1484-39-5Relevant academic research and scientific papers
RUTHENIUM-CATALYSED REARRANGENMENTS OF AZOBENZENES II. THE PREPARATION OF 1-PHENYLBENZINIDAZOLES FROM AZOBENZENE DERIVATIVES AND PRIMARY ALCOHOLS CATALYSED BY RUTHENIUM COMPLEXES
Spencer, Alwyn
, p. 79 - 90 (1985)
RuCl3*3H2O in presence of PPh3 and a catalytic amount of a base and under an atmosphere of carbon monoxide catalyses the reaction of azobenzene derivatives and primary alcohols or their esters to give 2-substituted 1-phenylimidazoles.Substituents in the azobenzene derivatives have a marked effect on the product yields.Where isomer formation can occur, all possible isomers of the product are usually formed.In non-symmetrically substituted azobenzene derivatives, ortho-metallation occurs preferentially in the aromatic ring having the highest electron density.
Rhodium catalyzed 2-alkyl-benzimidazoles synthesis from benzene-1,2-diamines and tertiary alkylamines as alkylating agents
Yamini,Sharma, Saurabh,Das, Pralay
, (2021/05/17)
Substituted 2-alkyl-benzimidazoles were synthesized from benzene-1,2-diamine and tertiary amines as alkylating agent under polystyrene supported rhodium (Rh@PS) nanoparticles (NPs) catalyzed conditions. The heterogeneous rhodium catalyst was applied first time for the synthesis of 2-alkyl-benzimidazoles. The reaction followed through oxidation of alkylamines, transamination, and oxidative cyclisation with benzene-1,2-diamines for the corresponding products synthesis with good yields. The process is applicable for vast substrate scope, several functional groups are tolerable, and the Rh@PS catalyst is recyclable up to four cycles without significant loss in catalytic activity.
Divergent strategy for the chemoselective synthesis of N-Arylbenzimidazoles and N-Arylindazoles from arylamino oximes
Li, Zhen-Hua,Sun, Xiao-Meng,Qin, Jin-Jing,Tan, Zhi-Yong,Wang, Wen-Biao,Ma, Yao
, (2020/01/28)
An efficient and divergent synthesis of N-arylbenzimidazoles and N-arylindazoles from arylamino oximes based on reaction conditions selection was developed. The synthesis was approached by treating oximes with BTC and the chemoselectivity was regulated by the amount of Et3N. This switchable N–N and N–C bond formation process features mild reaction conditions, simple execution, high chemoselectivity and broad substrate scope.
Iridium-catalyzed intramolecular C–N and C–O/S cross-coupling reactions: Preparation of benzoazole derivatives
Shi, Yajie,Zhou, Qifan,Du, Fangyu,Fu, Yang,Du, Yang,Fang, Ting,Chen, Guoliang
supporting information, (2019/09/10)
The irdium-catalyzed intramolecular arylcarbon-hetero cross-coupling reactions with o-haloarylamides or o-haloarylamidine have been effectively achieved using KOAc and just 1 mol% catalyst. The [Ir(cod)Cl]2 was proved to be more potential for smoothly assembling functional structures benzimidazoles, benzoxazoles and benzothiazoles, which was superior to Cu- and Pd-catalyzed systems. Simultaneously, a concise and efficient synthesis of tafamidis was developed in 5-g scale.
α-d-Galacturonic Acid as Natural Ligand for Selective Copper-Catalyzed N-Arylation of N-Containing Heterocycles
Yuan, Chunling,Zhao, Yingdai,Zheng, Li
, p. 2173 - 2180 (2019/11/25)
The first application of α-d-galacturonic acid hydrate (GalA) is reported here, as a potential O-donor ligand. The C-N couplings of N-heterocycles with aryl halides or arylboronic acids could be readily conducted and exhibited good functional group tolerance with characters of selectivity. These N-Arylazoles allow rapid access to several pharmaceutical intermediates and can be easily transformed into a variety of other interesting scaffolds as well.
Efficient N-arylation of azole compounds utilizing selective aryl-transfer TMP-iodonium(III) reagents
Koseki, Daichi,Aoto, Erika,Shoji, Toshitaka,Watanabe, Kazuma,In, Yasuko,Kita, Yasuyuki,Dohi, Toshifumi
, p. 1281 - 1286 (2019/04/10)
It was determined that diaryliodonium(III) triflates bearing a trimethoxybenzene (TMP) auxiliary are more reactive than the reported selective aryl-transfer iodonium salts in the N-arylation of benzimidazoles and other types of azole compounds under catalytic conditions. The TMP-iodonium(III) salts can thus effectively facilitate the reaction at 50 °C or below, producing the corresponding N-arylated biaryls without the formation of TMP-derived coupling byproducts. Utilization of this TMP reagent under mild conditions would prevent the underlying problem of participation of the auxiliary group in the coupling reactions, which is observed while using the iodonium(III) salts that require elevated temperatures.
