- Nickel-Catalyzed Reductive Cross-Coupling of N-Acyl and N-Sulfonyl Benzotriazoles with Diverse Nitro Compounds: Rapid Access to Amides and Sulfonamides
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Herein we report a Ni-catalyzed reductive transamidation of conveniently available N-acyl benzotriazoles with alkyl, alkenyl, and aryl nitro compounds, which afforded various amides with good yields and a broad substrate scope. The same catalytic reaction conditions were also applicable for N-sulfonyl benzotriazoles, which could undergo smooth reductive coupling with nitroarenes and nitroalkanes to afford the corresponding sulfonamides.
- Qu, Erdong,Li, Shangzhang,Bai, Jin,Zheng, Yan,Li, Wanfang
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supporting information
p. 58 - 63
(2021/12/27)
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- Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling Involving C?O Bond Activation
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An efficient Suzuki-Miyaura cross-coupling reaction of ortho-phenoxy-substituted aromatic amides with aryl boronates is described. The use of LiOtBu is crucial for the success of the reaction. An amidate anion, which is formed through deprotonation of the amide NH bond by LiOtBu, functions as a directing group to activate a C?O bond.
- Morishige, Aoi,Iyori, Yasuaki,Chatani, Naoto
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- Synthesis ofortho-arylated and alkenylated benzamides by palladium-catalyzed denitrogenative cross-coupling reactions of 1,2,3-benzotriazin-4(3H)-ones with organoboronic acids
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An efficient palladium-catalyzed denitrogenative Suzuki-Miyaura type cross-coupling of 1,2,3-benzotriazin-4(3H)-ones with organoboronic acid is described. The reaction is compatible with various aryl and alkenyl boronic acids affordingortho-arylated and alkenylated benzamides in good to high yields. Heteroaromatic boronic acids were also successfully employed. Along with this, a coupling reaction was established by using phenyl boronate ester as the coupling partner. The reaction is believed to proceedviaa five-membered aza-palladacyclic intermediate. DFT calculations were studied comparing the reactivity of palladium and nickel complexes in the five-membered aza-metallacycle formation from 1,2,3-benzotriazin-4(3H)-ones. The application of the reaction was successfully demonstrated by convertingortho-alkenylated products toortho-alkylated products in high yieldsviaa reduction reaction.
- Balakrishnan, Madasamy Hari,Kanagaraj, Madasamy,Mannathan, Subramaniyan,Ravva, Mahesh Kumar,Sankar, Velayudham
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supporting information
p. 17190 - 17195
(2021/10/04)
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- Visible-light-induced direct construction of amide bond from carboxylic acids with amines in aqueous solution
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A novel visible-light-promoted N-acylation for the synthesis of amides from easily available carboxylic acids with amines in the presence of I2 within 2.5 h in aqueous solution has been developed. Using sunlight as the visible light source greatly reduces the cost of experiments and produces almost no toxic effects. Hence, this study provides an alternative catalytic system for the construction of a wide range of amides with readily available materials. Moreover, the strategy was successfully applied in the preparation of N-(3-(2,6-dimethoxyphenoxy)-7-nitroquinoxalin-2-yl)benzohydrazide, which displayed a signification anti-proliferation effect on A549, MCF-7 and HCT116 cell lines.
- Wang, Jin,Hou, Huiqing,Hu, Yongzhi,Lin, Jin,Wu, Min,Zheng, Zhiqiang,Xu, Xiuzhi
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supporting information
(2021/02/09)
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- Transition-Metal-Free Synthesis of Phenanthridinones through Visible-Light-Driven Oxidative C–H Amidation
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The treatment of N-aryl biphenylcarboxamide, 1-chloroanthraquinone (1-Cl-AQN) catalyst, and K2CO3 in CHCl3 under visible light irradiation affords phenanthridinone via radical cyclization. This reaction proceeds under transition-metal-free condition, room temperature, and direct C–H amidation. Mechanistic studies indicate that amidyl radical generation proceeds by visible light induced proton coupled electron transfer (PCET) from N–H bond of the amide.
- Usami, Kaoru,Yamaguchi, Eiji,Tada, Norihiro,Itoh, Akichika
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p. 1496 - 1504
(2019/06/27)
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- A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
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Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
- Feng, Boya,Yang, Yudong,You, Jingsong
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p. 6031 - 6035
(2020/07/10)
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- Methyl Esters as Cross-Coupling Electrophiles: Direct Synthesis of Amide Bonds
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Amide bond formation and transition metal-catalyzed cross-coupling are two of the most frequently used chemical reactions in organic synthesis. Recently, an overlap between these two reaction families was identified when Pd and Ni catalysts were demonstrated to cleave the strong C-O bond present in esters via oxidative addition. When simple methyl and ethyl esters are used, this transformation provides a powerful alternative to classical amide bond formations, which commonly feature stoichiometric activating agents. Thus far, few redox-active catalysts have been demonstrated to activate the C(acyl)-O bond of alkyl esters, which makes it difficult to perform informed screening when a challenging reaction needs optimization. We demonstrate that Ni catalysts bearing diverse NHC, phosphine, and nitrogen-containing ligands can all be used to activate methyl esters and enable their use in direct amide bond formation.
