23309-16-2Relevant academic research and scientific papers
A post-synthetically modified metal-organic framework for copper catalyzed denitrative C-N coupling of nitroarenes under heterogeneous conditions
Maity, Tanmoy,Ghosh, Pameli,Das, Soma,Saha, Debraj,Koner, Subratanath
, p. 5568 - 5575 (2021/04/06)
Here we report, for the first time, the Ullmann C-N coupling reaction of nitroarenes which is achieved by using a copper containing metal-organic framework (MOF) catalyst under heterogenous conditions. The ready availability of nitroarenes and their low cost have made them ideal replacements for haloarenes as electrophilic coupling partners. Notably, the reaction protocol suppresses the by-product formation in the catalytic reaction. The catalyst has been designed and synthesized by two step post-synthesis functionalization of a MOF,viz.dabco MOF-1 with a -NH2functional group (DMOF-NH2). In the post-synthetic treatment, salicylaldehyde has been used for organic modification first and then copper(ii) was successfully incorporated onto the inner surface of the porous material. The hybrid porous solid thus obtained has been employed in the catalytic C-N coupling reaction of nitroarenes with a wide variety of amines under heterogeneous conditions, which displayed very high turnover frequencies (TOF) in catalytic reactions attesting its efficacy towards theN-arylation reaction.
A green and practical reduction of N-(4-chlorophenyl)-2-nitroaniline and its derivatives to corresponding N-substituted-benzene-1,2-diamines using thiourea dioxide
Cui, Jian-Lan,Wang, Ning,Wang, Xiao,Yu, Si-Yuan,Zhong, Cong-Shan
supporting information, (2020/01/22)
A new effective approach for synthesizing diverse N-substituted-benzene-1,2-diamines is reported. The treatment of N-substituted-2-nitroanilines with thiourea dioxide in the presence of sodium hydroxide efficiently formed the corresponding N-substituted-benzene-1,2-diamines, including N-(4-chlorophenyl)benzene-1,2-diamine with a good yield of 94%. The by-product is environmentally-friendly urea and is easy to separate from the product by filtration procedure that enhances the convenience of the approach.
Synthesis of indolo- And pyrrolo[1,2-: a] quinoxalinones through a palladium-catalyzed oxidative carbonylation of the C 2 position of indole
Chandrasekhar, Attoor,Sankararaman, Sethuraman
supporting information, p. 1612 - 1622 (2020/03/06)
A methodology that involves the Pd-catalyzed direct C(sp2)-H bond carbonylation of the C2 position of indole has been introduced for the synthesis of indolo[1,2-a]quinoxalin-6(5H)-ones. The methodology developed herein was used for the synthesis of pyrrolo[1,2-a]quinoxalin-4(5H)-ones. The reaction of N-substituted 2-(1H-indol-1-yl)anilines or 2-(1H-pyrrol-1-yl)anilines and carbon monoxide in the presence of Pd(OCOCF3)2 as a catalyst and Cu(OAc)2 as an oxidant in toluene at 80 °C forms the corresponding quinoxalinones as exclusive products in good yields. The catalytically active C-H activated intermediate Pd complex was isolated and characterized for the first time which on exposure to CO gas in toluene at 80 °C gave the corresponding quinoxalinone derivative. On the basis of isolation of the intermediate, a possible mechanism has been proposed for the C-H activated direct carbonylative annulation of 2-(5-methoxy-1H-indol-1-yl)-N,4-dimethylaniline.
N -Arylation of (hetero)arylamines using aryl sulfamates and carbamates via C-O bond activation enabled by a reusable and durable nickel(0) catalyst
Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
, p. 13266 - 13278 (2020/10/07)
An effective and general aryl amination protocol has been developed using a magnetically recoverable Ni(0) based nanocatalyst. This new stable catalyst was prepared on Fe3O4@SiO2 modified by EDTA and investigated by FT-IR, EDX, TEM, XRD, DLS, FE-SEM, XPS, NMR, TGA, VSM, ICP and elemental analysis techniques. The reaction proceeded via carbon-oxygen bond cleavage of (hetero)aryl carbamates and sulfamates under simple and mild conditions without the use of any external ligands. This method demonstrated functional group tolerance in the N-arylation of various nitrogen-containing compounds as well as aliphatic amines, anilines, pyrroles, pyrazoles, imidazoles, indoles, and indazoles with good to excellent yields. Furthermore, the catalyst could be easily recovered by using an external magnetic field and directly reused at least six times without notable reduction in its activity. This journal is
Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
, (2019/05/01)
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
, p. 3924 - 3939 (2019/05/06)
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Optimization of Drug Candidates That Inhibit the D-Loop Activity of RAD51
Budke, Brian,Tueckmantel, Werner,Miles, Kelsey,Kozikowski, Alan P.,Connell, Philip P.
