57152-94-0Relevant academic research and scientific papers
Ammonia-borane as a Catalyst for the Direct Amidation of Carboxylic Acids
Ramachandran, P. Veeraraghavan,Hamann, Henry J.
supporting information, p. 2938 - 2942 (2021/05/04)
Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylic acids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification but is not amenable for esterification. The latter feature has been exploited to prepare hydroxyl- and thiol-containing amides.
Br?nsted Acid Mediated Nucleophilic Functionalization of Amides through Stable Amide C?N Bond Cleavage; One-Step Synthesis of 2-Substituted Benzothiazoles
Biswas, Srijit,Biswas, Subrata,Duari, Surajit,Elsharif, Asma M.,Maity, Srabani,Roy, Arnab
supporting information, p. 3569 - 3572 (2021/07/22)
We have developed a Br?nsted acid mediated synthetic method to directly cleave stable amide C?N bonds by a variety of alcohol and amine nucleophiles. Reverse reactivity was observed and alcoholysis of amides by activated primary and secondary benzylic, and propargylic alcohols have been achieved instead of the expected nucleophilic substitution of alcohols. As an application, 2-substituted benzothiazole derivatives have been synthesized in one pot employing 2-aminothiophenol as nucleophile.
Chlorination Reaction of Aromatic Compounds and Unsaturated Carbon-Carbon Bonds with Chlorine on Demand
Liu, Feng,Wu, Na,Cheng, Xu
supporting information, p. 3015 - 3020 (2021/05/05)
Chlorination with chlorine is straightforward, highly reactive, and versatile, but it has significant limitations. In this Letter, we introduce a protocol that could combine the efficiency of electrochemical transformation and the high reactivity of chlorine. By utilizing Cl3CCN as the chloride source, donating up to all three chloride atom, the reaction could generate and consume the chlorine in situ on demand to achieve the chlorination of aromatic compounds and electrodeficient alkenes.
Radical-Mediated Activation of Esters with a Copper/Selectfluor System: Synthesis of Bulky Amides and Peptides
Matsumoto, Akira,Wang, Zhe,Maruoka, Keiji
, p. 5401 - 5411 (2021/04/12)
Herein, we describe a new approach for the activation of esters via a radical-mediated process enabled by a copper/Selectfluor system. A variety of para-methoxybenzyl esters derived from bulky carboxylic acids and amino acids can be easily converted into the corresponding acyl fluorides, directly used in the one-pot synthesis of amides and peptides. As a proof of concept, this method was applied to the iterative formation of sterically hindered amide bonds.
Manganese Catalyzed Direct Amidation of Esters with Amines
Fu, Zhengqiang,Wang, Xinghua,Tao, Sheng,Bu, Qingqing,Wei, Donghui,Liu, Ning
, p. 2339 - 2358 (2021/02/03)
The transition metal catalyzed amide bond forming reaction of esters with amines has been developed as an advanced approach for overcoming the shortcomings of traditional methods. The broad scope of substrates in transition metal catalyzed amidations remains a challenge. Here, a manganese(I)-catalyzed method for the direct synthesis of amides from a various number of esters and amines is reported with unprecedented substrate scope using a low catalyst loading. A wide range of aromatic, aliphatic, and heterocyclic esters, even in fatty acid esters, reacted with a diverse range of primary aryl amines, primary alkyl amines, and secondary alkyl amines to form amides. It is noteworthy that this approach provides the first example of the transition metal catalyzed amide bond forming reaction from fatty acid esters and amines. The acid-base mechanism for the manganese(I)-catalyzed direct amidation of esters with amines was elucidated by DFT calculations.
