." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539483.

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Beluocine, T. "Chemoenzymatic synthesis of enantiopure arene cis-diols : applications in asymmetric homogenous catalysis." Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431407.

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Gairola, Priyanka. "Association of Metal-Organic Framework and Transaminase for chemoenzymatic production of amines." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS107.

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Du fait de la raréfaction des ressources fossiles, l’industrie chimique doit aujourd’hui évoluer pour se tourner vers de nouvelles sources de matière première. A cela s’ajoutent les pressions environnementales toujours croissantes qui imposent une réduction de l’impact écologique et énergétique des procédés. Répondre à ces enjeux technologiques majeurs implique la conception de nouveaux procédés chimiques rendant notamment possible la transformation massive des ressources chimiques d’origine naturelle (cellulose, lignine, algues...etc) en produits chimiques à haute valeur ajoutée et répondant aux critères dits de « chimie verte ». , Dans ce contexte, la catalyse hétérogène est un outil incontournable puisqu’elle permet d’accélérer les réactions chimiques, dans des conditions durables, en rendant possible le recyclage des phases actives. Le développement de procédés toujours plus adaptés aux enjeux industriels et environnementaux actuels nécessite cependant l’élaboration de nouveaux catalyseurs, notamment capables de réduire toujours davantage la consommation d’énergie, de faire des économie d’atomes et de réduire autant que possible les quantités de réactifs et de solvants utilisés ainsi que les déchets produits. Pour ce faire, les catalyseurs hétérogènes capables de catalyser plusieurs réactions chimiques en une seule étape « en cascade » sont particulièrement prometteurs. [...] L’objectif global de [ma] thèse était de fabriquer un système chimioenzymatique capable de réaliser une cascade de deux réactions permettant la transformation d’alcools en amines. Pour cela il était proposé d’immobiliser sur un matériau hybride organique-inorganique poreux cristallin appelé MOF (Metal-Organic Framework), un catalyseur chimique, responsable d’une première étape d'oxydation d'alcool en composé carbonylé, et une enzyme transaminase catalysant l’étape ultérieure de transfert d'amine. La mise en œuvre d'un tel système sophistiqué était un réel défi, notamment parce qu’il s’agissait de trouver des conditions de réaction (solvant, température, pH, et choix des réactifs chimiques) qui soient compatibles avec les conditions de travail des transaminases (températures de réaction douces ≤ 60 ° C, solvants au moins partiellement aqueux). Ceci était un pré-requis nécessaire à la réalisation des synthèses "one-pot", où les deux réactions visées devaient être catalysées consécutivement par le catalyseur chimique et l’enzyme dans le même milieu réactionnel sans isolement du carbonylé intermédiaire. Il fallait également s’assurer de la stabilité du MOF dans le milieu réactionnel, et notamment de l’intégrité de sa structure dans des solvants contenant les solutions tampons aqueuses nécessaires à la stabilité des enzymes. [...]
Due to the scarcity of fossil resources, the chemical industry must today evolve to turn to new sources of raw material. Added to this are the ever-increasing environmental pressures that impose a reduction in the ecological and energy impact of the processes. Responding to these major technological challenges involves the design of new chemical processes making it possible, in particular, for the massive transformation of natural chemical resources (cellulose, lignin, algae, etc.) into high value-added chemicals that meet the so-called "Green chemistry" i, ii. In this context, heterogeneous catalysis is an essential tool since it makes it possible to accelerate the chemical reactions under sustainable conditions by making it possible to recycle the active phases ii. The development of processes that are increasingly adapted to today's industrial and environmental challenges, however, requires the development of new catalysts, in particular capable of reducing energy consumption even more, of saving atoms and of reducing as much as possible the quantities of reagents and solvents used as well as the waste produced. To do this, heterogeneous catalysts capable of catalyzing several chemical reactions in one step "in cascade" are particularly promising. [...] The overall goal of this thesis was to build a chemoenzymatic system capable of carrying out a cascade of two reactions allowing the transformation of alcohols into amines. For that it was proposed to immobilize on a crystalline organic-inorganic hybrid material called MOF (Metal-Organic Framework), a chemical catalyst, responsible for a first step of oxidation of alcohol to carbonyl compound, and a transaminase enzyme catalyzing the subsequent amine transfer step. The implementation of such a sophisticated system was a real challenge, especially because it was a question of finding reaction conditions (solvent, temperature, pH, and choice of chemical reagents) that are compatible with the working conditions of transaminases (mild reaction temperatures ≤ 60 ° C, at least partially aqueous solvents). This was a prerequisite for carrying out "one-pot" syntheses, where the two targeted reactions were to be catalyzed consecutively by the chemical catalyst and the enzyme in the same reaction medium without isolation of the intermediate carbonyl. It was also necessary to ensure the stability of the MOF in the reaction medium, and in particular the integrity of its structure in solvents containing the aqueous buffer solutions necessary for the stability of the enzymes. [...]

