94-33-7Relevant academic research and scientific papers
Kinetic Modeling of Ethylene Glycol Monoesterification
Pe?ar, Darja,Gor?ek, Andreja
, p. 658 - 663 (2015)
The monoesterification of ethylene glycol under isothermal conditions was conducted using benzoic acid in methane-sulfonic acid/Al2O3 as a catalyst. Using this reagent, glycol was selectively monoesterified with high yield. The reactions were performed within an automated batch reactor under equimolar conditions, constant rotational frequency of the stirrer, and within the temperature range from 65 to 85°C. The rate constant related to this reaction and to the corresponding reverse reaction, activation energy, and preexponential factor was derived from experimental data. It has been concluded that under these conditions the formation of dibenzoate was successfully prevented.
Expanding the Tool Kit of Automated Flow Synthesis: Development of In-line Flash Chromatography Purification
Thomson, Christopher G.,Banks, Colin,Allen, Mark,Barker, Graeme,Coxon, Christopher R.,Lee, Ai-Lan,Vilela, Filipe
supporting information, p. 14079 - 14094 (2021/07/31)
Recent advancements in in-line extraction and purification technology have enabled complex multistep synthesis in continuous flow reactor systems. However, for the large scope of chemical reactions that yield mixtures of products or residual starting materials, off-line purification is still required to isolate the desired compound. We present the in-line integration of a commercial automated flash chromatography system with a flow reactor for the continuous synthesis and isolation of product(s). A proof-of-principle study was performed to validate the system and test the durability of the column cartridges, performing an automated sequence of 100 runs over 2 days. Three diverse reaction systems that highlight the advantages of flow synthesis were successfully applied with in-line normal- or reversed-phase flash chromatography, continuously isolating products with 97-99% purity. Productivity of up to 9.9 mmol/h was achieved, isolating gram quantities of pure product from a feed of crude reaction mixture. Herein, we describe the development and optimization of the systems and suggest guidelines for selecting reactions well suited to in-line flash chromatography.
Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
, p. 2084 - 2092 (2021/04/02)
Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
supporting information, p. 2652 - 2657 (2021/04/21)
The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
Protecting-group-free synthesis of hydroxyesters from amino alcohols
Joseph-Valcin, Eve-Marline,Lebel, Hélène,Reynard, Guillaume
supporting information, p. 10938 - 10941 (2020/10/02)
The synthesis of hydroxyesters from carboxylic acids and unprotected amino alcohols in both continuous flow and batch processes is reported. The formation of a transient diazonium species with a dinitrite reagent is key in this transformation. The reaction conditions are compatible with a variety of functional groups.
Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions
Chan, Kaai-Tung,Che, Chi-Ming,Du, Lili,Liu, Yungen,Phillips, David Lee,To, Wai-Pong,Tong, Glenna So Ming,Wu, Liang-Liang,Yu, Daohong
, p. 6370 - 6382 (2020/07/15)
The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
Design and synthesis of tricyclic terpenoid derivatives as novel PTP1B inhibitors with improved pharmacological property and in vivo antihyperglycaemic efficacy
Chen, Feng,Chen, Jiabao,Gao, Cheng,Li, Junyan,Liu, Siyan,Qian, Shan,Wang, Zhouyu,Yang, Lingling,Zhang, Yuanyuan
, p. 152 - 164 (2019/11/25)
Overexpression of protein tyrosine phosphatase 1B (PTP1B) induces insulin resistance in various basic and clinical research. In our previous work, a synthetic oleanolic acid (OA) derivative C10a with PTP1B inhibitory activity has been reported. However, C10a has some pharmacological defects and cytotoxicity. Herein, a structure-based drug design approach was used based on the structure of C10a to elaborate the smaller tricyclic core. A series of tricyclic derivatives were synthesised and the compounds 15, 28 and 34 exhibited the most PTP1B enzymatic inhibitory potency. In the insulin-resistant human hepatoma HepG2 cells, compound 25 with the moderate PTP1B inhibition and preferable pharmaceutical properties can significantly increase insulin-stimulated glucose uptake and showed the insulin resistance ameliorating effect. Moreover, 25 showed the improved in vivo antihyperglycaemic potential in the nicotinamide–streptozotocin-induced T2D. Our study demonstrated that these tricyclic derivatives with improved molecular architectures and antihyperglycaemic activity could be developed in the treatment of T2D.
Stannous chloride as a low toxicity and extremely cheap catalyst for regio-/site-selective acylation with unusually broad substrate scope
Dong, Hai,Feng, Guang-Jing,Luo, Tao,Lv, Jian,Yu, Jian-Cheng
supporting information, p. 6936 - 6942 (2020/11/09)
This work reports stannous chloride (SnCl2)-catalyzed regio-/site-selective acylation with unusually broad substrate scope. In addition to 1,2- and 1,3-diols and glycosides containing cis-vicinal diol, the substrate scope also includes glycosides without cis-vicinal diol. For such a substrate scope, usually, only methods using stoichiometric amounts of organotin reagents can lead to the same protection pattern with high selectivities and highly isolated yields (84-97% in most cases). Therefore, SnCl2, as a low toxicity and extremely cheap reagent, should be the best catalyst for regio-/site-selective acylation compared with any previously reported reagents. This journal is
Selective Acylation of Aryl- A nd Heteroarylmagnesium Reagents with Esters in Continuous Flow
Heinz, Benjamin,Djukanovic, Dimitrije,Ganiek, Maximilian A.,Martin, Benjamin,Schenkel, Berthold,Knochel, Paul
supporting information, p. 493 - 496 (2020/01/31)
A selective acylation of readily accessible organomagnesium reagents with commercially available esters proceeds at convenient temperatures and short residence times in continuous flow. Flow conditions allow us to prevent premature collapse of the hemiacetal intermediates despite noncryogenic conditions, thus furnishing ketones in good yields. Throughout, the coordinating ability of the ester and/or Grignard was crucial for the reaction outcome. This was leveraged by the obtention of several bisaryl ketones using 2-hydroxy ester derivatives as substrates.
Electrochemical esterification reaction of alkynes with diols: Via cleavage of carbon-carbon triple bonds without catalyst and oxidant
Cheng, Hui-Hui,Gao, Hui,Li, Pin-Hua,Shen, Hui-Zhi,Wang, Pei-Long
supporting information, p. 6783 - 6791 (2020/11/09)
A novel electrochemical esterification of alkynes for the synthesis of esters was developed in which diols and their derivatives were used as the partners. This method is green as it is catalyst-free, oxidant-free, and additive-free and shows atom-economy. This is the first example of an electrochemical reaction via cleavage of carbon-carbon triple bonds. Meanwhile, this is also the first example of a carbon-carbon triple bond cleavage reaction of alkynes with diols. This journal is
