625-38-7Relevant academic research and scientific papers
Nickel-catalyzed electrocarboxylation of allylic halides with CO2
Wu, La-Xia,Deng, Fang-Jie,Wu, Lin,Wang, Huan,Chen, Tai-Jie,Guan, Ye-Bin,Lu, Jia-Xing
, p. 13137 - 13141 (2021/08/03)
Nickel-catalyzed regioselective electrocarboxylation of allylic halides with CO2at atmospheric pressure has been developed by adjusting reaction parameters, including catalyst, solvent, temperature and additive. β,γ-Unsaturated carboxylic acids were obtained in moderate to good yields and with high chain selectivity. This reaction shows tolerance to functional groups. In addition, cyclic voltammetry was performed to provide the possible mechanism of nickel-catalyzed CO2allylation.
Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles
Drikermann, Denis,G?rls, Helmar,Kerndl, Valerie,Vilotijevic, Ivan
supporting information, p. 1158 - 1162 (2020/07/20)
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95percent. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- A nd tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.
Revisiting the Palladium-Catalyzed Carbonylation of Allyl Alcohol: Mechanistic Insight and Improved Catalytic Efficiency
Jiang, Jianwei,Padmanaban, Sudakar,Yoon, Sungho
, p. 1881 - 1886 (2020/06/10)
Although crotonic acid (CA) is in high demand due to its use in various industrial applications, the preparation of CA currently requires a multi-step process from the petrochemical cracking of ethane with a very low overall yield and poor selectivity. An atom economical, one-step, carbonylation of readily accessible allyl alcohol to CA is one of the attractive approaches. In this study, the direct carbonylative transformation of allyl alcohol to CA was analyzed in detail to detect the reaction intermediates and propose a reaction mechanism. Following the reaction mechanism, the process was optimized to synthesize CA via the direct carbonylation of allyl alcohol with improved efficiency and productivity (TON = 420) under mild reaction conditions using Pd-based catalytic systems.
Silver encapsulated copper salen complex: Efficient catalyst for electrocarboxylation of cinnamyl chloride with CO2
Wu, La-Xia,Zhao, Ying-Guo,Guan, Ye-Bin,Wang, Hui,Lan, Yang-Chun,Wang, Huan,Lu, Jia-Xing
, p. 32628 - 32633 (2019/10/28)
An active catalyst, [Cu]?Ag composite, was synthesized for the first time and used as a cathode for electrocarboxylation of cinnamyl chloride with CO2. β,γ-Unsaturated carboxylic acids were obtained with excellent yield and moderate selectivity. Moreover, reasonable yields and selectivities of carboxylic acids were also achieved with several allylic halides and aryl halides.
Combined high degree of carboxylation and electronic conduction in graphene acid sets new limits for metal free catalysis in alcohol oxidation
Blanco, Matiás,Mosconi, Dario,Otyepka, Michal,Medve?, Miroslav,Bakandritsos, Aristides,Agnoli, Stefano,Granozzi, Gaetano
, p. 9438 - 9445 (2019/11/11)
Graphene oxide, the most prominent carbocatalyst for several oxidation reactions, has severe limitations due to the overstoichiometric amounts required to achieve practical conversions. Graphene acid, a well-defined graphene derivative selectively and homogeneously covered by carboxylic groups but maintaining the high electronic conductivity of pristine graphene, sets new activity limits in the selective and general oxidation of a large gamut of alcohols, even working at 5 wt% loading for at least 10 reaction cycles without any influence from metal impurities. According to experimental data and first principles calculations, the selective and dense functionalization with carboxyl groups, combined with excellent electron transfer properties, accounts for the unprecedented catalytic activity of this graphene derivative. Moreover, the controlled structure of graphene acid allows shedding light upon the critical steps of the reaction and regulating precisely its selectivity toward different oxidation products.
Stereoselective Synthesis of Highly Substituted Tetrahydropyrans through an Evans Aldol-Prins Strategy
álvarez-Méndez, Sergio J.,Fari?a-Ramos, Marta,Villalba, María Luisa,Perretti, Marcelle D.,García, Celina,Moujir, Laila M.,Ramírez, Miguel A.,Martín, Víctor S.
, p. 9039 - 9066 (2018/08/06)
A direct and general method for the synthesis of naturally occurring 2,3,4,5,6-pentasubstituted tetrahydropyrans has been developed, employing β,γ-unsaturated N-acyl oxazolidin-2-ones as key starting materials. The combination of the Evans aldol addition and the Prins cyclization allowed the diastereoselective and efficient generation of the desired oxacycles in two fashions: a one-pot Evans aldol-Prins protocol, in which five new σ bonds and five contiguous stereocenters were straightforwardly generated, and a two-step version, which additionally permitted the isolation of β,γ-unsaturated alcohol precursors bearing an N-acyl oxazolidin-2-one in the α position. From these alcohols were also obtained halogenated pentasubstituted tetrahydropyrans as well as 2,3,4,5-tetrasubstituted tetrahydrofurans, shedding light on the mechanism of the process. Computational studies were consistent with the experimental findings, and this innovative Evans aldol-Prins strategy was performed for the preparation of a battery of more than 30 densely substituted tetrahydropyrans, unprecedentedly fused to a 1,3-oxazinane-2,4-dione ring, both in a racemic fashion and in an enantiomeric fashion. These novel molecules were successfully submitted to several transformations to permit simple access to a variety of differently functionalized tetrahydropyrans. Most of these unique molecules were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and the yeast Candida albicans, and some structure-activity relationships were established.
