- Copper-promoted difunctionalization of unactivated alkenes with silanes
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An efficient copper-catalyzed cascade difunctionalization of N-allyl anilines toward the synthesis of silylated indolines using commercially available silanes has been reported. This strategy provides a new avenue for the synthesis of a diverse array of i
- Chen, Xiaoyu,Guo, Zhuangzhuang,Li, Jingya,Wu, Yangjie,Wu, Yusheng,Xue, Yingying,Zou, Dapeng
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supporting information
p. 989 - 994
(2022/02/11)
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- Dehydrative Beckmann rearrangement and the following cascade reactions
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The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam. By strategically using the in situ generated Appel's salt or Mitsunobu's zwitterionic adduct as the dehydrating agent, a series of Beckmann rearrangement and following cascade reactions have been developed herein. The protocol allows the conversion of various ketoximes into amide, thioamide, tetrazole and imide products in modular procedures. The generality and tolerance of functionalities of this method have been demonstrated.
- Liu, Yinghui,Wei, Yongjiao,Xie, Lan-Gui
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supporting information
(2021/11/16)
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- An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
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Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
- Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
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p. 5627 - 5639
(2021/11/11)
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- Synthesis and antileishmanial activity of fluorinated rhodacyanine analogues: The ‘fluorine-walk’ analysis
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In a search for potent antileishmanial drug candidates, eighteen rhodacyanine analogues bearing fluorine or perfluoroalkyl substituents at various positions were synthesized. These compounds were tested for their inhibitory activities against Leishmania martiniquensis and L. orientalis. This ‘fluorine-walk’ analysis revealed that the introduction of fluorine atom at C-5, 6, 5′, or 6′ on the benzothiazole units led to significant enhancement of the activity, correlating with the less negative reduction potentials of the fluorinated analogues confirmed by the electrochemical study. On the other hand, [sbnd]CF3 and [sbnd]OCF3 groups were found to have detrimental effects, which agreed with the poor aqueous solubility predicted by the in silico ADMET analysis. In addition, some of the analogues including the difluorinated species showed exceptional potency against the promastigote and axenic amastigote stages (IC50 = 40–85 nM), with the activities surpassing both amphotericin B and miltefosine.
- Lasing, Thitiya,Phumee, Atchara,Siriyasatien, Padet,Chitchak, Kantima,Vanalabhpatana, Parichatr,Mak, Kit-Kay,Hee Ng, Chew,Vilaivan, Tirayut,Khotavivattana, Tanatorn
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supporting information
(2019/12/09)
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- TRIFLUOROMETHOXYLATION OF ARENES VIA INTRAMOLECULAR TRIFLUOROMETHOXY GROUP MIGRATION
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The present invention provides a process of producing a trifluoromethoxylated aryl or trifluoromethoxylated heteroaryl having the structure: (I), wherein A is an aryl or heteroaryl, each with or without subsutitution; and R1 is -H, -(alkyl), -(alkenyl), -(alkynyl), -(aryl), -(heteroaryl), - (alkylaryl), - (alkylheteroaryl), -NH-(alkyl), -N(alkyl)2, -NH-(alkenyl), -NH-(alkynyl) -NH-(aryl), -NH-(heteroaryl), -O-(alkyl), -O-(alkenyl), -O-(alkynyl), -O-(aryl), -O-(heteroaryl), -S-(alkyl), -S- (alkenyl), -S-(alkynyl), -S-(aryl), or -S-(heteroaryl), comprising: (a) reacting a compound having the structure: (II), with a trifluoromethylating agent in the presence of a base in a first suitable solvent under conditions to produce a compound having the structure: (III); and (b) maintaining the compound produced in step (a) in a second suitable solvent under conditions sufficient to produce the trifluoromethoxylated aryl or trifluormethoxylated heteroaryl having the structure: (I).
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Page/Page column 100
(2016/05/02)
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- Mechanistic studies on intramolecular C-H trifluoromethoxylation of (hetero)arenes via OCF3-migration
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The one-pot two-step intramolecular aryl and heteroaryl C-H trifluoromethoxylation recently reported by our group has provided a general, scalable, and operationally simple approach to access a wide range of unprecedented and valuable OCF3-containing building blocks. Herein we describe our investigations to elucidate its reaction mechanism. Experimental data indicate that the O-trifluoromethylation of N-(hetero)aryl-N-hydroxylamine derivatives is a radical process, whereas the OCF3-migration step proceeds via a heterolytic cleavage of the N-OCF3 bond followed by rapid recombination of a short-lived ion pair. Computational studies further support the proposed ion pair reaction pathway for the OCF3-migration process. We hope that the current study would provide useful insights for the development of new transformations using versatile N-(hetero)aryl-N-hydroxylamine synthons.