- Zheng, Yan-Long,Newman, Stephen G.
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p. 4426 - 4433
(2019/05/08)
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- Palladium Catalyzed Regioselective Synthesis of Substituted Biaryl Amides through Decarbonylative Arylation of Phthalimides
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The Pd(OAc)2 catalyzed cross-coupling of N-substituted phthalimides with aryl halide provides a single step direct access of a wide range of synthetically appealing ortho-substituted biarylamides in high yields through unique carbonyl (CO) replacement. The reaction proceeds through a ligand-free condition and is well tolerant to the diverse functionality of both imide and halide units. The reaction negates any requirement of organometallic reagent and needs a shorter reaction time and comparatively lower temperature as required for previously reported decarbonylative processes.
- Samanta, Partha Kumar,Biswas, Papu
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p. 3968 - 3976
(2019/03/26)
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- NIS-mediated oxidative arene C(sp2)-H amidation toward 3,4-dihydro-2(1H)-quinolinone, phenanthridone, and N-fused spirolactam derivatives
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A new radical-mediated intramolecular arene C(sp2)-H amidation of 3-phenylpropanamides or [1,1′-biphenyl]-2-carboxamides was developed to prepare a series of 3,4-dihydro-2(1H)-quinolinone and phenanthridone derivatives in moderate to excellent yields (33-94%). Spirolactams could also be obtained using this protocol.
- Wu, Lingang,Hao, Yanan,Liu, Yuxiu,Wang, Qingmin
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p. 6762 - 6770
(2019/07/22)
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- Nickel-Catalyzed Denitrogenative ortho-Arylation of Benzotriazinones with Organic Boronic Acids: an Efficient Route to Losartan and Irbesartan Drug Molecules
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Denitrogenative ortho-arylation, vinylation and methylation of 1,2,3-benzotriazin-4-(3H)-ones with organic boronic acids catalyzed by nickel complexes to give a wide range of o-substituted benzamides were demonstrated. Further, the catalytic reaction is successfully applied to the synthesis of the popular hypertensive drugs losartan and irbesartan in high yields. (Figure presented.).
- Thorat, Vijaykumar H.,Upadhyay, Nitinkumar Satyadev,Cheng, Chien-Hong
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supporting information
p. 4784 - 4789
(2018/11/10)
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- Electrochemical Synthesis of 5-Aryl-phenanthridin-6-one by Dehydrogenative N,C Bond Formation
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Currently, the general synthesis of 5-aryl-phenanthridin-6-ones relies on the involvement of metal catalysis. Despite the urgent demand for green alternatives, avoiding synthetic routes that require transition metals for key roles is still challenging. Electrochemical efforts employing a constant potential protocol in divided cells revealed a possible alternative to the catalytic approach. A constant current protocol, undivided cells, and a remarkably low supporting electrolyte concentration enable a novel access to N-aryl-phenanthridin-6-ones by anodic N,C bond formation using directly generated amidyl radicals. Easy accessible starting materials, a broad scope of applicable functional groups, good yields, and a very simple set-up are the benefits of this sustainable method.
- Kehl, Anton,Breising, Valentina M.,Schollmeyer, Dieter,Waldvogel, Siegfried R.
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p. 17230 - 17233
(2018/11/10)
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- Unified Protocol for Cobalt-Catalyzed Oxidative Assembly of Two Aryl Metal Reagents Using Oxygen as an Oxidant
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The first cobalt-catalyzed oxidative cross-coupling reaction of two aryl metal reagents is described. An equivalent amount of two aryl Grignard or lithium reagents, after mediation by an equivalent amount of simple ClTi(OEt)3, was facilely assembled under the catalysis of 1 mol % of CoCl2/10 mol % of DMPU using oxygen. The cross-couplings between various aryl metal reagents, especially between two structurally similar aryl Grignard reagents, proceeded smoothly and selectively and, thus, provided a highly general and efficient method for the construction of biaryl compounds.
