2503-55-1Relevant academic research and scientific papers
Reductive N-alkylation of primary amides using nickel-nanoparticles
Alenad, Asma M.,Alshammari, Ahmad S.,Jagadeesh, Rajenahally V.,Murugesan, Kathiravan,Sohail, Manzar
, (2021/11/22)
Here we report Ni-nanoparticles as reusable catalysts for reductive N-alkylation of amides. These Ni-nanoparticles based catalysts have been prepared by the template synthesis of tartaric acid and 2-methyl imidazole ligated Ni-complex on SiO2 and subsequent pyrolysis under argon. Applying optimal Ni-nanostructured catalyst, N-alkylation of aromatic and heterocyclic primary amides with different aldehydes in presence of molecular hydrogen was performed to access structurally diverse N-alkylated amides in good to excellent yields. In addition, the applicability of this N-alkylation protocol has been demonstrated for the selective functionalization of primary amide group in Levetiracetam drug.
Water-promoted dehydrative coupling of 2-aminopyridines in heptane: Via a borrowing hydrogen strategy
Azumaya, Isao,Hikawa, Hidemasa,Kikkawa, Shoko,Nakayama, Taku
, p. 23144 - 23150 (2021/07/21)
A synthetic method for dehydrative N-benzylation promoted by water molecules in heptane using a π-benzylpalladium system has been developed. The presence of water significantly accelerates carbon-nitrogen bond formation, which is accomplished in an atom-economical process to afford the corresponding N-monobenzylated products. A crossover experiment afforded H/D scrambled products, which is consistent with a borrowing hydrogen mechanism. Kinetic isotope effect measurements revealed that benzylic carbon-hydrogen bond cleavage was the rate-determining step.
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.
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.
Nickel-catalyzed reductive amidation of aryl-triazine ethers
Heravi, Majid M.,Panahi, Farhad,Iranpoor, Nasser
supporting information, p. 1992 - 1995 (2020/02/22)
The reaction of activated phenolic compounds, 2,4,6-triaryloxy-1,3,5-triazine (aryl-triazine ethers), with various isocyanates or carbodiimides in the presence of a nickel pre-catalyst resulted in the synthesis of aryl amides in good to excellent yields.
Solvent-Free N-Alkylation of Amides with Alcohols Catalyzed by Nickel on Silica–Alumina
Charvieux, Aubin,Le Moigne, Louis,Borrego, Lorenzo G.,Duguet, Nicolas,Métay, Estelle
supporting information, p. 6842 - 6846 (2019/11/11)
The N-alkylation of phenylacetamide with benzyl alcohol has been studied using Ni/SiO2–Al2O3. In the optimized conditions, the desired product was isolated in an excellent 98 % yield. The reaction could advantageously be performed in neat conditions, with a slight excess of amide and a catalytic amount of base. These conditions were tested on a large range of amides and alcohols, affording 24 compounds in 13 to 99 % isolated yields.
Water-Tolerant and Atom Economical Amide Bond Formation by Metal-Substituted Polyoxometalate Catalysts
De Azambuja, Francisco,Parac-Vogt, Tatjana N.
, p. 10245 - 10252 (2019/11/03)
A simple, safe, and inexpensive amide bond formation directly from nonactivated carboxylic acids and free amines is presented in this work. Readily available Zr(IV)- and Hf(IV)-substituted polyoxometalates (POM) are shown to be catalysts for the amide bond formation reaction under mild conditions, low catalyst loading, and without the use of water scavengers, dry solvents, additives for facilitating the amine attack, or specialized experimental setups commonly employed to remove water. Detailed mechanistic investigations revealed the key role of POM scaffolds which act as inorganic ligands to protect Zr(IV) and Hf(IV) Lewis acidic metals against hydrolysis and preserve their catalytic activity in amide bond formation reactions. The catalysts are compatible with a range of functional groups and heterocycles useful for medicinal, agrochemical, and material chemists. The robustness of the Lewis acid-POM complexes is further supported by the catalyst reuse without loss of activity. This prolific combination of Zr(IV)/Hf(IV) and POMs inaugurates a powerful class of catalysts for the amide bond formation, which overcomes key limitations of previously established Zr(IV)/Hf(IV) salts and boron-based catalysts.
All Non-Carbon B3NO2 Exotic Heterocycles: Synthesis, Dynamics, and Catalysis
Opie, Christopher R.,Noda, Hidetoshi,Shibasaki, Masakatsu,Kumagai, Naoya
supporting information, p. 4648 - 4653 (2019/03/17)
The B3NO2 six-membered heterocycle (1,3-dioxa-5-aza-2,4,6-triborinane=DATB), comprising three different non-carbon period 2 elements, has been recently demonstrated to be a powerful catalyst for dehydrative condensation of carboxylic acids and amines. The tedious synthesis of DATB, however, has significantly diminished its utility as a catalyst, and thus the inherent chemical properties of the ring system have remained virtually unexplored. Here, a general and facile synthetic strategy that harnesses a pyrimidine-containing scaffold for the reliable installation of boron atoms is disclosed, giving rise to a series of Pym-DATBs from inexpensive materials in a modular fashion. The identification of a soluble Pym-DATB derivative allowed for the investigation of the dynamic nature of the B3NO2 ring system, revealing differential ring-closing and -opening behaviors depending on the medium. Readily accessible Pym-DATBs proved their utility as efficient catalysts for dehydrative amidation with broad substrate scope and functional-group tolerance, offering a general and practical catalytic alternative to reagent-driven amidation.
Synthesis, biological evaluation and in silico studies of tetrazole-heterocycle hybrids
Sribalan, Rajendran,Banuppriya, Govindharasu,Kirubavathi, Maruthan,Padmini, Vediappen
, p. 577 - 586 (2018/09/14)
The series of three different chemical entities of tetrazole-heterocycle hybrids such as thiophene, pyridine and quinoline tetrazoles were synthesized and characterized for the purpose to develop new lead molecules. Biological evaluations such as in vitro antimicrobial and anti-inflammatory activities were studied. Further, the in silico studies such as Molecular docking (with COX-1, COX-2 and 3TTZ), DFT calculations, the Molecular electrostatic potential (MEP) and ADME were investigated.