- Lee, Katarzyna N.,Lei, Zhen,Morales-Rivera, Cristian A.,Liu, Peng,Ngai, Ming-Yu
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supporting information
p. 5599 - 5605
(2016/07/06)
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- Highly efficient dehydrogenative cross-coupling of aldehydes with amines and alcohols
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A common protocol for the synthesis of amides, esters and α-ketoesters via cross dehydrogenative coupling of aldehydes and amines/alcohols has been developed. The method is applicable to a wide variety of alcohols and amines as well as aliphatic and aromatic aldehydes. Also, the use of acetaldehyde for acetylation and ethyl glyoxalate to access 2-oxo-amino esters is presented for the first time.
- Deshidi, Ramesh,Rizvi, Masood Ahmad,Shah, Bhahwal Ali
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p. 90521 - 90524
(2015/11/11)
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- Sulphuric acid immobilized on silica gel (H2SO4-SiO2) as an eco-friendly catalyst for transamidation
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A novel method of transamidation of carboxamides with amines by using catalytic amounts of H2SO4-SiO2 has been developed under solvent free conditions. The transamidation is compatible with a wide range of aromatic, heteroaromatic, aliphatic, cyclic/acyclic primary or secondary amines. The metal/solvent-free conditions represent a significant improvement over other existing methods as the reaction can be performed in open air conditions and no column purification is required. The versatility of this methodology was further demonstrated by synthesizing the commercially available drug procainamide.
- Rasheed,Rao, D. Nageswar,Reddy, A. Siva,Shankar, Ravi,Das, Parthasarathi
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p. 10567 - 10574
(2015/02/05)
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- Trifluoromethoxylation of arenes: Synthesis of ortho- Trifluoromethoxylated aniline derivatives by OCF3 migration
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Aryl trifluoromethoxylation by a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxylamine derivatives and intramolecular OCF3 migration is presented. This protocol allows easy access to a wide range of synthetically useful ortho-OCF3 aniline derivatives. In addition, it utilizes bench-stable reagents, is operationally simple, shows high functional-group tolerance, and is amenable to gram-scale as well as one-pot synthesis.Areaction mechanism of a heterolytic cleavage of the N-OCF3 bond followed by recombination of the resulting nitrenium ion and trifluoromethoxide is proposed for the OCF3-migration reaction.
- Hojczyk, Katarzyna N.,Feng, Pengju,Zhan, Chengbo,Ngai, Ming-Yu
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supporting information
p. 14559 - 14563
(2015/01/09)
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- Pd-Catalyzed C-H activation/oxidative cyclization of acetanilide with norbornene: Concise access to functionalized indolines
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An efficient Pd-catalyzed oxidative cyclization reaction for the synthesis of functionalized indolines by direct C-H activation of acetanilide has been developed. The norbornylpalladium species formed via direct ortho C-H activation of acetanilides is supposed to be a key intermediate in this transformation. This journal is the Partner Organisations 2014.
- Gao, Yang,Huang, Yubing,Wu, Wanqing,Huang, Kefan,Jiang, Huanfeng
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supporting information
p. 8370 - 8373
(2014/07/22)
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- Benzimidazolones: A new class of selective peroxisome proliferator- activated receptor γ (PPARγ) modulators
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A series of benzimidazolone carboxylic acids and oxazolidinediones were designed and synthesized in search of selective PPARγ modulators (SPPARγMs) as potential therapeutic agents for the treatment of type II diabetes mellitus (T2DM) with improved safety profiles relative to rosiglitazone and pioglitazone, the currently marketed PPARγ full agonist drugs. Structure-activity relationships of these potent and highly selective SPPARγMs were studied with a focus on their unique profiles as partial agonists or modulators. A variety of methods, such as X-ray crystallographic analysis, PPARγ transactivation coactivator profiling, gene expression profiling, and mutagenesis studies, were employed to reveal the differential interactions of these new analogues with PPARγ receptor in comparison to full agonists. In rodent models of T2DM, benzimidazolone analogues such as (5R)-5-(3-{[3-(5-methoxybenzisoxazol-3-yl)benzimidazol-1-yl]methyl}phenyl) -5-methylox-azolidinedione (51) demonstrated efficacy equivalent to that of rosiglitazone. Side effects, such as fluid retention and heart weight gain associated with PPARγ full agonists, were diminished with 51 in comparison to rosiglitazone based on studies in two independent animal models. (Figure presented)
- Liu, Weiguo,Lau, Fiona,Liu, Kun,Wood, Harold B.,Zhou, Gaochao,Chen, Yuli,Li, Ying,Akiyama, Taro E.,Castriota, Gino,Einstein, Monica,Wang, Chualin,McCann, Margaret E.,Doebber, Thomas W.,Wu, Margaret,Chang, Ching H.,McNamara, Lesley,McKeever, Brian,Mosley, Ralph T.,Berger, Joel P.,Meinke, Peter T.
