- Single-Site Molybdenum Catalyst for the Synthesis of Fumarate
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The catalysts with well-defined mononuclear active sites are expected to develop more active catalytic systems for the key chemical transformations. But the rational design of catalyst with stable mononuclear Mo site is still a crucial challenge because of its oligomerization tendency under reaction condition. Herein, Molybdenum catalyst (Mo-8-HQ) with single Mo sites was designed via the pyridine nitrogen and oxygen in hydroxyl of 8-hydroxyquinoline coordinated with Mo atom. The crystal catalyst was stabilized by π-π stacking interaction and hydrogen bonds to form isolated Mo specie. The single-site molybdenum catalyst exhibited excellent catalytic performance in didehydroxylation reactions with high selectively of dibutyl fumarate (86 %) product at mild reaction condition. Deuterium isotopic studies demonstrated that the mechanism feature of didehydroxylation reaction catalyzed by Mo-8-HQ was through concerted cleavage of two C?O bonds process, which could be accelerated by single-site molybdenum catalysts with electron-rich Mo centers.
- Jiang, Huifang,Lu, Rui,Si, Xiaoqin,Luo, Xiaolin,Xu, Jie,Lu, Fang
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Read Online
- Face-to-Face Packing of 2,3,9,10-Tetrasubstituted Pentacene Derivatives Revealed through a Solid State [4 + 4] Thermal Cycloaddition and Molecular Dynamic Simulation
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2,3,9,10-Substituted pentacene tetraesters and pentacene diester-dinitriles were synthesized. These pentacene derivatives underwent an unusual solid state [4 + 4] thermal dimerization with good efficiency and complete stereoselectivity. This observation indicates this series of pentacene derivatives adopt π-π stacking geometry with large mutual overlap in solid state. This notion was confirmed by molecualr dynamic simulation.
- Pal, Bikash,Lin, Bo-Chao,Dela Cerna, Mark Vincent Carreon,Hsu, Chao-Ping,Lin, Chih-Hsiu
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Read Online
- Ruthenium-catalysed oxidative coupling of vinyl derivatives and application in tandem hydrogenation
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The first ruthenium-catalyzed oxidative homo- and cross-coupling of exclusive vinyl derivatives giving highly valued 1,3-diene building blocks is reported. The catalytic system is based on readily available reagents and it mainly delivers the E,E isomer. This methodology also enables the synthesis of adipic acid ester derivatives in a one-pot fashion after in situ ruthenium-catalyzed hydrogenation.
- Abuhafez, Naba,Bruneau, Christian,Gramage-Doria, Rafael,Kamaraj, Raghu,Ruffin, Hervé
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p. 5772 - 5776
(2021/09/10)
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- Method for preparing succinate by double carbonylation of acetylene
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The invention provides a method for preparing succinate by double carbonylation of acetylene. Acetylene, carbon monoxide and an alcohol compound are used as raw materials and subjected to the double carbonylation reaction in a solvent under the catalysis of a catalyst, and the succinate compound is obtained. The catalyst is composed of a palladium compound, a lithium halide/acid auxiliary agent and a nitrogen-oxygen ligand, wherein the nitrogen-oxygen ligand is one or more of 2-hydroxypyridine, 3-hydroxypyridine and 2-picolinic acid, and the dosage of the catalyst is 0.0001-1.0% of the total weight of the reaction system; in the reaction system, the molar ratio of acetylene to the alcohol compound is 1:(2-16), and the molar ratio of the alcohol compound to the solvent is 1:(7-35). According to the method, the succinate compounds can be produced by a one-pot method, wherein the process is simple, and the investment cost of an industrial device is low; the reaction conditions in the production process are mild, the catalytic activity of the catalyst is high, the stability is high, the service life is long, the yield can reach 90% or above, and the higher technical competitive advantage is achieved.
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Paragraph 0027-0038
(2019/12/02)
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- POLYGLYOXYLATES, MANUFACTURE AND USE THEREOF
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Self-immolative polymers degrade by an end-to-end depolymerisation mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus. Examples include homopolymers, mixed polymers including block copolymers, suitable for a variety of applications. A polyglyoxylate can be end-capped or capped with a linker as in a block copolymer.