- Liao, Lian-Yan,Liu, Kun-Ming,Duan, Xin-Fang
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p. 9856 - 9867
(2015/11/03)
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- Cobalt-catalyzed C-H arylations with weakly-coordinating amides and tetrazoles: Expedient route to angiotensin-ii-receptor blockers
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Cobalt-catalyzed C-H arylations enabled the synthesis of biaryl tetrazoles, which are key structural motifs in antihypertensive angiotensin-II-receptor blockers. Thus, weakly-coordinating benzamides were employed for step-economical C-H arylations with ample scope. Further, a low-valent NHC complex enabled first cobalt-catalyzed C-H functionalization by tetrazole assistance.
- Li, Jie,Ackermann, Lutz
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supporting information
p. 5718 - 5722
(2015/03/31)
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- A fluorous Mukaiyama coupling reagent for a concise condensation reaction: Utility of medium-fluorous strategy
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The entire study of condensation reactions using various fluorous Mukaiyama reagents, including a novel medium-fluorous strategy, is described. A Mukaiyama reagent bearing a medium-fluorous content tag, between 40 and 60% fluorine by weight, was prepared and examined in ester and amide-forming condensation reactions. At the end of the reactions, the fluorous pyridone by-product was effectively separated from non-fluorous components by increasing the water content of the crude reaction mixture and subsequent filtration of the precipitate. It is also shown that Mukaiyama reagents bearing a fluorous tag increase the reaction rate considerably when compared to their non-fluorous tagged counterpart. Interestingly, it was observed that the longer the fluorous chain, the higher the activity of the Mukaiyama reagent.
- Sugiyama, Yuya,Kurata, Yuki,Kunda, Yoko,Miyazaki, Atsushi,Matsui, Junko,Nakamura, Shuichi,Hamamoto, Hiromi,Shioiri, Takayuki,Matsugi, Masato
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experimental part
p. 3885 - 3892
(2012/07/02)
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- 3D-QSAR and 3D-QSSR models of negative allosteric modulators facilitate the design of a novel selective antagonist of human α4β2 neuronal nicotinic acetylcholine receptors
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Subtype selective molecules for α4β2 neuronal nicotinic acetylcholine receptors (nAChRs) have been sought as novel therapeutics for nicotine cessation. α4β2 nAChRs have been shown to be involved in mediating the addictive properties of nicotine while other subtypes (i.e., α3β4 and a7) are believed to mediate the undesired effects of potential CNS drugs. To obtain selective molecules, it is important to understand the physiochemical features of ligands that affect selectivity and potency on nAChR subtypes. Here we present novel QSAR/QSSR models for negative allosteric modulators of human α4β2 nAChRs and human α3β4 nAChRs. These models support previous homology model and site-directed mutagenesis studies that suggest a novel mechanism of antagonism. Additionally, information from the models presented in this work was used to synthesize novel molecules; which subsequently led to the discovery of a new selective antagonist of human α4β2 nAChRs.
- Henderson, Brandon J.,Orac, Crina M.,MacIagiewicz, Iwona,Bergmeier, Stephen C.,McKay, Dennis B.
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scheme or table
p. 1797 - 1813
(2012/04/10)
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- Nickel-mediated decarbonylative cross-coupling of phthalimides with in situ generated diorganozinc reagents
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The nickel-mediated cross-coupling of phthalimides with diorganozinc reagents proceeds via a decarbonylative process to produce ortho-substituted benzamides in high yields. In addition to tolerating diverse phthalimide functionality, including alkyl, aryl
- Havlik, Sarah E.,Simmons, Jessica M.,Winton, Valerie J.,Johnson, Jeffrey B.
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experimental part
p. 3588 - 3593
(2011/06/26)
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- Preparation and condensation reactions of a new light-fluorous Mukaiyama reagent: reliable purification with fluorous solid phase extraction for esters and amides
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A modified light-fluorous Mukaiyama reagent bearing a C8F17 tag was prepared and examined in ester and amide forming condensation reactions. Following the reactions, the desired product was effectively separated from the fluorous pyridone by-product using a simple fluorous solid phase extraction.
- Matsugi, Masato,Hasegawa, Masakazu,Sadachika, Daisuke,Okamoto, Sachina,Tomioka, Mami,Ikeya, Yoshimi,Masuyama, Araki,Mori, Yuji
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p. 4147 - 4150
(2008/02/03)
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- Regioselective arylation of benzanilides with aryl triflates or bromides under palladium catalysis
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Benzanilides efficiently undergo diarylation upon treatment with aryl triflates or bromides in the presence of a palladium-based catalyst system to give the corresponding N-(2,6-diarylbenzoyl)anilines in good to excellent yields. (C) 2000 Elsevier Science Ltd.
- Kametani, Yoko,Satoh, Tetsuya,Miura, Masahiro,Nomura, Masakatsu
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p. 2655 - 2658
(2007/10/03)
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