24560-98-3Relevant academic research and scientific papers
PROCESS FOR THE PREPARATION OF HYDROPEROXY ALCOHOLS USING A HETEROGENOUS CATALYST
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Page/Page column 14-16-20, (2021/07/02)
The present invention relates to a process for preparing hydroperoxy alcohols using hydrogen peroxide as an oxidant in a solvent selected from water-soluble carboxylic acids, in the presence of a metallic mixed oxide heterogeneous catalyst. It also pertains to the use of this catalyst in the synthesis of hydroperoxy alcohols.
Lipase catalysed oxidations in a sugar-derived natural deep eutectic solvent
Vagnoni, Martina,Samorì, Chiara,Pirini, Daniele,Vasquez De Paz, Maria Katrina,Gidey, Dawit Gebremichael,Galletti, Paola
, (2021/05/06)
Chemoenzymatic oxidations involving the CAL-B/H2O2 system was developed in a sugar derived Natural Deep Eutectic Solvent (NaDES) composed by a mixture of glucose, fructose and sucrose. Good to excellent conversions of substrates like cyclooctene, limonene, oleic acid and stilbene to their corresponding epoxides, cyclohexanone to its corresponding lactone and 2-phenylacetophenone to its corresponding ester, demonstrate the viability of the sugar NaDES as a reaction medium for epoxidation and Baeyer-Villiger oxidation.
Reactive Species and Reaction Pathways for the Oxidative Cleavage of 4-Octene and Oleic Acid with H2O2over Tungsten Oxide Catalysts
Yun, Danim,Ayla, E. Zeynep,Bregante, Daniel T.,Flaherty, David W.
, p. 3137 - 3152 (2021/04/06)
Oxidative cleavage of carbon-carbon double bonds (C-C) in alkenes and fatty acids produces aldehydes and acids valued as chemical intermediates. Solid tungsten oxide catalysts are low cost, nontoxic, and selective for the oxidative cleavage of C-C bonds with hydrogen peroxide (H2O2) and are, therefore, a promising option for continuous processes. Despite the relevance of these materials, the elementary steps involved and their sensitivity to the form of W sites present on surfaces have not been described. Here, we combine in situ spectroscopy and rate measurements to identify significant steps in the reaction and the reactive species present on the catalysts and examine differences between the kinetics of this reaction on isolated W atoms grafted to alumina and on those exposed on crystalline WO3 nanoparticles. Raman spectroscopy shows that W-peroxo complexes (W-(η2-O2)) formed from H2O2 react with alkenes in a kinetically relevant step to produce epoxides, which undergo hydrolysis at protic surface sites. Subsequently, the CH3CN solvent deprotonates diols to form alpha-hydroxy ketones that react to form aldehydes and water following nucleophilic attack of H2O2. Turnover rates for oxidative cleavage, determined by in situ site titrations, on WOx-Al2O3 are 75% greater than those on WO3 at standard conditions. These differences reflect the activation enthalpies (ΔH?) for the oxidative cleavage of 4-octene that are much lower than those for the isolated WOx sites (36 ± 3 and 60 ± 6 kJ·mol-1 for WOx-Al2O3 and WO3, respectively) and correlate strongly with the difference between the enthalpies of adsorption for epoxyoctane (ΔHads,epox), which resembles the transition state for epoxidation. The WOx-Al2O3 catalysts mediate oxidative cleavage of oleic acid with H2O2 following a mechanism comparable to that for the oxidative cleavage of 4-octene. The WO3 materials, however, form only the epoxide and do not cleave the C-C bond or produce aldehydes and acids. These differences reflect the distinct site requirements for these reaction pathways and indicate that acid sites required for diol formation are strongly inhibited by oleic acids and epoxides on WO3 whereas the Al2O3 support provides sites competent for this reaction and increase the yield of the oxidative cleavage products.
