68571-10-8Relevant academic research and scientific papers
A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects
Ghinato, Simone,Territo, Davide,Maranzana, Andrea,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
supporting information, p. 2868 - 2874 (2021/01/21)
We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
Amide Bond Formation via Aerobic Photooxidative Coupling of Aldehydes with Amines Catalyzed by a Riboflavin Derivative
Hassan Tolba, Amal,Krupi?ka, Martin,Chudoba, Josef,Cibulka, Radek
supporting information, p. 6825 - 6830 (2021/09/11)
We report an effective, operationally simple, and environmentally friendly system for the synthesis of tertiary amides by the oxidative coupling of aromatic or aliphatic aldehydes with amines mediated by riboflavin tetraacetate (RFTA), an inexpensive organic photocatalyst, and visible light using oxygen as the sole oxidant. The method is based on the oxidative power of an excited flavin catalyst and the relatively low oxidation potential of the hemiaminal formed by amine to aldehyde addition.
Method for preparing amide compound by photocatalysis of nitrogen-containing heterocyclic compound
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Paragraph 0067-0070; 0093; 0094, (2021/06/06)
The invention provides a method for preparing an amide compound by photocatalysis of a nitrogen-containing heterocyclic compound. The method comprises the following steps: mixing the nitrogen-containing heterocyclic compound, organic carboxylic acid and tetrahalomethane in a solvent, adding a catalyst, and reacting under the illumination condition to prepare the amide compound. According to the invention, the organic carboxylic acid, the nitrogen-containing heterocyclic compound containing reactive hydrogen on nitrogen atoms and the tetrahalomethane are used as raw materials, so the raw materials are wide in source, low in cost and high in safety, and large-scale production is facilitated; the halogen simple substance is co-produced in the reaction process, the added value is high, a large amount of waste is prevented from being generated, and the method has high atom economy and environmental friendliness; light conditions are adopted to replace traditional heating and high-pressure conditions, the reaction conditions are mild, environmental pollution is reduced, and the reaction cost is reduced; the method has the advantages of good substrate applicability, mild process conditions, environmental protection, simple process, simple and feasible operation method, and facilitation of popularization and application.
Tandem Photoredox Catalysis: Enabling Carbonylative Amidation of Aryl and Alkylhalides
Connell, Timothy U.,Forni, José A.,Micic, Nenad,Polyzos, Anastasios,Weragoda, Geethika
supporting information, p. 18646 - 18654 (2020/08/21)
We report a new visible-light-mediated carbonylative amidation of aryl, heteroaryl, and alkyl halides. A tandem catalytic cycle of [Ir(ppy)2(dtb-bpy)]+ generates a potent iridium photoreductant through a second catalytic cycle in the presence of DIPEA, which productively engages aryl bromides, iodides, and even chlorides as well as primary, secondary, and tertiary alkyl iodides. The versatile in situ generated catalyst is compatible with aliphatic and aromatic amines, shows high functional-group tolerance, and enables the late-stage amidation of complex natural products.
Synthesis of secondary and tertiary amides without coupling agents from amines and potassium acyltrifluoroborates (KATs)
Bode, Jeffrey W.,Ryan, Sarah J.,Schuhmacher, Anne,Shiro, Tomoya
, p. 7609 - 7614 (2020/08/14)
Although highly effective for most amide syntheses, the activation of carboxylic acids requires the use of problematic coupling reagents and is often poorly suited for challenging cases such as N-methyl amino acids. As an alternative to both secondary and tertiary amides, we report their convenient synthesis by the rapid oxidation of trifluoroborate iminiums (TIMs). TIMs are easily prepared by acid-promoted condensation of potassium acyltrifluoroborates (KATs) and amines and are cleanly and rapidly oxidized to amides with hydrogen peroxide. The overall transformation can be conducted either as a one-pot procedure or via isolation of the TIM. The unique nature of the neutral, zwitterionic TIMs makes possible the preparation of tertiary amides via an iminium species that would not be accessible from other carbonyl derivatives and can be conducted in the presence of unprotected functional groups including acids, alcohols and thioethers. In preliminary studies, this approach was applied to the late-stage modifications of long peptides and the iterative synthesis of short, N-methylated peptides without the need for coupling agents.