Iron-Catalyzed/Mediated C-N Bond Formation: Competition between Substrate Amination and Ligand Amination
Sinha, Suman,Sikari, Rina,Sinha, Vivek,Jash, Upasona,Das, Siuli,Brand?o, Paula,Demeshko, Serhiy,Meyer, Franc,De Bruin, Bas,Paul, Nanda D.
, p. 1935 - 1948 (2019/01/25)
Iron catalyzed carbon-nitrogen bond formation reactions of a wide variety of nucleophiles and aryl halides using well-defined iron-complexes featuring redox noninnocent 2-(arylazo)-1,10-phenanthroline (L1) ligands are reported. Besides substrate centered C-N coupling, C-N bond formation reactions were also observed at the ortho- and para-positions of the phenyl ring of the coordinated azo-aromatic scaffolds affording new tetradentate ligands, 2-N-aryl-(2-arylazo)-1,10-phenanthroline (L2), and tridentate ligands, 4-N-aryl-(2-arylazo)-1,10-phenanthroline (L3), respectively. Control experiments and mechanistic studies reveal that the complex [FeL1Cl2] (1) undergoes in situ reduction during the catalytic reaction to produce the monoanionic complex [1]-, which then acts as the active catalyst. The metal (iron) and the coordinated ligand were found to work in a cooperative manner during the transfer processes involved in the fundamental steps of the catalytic cycle. Detailed experimental and theoretical (DFT) studies were performed to get insight into the competitive substrate versus ligand centered amination reactions.
C?N Cross-Coupling Reactions Under Mild Conditions Using Singlet Di-Radical Nickel(II)-Complexes as Catalyst: N-Arylation and Quinazoline Synthesis
Sikari, Rina,Sinha, Suman,Chakraborty, Gargi,Das, Siuli,van Leest, Nicolaas Petrus,Paul, Nanda D.
supporting information, p. 4342 - 4353 (2019/08/21)
Herein we report a cost-effective synthetic approach for C?N cross-coupling reactions of a broad array of nitrogen nucleophiles and aryl halides under mild conditions. These reactions are catalyzed by an inexpensive, air-stable, earth-abundant and easy-to-prepare singlet di-radical nickel(II)-catalyst containing two antiferromagnetically coupled single-electron oxidized diiminosemiquinonato type ligands. This protocol provides an alternative method for C?N cross-coupling reactions avoiding nickel(0)/nickel(II) or nickel(I)/nickel(III) redox processes via cooperative participation of metal and ligand-centered redox events. Besides a wide range of N-arylation reactions, by judicious choice of aryl halides and nitrogen nucleophiles the synthesis of a variety of polysubstituted quinazolines has been achieved in moderate to good yields under relatively mild reaction conditions. Our catalyst has been found to be almost equally effective in quinazoline synthesis via C?N cross-coupling of (i) 2-bromobenzylamine with benzamide, and (ii) 2-bromobenzylbromide with amidine. Control experiments and DFT studies were performed to improve the understanding of the cooperative participation of ligand and metal (nickel)-centered redox events during oxidative addition/reductive elimination processes of the catalytic cycle and to shed light on the plausible mechanistic pathway of the C?N cross-coupling reactions. (Figure presented.).
Access to Amidines and Arylbenzimidazoles: Zinc-Promoted Rearrangement of Oxime Acetates
Zhu, Zhongzhi,Cen, Jinghe,Tang, Xiaodong,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
, p. 2020 - 2031 (2018/04/09)
An efficient and straightforward zinc-promoted rearrangement of oxime acetates with arylamines for the synthesis of amidines has been developed under mild conditions. This process involves N?O/C?C bond cleavages and C?C/C?N bond formations. Various oxime
Synthesis of 1,2-disubstituted benzimidazoles using an aza-Wittig-equivalent process
Chen, Yuan,Xu, Fanghui,Sun, Zhihua
, p. 44421 - 44425 (2017/09/26)
A synthetic approach for 1,2-disubstituted benzimidazoles has been successfully designed based on effective C-N bond construction, which demonstrated mild reaction conditions and excellent yields. The method involves treating derivatives of o-phenylenediamine with tert-butanesulfoxide and NBS under acidic conditions, which undergoes an aza-Wittig-equivalent process to afford the desired products. Using this method, a series of benzimidazoles containing multiple functional groups with varying electronic effects have been successfully constructed.
