4030-18-6Relevant academic research and scientific papers
Amide rotation trajectories probed by symmetry
Kubyshkin, Vladimir,Budisa, Nediljko
, p. 6764 - 6772 (2017)
Amide rotation of peptidyl-prolyl fragments is an important factor in backbone structure organization of proteins. Computational studies have indicated that this rotation preferentially proceeds through a defined transition-state structure (syn/exo). Here, we complement the computational findings by determining the amide bond rotation barriers for derivatives of the two symmetric proline analogues, meso and racemic pyrrolidine-2,5-dicarboxylic acids. The rotations around these residues represent syn/exo-syn/exo and anti/endo-syn/exo hybrid transition states for the meso and racemic diastereomer, respectively. The rotation barriers are lower for the former rotation by about 9 kJ mol-1 (aqueous medium), suggesting a strong preference for the syn/exo (clockwise) rotation over the anti/endo (anticlockwise) rotation. The results show that both hybrid rotation processes are enthalpically driven but respond differently to solvent polarity changes due to the different transition state dipole-dipole interactions.
Environmentally benign decarboxylative: N-, O-, and S-Acetylations and acylations
Ghosh, Santanu,Purkait, Anisha,Jana, Chandan K.
supporting information, p. 8721 - 8727 (2020/12/30)
An operationally simple and general method for acetylation and acylation of a wide variety of substrates (amines, alcohols, phenols, thiols, and hydrazones) has been reported. Meldrum's acid and its derivatives have been used as an air-stable, non-volatile, cost-effective, and easy to handle acetylating/acylating agent. Easily separable byproducts (CO2 and acetone) allowed the isolation of analytically pure acetylated products without the requirement of work-up and any chromatography. This journal is
An organocatalytic C-C bond cleavage approach: A metal-free and peroxide-free facile method for the synthesis of amide derivatives
Vodnala, Nagaraju,Gujjarappa, Raghuram,Polina, Saibabu,Satheesh, Vanaparthi,Kaldhi, Dhananjaya,Kabi, Arup K.,Malakar, Chandi C.
supporting information, p. 20940 - 20944 (2020/12/31)
A facile organocatalytic approach has been devised towards the synthesis of amide derivatives using 1,3-dicarbonyls as easily available acyl-sources under peroxide-free reaction conditions. This transformation was accomplished by the cleavage of the C-C bond in the presence of TEMPO as an organocatalyst and excludes the use of transition-metals and harsh reaction conditions. A broad range of substrates with diverse functional groups were well tolerated and delivered the products in high yields.
IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
Talukdar, Ranadeep
supporting information, p. 5303 - 5308 (2020/04/17)
An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
Synthesis of Benzofurans and Benzoxazoles through a [3,3]-Sigmatropic Rearrangement: O-NHAc as a Multitasking Functional Group
Yan, Dingyuan,Jiang, Heming,Sun, Wenxue,Wei, Wei,Zhao, Jing,Zhang, Xinhao,Wu, Yun-Dong
supporting information, p. 1646 - 1653 (2019/09/04)
The synthesis of heterocycles relies heavily on diverse sigmatropic rearrangements triggered by the cleavage of X-Y (X, Y = C, O, N, S, I) bonds. However, a unified rearrangement approach for constructing heterocyclic libraries is highly desirable. Encouraged by computational analysis of [3,3]-sigmatropic rearrangements, we can now rapidly synthesize oxa-heterocycles by treating N-phenoxyacetamides (Ph-ONHAc) with compounds containing an sp-hybridized carbon. The generality of the process is illustrated by the late-stage diversification of natural products, including estrone and an approved drug. A combination of experimental and computational studies revealed that the reactions proceed through a facile Claisen-like [3,3]-sigmatropic rearrangement/annulation process.
Synthesis of acetamides using CO2, methanol, H2 and amines
Zhang, Jingjing,Qian, Qingli,Wang, Ying,Asare Bediako, Bernard Baffour,Cui, Meng,Yang, Guanying,Han, Buxing
supporting information, p. 233 - 237 (2019/01/28)
Herein, we report the synthesis of acetamides from CO2, methanol, H2 and corresponding amines, which is a new route used to synthesize acetamides. It was found that the Rh catalyst with LiI/LiCl as promoters could effectively catalyze this reaction. Interestingly, no ligand was required and amine substrates played a role in accelerating the reaction.
Manganese-Catalyzed Direct Conversion of Ester to Amide with Liberation of H2
Mondal, Akash,Subaramanian, Murugan,Nandakumar, Avanashiappan,Balaraman, Ekambaram
supporting information, p. 3381 - 3384 (2018/06/11)
A simple and efficient Mn-catalyzed acylation of amines is achieved using both acyl and alkoxy functions of unactivated esters with the liberation of molecular hydrogen as a sole byproduct. The present protocol provides an atom-economical and sustainable route for the synthesis of amides from esters by employing an earth-abundant manganese salt and inexpensive phosphine-free tridentate ligand.
Synthesis of 4-Vinylmorpholine Based on Acetylene
Asratyan,Bagdasaryan,Markosyan, A. Dzh.,Badalyan,Attaryan
, p. 342 - 345 (2018/05/15)
It has been shown that from the possible methods for the synthesis of 4-vinylmorpholine, the vinylation of morpholine with acetylene remains acceptable. A technologically accessible method for vinylation of morpholine with acetylene at atmospheric pressure was developed.
Cu(II)-Mediated keto C(sp3)-H bond α-acyloxylation of N, N-dialkylamides with aromatic carboxylic acids
Li, Wenjing,Yin, Changzhen,Yang, Xiao,Liu, Hailong,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Fu, Haiyan,Chen, Hua
supporting information, p. 7594 - 7599 (2017/09/27)
The selective oxidative coupling of aromatic carboxylic acids with the C(sp3)-H bond adjacent to the keto group of alkylamides has been developed by employing a low cost copper source. This provides an efficient approach for synthesis of O-benzoylglycolamides. The protocol displayed good functional group tolerance. A broad range of benzoic acids directly coupled with alkylamides to afford a variety of O-benzoylglycolamides in moderate to good yields. In addition, a reasonable radical mechanism was proposed based on EPR experiments.
Amine-mediated synthesis of amides from 1,3-dicarbonyl compounds through a domino diazo transfer/aminolysis process
Costin, Taíssa A.,Dutra, Luiz G.,Bortoluzzi, Adailton J.,Sá, Marcus M.
, p. 4549 - 4559 (2017/07/11)
The dual role of amines as both catalysts and substrates for the synthesis of diazo compounds or carboxamides from 1,3-dicarbonyl compounds is described herein. In the presence of a suitable diazo transfer agent, primary and cyclic secondary amines act as basic catalysts for the diazo transfer reaction to malonates, β-keto esters, and β-diketones. Depending on the structure of the 1,3-dicarbonyl compound and the nucleophilicity of the amine, the resulting α-diazo-β-keto ester undergoes cleavage of the acyl group to give amides. A multifunctionalized γ-azido-α-diazo-β-keto ester was cleanly prepared in good yields by this one-pot protocol under practical and safe conditions, being employed in a Knoevenagel-type condensation with aromatic aldehydes to give densely functionalized diazo azido compounds. Further treatment of these unsaturated γ-azido-α-diazo-β-keto esters with primary amines readily furnished the corresponding α-azidocinnamamides in high yields, which were used in the synthesis of novel indole-2-carboxamides through the rhodium-catalyzed intramolecular C–H insertion.