Warner, Madeleine. "Ruthenium-Catalyzed Hydrogen Transfer Reactions : Mechanistic Studies and Chemoenzymatic Dynamic Kinetic Resolutions." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-89263.

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The main focus of this thesis lies on transition metal-catalyzed hydrogen transfer reactions. In the first part of the thesis, the mechanism for racemization of sec-alcohols with a ruthenium complex, Ru(CO)2Cl(η5-C5Ph5) was studied. The reaction between 5-hexen-2-ol and Ru(CO)2(Ot-Bu)(η5-C5Ph5) was studied with the aim to elucidate the origin of the slow racemization observed for this sec-alcohol. Two diastereomers of an alkoxycarbonyl complex, which has the double bond coordinated to ruthenium, were characterized by NMR and in situ FT-IR spectroscopy. The observed inhibition of the rate of racemization for substrates with double bonds provided further confirmation of the importance of a free coordination site on ruthenium for β-hydride elimination. Furthermore, we observed that CO exchange, monitored by 13C NMR using 13CO, occurs with both the precatalyst, Ru(CO)2Cl(η5-C5Ph5), and the active catalytic intermediate, Ru(CO)2(Ot-Bu)(η5-C5Ph5). It was also found that added CO has an inhibitory effect on the rate of racemization of (S)-1-phenylethanol. Both these observations provide strong support for reversible CO dissociation as a key step in the racemization mechanism. In the second part of this thesis, Ru(CO)2Cl(η5-C5Ph5) was combined with an enzymatic resolution catalyzed by a lipase, leading to several efficient dynamic kinetic resolutions (DKR). DKR of exocyclic allylic alcohols afforded the corresponding acetates in high yields and with excellent enantiomeric excess (ee). The products were utilized as synthetic precursors for α-substituted ketones and lactones. DKR of a wide range of homoallylic alcohols afforded the products in good to high yields and with high ee. The homoallylic acetates were transformed into 5,6-dihydropyran-2-ones in a short reaction sequence. Furthermore, DKR of a wide range of aromatic β-chloroalcohols afforded the products in high yields and with excellent ee. The β-chloro acetates were further transformed into chiral epoxides.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Mansucript.

Zan, Yifan. "Development of heterogeneous chemoenzymatic catalysts based on Metal-Organic Framework for the selective and eco-friendly amination of alcohols." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS518.pdf.

