8014-16-2Relevant academic research and scientific papers
ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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Paragraph 0015; 0028, (2021/01/29)
An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
Iodine-catalyzed synthesis of β-uramino crotonic esters as well as oxidative esterification of carboxylic acids in choline chloride/urea: a desirable alternative to organic solvents
Moayyed, Mohammadesmaeil,Saberi, Dariush
, p. 445 - 455 (2020/09/07)
Abstract: Iodine-mediated selective synthesis of β-uramino crotonic esters was achieved via the reaction of β-dicarbonyls and urea at room temperature. Choline chloride/urea mixture, as an eco-friendly, cheap, non-toxic, and recyclable deep eutectic solvent (DES), was employed as sustainable media as well as reagent at the same time in these transformations. Some derivatives of β-uramino crotonic esters were synthesized with good to high yields without a tedious work-up. The process could be done to synthesize the above-mentioned compounds in gram scale. Moreover, oxidative cross-esterification of carboxylic acids with alkyl benzenes was carried out in the above-mentioned DES by the employment of tetrabutylammonium iodide (TBAI) as the catalyst and tert-butyl hydroperoxide (TBHP) as the oxidant at 80?°C. DES/TBAI system was reused up to five consecutive times. Graphic abstract: Iodine-catalyzed C–N and C–O bond formation in choline chloride/urea as a green solvent under the mild reaction conditions. Providing the clean procedure toward synthesis of β-uramino crotonic esters and benzylic esters.[Figure not available: see fulltext.].
Valorisation of urban waste to access low-cost heterogeneous palladium catalysts for cross-coupling reactions in biomass-derived γ-valerolactone
Valentini, Federica,Ferlin, Francesco,Lilli, Simone,Marrocchi, Assunta,Ping, Liu,Gu, Yanlong,Vaccaro, Luigi
supporting information, p. 5887 - 5895 (2021/08/23)
Herein we report a simple protocol for the valorisation of a common urban biowaste. The lignocellulosic biomass obtained after the pre-treatment of pine needle urban waste is efficiently transformed into a low-cost support (PiNe) for the immobilization of Pd nanoparticles. The final Pd/PiNe heterogeneous catalyst features a small particle size (4.5 nm) and a metal loading (9.9 wt%) comparable with most commercially available and generally used counterparts. In this contribution, we tested the catalytic efficiency of the Pd/PiNe system in two representative cross-couplings, Heck and Hiyama reactions, and compared the results obtained with commercial Pd/C catalyst. The good reactivity in the biomass-derived solvent (GVL) confirms that the Pd/PiNe heterogeneous catalyst is a valid system that can be integrated into a waste valorization chain within a circular economy approach. In addition, the efficiency of the catalyst has also been extended to perform the challenging consecutive Hiyama-Heck reaction to afford differently substituted (E)-1,2-diarylethenes.
Application of acidic ionic liquid to catalyze reaction of cinnamic acid and benzyl alcohol to prepare benzyl cinnamate and method for preparing benzyl cinnamate
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Paragraph 0039-0062, (2021/09/22)
The invention provides an application of an acidic ionic liquid to catalyze the reaction of cinnamic acid and benzyl alcohol to prepare benzyl cinnamate and a method for preparing benzyl cinnamate, and belongs to the technical field of chemical synthesis. The method provided by the invention comprises the following steps of cinnamic acid. The benzyl alcohol and the acidic ionic liquid are mixed to carry out esterification reaction to obtain benzyl cinnamate. By using the acidic ionic liquid as the catalyst, the esterification reaction of cinnamic acid and benzyl alcohol can be effectively catalyzed, the acidic ionic liquid toxicity belongs to low toxic substances, and the pollution to the environment is reduced. Compared with concentrated sulfuric acid, the acidic ionic liquid can greatly reduce the corrosion to equipment. The results show that the yield of benzyl cinnamate provided by the invention is 56.3 ±2.5% - 92.1 ±2.6%.
Discriminating non-ylidic carbon-sulfur bond cleavages of sulfonium ylides for alkylation and arylation reactions
Cai, Lei,Chen, Qi,Fang, Jing,Li, Ting,Liao, Zhiwen,Ma, Xiang,Meng, Lingkui,Sun, Jiuchang,Wan, Qian,Zeng, Jing
, (2021/07/25)
A sulfonium ylide participated alkylation and arylation under transition-metal free conditions is described. The disparate reaction pattern allowed the separate activation of non-ylidic S-alkyl and S-aryl bond. Under acidic conditions, sulfonium ylides serve as alkyl cation precursors which facilitate the alkylations. While under alkaline conditions, cleavage of non-ylidic S-aryl bond produces O-arylated compounds efficiently. The robustness of the protocols were established by the excellent compatibility of wide variety of substrates including carbohydrates.
