785-81-9Relevant articles and documents
Cyclometalated Half-Sandwich Iridium(III) Complexes: Synthesis, Structure, and Diverse Catalytic Activity in Imine Synthesis Using Air as the Oxidant
Li, Rong-Jian,Ling, Chun,Lv, Wen-Rui,Deng, Wei,Yao, Zi-Jian
, p. 5153 - 5162 (2021/05/04)
Four air-stable cyclometalated half-sandwich iridium complexes 1-4 with C,N-donor Schiff base ligands were prepared through C-H activation in moderate-to-good yields. These complexes have been well characterized, and their exact structure was elaborated on by single-crystal X-ray analysis. The iridium(III) complexes 1-4 showed good catalytic activity in the imine synthesis under open-flask conditions (air as the oxidant) from primary amine oxidative homocoupling, secondary amine dehydrogenation, and the cross-coupling reaction of amine and alcohol. Substituents bonded on the ligands of the iridium complexes displayed little effect on the catalytic efficiency. The stability and good catalytic efficiency of the iridium catalysts, mild reaction conditions, and substrate universality showed their potential application in industrial production.
Triarylmethyl Cation-Catalyzed Three-Component Coupling for the Synthesis of Unsymmetrical Bisindolylmethanes
Bardelski, Kevin,Brindle, Cheyenne S.,Chen, Zhenghua,Guarino-Hotz, Melissa,Jones, Vanessa A.,Lucas, Kelly,Patterson, William J.
supporting information, p. 6737 - 6742 (2021/12/31)
An efficient synthesis of unsymmetrical bisindolylmethanes has been accomplished using triarylmethyl cations to catalyze the reaction of N-arylimines with two different indoles. Optimization of the organocatalyst by tuning cation stability allows for excellent single addition selectivity when coupled with p-nitrophenyl imines. The optimal catalyst is commercially available, and the reaction minimizes waste and environmental impact by employing a one-to-one ratio of starting materials. The intermediates can be isolated or used in situ in a one-pot two-step reaction to generate unsymmetrical bisindolylmethanes in high yields. The reaction tolerates a broad range of imines with the highest yields observed for electron-poor and neutral imines. A wide range of indole nucleophiles are also successfully employed allowing for the creation of a large variety of unsymmetrical bisindolylmethanes.
Trimethyl Borate-Catalyzed, Solvent-Free Reductive Amination
Ramachandran, P. Veeraraghavan,Choudhary, Shivani,Singh, Aman
, p. 4274 - 4280 (2021/03/09)
Solvent-free reductive amination of aldehydes and ketones with aliphatic and aromatic amines in high-to-excellent yields has been achieved with sub-stoichiometric trimethyl borate as promoter and ammonia borane as reductant.
Air-Stable Half-Sandwich Iridium Complexes as Aerobic Oxidation Catalysts for Imine Synthesis
Deng, Wei,Fan, Xiao-Nan,Ou, Hui-Dan,Yao, Zi-Jian
supporting information, (2020/04/02)
Several N,O-coordinate half-sandwich iridium complexes, 1-5, containing constrained bulky β-enaminoketonato ligands were prepared and clearly characterized. Single-crystal X-ray diffraction characterization of these complexes indicates that the iridium center adopts a distorted octahedral geometry. Complexes 1-5 showed good catalytic efficiency in the oxidative homocoupling of primary amines, dehydrogenation of secondary amines, and the oxidative cross-coupling of amines and alcohols, which furnished various types of imines in good yields and high selectivities using O2 as an oxidant under mild conditions. No distinctive substituent effects of the iridium catalysts were observed in these reactions. The diverse catalytic activity, broad substrate scope, mild reaction conditions, and high yields of the products made this catalytic system attractive in industrial processes.
Catalytic activity of Mg-Al hydrotalcites and derived mixed oxides for imination reactionsviaan oxidative-dehydrogenation mechanism
Vala, Naresh,Joshi, Pradyuman A.,Mishra, Manish
, p. 8859 - 8868 (2020/06/08)
The catalytic activities of Mg-Al hydrotalcites and derived Mg-Al mixed oxides were studied for the imination of benzylic substrates (benzyl amine and benzyl alcohol), with aniline as a model reaction, to establish a green and cost-effective catalytic (precious metal free) process for imination and tandem reactions utilizing alcohols as reagents. The Mg-Al mixed oxide (Mg/Al ratio = 3.0) was found to be an efficient catalyst for imination reactions to synthesize cross-imines with high selectivity as well as for tandem reactions of alcohols. Basic sites of catalysts adsorb benzylic substrates through the hydrogen of their functional groups (-NH2/-OH) and activate (weaken) benzylic C-H bonds for hydride elimination. Thus, basic sites catalyze the reaction by activating benzylic substrates for oxidative-dehydrogenation (i.e., deprotonation followed by hydride elimination with the help of oxygen) to produce reactive imine/carbonyl intermediates, which undergo subsequent nucleophilic reactions with amine.