Quantification and molecular imaging of fatty acid isomers from complex biological samples by mass spectrometry
Jagodinsky, Justin C.,Li, Lingjun,Li, Zihui,Liu, Yuan,Ma, Min,Morris, Zachary S.,Shi, Xudong,Welham, Nathan V.,Xu, Meng,Zhang, Hua
, p. 8115 - 8122 (2021/06/22)
Elucidating the isomeric structure of free fatty acids (FAs) in biological samples is essential to comprehend their biological functions in various physiological and pathological processes. Herein, we report a novel approach of using peracetic acid (PAA) induced epoxidation coupled with mass spectrometry (MS) for localization of the CC bond in unsaturated FAs, which enables both quantification and spatial visualization of FA isomers from biological samples. Abundant diagnostic fragment ions indicative of the CC positions were produced upon fragmentation of the FA epoxides derived from either in-solution or on-tissue PAA epoxidation of free FAs. The performance of the proposed approach was evaluated by analysis of FAs in human cell lines as well as mapping the FA isomers from cancer tissue samples with MALDI-TOF/TOF-MS. Merits of the newly developed method include high sensitivity, simplicity, high reaction efficiency, and capability of spatial characterization of FA isomers in tissue samples.
An assay for DNA polymerase β lyase inhibitors that engage the catalytic nucleophile for binding
Chen, Shengxi,Cheng, Qi,Daskalova, Sasha M.,Eisenhauer, Brian M.,Fahmi, NourEddine,Feng, Xizhi,Gao, Mingxuan,Hecht, Sidney M.,Ji, Xun,Khdour, Omar M.
supporting information, (2020/07/21)
DNA polymerase β (Pol β) repairs cellular DNA damage. When such damage is inflicted upon the DNA in tumor cells treated with DNA targeted antitumor agents, Pol β thus diminishes their efficacy. Accordingly, this enzyme has long been a target for antitumor therapy. Although numerous inhibitors of the lyase activity of the enzyme have been reported, none has yet proven adequate for development as a therapeutic agent. In the present study, we developed a new strategy to identify lyase inhibitors that critically engage the lyase active site primary nucleophile Lys72 as part of the binding interface. This involves a parallel evaluation of the effect of the inhibitors on the wild-type DNA polymerase β (Pol β) and Pol β modified with a lysine analogue at position 72. A model panel of five structurally diverse lyase inhibitors identified in our previous studies (only one of which has been published) with unknown modes of binding were used for testing, and one compound, cis-9,10-epoxyoctadecanoic acid, was found to have the desired characteristics. This finding was further corroborated by in silico docking, demonstrating that the predominant mode of binding of the inhibitor involves an important electrostatic interaction between the oxygen atom of the epoxy group and Nε of the main catalytic nucleophile, Lys72. The strategy, which is designed to identify compounds that engage certain structural elements of the target enzyme, could find broader application for identification of ligands with predetermined sites of binding.
Highly efficient epoxidation of vegetable oils catalyzed by a manganese complex with hydrogen peroxide and acetic acid
Chen, Jianming,De Liedekerke Beaufort, Marc,Gyurik, Lucas,Dorresteijn, Joren,Otte, Matthias,Klein Gebbink, Robertus J. M.
, p. 2436 - 2447 (2019/05/21)
Epoxidized vegetable oils (EVOs) are versatile building blocks for lubricants, plasticizers, polyvinyl chloride (PVC) stabilizers, and surface coating formulations. In this paper, a catalytic protocol for the efficient epoxidation of vegetable oils is presented that is based on a combination of a manganese catalyst, H2O2 as an oxidant, and acetic acid as an additive. This protocol relies on the use of a homogeneous catalyst based on the non-noble metal manganese in combination with a racemic mixture of the N,N′-bis(2-picolyl)-2,2′-bispyrrolidine ligand (rac-BPBP). The optimized reaction conditions entail only 0.03 mol% of the manganese catalyst with respect to the number of double bonds (ca. 0.1 wt% with respect to the oil) and ambient temperature. This epoxidation protocol is highly efficient, since it allows most of the investigated vegetable oils, including cheap waste cooking oil, to be fully epoxidized to EVOs in more than 90% yield with excellent epoxide selectivities (>90%) within 2 h of reaction time. In addition, the protocol takes place in a biphasic reaction medium constituted by the vegetable oil itself and an aqueous acetic acid phase, from which the epoxidized product can be easily separated via simple extraction. In terms of efficiency and reaction conditions, the current epoxidation protocol outperforms previously reported catalytic protocols for plant oil epoxidation, representing a promising alternative method for EVO production.