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L'objectif de ce travail était de développer un catalyseur chimio-enzymatique hétérogène basé sur l'utilisation de polymères de coordination poreux (ou Metal-Organic Framework: MOF) comme supports pour l'amination durable d'alcools à travers un procédé en cascade réalisé en une seule étape. Le processus en cascade est composé de deux étapes: la reaction d’oxydation de l'alcool catalysée chimiquement et l'amination énantiosélective de l'intermédiaire carbonylé resultant, catalysée par une enzyme ω-transaminase (ω-TA). Le ZIF-8 a été choisi comme support pour sa stabilité dans l’eau et à hautes températures, ce qui en fait un support idéal pour l’immobilisation de catalyseurs chimiques et biologiques. Dans ce travail, l'un des principaux défis consistait à sélectionner un système catalytique chimique dédié à la réaction d'oxydation de l'alcool dans des conditions aqueuses douces, compatibles avec les conditions de travail des enzymes ω-TAs. Dans ce contexte, deux systèmes catalytiques à base de nanoparticules supportées ont été développés. Dans le premier système, des sites actifs Cu2+ ont été hétérogénéisés dans la structure du ZIF-8 en vue de l'oxydation de l'alcool benzylique en présence de 2,2,6,6-Tétraméthylpipéridine-1-oxyle (TEMPO). Le problème de la lixiviation du Cu2+ au cours du processus catalytique a été résolu en réduisant le Cu2+ in situ dans les pores du ZIF-8 pour former des nanoparticules de Cu0 supportées et bien dispersées au sein du support. Ce catalyseur présente une stabilité et une sélectivité élevées, mais n'est pas actif lorsque l'eau est utilisée comme solvant. Dans le second système, des nanoparticules d'alliage bimétallique PdAu dispersées au sein du ZIF-8 ont été formées (PdAu@ZIF-8) pour catalyser l'oxydation aérobie de l'alcool en milieu aqueux à pH neutre. Le catalyseur présente une excellente activité dans des conditions douces, la meilleure performance étant obtenue pour un rapport atomique Pd/Au de 9:1. Les deux catalyseurs ont été caractérisés par PXRD, physisorption d’azote, microscopie électronique à haute résolution et XPS. La deuxième étape du processus en cascade implique l'amination biocatalysée du composé carbonylé obtenu lors de la première étape. Deux ω-TA S-sélectives issues des bactéries Silicibacter pomeroyi (3HMU) et Chromobacterium violaceum ont été testées. Le rendement maximal en S-α-méthylbenzylamine obtenu par amination de l'acétophénone en présence de 3HMU en utilisant la L-alanine comme donneur d'amine était de 77%. Les efforts visant à combiner ensuite l'oxydation de l'alcool catalysée par les nanoparticules de PdAu supportées sur le ZIF-8 et la catalyse enzymatique utilisant la 3HMU dans un processus en une seule étape ont révélé des interférences entre les composants chimiques indispensables à la réalisation de chaque étape. En conséquence, un processus en cascade alternatif réalisé dans un même milieu réactionnel mais dans lequel les deux étapes sont découplées a été mis au point. Celui-ci a permis d'obtenir un rendement global de S-MBA de 49%. Des tentatives ont finalement été effectuées pour immobiliser la 3HMU sur le catalyseur PdAu@ZIF-8 afin d'obtenir le catalyseur entièrement hétérogène ciblé. L’immobilisation a tout d’abord été réalisée par adsorption physique, mais l'activité des ω-TAs ainsi immobilisées s’est avérée être limitée. La modification de PdAu@ZIF-8 par adsorption de Ni2+ a légèrement amélioré l'immobilisation de l'enzyme. Dans une autre approche, le ZIF-8 fonctionnalisé avec des fonctions carbonyles grâce à un échange partiel “post-synthèse” des ligands 2-méthylimidazole du ZIF-8 avec des dérivés carbonylés d’imidazole, a conduit à des résultats encourageants, avec une amélioration de l'activité de la 3HMU immobilisée sur le ZIF-8 ainsi préparé d'un facteur 4. Cette approche prometteuse sera exploitée plus avant prochainement afin de synthétiser le catalyseur entièrement hétérogène 3HMU@PdAu@ZIF-8 visé dans ce projet de doctorat
The aim of this work was to develop a heterogeneous chemoenzymatic catalyst based on the use of Metal-Organic Frameworks (MOFs) as support for the eco-friendly amination of alcohols in a one-pot cascade synthesis. The cascade process is divided into two steps: an alcohol oxidation chemically catalyzed and the subsequent enantioselective amination of the resulting carbonyl intermediate catalyzed by a ω-transaminase enzyme (ω-TA). ZIF-8 was selected as MOF for its hydro- and thermo- stability, making it an ideal support for both chemical and biological catalysts. One of the key challenges was to select a chemical catalytic system for alcohol oxidation under mild aqueous conditions that is compatible with the working conditions of ω-TAs. In this context, two supported nanoparticles catalytic systems were developed for the aerobic alcohol oxidation. In the first system, Cu2+ active sites were heterogenized on ZIF-8 for benzyl alcohol oxidation in the presence of 2,2,6,6-Tetramethylpiperidine 1-oxyl (TEMPO). The leaching issue of Cu2+ during the catalytic process was overcome by reducing Cu2+ into Cu0 within ZIF-8 pores to form supported well-dispersed Cu0 nanoparticles. This catalyst exhibits high stability and selectivity, but is not active when using water as a solvent. In the second system, well-dispersed PdAu bimetallic alloy nanoparticles were formed on ZIF-8 (PdAu@ZIF-8) to catalyze base-free aerobic alcohol oxidation in water. The catalyst shows excellent activity under mild conditions, with the best performance obtained fora Pd/Au atomic ratio 9:1. Both catalysts were characterized using PXRD, N2-adsorption, TEM, HRTEM, and XPS. The second step of the cascade process involves the biocatalytic amination of the ketone. Two S-selective ω-TAs from Silicibacter pomeroyi (3HMU) and Chromobacterium violaceum were tested. The maximum yield of S-α-methylbenzylamine obtained by amination of acetophenone in the presence of 3HMU using L-alanine as the amine donor was 77%. Efforts to combine alcohol oxidation catalyzed by the ZIF-8-supported PdAu nanoparticles and enzymatic catalysis with 3HMU in a one-pot/one-step process revealed interferences between components of the two steps. Instead, a one-pot/two-step cascade process was developed, achieving an overall S-MBA yield of 49%. Attempts were finally made to immobilize 3HMU on PdAu@ZIF-8 in order to obtain the targeted fully heterogenized catalyst by first using physical adsorption, but the activity of the hence-immobilized ω-TAs was limited. Ni2+ modification of PdAu@ZIF-8 slightly improved the enzyme immobilization. Carbonyl-functionalized ZIF-8, obtained by a partial post-synthesis exchange of the 2-methylimidazolate ligands with carbonyl-imidazolate derivatives produced encouraging results, with a 4-fold improvement in activity of 3HMU immobilized on ZIF-8-90. As outlooks, this promising approach will be further investigated in forthcoming attempts to synthesize the entirely heterogeneous 3HMU@PdAu@ZIF-8 targeted in this PhD project