Mizoroki-Heck Reaction of Unstrained Aryl Ketones via Ligand-Promoted C-C Bond Olefination
Wang, Mei-Ling,Xu, Hui,Li, Han-Yuan,Ma, Biao,Wang, Zhen-Yu,Wang, Xing,Dai, Hui-Xiong
, p. 2147 - 2152 (2021/04/05)
Mizoroki-Heck reaction of unstrained aryl ketone with acrylate/styrene is accomplished via palladium-catalyzed ligand-promoted C-C bond cleavage. Various (hetero)aryl ketones are compatible in the reaction, affording the alkene product in good to excellent yields. Further applications in the late-stage olefination of some drugs, natural products, and fragrance-derived aryl ketones demonstrate the synthetic utility of this protocol. By employing ketone as both the directing group and the leaving group, 1,2-bifunctionalization is achieved via sequential ortho-C-H alkylation/ipso-Heck olefination.
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
supporting information, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
Ruthenium-Catalyzed Oxidative Cross-Coupling Reaction of Activated Olefins with Vinyl Boronates for the Synthesis of (E, E)-1,3-Dienes
Dethe, Dattatraya H.,Beeralingappa, Nagabhushana C.,Uike, Amar
, p. 3444 - 3455 (2021/02/16)
An oxidative cross-coupling reaction between activated olefins and vinyl boronate derivatives has been developed for the highly stereoselective construction of synthetically useful (E,E)-1,3-dienes. The highlight of this reaction is that exclusive stereoselectivity (only E,E-isomer) was achieved from a base-free, ligand-free, and mild catalytic condition with a less expensive [RuCl2(p-cymene)]2 catalyst.
Benzyne-Mediated Esterification Reaction
Li, Yang,Shi, Jiarong,Zhao, Jinlong
supporting information, p. 7274 - 7278 (2021/10/01)
A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
4-Alkyl-1,2,4-triazole-3-thione analogues as metallo-β-lactamase inhibitors
Gavara, Laurent,Legru, Alice,Verdirosa, Federica,Sevaille, Laurent,Nauton, Lionel,Corsica, Giuseppina,Mercuri, Paola Sandra,Sannio, Filomena,Feller, Georges,Coulon, Rémi,De Luca, Filomena,Cerboni, Giulia,Tanfoni, Silvia,Chelini, Giulia,Galleni, Moreno,Docquier, Jean-Denis,Hernandez, Jean-Fran?ois
supporting information, (2021/06/15)
In Gram-negative bacteria, the major mechanism of resistance to β-lactam antibiotics is the production of one or several β-lactamases (BLs), including the highly worrying carbapenemases. Whereas inhibitors of these enzymes were recently marketed, they only target serine-carbapenemases (e.g. KPC-type), and no clinically useful inhibitor is available yet to neutralize the class of metallo-β-lactamases (MBLs). We are developing compounds based on the 1,2,4-triazole-3-thione scaffold, which binds to the di-zinc catalytic site of MBLs in an original fashion, and we previously reported its promising potential to yield broad-spectrum inhibitors. However, up to now only moderate antibiotic potentiation could be observed in microbiological assays and further exploration was needed to improve outer membrane penetration. Here, we synthesized and characterized a series of compounds possessing a diversely functionalized alkyl chain at the 4-position of the heterocycle. We found that the presence of a carboxylic group at the extremity of an alkyl chain yielded potent inhibitors of VIM-type enzymes with Ki values in the μM to sub-μM range, and that this alkyl chain had to be longer or equal to a propyl chain. This result confirmed the importance of a carboxylic function on the 4-substituent of 1,2,4-triazole-3-thione heterocycle. As observed in previous series, active compounds also preferentially contained phenyl, 2-hydroxy-5-methoxyphenyl, naphth-2-yl or m-biphenyl at position 5. However, none efficiently inhibited NDM-1 or IMP-1. Microbiological study on VIM-2-producing E. coli strains and on VIM-1/VIM-4-producing multidrug-resistant K. pneumoniae clinical isolates gave promising results, suggesting that the 1,2,4-triazole-3-thione scaffold worth continuing exploration to further improve penetration. Finally, docking experiments were performed to study the binding mode of alkanoic analogues in the active site of VIM-2.