Telescoped Synthesis of γ-Bromo-β-Lactones from Allylic Bromides Employing Carbon Dioxide
Vellalath, Sreekumar,Romo, Daniel
, p. 335 - 339 (2017/04/13)
A direct synthesis of the title compounds involving a stepwise Zn-mediated carboxylation of allylic bromides with CO2 delivering β, γ-unsaturated carboxylic acids and a subsequent bromolactonization is reported. The described method demonstrates the use of readily prepared allylzinc bromides by the method of Knochel for fixation of CO2 employing commodity chemicals and zinc dust. This process was then optimized into a two-stage, telescoped process for the direct synthesis of γ-bromo-β-lactones from allyl bromides. The described strategy delivers functionalized β-lactones with dual reactivity as acylating and alkylating agents, which have utility as synthetic intermediates and are attracting growing interest as proteomic tools for activity-based protein profiling.
PROCESS FOR PREPARING MONO AND DICARBOXYLIC ACIDS
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Page/Page column 33; 34, (2018/02/03)
The present application relates to a process for preparing a dicarboxylic acid or dicarboxylic ester according to general formula (IV) R1OOC-(CH2)m-CH2CH2-(CH2)y-COOR4 (IV), comprising the steps of subjecting alkenoic acid or alkenoate of formula (II) R1OOC-(CH2)m-CH=CH-(CH2)x-H (II) to a metathesis reaction in the presence of a metathesis catalyst to form a longer-chain alkenoic acid or alkenoate of formula (III) R1OOC-(CH2)m-CH=CH-(CH2)y-H (III) where xa carbonylation reaction in the presence of a carbonylation catalyst and a carbonyl source to form said compound of Formula (IV). Alternative embodiments provide: a process for preparing an alkenoic acid or alkenoate comprising the step of subjecting a lactone to a ring opening reaction; a process for preparing a monocarboxylic acid or monocarboxylic ester according to general formula (XI) R1OOC-(CH2)m-CH2-(CH2)y-CH3 (XI) by subjecting an alkenoic acid or alkenoate to alkene hydrogenation; and a process for preparing an alcohol or ether according to general formula (XII) R1O-CH2-(CH2)m-CH2-(CH2)y-CH3 (XII) by subjecting an alkenoic acid or alkenoate to hydrogenation. The use of the respective mono/dicarboxylic acid, mono/dicarboxylic ester, ethers or alcohols in a variety of applications is also disclosed.
Design of Core-Pd/Shell-Ag Nanocomposite Catalyst for Selective Semihydrogenation of Alkynes
Mitsudome, Takato,Urayama, Teppei,Yamazaki, Kenji,Maehara, Yosuke,Yamasaki, Jun,Gohara, Kazutoshi,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
supporting information, p. 666 - 670 (2016/02/18)
We designed core-Pd/shell-Ag nanocomposite catalyst (Pd@Ag) for highly selective semihydrogenation of alkynes. The construction of the core-shell nanocomposite enables a significant improvement in the low activity of Ag NPs for the selective semihydrogenation of alkynes because hydrogen is supplied from the core-Pd NPs to the shell-Ag NPs in a synergistic manner. Simultaneously, coating the core-Pd NPs with shell-Ag NPs results in efficient suppression of overhydrogenation of alkenes by the Pd NPs. This complementary action of core-Pd and shell-Ag provides high chemoselectivity toward a wide range of alkenes with high Z-selectivity under mild reaction conditions (room temperature and 1 atm H2). Moreover, Pd@Ag can be easily separated from the reaction mixture and is reusable without loss of catalytic activity or selectivity.
Method for producing vinyl acetate, vinyl acetate and its manufacturing method deriv.
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Paragraph 0084-0085, (2019/10/02)
PROBLEM TO BE SOLVED: To provide a new vinyl acetic acid derivative, namely, to provide high-purity vinyl acetic acid and vinyl acetic acid derivatives having few isomers. SOLUTION: The 2-butene acid is mixed with water, converted into vinyl acetic acid highly selectively through isomerization by underwater photoreaction, and subjected to a solvent extraction/concentration step to obtain vinyl acetic acid, and thereafter induced into various vinyl acetic acid esters including new structures by an esterification reaction with an alcohol compound. COPYRIGHT: (C)2013,JPOandINPIT