Zhang, Yan. "Chemoenzymatic Resolution in Dynamic Systems : Screening, Classification and Asymmetric Synthesis." Doctoral thesis, KTH, Organisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123089.

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This thesis is divided into four parts, all centered around Constitutional Dynamic Chemistry (CDC) and Dynamic Kinetic Resolution (DKR) using biocatalysts for selective transformations, and their applications in screening of bioactive compounds, organic synthesis, and enzyme classification. In part one, an introduction to CDC and DKR is presented, illustrating the basic concepts, practical considerations and potential applications of such dynamic systems, thus providing the background information for the studies in the following chapters. In part two, Dynamic Systemic Resolution (DSR), a concept based on CDC is exemplified. With enzyme-catalyzed transformations as external selection pressure, optimal structures can be selected and amplified from the system. This concept is expanded to various types of dynamic systems containing single, double cascade/parallel, and multiple reversible reactions. In addition, the substrate selectivity and catalytic promiscuity of target enzymes are also investigated. In part three, DKR protocols using reversible reactions for substrate racemizations are illustrated. Biocatalysts are here employed for asymmetric transformations, resulting in efficient synthetic pathways for enantioenriched organic compounds. Part four demonstrates two unique applications of CDC: one resulting in enzyme classification by use of pattern recognition methodology; the other involving enzyme self-inhibition through in situ transformation of stealth inhibitors employing the catalytic activity of the target enzyme.

QC 20130614

Farzam, Ali. "Preliminary Efforts Towards Achieving Transient Directing Group Chemistry Enabled via a Tandem and Cooperative Concurrent Chemoenzymatic Cascade." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42405.