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supporting information; experimental part
p. 8541 - 8554
(2012/02/04)
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- Practical, highly convergent, asymmetric synthesis of a selective PPARγ modulator
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A practical, highly convergent, asymmetric synthesis of a selective PPARγ modulator 1 is described. The inhibitor contains two key components, a 6-trifluoromethoxy-3-acylindole (6) and (R)-raryloxybutanoic acid derivative (10). Twomethods were developed to overcome the regioselectivity issues encountered in the preparation of the 6-substituted indole. The first involved an intramolecular Heck reaction of an iodoaryl enamine. The second involved application of a catalytic Meerwein arylation reaction between 2-nitro-4-trifluoromethoxyaniline and isopropenyl acetate and subsequent reductive cyclization. The α-aryloxybutanoic acid was prepared via an asymmetric hydrogenation of the corresponding α-aryloxy-α,β- unsaturated acid. Tetrabutylammonium iodidecatalyzed coupling of the two fragments and ester hydrolysis completed the convergent synthesis. The described convergent synthesis was used to prepare >3 kg of drug substance 1 in 50% overall yield and with >99.5% ee.
- Maligres, Peter E.,Humphrey, Guy R.,Marcoux, Jean-Francois,Hillier, Michael C.,Zhao, Dalian,Krska, Shane,Grabowski, Edward J.J.
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experimental part
p. 525 - 534
(2010/04/22)
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- Hypoxia-Selective Agents Derived from Quinoxaline 1,4-Di-N-oxides
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Hypoxic cells, which are a common feature of solid tumors, but not normal tissues, are resistant to both anticancer drugs and radiation therapy.Thus the identification of drugs with selective toxicity toward hypoxic cells is an important objective in anticancer chemotherapy.The benzotriazine di-N-oxide (SR 4233, Tirapazamine) has been shown to be an efficient and selective cytotoxin for hypoxic cells.Since the bioreductive activation of Tirapazamine is thought to be due to the presence of the 1,4-di-N-oxide moiety, a series of 3-aminoquinoxaline-2-carbonitrile 1,4-di-N-oxides with a range of electron-donating and -withdrawing substituents in the 6- and /or 7- positions has been synthesized and evaluated for toxicity to hypoxic cells.Electrochemical studies of the quinoxaline di-N-oxides and Tirapazamine showed that as the electron-withdrawing nature of the 6(7)-substituent increases, the reduction potential becomes more positive and the compound is more readily reduced.Apart from the unsubstituted 6a and the 6,7-dimethyl derivative 6c, the quinoxaline di-N-oxide have reduction potentials significantly more positive than Tirapazamine (Epc -0.90 V).The most potent cytotoxins to cells in culture were the 6,7-dichloro and 6,7-difluoro derivatives 6i and 6l, which were 30-fold more potent than Tirapazamine.The 6(7)-fluoro and 6(7)-chloro compounds, 6e and 6h, showed the greatest hypoxia selectivity.Four of the compounds, 6e, 6f, 6h and 6i, killed the inner cells of multicellular tumor spheroids in vitro.In vivo Balb/c mice tolerated a dose of these four compounds twice the size of that of Tirapazamine.This study demonstrates that quinoxaline 1,4-di-N-oxides could provide useful hypoxia-selective therapeutic agents.
- Monge, Antonio,Palop, Juan A.,Cerain, Adela Lopez de,Senador, Virginia,Martinez-Crespo, Francisko J.,et al.
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p. 1786 - 1792
(2007/10/02)
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- Electrophotographic member
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Disclosed is an electrophotographic member containing as a charge transport material a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative which is remarkably excellent in solubility in an organic solvent and/or a binder such as polycarbonate resin, etc., can show very excellent electrophotographic properties such as high sensitivity, low residual potential and high durability. Further, a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative usable as a charge transport material, and a process for producing the same are disclosed. Furthermore, a fluorine-containing diarylamine usable for producing the fluorine-containing N,N,N',N'-tetraarylbenzidine derivative, and a process for producing the same are disclosed.
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