58550-50-8Relevant academic research and scientific papers
Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
, p. 66 - 71 (2020/11/18)
The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
Esterification of Tertiary Amides by Alcohols Through C?N Bond Cleavage over CeO2
Toyao, Takashi,Nurnobi Rashed, Md.,Morita, Yoshitsugu,Kamachi, Takashi,Hakim Siddiki,Ali, Md. A.,Touchy,Kon, Kenichi,Maeno, Zen,Yoshizawa, Kazunari,Shimizu, Ken-ichi
, p. 449 - 456 (2018/09/11)
CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (>45 examples; up to 93 % isolated yield). Results of a density functional theory (DFT) study combined with in situ FT-IR observations indicate that the process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT-IR and temperature programmed desorption using probe molecules demonstrate that both acidic and basic properties are important, and consequently, CeO2 showed the best performance for the C?N bond cleavage reaction.
Base-Promoted Amidation and Esterification of Imidazolium Salts via Acyl C-C bond Cleavage: Access to Aromatic Amides and Esters
Karthik, Shanmugam,Muthuvel, Karthick,Gandhi, Thirumanavelan
, p. 738 - 751 (2019/01/24)
Imidazolium salts have been effectively employed as suitable acyl transfer agents in amidation and esterification in organic synthesis. The weak acyl C(O)-C imidazolium bond was exploited to generate acyl electrophiles, which further react with amines and alcohols to afford amides and esters. The broad substrate scope of anilines and benzylic amines and base-promoted conditions are the benefits of this route. Interestingly, phenol, benzylic alcohols, and a biologically active alcohol can also be subjected to esterification under the optimized conditions.
Base-catalyzed retro-Claisen condensation: A convenient esterification of alcohols via C-C bond cleavage of ketones to afford acylating sources
Xie, Feng,Yan, Fengxia,Chen, Mengmeng,Zhang, Min
, p. 29502 - 29508 (2014/08/05)
The base-catalyzed esterification of alcohols via retro-Claisen condensation has been demonstrated for the first time. A variety of alcohols including aryl- and heteroaryl methanols as well as aliphatic ones underwent efficient acylation to give the ester products in reasonable to good yields upon isolation. Not only conventional 1,3-diketones but also strong electron-withdrawing group containing acetophenones could serve as the acylating suppliers. The synthetic protocol is operationally simple and adaptable to a broad substrate scope. It complements the existed esterification via the retro-Claisen condensation, and enlarges this benign synthetic methodology.