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Directing groups (DGs) are moieties installed onto organic molecules to confer regioselectivity in subsequent reactions. DGs have found utility in selective CH activations catalyzed by transition metal (TM) catalysis on starting materials with multiple CH bonds. Despite their utility, DGs are scarcely used in industrial applications due to the generally wasteful nature of conventional DG strategies and their associated increase in step-count. Transient directing groups (TDGs) have been developed to overcome these limitations, with additives reversibly forming adducts with compounds of interest prior to the DG-mediated CH activation, in one-pot processes. However, the use of TDGs still requires harsh conditions to achieve significant yields, hindering broad applications. Chemoenzymatic catalytic cascades have attracted attention due to the mild and environmentally friendly nature of biocatalysis, with the greatest challenge being compatibility issues between biocatalytic and traditional chemical transformations. Here we propose a concurrent chemoenzymatic catalytic cascade that would enable TM-catalyzed DG chemistry via flanking biocatalytic reductive amination to install, and oxidative deamination to remove, a TDG. Preliminary efforts have identified some incompatibilities arising from the biocatalytic portion of the cascade, namely substrate specificity and organic co-solvent tolerance, that need to be addressed to achieve the proposed chemoenzymatic cascade in a one-pot concurrent protocol.

Concia, Alda Lisa. "Chemoenzymatic synthesis of sugar-related polyhydroxylated compounds, iminocyclitols and their derivatives as glycosidase inhibitors." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/113239.

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Section 1 (Introduction) is a comprehensive review of the subjects discussed in this thesis: biocatalysis, aldolases and iminocyclitols. It contains a description of the application of dihydroxyacetone phosphate (DHAP) and dihydroxyacetone (DHA) utilizing aldolases to the chemoenzymatic synthesis of bioactive compounds and an introduction to the structure, biological activities and synthesis of iminocyclitols. Recent bibliographic references are included at the end of the section. Section 2 (Objectives) outlines the aims of this thesis. Section 3 (Results and discussion) describes the studies carried out in this thesis. Bibliographic references are included as an overview of previous results and to support our statements at the end of each chapter. - Section 3.1 deals with the application of D-fructose-6-phosphate aldolase in organic chemistry. It describes the chemoenzymatic preparation of polyhydroxylated compounds, sugars 1-deoxy-D-xylulose and 1-deoxy-D-ido-hept-2-ulose and iminocyclitols 1-deoxynojirimycin, 1-deoxymannojirimycin and N-alkylated derivatives, 1,4-dideoxy-1,4-imino-D-arabinitol and 1,4,5-trideoxy-1,4-imino-D-arabinitol. An unprecedented methodology, having as a key step a novel enzymatic aldol addition reactions catalyzed by D-fructose-6-phosphate aldolase, is presented. - Section 3.2 presents the cascade chemical-enzymatic synthesis of a collection of novel 1,4-dideoxy-1,4-imino-D- and -L-arabinitol (DAB and LAB) 2-aminomethyl derivatives including 2-oxopiperazine conjugates which have an interest as potential glycosidase inhibitors. - Section 3.3 describes the chemoenzymatic synthesis of novel polyhydroxylated pyrrolizidines of the family of casuarines by means of an asymmetric strategy based on cascade aldol additions catalyzed by dihydroxyacetone phosphate (DHAP) and dihydroxyacetone (DHA) aldolases. - Section 3.4 describes the methodology and results of the preliminary in vitro assays for glycosidases inhibition activity of some of the compounds synthetized during the course of this thesis. Section 4 (Experimental) describes the procedure for the experimental work carried out in this project. 1H and 13C NMR spectra can be found in the attached CD.
La reacción aldólica es uno de los métodos más útiles y potentes para la formación de enlaces carbono carbono que permite, simultáneamente, la funcionalización y generación de nuevos centros estereogénicos adyacentes. Las aldolasas dependientes del fosfato de dihidroxiacetona (DHAP) catalizan estereoselectivamente la adición aldólica de DHAP a una gran variedad de aldehídos aceptores y han sido objeto de numerosos estudios que demuestran su utilidad como catalizadores en síntesis orgánica asimétrica. La principal limitación de esta clase de aldolasa es su estricta especificidad por el sustrato dador, la DHAP, que es un reactivo costoso y químicamente inestable. Por ello, los estudios dirigidos a la eliminación de la necesidad de la utilización de DHAP mediante estrategias de ingeniería de reacción, evolución dirigida, o a través del descubrimiento de nuevas enzimas naturales, son de gran interés. En este contexto el descubrimiento de la D-fructosa 6-fosfato aldolasa (FSA), una enzima natural que acepta dihidroxiacetona (DHA) como dador, ha sido de enorme importancia. El objeto de esta tesis es la aplicación de aldolasas dependientes de DHA y DHAP a la síntesis de compuestos quirales bioactivos. Los iminociclitoles son una clase de glicomiméticos muy atractivos en química médica ya que poseen actividad inhibidora de glicosidasas y glicosiltransferasas y, por tanto, con un vasto potencial terapéutico para el tratamiento de enfermedades como diabetes, infecciones virales y cáncer, entre otras. En este trabajo se describe una metodología quimioenzimática para la preparación de desoxiazúcares e iminociclitoles cuyas etapas clave son nuevas adiciones aldólicas estereoselectivas de dihidroxiacetona (DHA) e hidroxiacetona (HA) a diferentes aldehídos catalizadas por FSA. Mediante esta estrategia se han obtenido los iminociclitoles 1-deoxinojirimicina, 1-deoximannojirimicina y sus derivados N-alquilados, 1,4-dideoxi-1,4-imino-D-arabinitol y 1,4,5 trideoxi-1,4-imino-D-arabinitol y los desoxiazúcares 1-deoxi-D-xilulosa y 1 deoxi-D-ido-hept-2-ulosa. El 1,4-dideoxi-1,4-imino-D-arabinitol (DAB) y su enantiómero (LAB) son pirrolidinas polihidroxiladas con una amplia actividad inhibidora de varias glicosidasas. Las pirrolizidinas polihidroxilados son una clase de iminociclitoles bicíclicos que también poseen una importante actividad biológica. En este trabajo se presenta una estrategia quimioenzimática que emplea aldolasas dependientes de DHA y DHAP, para la síntesis de DAB y LAB, de una colección de sus derivados 2-aminometílicos y conjugados 2 oxo-piperazinicos y de nuevas pirrolizidinas polihidroxiladas de la familia de las casuarinas, todos con potencial actividad inhibidora de glicosidasas.

