94-50-8Relevant articles and documents
LiHMDS: Facile, highly efficient and metal-free transesterification under solvent-free condition
Gore, Kiran R.,Mittapelli, Lavanya L.
, (2020/10/27)
Transesterification is one of the important organic reactions employed in numerous industrial as well as laboratory applications for the synthesis of various esters. Herein, we report a rapid, highly efficient, and transition metal-free transesterification reaction in the presence of LiHMDS under solvent-free conditions. The transesterification reaction was carried out with three different benzoate esters and a wide range of primary and secondary alcohols (from C3-C18) in good to excellent yields (45 examples). By considering the commercial role of esters, this method will be promising for the facile synthesis of esters in industry-relevant applications.
Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
Nikitas, Nikolaos F.,Apostolopoulou, Mary K.,Skolia, Elpida,Tsoukaki, Anna,Kokotos, Christoforos G.
supporting information, p. 7915 - 7922 (2021/05/03)
A cheap, facile and metal-free photochemical protocol for the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a drug against depression and social anxiety. Extended and detailed mechanistic studies have been conducted, in order to determine a plausible mechanism for the reaction.
Method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds
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Paragraph 0090-0091; 0093, (2021/06/02)
The invention discloses a method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds. The method comprises the following steps: adding a secondary alcohol compound, an additive and a nitrogen-doped mesoporous carbon loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1 MPa and the reaction temperature to be 80-150 DEG C, and obtaining a product after the reaction to be the carboxylic ester compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the carboxylic ester compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
Copper-mediated simple and direct aerobic oxidative esterification of arylacetonitriles with alcohols/phenols
Dong, Jianyu,Chen, Xiuling,Ji, Fangyan,Liu, Lixin,Su, Lebin,Mo, Min,Tang, Jian-Sheng,Zhou, Yongbo
, (2020/10/20)
A simple and direct aerobic oxidative esterification reaction of arylacetonitriles with alcohols/phenols is achieved in the presence of a copper salt and molecular oxygen, which produces a broad range of aryl carboxylic acid esters in good to high yields. Copper salt plays multiple roles in the transformation, which allows the oxygenation of C-H bond, cleavage of inert C-C bond, and formation of C-O bond in one pot without the assistance of any of the acids, bases, ligands, and so on. The reaction provides a simple, direct, and efficient protocol towards functionalized esters, especially aryl benzoates, from readily available starting materials.
Zr-MOF-808 as Catalyst for Amide Esterification
Villoria-del-álamo, Beatriz,Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
supporting information, p. 4588 - 4598 (2020/12/25)
In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.
Tropolonate salts as acyl-transfer catalysts under thermal and photochemical conditions: Reaction scope and mechanistic insights
Mai, Binh Khanh,Koenigs, Rene M.,Nguyen, Thanh Vinh,Lyons, Demelza J.M.,Empel, Claire,Pace, Domenic P.,Dinh, An H.
, p. 12596 - 12606 (2020/11/18)
Acyl-transfer catalysis is a frequently used tool to promote the formation of carboxylic acid derivatives, which are important synthetic precursors and target compounds in organic synthesis. However, there have been only a few structural motifs known to efficiently catalyze the acyl-transfer reaction. Herein, we introduce a different acyl-transfer catalytic paradigm based on the tropolone framework. We show that tropolonate salts, due to their strong nucleophilicity and photochemical activity, can promote the coupling reaction between alcohols and carboxylic acid anhydrides or chlorides to give products under thermal or blue light photochemical conditions. Kinetic studies and density functional theory calculations suggest interesting mechanistic insights for reactions promoted by this acyl-transfer catalytic system.
Red-light-mediated BartonMcCombie reaction
Ichii, Naoki,Ogura, Akihiro,Shibata, Kouhei,Takao, Ken-Ichi
supporting information, p. 936 - 941 (2020/11/09)
A red-light-mediated BartonMcCombie reaction is described, in which chlorophyll a is used as a photocatalyst and tris(trimethylsilyl)silane or Hantzsch ester is used as the hydrogen source. The reaction can be performed with a set of easily available equipment and reagents, and a variety of linear and cyclic xanthates could be applied. In contrast to the traditional conditions, the reaction does not involve toxic organotin or an explosive radical initiator. The reaction mechanism was analyzed both by experiments and computation, and it was suggested that the radical chain mechanism initiated by excitation of complex followed by charge transfer is likely to be operative.