Electron-Catalyzed Aminocarbonylation: Synthesis of α,β-Unsaturated Amides from Alkenyl Iodides, CO, and Amines
Picard, Baptiste,Fukuyama, Takahide,Bando, Takanobu,Hyodo, Mamoru,Ryu, Ilhyong
supporting information, p. 9505 - 9509 (2021/12/09)
Aminocarbonylation of alkenyl iodides with CO and amines proceeded under heating to produce α,β-unsaturated amides in good yields (23 examples, 71% average yield). This catalyst-free method exhibited good functional-group tolerance, and open a straightforward access to functionalized acrylamides, as illustrated by the synthesis of Ilepcimide. A hybrid radical/ionic mechanism involving chain electron transfer is proposed for this transformation.
Simple Synthesis of Amides via Their Acid Chlorides in Aqueous TPGS-750-M
Shi, Min,Ye, Ning,Chen, Wei,Wang, Hui,Cheung, Chiming,Parmentier, Michael,Gallou, Fabrice,Wu, Bin
supporting information, p. 1543 - 1548 (2020/11/23)
The technology of surfactant chemistry is employed for amide bond construction via the reaction of acyl chlorides with amines in 2 wt % TPGS-750-M aqueous solution. Specifically, this highly efficient method enables a chromatography-free scalable process and recycling of the TPGS-750-M solution.
N-Hydroxybenzimidazole as a structurally modifiable platform forN-oxyl radicals for direct C-H functionalization reactions
Hatanaka, Miho,Jiang, Julong,Maruoka, Keiji,Matsumoto, Akira,Sakamoto, Ryu,Sakurai, Shunya,Tsuzuki, Saori,Yoshii, Tomomi
, p. 5772 - 5778 (2020/06/22)
Methods for direct functionalization of C-H bonds mediated byN-oxyl radicals constitute a powerful tool in modern organic synthesis. While severalN-oxyl radicals have been developed to date, the lack of structural diversity for these species has hampered further progress in this field. Here we designed a novel class ofN-oxyl radicals based onN-hydroxybenzimidazole, and applied them to the direct C-H functionalization reactions. The flexibly modifiable features of these structures enabled facile tuning of their catalytic performance. Moreover, with these organoradicals, we have developed a metal-free approach for the synthesis of acyl fluoridesviadirect C-H fluorination of aldehydes under mild conditions.
Efficient cleavage of tertiary amide bonds: Via radical-polar crossover using a copper(ii) bromide/Selectfluor hybrid system
Maruoka, Keiji,Matsumoto, Akira,Wang, Zhe
, p. 12323 - 12328 (2020/12/08)
A novel approach for the efficient cleavage of the amide bonds in tertiary amides is reported. Based on the selective radical abstraction of a benzylic hydrogen atom by a CuBr2/Selectfluor hybrid system followed by a selective cleavage of an N-C bond, an acyl fluoride intermediate is formed. This intermediate may then be derivatized in a one-pot fashion. The reaction proceeds under mild conditions and exhibits a broad substrate scope with respect to the tertiary amide moiety as well as to nitrogen, oxygen, and carbon nucleophiles for the subsequent derivatization. Mechanistic studies suggest that the present reaction proceeds via a radical-polar crossover process that involves benzylic carbon radicals generated by the selective radical abstraction of a benzylic hydrogen atom by the CuBr2/Selectfluor hybrid system. Furthermore, a synthetic application of this method for the selective cleavage of peptides is described. This journal is
Graphene oxide: A convenient metal-free carbocatalyst for facilitating amidation of esters with amines
Patel, Khushbu P.,Gayakwad, Eknath M.,Shankarling, Ganapati S.
, p. 2661 - 2668 (2020/02/20)
Herein, we report a graphene oxide (GO) catalyzed condensation of non-activated esters and amines, that can enable diverse amides to be synthesized from abundant ethyl esters forming only volatile alcohol as a by-product. GO accelerates ester to amide conversion in the absence of any additives, unlike other catalysts. A wide range of ester and amine substrates are screened to yield the respective amides in good to excellent yields. The improved catalytic activity can be ascribed to the oxygenated functionalities present on the graphene oxide surface which forms H-bonding with the reactants accelerating the reaction. Improved yields and a wide range of functional group tolerance are some of the important features of the developed protocol.