Fanfoni, Lidia. "Development of chiral nitrogen ligands for application in homogeneous catalysis." Doctoral thesis, Università degli studi di Trieste, 2010. http://hdl.handle.net/10077/3521.

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2008/2009
Aim of this thesis is the synthesis of enantiomerically pure ligands for their application in asymmetric catalysis. In particular, the work is focused on the synthesis of three different classes of ligands. Chapters 2 and 3 deal with the synthesis of CNN-pincer and N-Nˈ(bipyridine) ligands respectively, obtained in both enantiomeric forms by stereocomplementary chemoenzymatic methods, while Chapter 4 presents the synthesis of P-N type ligands obtained from L-proline. The activity of the complexes that containing the optically pure synthesized ligands was also investigated.
XXII Ciclo
1980

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Книги з теми "Chemoenzymatic catalysis":

Garcia-Junceda, Eduardo. Multi-step enzyme catalysis: Biotransformations and chemoenzymatic synthesis. Weinheim: Wiley-VCH, 2008.

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Garcia-Junceda, Eduardo. Multi-Step Enzyme Catalysis: Biotransformations and Chemoenzymatic Synthesis. Wiley-VCH Verlag GmbH, 2008.

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Garcia-Junceda, Eduardo. Multi-Step Enzyme Catalysis: Biotransformations and Chemoenzymatic Synthesis. Wiley & Sons, Incorporated, John, 2008.

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Grunwald, Peter. Pharmaceutical Biocatalysis: Chemoenzymatic Synthesis of Active Pharmaceutical Ingredients. Jenny Stanford Publishing, 2019.

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Grunwald, Peter. Pharmaceutical Biocatalysis: Chemoenzymatic Synthesis of Active Pharmaceutical Ingredients. Jenny Stanford Publishing, 2019.

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Grunwald, Peter. Pharmaceutical Biocatalysis: Chemoenzymatic Synthesis of Active Pharmaceutical Ingredients. Jenny Stanford Publishing, 2019.

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Grunwald, Peter. Pharmaceutical Biocatalysis: Chemoenzymatic Synthesis of Active Pharmaceutical Ingredients. Jenny Stanford Publishing, 2019.

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Частини книг з теми "Chemoenzymatic catalysis":

Holt, Robert A., and Christopher D. Reeve. "Chemoenzymatic Route to the Side-Chain of Rosuvastatin." In Asymmetric Catalysis on Industrial Scale, 111–26. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527630639.ch7.

