629-41-4Relevant articles and documents
Multi-enzymatic cascade reactions with Escherichia coli-based modules for synthesizing various bioplastic monomers from fatty acid methyl esters?
Jung, Hyunsang,Kim, Byung-Gee,Kim, Ye Chan,Park, Beom Gi,Patil, Mahesh D.,Sarak, Sharad,Yoo, Hee-Wang,Yun, Hyungdon
supporting information, p. 2222 - 2231 (2022/04/03)
Multi-enzymatic cascade reaction systems were designed to generate biopolymer monomers using Escherichia coli-based cell modules, capable of carrying out one-pot reactions. Three cell-based modules, including a ω-hydroxylation module (Cell-Hm) to convert fatty acid methyl esters (FAMEs) to ω-hydroxy fatty acids (ω-HFAs), an amination module (Cell-Am) to convert terminal alcohol groups of the substrate to amine groups, and a reduction module (Cell-Rm) to convert the carboxyl groups of fatty acids to alcohol groups, were constructed. The product-oriented assembly of these cell modules involving multi-enzymatic cascade reactions generated ω-ADAs (up to 46 mM), α,ω-diols (up to 29 mM), ω-amino alcohols (up to 29 mM) and α,ω-diamines (up to 21 mM) from 100 mM corresponding FAME substrates with varying carbon chain length (C8, C10, and C12). Finally 12-ADA and 1,12-diol were purified with isolated yields of 66.5% and 52.5%, respectively. The multi-enzymatic cascade reactions reported herein present an elegant ‘greener’ alternative for the biosynthesis of various biopolymer monomers from renewable saturated fatty acids.
Depolymerization of Hydroxylated Polymers via Light-Driven C-C Bond Cleavage
Nguyen, Suong T.,McLoughlin, Elizabeth A.,Cox, James H.,Fors, Brett P.,Knowles, Robert R.
, p. 12268 - 12277 (2021/08/23)
The accumulation of persistent plastic waste in the environment is widely recognized as an ecological crisis. New chemical technologies are necessary both to recycle existing plastic waste streams into high-value chemical feedstocks and to develop next-generation materials that are degradable by design. Here, we report a catalytic methodology for the depolymerization of a commercial phenoxy resin and high molecular weight hydroxylated polyolefin derivatives upon visible light irradiation near ambient temperature. Proton-coupled electron transfer (PCET) activation of hydroxyl groups periodically spaced along the polymer backbone furnishes reactive alkoxy radicals that promote chain fragmentation through C-C bond β-scission. The depolymerization produces well-defined and isolable product mixtures that are readily diversified to polycondensation monomers. In addition to controlling depolymerization, the hydroxyl group modulates the thermomechanical properties of these polyolefin derivatives, yielding materials with diverse properties. These results demonstrate a new approach to polymer recycling based on light-driven C-C bond cleavage that has the potential to establish new links within a circular polymer economy and influence the development of new degradable-by-design polyolefin materials.
Erbium-Catalyzed Regioselective Isomerization-Cobalt-Catalyzed Transfer Hydrogenation Sequence for the Synthesis of Anti-Markovnikov Alcohols from Epoxides under Mild Conditions
Liu, Xin,Longwitz, Lars,Spiegelberg, Brian,T?njes, Jan,Beweries, Torsten,Werner, Thomas
, p. 13659 - 13667 (2020/11/30)
Herein, we report an efficient isomerization-transfer hydrogenation reaction sequence based on a cobalt pincer catalyst (1 mol %), which allows the synthesis of a series of anti-Markovnikov alcohols from terminal and internal epoxides under mild reaction conditions (≤55 °C, 8 h) at low catalyst loading. The reaction proceeds by Lewis acid (3 mol % Er(OTf)3)-catalyzed epoxide isomerization and subsequent cobalt-catalyzed transfer hydrogenation using ammonia borane as the hydrogen source. The general applicability of this methodology is highlighted by the synthesis of 43 alcohols from epoxides. A variety of terminal (23 examples) and 1,2-disubstituted internal epoxides (14 examples) bearing different functional groups are converted to the desired anti-Markovnikov alcohols in excellent selectivity and yields of up to 98%. For selected examples, it is shown that the reaction can be performed on a preparative scale up to 50 mmol. Notably, the isomerization step proceeds via the most stable carbocation. Thus, the regiochemistry is controlled by stereoelectronic effects. As a result, in some cases, rearrangement of the carbon framework is observed when tri-and tetra-substituted epoxides (6 examples) are converted. A variety of functional groups are tolerated under the reaction conditions even though aldehydes and ketones are also reduced to the respective alcohols under the reaction conditions. Mechanistic studies and control experiments were used to investigate the role of the Lewis acid in the reaction. Besides acting as the catalyst for the epoxide isomerization, the Lewis acid was found to facilitate the dehydrogenation of the hydrogen donor, which enhances the rate of the transfer hydrogenation step. These experiments additionally indicate the direct transfer of hydrogen from the amine borane in the reduction step.