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Page/Page column 23; 24
(2015/11/27)
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- Polyglyoxylates: A versatile class of triggerable self-immolative polymers from readily accessible monomers
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Self-immolative polymers, which degrade by an end-to-end depolymerization mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus, are of increasing interest for a wide variety of applications ranging from sensors to controlled release. However, the preparation of these materials often requires expensive, multistep monomer syntheses, and the degradation products such as quinone methides or phthalaldehydes are potentially toxic to humans and the environment. We demonstrate here that polyglyxoylates can serve as a new and versatile class of self-immolative polymers. Polymerization of the commercially available monomer ethyl glyoxylate, followed by end-capping with a 6-nitroveratryl carbonate, provides a poly(ethyl glyoxylate) that depolymerizes selectively upon irradiation with UV light, ultimately generating ethanol and the metabolic intermediate glyoxylic acid hydrate. To access polyglyoxylates with different properties, the polymerization and end-capping approach can also be extended to other glyoxylate monomers including methyl glyoxylate, n-butyl glyoxylate, and benzyl glyoxylate, which can be easily prepared from their corresponding fumaric or maleic acid derivatives. Random copolymers of these monomers with ethyl glyoxylate can also be prepared. Furthermore, using a multifunctional end-cap that is UV-responsive and also enables the conjugation of another polymer block via an azide-alkyne "click" cycloaddition, amphiphilic self-immolative block copolymers are also prepared. These block copolymers self-assemble into micelles in aqueous solution, and their poly(ethyl glyoxylate) blocks rapidly depolymerize upon UV irradiation. Overall, these strategies are expected to greatly expand the utility of self-immolative polymers by providing access for the first time to self-immolative polymers with tunable properties that can be readily obtained from simple monomers and can be designed to depolymerize into nontoxic products.
- Fan, Bo,Trant, John F.,Wong, Andrew D.,Gillies, Elizabeth R.
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supporting information
p. 10116 - 10123
(2014/08/05)
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- One-pot esterification and amide formation via acid-catalyzed dehydration and ritter reactions
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Esterification of carboxylic acid is achieved using acetonitrile as a water trap. Water liberated during esterification is consumed in cyanide hydrolysis, thereby driving the esterification to completion. Substrates having carboxylic acid and nitrile groups undergo intramolecular dehydration and rehydration to amido esters in the absence of acetonitrile. Cyano acids also undergo esterification and Ritter reaction in one pot when excess alcohol is used. For the first time, we have observed an interesting Ritter reaction of primary alcohols, leading to ester amide product in one pot. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Dawar, Pankaj,Raju, M. Bagavan,Ramakrishna, Ramesha Andagar
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supporting information
p. 836 - 846
(2014/03/21)
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- Expanding the scope of biomass-derived chemicals through tandem reactions based on oxorhenium-catalyzed deoxydehydration
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New modes of DODH: Oxorhenium compounds act as deoxydehydration(DODH)/acid dual-purpose catalysts to transform biomass-derived diol substrates into a variety of commodity chemical precursors. The power of this approach is highlighted by a tandem [1,3]-OH shift/DODH of 2-ene-1,4-diols and 2,4-diene-1,6-diols, and by a DODH/esterification sequence of sugar acids to unsaturated esters for the production of polymers and plasticizers. Copyright
- Shiramizu, Mika,Toste, F. Dean
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supporting information
p. 12905 - 12909
(2014/01/06)
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- Efficient synthesis of symmetrical phthalate and maleate diesters using phosphinite ionic liquids
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Symmetrical dialkyl phthalates and maleates were synthesized using phosphinite ionic liquid as a catalyst and reaction medium. The results indicated that phosphinite ionic liquid shows better catalytic and reusable performance without using any acid or base catalyst. Under the optimum conditions, using 1-methyl-3-(4-phosphinitebutyl) imidazolium chloride as catalyst, the conversion of phthalic and maleic anhydrides to the corresponding diesters of primary and secondary alcohols was occurred in 72-85% yields. The diesters of tertiary alcohols and phenols could not be prepared by this method. A kind of widely used plasticizer, dioctyl phthalate, was prepared in good yield under these conditions. The ionic liquid could be reused three times after easy separation from the products without any disposal. Iranian Chemical Society 2012.
- Valizadeh,Khalili
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p. 529 - 534
(2013/02/22)
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- Reductive coupling of aldehydes by H2S in aqueous solutions, a C-C bond forming reaction of prebiotic interest
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We report here a novel reductive coupling reaction of conjugated, non- or poorly enolizable aldehydes induced by H2S and operative in aqueous solutions under prebiotically relevant conditions. This reaction leads from retinal to β-carotene, and from benzylic aldehydes to the corresponding diarylethylenes. This novel reaction also opens a new potentially prebiotic pathway leading from glyoxylic acid to various compounds that are involved in the reductive tricarboxylic acid cycle. This C-C bond forming reaction of prebiotic interest might have been operative, notably, in the sulfide-rich environments of hydrothermal vents, which have been postulated as possible sites for the first steps of organic chemical evolution.
- Kajjout, Mohammed,Hebting, Yanek,Albrecht, Pierre,Adam, Pierre
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experimental part
p. 714 - 726
(2012/07/14)
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- METHOD OF PRODUCING A CARBOXYLIC ALKYL ESTER
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The present invention relates to a novel process for preparing alkyl polycarboxylates from an aqueous solution of an ammonium salt of the polycarboxylic acid by reactive distillation, and to a process for hydrogenating the alkyl carboxylates prepared in this way.
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Page/Page column 8-9
(2009/06/27)
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- Highly chemo- and stereoselective intermolecular coupling of diazoacetates to give cis-olefins by using Grubbs second-generation catalyst
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Highly stereoselective formation of cis-2-ene-1,4-diesters by homo- and heterocoupling of α-diazoacetates in the presence of Grubbs second-generation catalyst is demonstrated. The dual reactivity of the catalyst in alkene metathesis and diazocoupling has been exploited in the synthesis of 12-26-membered macrocyclic dienyl dilactones by one-pot carbene dimerisation/ring-closing metathesis.
