61439-54-1Relevant academic research and scientific papers
Iron-Catalyzed Oxidative Amination of Benzylic C(sp3)–H Bonds with Anilines
Song, Yan-Ling,Li, Bei,Xie, Zhen-Biao,Wang, Dan,Sun, Hong-Mei
, p. 17975 - 17985 (2021/12/13)
Iron-catalyzed oxidative amination of benzylic C(sp3)–H bonds with anilines bearing electron-withdrawing groups (EWGs) or electron-donating groups (EDGs) is realized based on simple variations of N-substituents on imidazolium cations in novel ionic Fe(III) complexes. The structural modification of the imidazolium cation resulted in regulation of the redox potential and the catalytic performance of the iron metal center. Using DTBP as oxidant, [HItBu][FeBr4] showed the highest catalytic activity for anilines bearing EWGs, while [HIPym][FeBr4] was more efficient for EDG-substituted anilines. This work provides alternative access to benzylamines with the advantages of both a wide substrate scope and iron catalysis.
Cobalt nanoclusters coated with N-doped carbon for chemoselective nitroarene hydrogenation and tandem reactions in water
Agostini, Giovanni,Calvino, Jose. J.,Corma, Avelino,Gutiérrez-Tarri?o, Silvia,Lopes, Christian W.,O?a-Burgos, Pascual,Rojas-Buzo, Sergio
supporting information, p. 4490 - 4501 (2021/06/28)
The development of active and selective non-noble metal-based catalysts for the chemoselective reduction of nitro compounds in aquo media under mild conditions is an attractive research area. Herein, the synthesis of subnanometric and stable cobalt nanoclusters, covered by N-doped carbon layers as core-shell (Co@NC-800), for the chemoselective reduction of nitroarenes is reported. TheCo@NC-800catalyst was prepared by the pyrolysis of the Co(tpy)2complex impregnated on Vulcan carbon. In fact, the use of a molecular complex based on six N-Co bonds drives the formation of a well-defined and distributed cobalt core-shell nanocluster covered by N-doped carbon layers. In order to elucidate its nature, it has been fully characterized by using several advanced techniques. In addition, this as-prepared catalyst showed high activity, chemoselectivity and stability toward the reduction of nitro compounds with H2and under mild reaction conditions; water was used as a green solvent, improving the previous results based on cobalt catalysts. Moreover, theCo@NC-800catalyst is also active and selective for the one-pot synthesis of secondary aryl amines and isoindolinones through the reductive amination of nitroarenes. Finally, based on diffraction and spectroscopic studies, metallic cobalt nanoclusters with surface CoNxpatches have been proposed as the active phase in theCo@NC-800material.
Aminobenzoic acid derivatives as antioxidants and cholinesterase inhibitors; synthesis, biological evaluation and molecular docking studies
Iftikhar, Kiran,Murtaza, Shahzad,Kousar, Naghmana,Abbas, Aadil,Tahir, Muhammad Nawaz
, p. 385 - 396 (2018/04/23)
Cholinesterase namely, acetyl- and butyrylcholinesterase (AChE and BChE, respectively), has been recognized as a primary class of enzyme that hydrolyzes the acetylcholine (ACh) neurotransmitter in synaptic junctions. Diminished levels of the neurotransmitter in synaptic junction lead to Alzheimerís disease (AD). Inhibition of cholinesterase is thus, an attractive strategy for AD treatment. The study includes the synthesis and characterization of a series of 2-, 3- and 4-aminobenzoic acid derivatives (1a?5c), their biological screening against cholinesterase enzyme and molecular docking study to demonstrate putative binding modes. Antioxidant potential of the synthesized series was also determined. The cholinesterase enzyme inhibition assay showed that compound 5b has the highest inhibition potential against acetylcholinesterase with an IC50 value of 1.66 ± 0.03 μM while in case of butyrylcholinesterase, compound 2c has the highest inhibitory potential with an IC50 value of 2.67 ± 0.05 μM. Molecular docking studies supports the results of enzyme inhibition potential with binding energy value ?G = -9.54 Kcal mol-1 for compound 5b in case for acetylcholinesterase while for butyrylcholinesterase, ?G = -5.53 Kcal mol-1 was obtained for compound 2c. The synthesized series of compounds also shows mild to moderate antioxidant potential. The benzoyl- containing compounds shows better antioxidant activity as compared to other derivatives of the synthesized series. Based on the molecular docking studies and enzyme inhibition potential, the synthesized series of compounds can be regarded as potent cholinesterase inhibitors and can be used for designing and synthesizing more potent drugs for Alzheimerís disease and neurodegenerative diseases.