One-pot biosynthesis of 1,6-hexanediol from cyclohexane by: De novo designed cascade biocatalysis
Kang, Lixin,Li, Aitao,Li, Qian,Li, Renjie,Wang, Fei,Yu, Xiaojuan,Zhang, Zhongwei,Zhao, Jing
, p. 7476 - 7483 (2020/11/23)
1,6-Hexanediol (HDO) is an important precursor in the polymer industry. The current industrial route to produce HDO involves energy intensive and hazardous multistage (four-pot-four-step) chemical reactions using cyclohexane (CH) as the starting material, which leads to serious environmental problems. Here, we report the development of a biocatalytic cascade process for the biotransformation of CH to HDO under mild conditions in a one-pot-one-step manner. This cascade biocatalysis operates by using a microbial consortium composed of three E. coli cell modules, each containing the necessary enzymes. The cell modules with assigned functions were engineered in parallel, followed by combination to construct E. coli consortia for use in biotransformations. The engineered E. coli consortia, which contained the corresponding cell modules, efficiently converted not only CH or cyclohexanol to HDO, but also other cycloalkanes or cycloalkanols to related dihydric alcohols. In conclusion, the newly developed biocatalytic process provides a promising alternative to the current industrial process for manufacturing HDO and related dihydric alcohols. This journal is
Robust cobalt oxide catalysts for controllable hydrogenation of carboxylic acids to alcohols
Song, Song,Wang, Dong,Di, Lu,Wang, Chuanming,Dai, Weili,Wu, Guangjun,Guan, Naijia,Li, Landong
, p. 250 - 257 (2018/02/20)
The selective catalytic hydrogenation of carboxylic acids is an important process for alcohol production, while efficient heterogeneous catalyst systems are still being explored. Here, we report the selective hydrogenation of carboxylic acids using earth-abundant cobalt oxides through a reaction-controlled catalysis process. The further reaction of the alcohols is completely hindered by the presence of carboxylic acids in the reaction system. The partial reduction of cobalt oxides by hydrogen at designated temperatures can dramatically enhance the catalytic activity of pristine samples. A wide range of carboxylic acids with a variety of functional groups can be converted to the corresponding alcohols at a yield level applicable to large-scale production. Cobalt monoxide was established as the preferred active phase for the selective hydrogenation of carboxylic acids.
Hydrogenation of dicarboxylic acids to diols over Re-Pd catalysts
Takeda, Yasuyuki,Tamura, Masazumi,Nakagawa, Yoshinao,Okumura, Kazu,Tomishige, Keiichi
, p. 5668 - 5683 (2016/07/21)
A Re-Pd/SiO2 (Re/Pd = 8) catalyst was applied to hydrogenation of dicarboxylic acids (succinic acid, glutaric acid and adipic acid) to diols. In the hydrogenation of dicarboxylic acids, ex situ liquid-phase (in only 1,4-dioxane solvent) reduced Re-Pd/SiO2 showed much higher activity than in situ liquid-phase (in the mixture of dicarboxylic acid and 1,4-dioxane) and gas-phase reduced ones, in which the in situ liquid-phase reduced catalyst has been reported to show good activity in the hydrogenation of monocarboxylic acids. High diol yields (71-89%) were achieved in the hydrogenation of dicarboxylic acids on the ex situ liquid-phase reduced catalyst at 413 K. Lactones and hydroxycarboxylic acids were first formed as intermediates in the reaction of C4-C5 and ≥C6 dicarboxylic acids, respectively. Characterization using XRD, XPS and XAS indicates that ex situ liquid-phase reduced catalysts with high activity contains comparable amounts of Re0 and Ren+ species, both of which have been reported to be necessary for good performance. The amount of Ren+ species on the in situ liquid-phase reduced catalysts is much larger than that of surface Re0 species. This result suggests that the presence of dicarboxylic acids suppresses the reduction of Re species to Re0 on the calcined catalysts while that of monocarboxylic acids does not, which leads to the low activity in the hydrogenation of dicarboxylic acids on in situ liquid-phase reduced catalysts.