Electrophilic Activation of Carboxylic Anhydrides for Nucleophilic Acylation Reactions
Kumar, Varun,Kumar, Yashwant,Lal Meena, Chhuttan,Mahajan, Dinesh,Rana, Anil,Sharma, Nidhi
, p. 3902 - 3910 (2018/09/29)
Nucleophilic acylation of symmetrical carboxylic anhydrides has inherited limitation of reaction efficiency along with relatively poor reactivity. Traditionally, one equivalent carboxylic acid is generated during nucleophilic acylation of a symmetrical anhydride, which always limits the yield of final product to 50percent or less. This is a major drawback, which discourages the use of anhydrides for laboratory or industrial applications. Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is found to be an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol found to be a mild and high yielding methodology for one-pot nucleophilic acylation of carboxylic anhydrides with several type of N- and S-nucleophiles demonstrating appreciable functional group tolerance.
Nickel-catalyzed transamidation of aliphatic amide derivatives
Dander, Jacob E.,Baker, Emma L.,Garg, Neil K.
, p. 6433 - 6438 (2017/08/29)
Transamidation, or the conversion of one amide to another, is a long-standing challenge in organic synthesis. Although notable progress has been made in the transamidation of primary amides, the transamidation of secondary amides has remained underdeveloped, especially when considering aliphatic substrates. Herein, we report a two-step approach to achieve the transamidation of secondary aliphatic amides, which relies on non-precious metal catalysis. The method involves initial Boc-functionalization of secondary amide substrates to weaken the amide C-N bond. Subsequent treatment with a nickel catalyst, in the presence of an appropriate amine coupling partner, then delivers the net transamidated products. The transformation proceeds in synthetically useful yields across a range of substrates. A series of competition experiments delineate selectivity patterns that should influence future synthetic design. Moreover, the transamidation of Boc-activated secondary amide derivatives bearing epimerizable stereocenters underscores the mildness and synthetic utility of this methodology. This study provides the most general solution to the classic problem of secondary amide transamidation reported to date.
Development of variously functionalized nitrile oxides
Asahara, Haruyasu,Arikiyo, Keita,Nishiwaki, Nagatoshi
, p. 1241 - 1245 (2015/08/18)
N-Methylated amides (N,4-dimethylbenzamide and N-methylcyclohexanecarboxamide) were systematically subjected to chemical transformations, namely, N-tosylation followed by nucleophilic substitution. The amide function was converted to the corresponding carboxylic acid, esters, amides, aldehyde, and ketone upon treatment with hydroxide, alkoxide, amine, diisobutylaluminium hydride and Grignard reagent, respectively. In these transformations, N-methyl-N-tosylcarboxamides behave like a Weinreb amide. Similarly, N-methyl-5-phenylisoxazole-3-carboxamide was converted into 3-functionalized isoxazole derivatives. Since the amide was prepared by the cycloaddition reaction of ethynylbenzene and N-methylcarbamoylnitrile oxide, the nitrile oxide served as the equivalent of the nitrile oxides bearing a variety of functional groups such as carboxy, alkoxycarbonyl, carbamoyl, acyl and formyl moieties.
Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines
Qian, Cunwei,Zhang, Xingmin,Zhang, Yong,Shen, Qi
experimental part, p. 747 - 752 (2010/04/27)
Reactions of triguanidinate lanthanide complexes Ln[(iPrN)(NC6H4p-Cl)C(NHiPr)]3 (Ln = Nd, Y) with 3 equiv. of n-BuLi gave [Li(THF)(DME)]3Ln[μ-η2η1 (iPrN)2C(NC6H4p-Cl)]3, which represents the first structurally characterized complexes of lanthanide and lithium metals with dianionic guanidinate ligands. The Nd complex was found to be an effective catalyst for amidation of aldehydes with amines under mild conditions with a wide scope of substrates.
Microwave acceleration in DABAL-Me3-mediated amide formation
Glynn, Daniel,Bernier, David,Woodward, Simon
, p. 5687 - 5688 (2008/12/22)
Facile direct coupling of esters and secondary amines to afford tertiary amides proceeds under microwave irradiation using the air-stable trimethylaluminium source DABAL-Me3 [(DABCO)(AlMe3)2]. Excellent yields (88-98%) are attained for cyclic secondary amines in reactions that are complete in 5-16 min. The process can be extended to the formation of Weinreb amides (upto 76% from commercial MeNHOMe·HCl) in a one-pot procedure using NaH to liberate the free methoxyamine.