- Hodgson, David M.,Angrish, Deepshikha
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p. 3470 - 3479
(2008/02/08)
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- Homobimetallic ruthenium-N-heterocyclic carbene complexes: Synthesis, characterization, and catalytic applications
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Two new homobimetallic ruthenium-arene complexes [(p-cymene)Ru(μ-Cl) 3RuCl(η2-C2H4)(L)], where L = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (3a) or 1,3-bis(2,4,6- trimethylphenyl)-4,5-dichloroimidazolin-2-ylidene (3b), were isolated in high yields upon heating a toluene solution of [RuCl2 (p-cymene)] 2 with 1 equivalent of carbene ligand under an ethylene atmosphere. They were characterized by NMR and TGA. Their catalytic activity was investigated in the atom transfer radical polymerization of vinyl monomers. In the polymerization of methyl methacrylate, complex 3a displayed faster reaction rates than 3b and the related phosphine-based complex 2a (L = tricyclohexylphosphine), although control was more effective with the latter catalyst. When n-butyl acrylate or styrene served as monomer, a major shift of reactivity was observed between complex 2a that promoted controlled radical polymerization, and complexes 3a or 3b that favored metathetical coupling. Further homocoupling experiments with various styrene derivatives confirmed the outstanding aptitude of complex 3a (and to a lesser extent of 3b) to catalyze olefin metathesis reactions. Contrary to monometallic ruthenium-arene complexes of the [RuCl2(p-cymene)(L)] type, the new homobimetallic species did not require the addition of a diazo compound or visible light illumination to initiate the ring-opening metathesis of norbornene or cyclooctene. When α,ω-dienes were exposed to 3a or 3b, a mixture of cycloisomerization and ring-closing metathesis products was obtained in a non-selective way. Addition of a terminal alkyne co-catalyst enhanced the metathetical activity while completely repressing the cycloisomerization process. Thus, quantitative conversions of diethyl 2,2-diallylmalonate and N,N-diallyltosylamide were achieved within 2 h at room temperature using 2 mol% of catalyst precursor 3 a and 6 mol % of phenylacetylene.
- Sauvage, Xavier,Borguet, Yannick,Noels, Alfred F.,Delaude, Lionel,Demonceau, Albert
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p. 255 - 265
(2008/02/03)
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- Immobilization of the Grubbs second-generation ruthenium-carbene complex on poly(ethylene glycol): A highly reactive and recyclable catalyst for ring-closing and cross-metathesis
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A poly(ethylene glycol)-bound Hoveyda-Grubbs Ru catalyst derived from the Grubbs second-generation Ru carbene complex was synthesized and shown to be highly reactive in the ring-closing metathesis of a wide variety of diene substrates, yielding di-, tri-, and tetra-substituted carbocyclic and heterocyclic olefins. The immobilized catalyst also proved to be highly reactive and recyclable in cross-metathesis and ring-opening/cross-metathesis. In all cases tested, the catalyst exhibited a high level of recyclability and reusability.
- Yao, Qingwei,Rodriguez Motta, Adalie
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p. 2447 - 2451
(2007/10/03)
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- Selective monoesterification of dicarboxylic acids catalysed by ion-exchange resins
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Symmetrical dicarboxylic acids with 4-14 carbon atoms gave selectively the corresponding monoesters in high yields in the transesterification catalysed by strongly acidic ion-exchange resins in ester-hydrocarbon mixtures. It was found that the rate of the esterification of the dicarboxylic acids is much higher than that of the monocarboxylic acids formed. This result can explain the high selectivity for the monoester formation and can also be explained by the existence of an aqueous layer on the surface of the resins. This method of selective esterification is quite simple and practical. The Royal Society of Chemistry 1999.
- Nishiguchi, Takeshi,Ishii, Yasuhiro,Fujisaki, Shizuo
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p. 3023 - 3027
(2007/10/03)
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- Enzymatic selective transformations of diethyl fumarate
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Candida antarctica lipase selectively catalyses transformations of diethyl fumarate in organic solvents. A range of nitrogen nucleophiles, including ammonia, can be successfully used in these enzymatic reactions, monoamides and monohydrazides being obtained in high to moderate yields. In contrast, diethyl maleate is not an adequate substrate for this enzyme.
- Quiros, Margarita,Astorga, Covadonga,Rebolledo, Francisca,Gotor, Vicente
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p. 7715 - 7720
(2007/10/02)
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- Reaction of cyclic sulfates with phosphines
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In their reactions with phosphines, cyclic sulfates 9, 10, 11, and 12 afforded corresponding olefins by way of phosphonium sulfate salts whereas sugar cyclic sulfates 21 and 22 gave anhydrosugar 23.
- Kim,Joo,Kim,Lee,Cho,Kim,Cho
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p. 1157 - 1163
(2007/10/02)
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