PROCESS FOR THE MANUFACTURE OF A SATURATED ALCOHOL
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, (2015/11/11)
The present invention relates to a process for the manufacture of a saturated primary alcohol from an unsaturated aliphatic ester comprising the steps of: a) Providing an aliphatic ester having at least one carbon-carbon double bond; b) Carrying out a metathesis of said ester in the presence of a ruthenium carbenebased catalyst thereby obtaining a first reaction mixture; c) Adding a ligand and a base to the first reaction mixture, wherein the ligand comprises at least one donor atom chosen from the group consisting of a nitrogen atom and a phosphorus atom thereby obtaining a second reaction mixture comprising an ester product resulting from the metathesis reaction ; d) Carrying out a homogeneous hydrogenation of the ester-product resulting from the metathesis, thereby obtaining a saturated primary alcohol. Further, the present invention relates to a catalyst for the hydrogenation of esters and to a process for the hydrogenation of esters using said catalyst.
ACYCLIC ALKENES VIA OZONOLYSIS OF MULTI-UNSATURATED CYCLOALKENES
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Paragraph 00156, (2015/02/02)
A method of making a compound of formula (IIa) by selective ozonolysis of a compound of formula (I) is provided, wherein A is a C6-C10 alkene chain with at least one double bond, R1 is a C1-C10 alkyl, and R3 is an oxygen-containing functional group.
A highly active and air-stable ruthenium complex for the ambient temperature anti-markovnikov reductive hydration of terminal alkynes
Zeng, Mingshuo,Li, Le,Herzon, Seth B.
supporting information, p. 7058 - 7067 (2014/06/09)
The conversion of terminal alkynes to functionalized products by the direct addition of heteroatom-based nucleophiles is an important aim in catalysis. We report the design, synthesis, and mechanistic studies of the half-sandwich ruthenium complex 12, which is a highly active catalyst for the anti-Markovnikov reductive hydration of alkynes. The key design element of 12 involves a tridentate nitrogen-based ligand that contains a hemilabile 3-(dimethylamino) propyl substituent. Under neutral conditions, the dimethylamino substituent coordinates to the ruthenium center to generate an air-stable, 18-electron, κ3-complex. Mechanistic studies show that the dimethylamino substituent is partially dissociated from the ruthenium center (by protonation) in the reaction media, thereby generating a vacant coordination site for catalysis. These studies also show that this substituent increases hydrogenation activity by promoting activation of the reductant. At least three catalytic cycles, involving the decarboxylation of formic acid, hydration of the alkyne, and hydrogenation of the intermediate aldehyde, operate concurrently in reactions mediated by 12. A wide array of terminal alkynes are efficiently processed to linear alcohols using as little as 2 mol % of 12 at ambient temperature, and the complex 12 is stable for at least two weeks under air. The studies outlined herein establish 12 as the most active and practical catalyst for anti-Markovnikov reductive hydration discovered to date, define the structural parameters of 12 underlying its activity and stability, and delineate design strategies for synthesis of other multifunctional catalysts.
Elaboration of the ether cleaving ability and selectivity of the classical Pearlman's catalyst [Pd(OH)2/C]: Concise synthesis of a precursor for a myo-inositol pyrophosphate
Mart, Alson,Shashidhar, Mysore S.
, p. 9769 - 9776,8 (2012/12/11)
The cleavage of propargyl, allyl, benzyl, and PMB ethers by Pd(OH) 2/C can be tuned in that order, by varying the reaction conditions. Other moieties such as C-C double bonds, esters, trityl ether, p-bromo and p-nitrobenzyl ethers are stable to these reaction conditions. Cleavage of allyl ethers can be made catalytic by using 1:1 mixture of Pd(OH)2/C and Pd/C. The synthetic potential of the selective ether cleaving ability of Pd(OH)2/C, essentially under neutral conditions, has been demonstrated by an efficient synthesis of a precursor for the preparation of an inositol pyrophosphate derivative.