Tailoring chemoenzymatic oxidation: Via in situ peracids
Re, Rebecca N.,Proessdorf, Johanna C.,La Clair, James J.,Subileau, Maeva,Burkart, Michael D.
supporting information, p. 9418 - 9424 (2019/11/14)
Epoxidation chemistry often suffers from the challenging handling of peracids and thus requires in situ preparation. Here, we describe a two-phase enzymatic system that allows the effective generation of peracids and directly translate their activity to the epoxidation of olefins. We demonstrate the approach by application to lipid and olefin epoxidation as well as sulfide oxidation. These methods offer useful applications to synthetic modifications and scalable green processes.
A fluorescence-based activity assay for immobilized lipases in non-native media
Ingenbosch, Kim N.,Rousek, Anna,Wunschik, Dennis S.,Hoffmann-Jacobsen, Kerstin
, p. 22 - 27 (2019/01/30)
A new method for the analysis of lipase activity in the immobilized state is developed. The fluorescence assay aims to quantify the potential of lipases for the application in organic solvents. As lipases are universally immobilized on polymeric carriers for the use in bioorganic synthesis, the assay includes an immobilization step on the walls of polymeric cuvettes. The activity of the immobilized lipase is probed by 4-methylumbelliferyl ester hydrolysis. The activity retention as a function of solvent concentration is used as a measure for the solvent resistance of the enzyme variant. The method is applied to two different lipases, Candida antarctica lipase B (CalB) and Bacillus subtilis lipase A (BSLA) in the presence of the solvents acetonitrile and ethanol. By comparison of the assay results with a commercial biocatalyst consisting of CalB on polymeric carrier (Novozyme 435) it is demonstrated that the assay allows a good prediction of the activity of the respective lipase as immobilisate on polymeric carriers. The assay surpasses the respective analysis in solution in terms of accuracy and precision.
Selective Epoxidation of Fatty Acids and Fatty Acid Methyl Esters by Fungal Peroxygenases
Aranda, Carmen,Olmedo, Andrés,Kiebist, Jan,Scheibner, Katrin,del Río, José C.,Martínez, Angel T.,Gutiérrez, Ana
, p. 3964 - 3968 (2018/08/11)
Recently discovered fungal unspecific peroxygenases from Marasmius rotula and Chaetomium globosum catalyze the epoxidation of unsaturated fatty acids (FA) and FA methyl esters (FAME), unlike the well-known peroxygenases from Agrocybe aegerita and Coprinopsis cinerea. Reactions of a series of unsaturated FA and FAME with cis-configuration revealed high (up to 100 %) substrate conversion and selectivity towards epoxidation, although some significant differences were observed between enzymes and substrates with the best results being obtained with the C. globosum enzyme. This and the M. rotula peroxygenase appear as promising biocatalysts for the environmentally-friendly production of reactive FA epoxides given their self-sufficient monooxygenase activity and the high conversion rate and epoxidation selectivity.
Allyl-Palladium-Catalyzed α,β-Dehydrogenation of Carboxylic Acids via Enediolates
Zhao, Yizhou,Chen, Yifeng,Newhouse, Timothy R.
supporting information, p. 13122 - 13125 (2017/09/13)
A highly practical and step-economic α,β-dehydrogenation of carboxylic acids via enediolates is reported through the use of allyl-palladium catalysis. Dianions underwent smooth dehydrogenation when generated using Zn(TMP)2?2 LiCl as a base in the presence of excess ZnCl2, thus avoiding the typical decarboxylation pathway of these substrates. Direct access to 2-enoic acids allows derivatization by numerous approaches.