supporting information, p. 1031 - 1040 (2019/04/30)
RAD51 is the central protein in homologous recombination (HR) repair, where it first binds ssDNA and then catalyzes strand invasion via a D-loop intermediate. Additionally, RAD51 plays a role in faithful DNA replication by protecting stalled replication forks; this requires RAD51 to bind DNA but may not require the strand invasion activity of RAD51. We previously described a small-molecule inhibitor of RAD51 named RI(dl)-2 (RAD51 inhibitor of D-loop formation #2, hereafter called 2 h), which inhibits D-loop activity while sparing ssDNA binding. However, 2 h is limited in its ability to inhibit HR in vivo, preventing only about 50 % of total HR events in cells. We sought to improve upon this by performing a structure–activity relationship (SAR) campaign for more potent analogues of 2 h. Most compounds were prepared from 1-(2-aminophenyl)pyrroles by forming the quinoxaline moiety either by condensation with aldehydes, then dehydrogenation of the resulting 4,5-dihydro intermediates, or by condensation with N,N′-carbonyldiimidazole, chlorination, and installation of the 4-substituent through Suzuki–Miyaura coupling. Many analogues exhibited enhanced activity against human RAD51, but in several of these compounds the increased inhibition was due to the introduction of dsDNA intercalation activity. We developed a sensitive assay to measure dsDNA intercalation, and identified two analogues of 2 h that promote complete HR inhibition in cells while exerting minimal intercalation activity.
A catalytic intramolecular nitrene insertion into a copper(i)-N-heterocyclic carbene bond yielding fused nitrogen heterocycles
Fauché, Kévin,Nauton, Lionel,Jouffret, Laurent,Cisnetti, Federico,Gautier, Arnaud
supporting information, p. 2402 - 2405 (2017/02/23)
N-(2-Azidophenyl)azolium salts were easily prepared and reacted with copper(i) under conditions allowing the formation of NHC complexes. Under these conditions, the formation of benzimidazo-fused heterocycles occurred under catalytic, efficient and very mild conditions. This reaction is proposed to proceed via dinitrogen elimination and imido/nitrene-NHC cyclization.
Copper immobilized on magnetite nanoparticles coated with ascorbic acid: An efficient and reusable catalyst for C─N and C─O cross-coupling reactions
Hajipour, Abdol R.,Check, Maryam,Khorsandi, Zahra
, (2017/09/30)
In a continuation of using magnetic nanoparticle (MNP)-supported catalysts, ascorbic acid (readily available, very safe and with strong affinity to MNPs) was used instead of the commonly used silica layer coating. This hybrid was used for immobilizing copper nanoparticles to produce Cu/ascorbic acid@MNPs catalyst. The catalyst was characterized and used in carbon–oxygen and carbon–nitrogen (various substrates) cross-coupling reactions in aqueous media and at room temperature with excellent product yields. Furthermore, the catalyst could be quickly and completely recovered using an external magnetic field and reused for six reaction cycles without significant change in catalytic activity.
Synthesis and characterization of 1,3-diamino-graphene as a heterogeneous ligand for a CuI-catalyzed C-N coupling reaction
Zhou, Limei,Yin, Mengyun,Jiang, Xiaohui,Huang, Qiang,Lang, Wencheng
, p. 1454 - 1459 (2016/02/19)
1,3-Diamino-graphene (NH2-G-NH2) materials were synthesized using a simple chemical method. The as-prepared materials were characterized using FT-IR, TG, XRD, XPS, and SEM measurements. The results revealed that a 1,3-diamino group was successfully grafted on graphene and could immobilize CuI by coordination interactions. The NH2-G-NH2 materials can be used as heterogeneous ligands for CuI-catalyzed C-N coupling reactions, and the desired products were obtained with good yields. The reaction system is much smoother at lower temperature compared with others previously reported. Additionally, the new method can easily realize the purification of products and recycling of catalysts.