Main-Group-Catalyzed Reductive Alkylation of Multiply Substituted Amines with Aldehydes Using H2
Hoshimoto, Yoichi,Kinoshita, Takuya,Hazra, Sunit,Ohashi, Masato,Ogoshi, Sensuke
supporting information, p. 7292 - 7300 (2018/06/01)
Given the growing demand for green and sustainable chemical processes, the catalytic reductive alkylation of amines with main-group catalysts of low toxicity and molecular hydrogen as the reductant would be an ideal method to functionalize amines. However, such a process remains challenging. Herein, a novel reductive alkylation system using H2 is presented, which proceeds via a tandem reaction that involves the B(2,6-Cl2C6H3)(p-HC6F4)2-catalyzed formation of an imine and the subsequent hydrogenation of this imine catalyzed by a frustrated Lewis pair (FLP). This reductive alkylation reaction generates H2O as the sole byproduct and directly functionalizes amines that bear a remarkably wide range of substituents including carboxyl, hydroxyl, additional amino, primary amide, and primary sulfonamide groups. The synthesis of isoindolinones and aminophthalic anhydrides has also been achieved by a one-pot process that consists of a combination of the present reductive alkylation with an intramolecular amidation and intramolecular dehydration reactions, respectively. The reaction showed a zeroth-order and a first-order dependence on the concentration of an imine intermediate and B(2,6-Cl2C6H3)(p-HC6F4)2, respectively. In addition, the reaction progress was significantly affected by the concentration of H2. These results suggest a possible mechanism in which the heterolysis of H2 is facilitated by the FLP comprising THF and B(2,6-Cl2C6H3)(p-HC6F4)2.
Water-Soluble Iridium N-Heterocyclic Carbene Complexes for the Alkylation of Amines with Alcohols
Fernandes, Ana,Royo, Beatriz
, p. 3912 - 3917 (2017/09/28)
A new series of water-soluble Ir complexes with N-heterocyclic carbene ligands that bear ester and amide groups has been obtained and fully characterized. The new complexes are highly reactive and selective for the alkylation of amines with alcohols with a 1:1 ratio of reactants in water and in the absence of base or other additives. The catalytic system has a broad substrate scope, which allows the synthesis of a variety of primary and secondary amines in excellent yields. A tolerance to a large range of functional groups was obtained.
Interfacing native and non-native peptides: using Affimers to recognise α-helix mimicking foldamers
Arrata, Irene,Barnard, Anna,Tomlinson, Darren C.,Wilson, Andrew J.
supporting information, p. 2834 - 2837 (2017/03/11)
Selection methods are used to identify Affimers that recognise α-helix mimicking N-alkylated aromatic oligoamides thus demonstrating foldamer and natural α-amino acid codes are compatible.
Chemoselective reductive amination of carbonyl compounds for the synthesis of tertiary amines using SnCl2·2H2O/PMHS/MeOH
Nayal, Onkar S.,Bhatt, Vinod,Sharma, Sushila,Kumar, Neeraj
, p. 5912 - 5918 (2015/06/16)
Stannous chloride catalyzed chemoselective reductive amination of a variety of carbonyl compounds with aromatic amines has been developed for the synthesis of a diverse range of tertiary amines using inexpensive polymethylhydrosiloxane as reducing agent in methanol. The present method is also applicable for the synthesis of secondary amines including heterocyclic ones.