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Hussain, Ibrar, and Jan-E. Bäckvall. "Chemoenzymatic Dynamic Kinetic Resolution and Related Dynamic Asymmetric Transformations." In Enzyme Catalysis in Organic Synthesis, 1777–806. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2012. http://dx.doi.org/10.1002/9783527639861.ch43.

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"Chemoenzymatic Synthesis of Amylose-Grafted Biopolymers by Utilizing Phosphorylase Catalysis." In Advances in the Engineering of Polysaccharide Materials, 79–90. Jenny Stanford Publishing, 2013. http://dx.doi.org/10.1201/b14781-8.

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"Chemoenzymatic Synthesis of Amylose-Grafted Synthetic Polymers by Utilizing Phosphorylase Catalysis." In Advances in the Engineering of Polysaccharide Materials, 61–78. Jenny Stanford Publishing, 2013. http://dx.doi.org/10.1201/b14781-7.

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Kanomata, K., and S. Akai. "6 Chemoenzymatic Dynamic Kinetic Resolution of Alcohols." In Dynamic Kinetic Resolution (DKR) and Dynamic Kinetic Asymmetric Transformations (DYKAT). Stuttgart: Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/sos-sd-237-00069.

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AbstractChemoenzymatic dynamic kinetic resolution is one of the simplest and most reliable methods to obtain optically pure alcohol derivatives from racemates. For this purpose, hydrolases, especially lipases, have been widely used in the enantioselective esterification processes, and a variety of racemization catalysts with high catalytic efficiency and compatibility with lipases have been developed. This review introduces chemoenzymatic DKR of alcohols based on the category of racemization catalysts. DKR of axially chiral hydroxybiaryls and the use of engineered lipases to obtain opposite enantiomers, as well as the synthetic applications of the DKR products, are also discussed.

González-Granda, S., and V. Gotor-Fernández. "7 Applications of Chemoenzymatic Dynamic Kinetic Resolution for the Synthesis of Biologically Active Compounds and Natural Products." In Dynamic Kinetic Resolution (DKR) and Dynamic Kinetic Asymmetric Transformations (DYKAT). Stuttgart: Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/sos-sd-237-00092.

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AbstractDynamic kinetic resolutions of racemic compounds provide elegant synthetic possibilities for the preparation of valuable enantiopure organic molecules with a theoretical maximum 100% yield. This chapter describes the combination of stereoselective enzymatic methods with suitable conditions for the racemization of the slow-reacting enantiomer from racemates of various types of compounds, such as alcohols, amines, and amino acids, for the synthesis of biologically active compounds and natural products. This contribution has been divided into three main topics based on the enzyme that catalyzes the asymmetric transformation and the racemization conditions of choice. These are: (i) the use of hydrolases and metal species; (ii) the use of hydrolases without requiring a metal catalyst for the racemization step; (iii) the use of other enzyme classes. A selection of scalable experimental procedures is provided in each case to demonstrate the robustness of the methodology described.

Li, Depeng, Cui Liu, Fanye Wang, and Yuanyuan Zhang. "The Best Performance of the Combined CAL-B/VOSO4 System Depending on the Good Mutual Coordination of Reactions." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220533.

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Enantiomerically pure secondary alcohols were prepared in the combined CAL-B/VOSO4 system in one-pot conditions. Under the optimum conditions, the conversion, enantiomeric excess, selectivity and enantioselectivity reached 92%, >99%, 99% and >200 respectively. The significant improvement of the system performance should be attributed to the mutual coordination of reactions in a chemoenzymatic dynamic kinetic resolution system and reduction of by-reaction. In conclusion, our experimental data and literature data confirm that there must be an optimal amount of V-MPS (VOSO4) to coordinate the in-situ racemic reaction with the kinetic resolution reaction with which the enantiomer required is produced and the adverse kinetic resolution reaction producing adverse enantiomer and minimize the rate of the side reaction in which the substrate was consumed and the selectivity was reduced, resulting in an optimal DKR system. Considering the large activation energy of the in-situ racemic reaction and at least 76% excess catalytic capacity of VOSO4, the strategy adopted is to greatly reduce the amount of VOSO4, and thus an optimal reaction condition should be established, making the DKR system optimal.