Polyoxometalate catalyzed imine synthesis: Investigation of mechanistic pathways
Adhikary, Subhasis D.,Mandal, Debaprasad
supporting information, (2020/05/25)
The syntheses of imines by oxidative coupling of primary alcohols and amines were achieved by using 2 molpercent polyoxometalate (POM) Na12[WZn3(H2O)2(ZnW9O34)2] (Zn–WZn3) catalyst in the presence of t-BuOK and di-oxygen with excellent conversion (up to 100percent) and selectivity (up to 100percent). Non-noble metal-based POM catalyst in the presence of base represents a new reaction protocol for the selective synthesis of imine from both aromatic and aliphatic primary amines with functional group tolerance. Control experiment shows the formation of di-oxygen bind Zn–WZn3 activated species. The electron-density of POM is mostly situated on the surface oxygen atoms of W–O–W bonds which can engage the alcoholic OH group and helps for the imine selectivity in the second step of imine synthesis.
T3P-promoted synthesis of a series of novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones
Silverberg, Lee J.,Pacheco, Carlos,Sahu, Debashish,Scholl, Peter,Sobhi, Hany F.,Bachert, Joshua T.,Bandholz, Kaitlyn,Bendinsky, Ryan V.,Bradley, Heather G.,Colburn, Baylee K.,Coyle, David J.,Dahl, Jonathon R.,Felty, Megan,Fox, Ryan F.,Gonzalez, Kyanna M.,Islam, Jasra M.,Koperna, Stacy E.,Moyer, Quentin J.,Noble, Duncan J.,Ramirez, Melissa E.,Yang, Ziwei
, p. 1797 - 1805 (2020/02/05)
A series of 11 novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-aryl-C-phenyl imines with thiosalicylic acid. This provides simple and ready access to N-aryl compounds in this family, which have been generally difficult to prepare.
Cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ
Xiong, Ruimei,Hussain, Muhammad Ijaz,Liu, Qing,Xia, Wen,Xiong, Yan
supporting information, (2019/12/11)
A cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ is reported, which uses nonmetallic quinone DDQ as an oxidant in the allylation of N-benzylanilines under mild conditions. C–C bond with high selectivity and activity was constructed in this reaction and homoallylic amines were obtained with yields of up to 99%.
Catalyst- And solvent-free efficient access to: N -alkylated amines via reductive amination using HBpin
Bauri, Somnath,Pandey, Vipin K.,Rit, Arnab
supporting information, p. 3853 - 3857 (2020/07/27)
A sustainable approach which works under catalyst- and solvent-free conditions for the synthesis of structurally diverse secondary amines has been uncovered. This one-pot protocol works efficiently at room temperature and is compatible with a wide range of sterically and electronically diverse aldehydes and primary amines. Notably, this simple process offers scalability, excellent functional group tolerance, chemoselectivity, and is also effective at the synthesis of biologically relevant molecules. This journal is
Synthesis of Imines via Reactions of Benzyl Alcohol with Amines Using Half-Sandwich (η6-p-cymene) Ruthenium(II) Complexes Stabilised by 2-aminofluorene Derivatives
Vinoth, Govindasamy,Indira, Sekar,Bharathi, Madheswaran,Durgadevi, Anandhan,Abinaya, Ravikumar,Alves, Luis G.,Martins, Ana Margarida,Bharathi, Kuppannan Shanmuga
, (2019/09/03)
A new class of half-sandwich (η6-p-cymene) ruthenium(II) complexes supported by 2-aminofluorene derivatives [Ru(η6-p-cymene)(Cl)(L)] (L?=?2-(((9H-fluoren-2-yl)imino)methyl)phenol (L1), 2-(((9H-fluoren-2-yl)imino)methyl)-3-methoxyphenol (L2), 1-(((9H-fluoren-2-yl)imino)methyl)naphthalene-2-ol (L3) and N-((1H-pyrrol-2-yl)methylene)-9H-fluorene-2-amine (L4)) were synthesized. All compounds were fully characterized by analytical and spectroscopic techniques (IR, UV–Vis, NMR) and also by mass spectrometry. The solid state molecular structures of the complexes [Ru(η6-p-cymene)(Cl)(L2)], [Ru(η6-p-cymene)(Cl)(L3)] and [Ru(η6-p-cymene)(Cl)(L4)] revealed that the 2-aminofluorene and p-cymene moieties coordinate to ruthenium(II) in a three-legged piano-stool geometry. The synthesized complexes were used as catalysts for the dehydrogenative coupling of benzyl alcohol with a range of amines (aliphatic, aromatic and heterocyclic). The reactions were carried out under thermal heating, ultrasound and microwave assistance, using solvent or solvent free conditions, and the catalytic performance was optimized regarding the solvent, the type of base, the catalyst loading and the temperature. Moderately high to very high isolated yields were obtained using [Ru(η6-p-cymene)(Cl)(L4)] at 1?mol%. In general, microwave irradiation produced better yields than the other two techniques irrespective of the nature of the substituents.