The synergistic role of the support surface and Au-Cu alloys in a plasmonic Au-Cu?LDH photocatalyst for the oxidative esterification of benzyl alcohol with methanol
Wang, Xiaoyu,Wang, Ruiyi,Wang, Jie,Fan, Chaoyang,Zheng, Zhanfeng
, p. 1655 - 1664 (2020/01/31)
Layered double hydroxide-supported Au-Cu alloy nanoparticles (NPs) were found to be highly efficient catalysts for the oxidative esterification of benzyl alcohol with methanol in the presence of molecular oxygen under visible-light irradiation to prepare methyl benzoate. Here, we report that alloying small amounts of copper into gold nanoparticles can increase the ability to activate oxygen molecules to O2- radicals and display greater charge heterogeneity to promote the cleavage of the C-H bond of benzyl alcohol molecules by reinforcing the coordination of the intermediate with unsaturated metal active sites due to the LSPR effect of alloy NPs, which is the rate-limiting step of the reaction. Besides the Au-Cu alloy NPs, the support also played a pivotal role in the catalytic process. The support with the presence of acid-base pairs, in which the basic sites served as the reactant molecule adsorption sites to provoke the intermediate formation and the acidic sites promoted the recovery of the support surface, showed better performances by affecting the overall reaction rate completely. Moreover, applying this photocatalyst in the cross-esterification of aromatic alcohols and aliphatic alcohols displayed excellent yields.
MnO2?Fe3O4 Magnetic Nanoparticles as Efficient and Recyclable Heterogeneous Catalyst for Benzylic sp3 C?H Oxidation
Pandey, Akanksha M.,Agalave, Sandip G.,Vinod, Chathakudath P.,Gnanaprakasam, Boopathy
supporting information, p. 3414 - 3423 (2019/10/19)
Herein, we report a highly chemoselective and efficient heterogeneous MnO2?Fe3O4 MNP catalyst for the oxidation of benzylic sp3 C?H group of ethers using TBHP as a green oxidant to afford ester derivatives in high yield under batch/continuous flow module. This catalyst was also effective for the benzylic sp3 C?H group of methylene derivatives to furnish the ketone in high yield which can be easily integrated into continuous flow condition for scale up. The catalyst is fully characterized by spectroscopic techniques and it was found that 0.424 % MnO2?Fe3O4 catalyzes the reaction; the magnetic nanoparticles of this catalyst could be easily recovered from the reaction mixture. The recovered catalyst was recycled for twelve cycles without any loss of the catalytic activity. The advantages of MnO2?Fe3O4 MNP are its catalytic activity, easy preparation, recovery, and recyclability, gram scale synthesis with a TOF of up to 14.93 h?1 and low metal leaching during the reaction.
1,3-Dibromo-5,5-dimethylhydantoin as a Precatalyst for Activation of Carbonyl Functionality
?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
, (2019/08/01)
Activation of carbonyl moiety is one of the most rudimentary approaches in organic synthesis and is crucial for a plethora of industrial-scale condensation reactions. In esterification and aldol condensation, which represent two of the most important reactions, the susceptibility of the carbonyl group to nucleophile attack allows the construction of a variety of useful organic compounds. In this context, there is a constant need for development of and improvement in the methods for addition-elimination reactions via activation of carbonyl functionality. In this paper, an advanced methodology for the direct esterification of carboxylic acids and alcohols, and for aldol condensation of aldehydes using widely available, inexpensive, and metal-free 1,3-dibromo-5,5-dimethylhydantoin under neat reaction conditions is reported. The method is air- and moisture-tolerant, allowing simple synthetic and isolation procedures for both reactions presented in this paper. The reaction pathway for esterification is proposed and a scale-up of certain industrially important derivatives is performed.