One-pot synthesis of secondary amines from alcohols and nitroarenes on TiO2 loaded with Pd nanoparticles under UV irradiation
Selvam, Kaliyamoorthy,Sakamoto, Hirokatsu,Shiraishi, Yasuhiro,Hirai, Takayuki
, p. 2467 - 2473 (2015/04/14)
Photoirradiation (λ > 300 nm) of TiO2 loaded with Pd nanoparticles (2 wt%, ca. 5 nm diameter) in water containing benzyl alcohol and nitrobenzene at room temperature successfully produces the corresponding secondary amine (N-benzylaniline) with 96% yield. This is achieved via three consecutive catalytic reactions: (i) photocatalytic oxidation of alcohol (aldehyde formation) and reduction of nitrobenzene (aniline formation); (ii) catalytic condensation of the formed aldehyde with aniline on the TiO2 surface (imine formation); and, (iii) photocatalytic hydrogenation of the formed imine (secondary amine formation). This catalytic system successfully produces several kinds of secondary amines, even those containing reducible substituents such as -CN, -COOH, or -CHO with >76% yields.
Photocatalytic secondary amine synthesis from azobenzenes and alcohols on TiO2 loaded with Pd nanoparticles
Selvam, Kaliyamoorthy,Sakamoto, Hirokatsu,Shiraishi, Yasuhiro,Hirai, Takayuki
, p. 2856 - 2860 (2015/04/22)
Photoirradiation (λ > 300 nm) of TiO2 loaded with Pd nanoparticles (ca. 2 wt%, 5 nm diameter) in water containing alcohols and azobenzene derivatives at room temperature successfully produces the corresponding secondary amines with high yields.
Palladium-catalyzed benzylic C-H benzylation via bis-benzylpalladium(II) complexes in water: An effective pathway for the direct construction of N-(1,2-diphenylethyl)anilines
Hikawa, Hidemasa,Izumi, Kyoko,Ino, Yukari,Kikkawa, Shoko,Yokoyama, Yuusaku,Azumaya, Isao
supporting information, p. 1037 - 1048 (2015/03/30)
A strategy for the N-benzylation/benzylic C-H benzylation cascade of anilines by the π-benzylpalladium system using a water-soluble palladium(0)/sodium diphenylphosphinobenzene-3-sulfonate (TPPMS) catalyst and benzyl alcohol in water has been developed. This tandem process is devised as a novel and efficient synthetic route for N-(1,2-diphenylethyl)anilines. Benzylic C-H activation of a mono-N-benzylated intermediate with a π-benzylpalladium(II) complex affords a bis-π-benzylated palladium(II) intermediate. The nucleophilic η1-σ-benzyl anion ligand attacks the electrophilic η3-π-benzyl ligand to give a dibenzylated product. The intermolecular competition between mono-N-benzylaniline and its monodeuterated form (monodeuterated at the benzylic group) with benzyl alcohol gave a KIE=4.6, suggesting that C-H bond cleavage was involved in the rate-determining step. Hammett studies on the rate constants of benzylation by various substituted anthranilic acids and mono-N-benzylanilines show a good correlation between the log(kX/kH) and the σ values of the respective substituents. From the slope, negative ρ values are obtained, suggesting that there is a build-up of positive charge in the transition state. The reaction of anilines with electron-donating and electron-withdrawing groups affords the corresponding N-(1,2-diphenylethyl)anilines in moderate to good yields (54-86%). Interestingly, the reaction of anthranilic acids proceeded smoothly to give only the corresponding dibenzylated products in good to excellent yields (70-87%). The carboxyl group of the anthranilic acids acts as a directing group in the benzylic C-H activation process.
