- Dehydroxyalkylative halogenation of C(aryl)-C bonds of aryl alcohols
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We herein report Cu mediated side-directed dehydroxyalkylative halogenation of aryl alcohols. C(aryl)-C bonds of aryl alcohols were effectively cleaved, affording the corresponding aryl chlorides, bromides and iodides in excellent yields. Aryl alcohols could serve as both aromatic electrophilic and radical synthetic equivalents during the reaction.
- Liu, Mingyang,Zhang, Zhanrong,Liu, Huizhen,Wu, Tianbin,Han, Buxing
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supporting information
p. 7120 - 7123
(2020/07/14)
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- The Trifluoromethyl Group as a Bioisosteric Replacement of the Aliphatic Nitro Group in CB1 Receptor Positive Allosteric Modulators
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The first generation of CB1 positive allosteric modulators (e.g., ZCZ011) featured a 3-nitroalkyl-2-phenyl-indole structure. Although a small number of drugs include the nitro group, it is generally not regarded as being "drug-like", and this is particularly true for aliphatic nitro groups. There are very few case studies where an appropriate bioisostere replaced a nitro group that had a direct role in binding. This may be indicative of the difficulty of replicating its binding interactions. Herein, we report the design and synthesis of ligands targeting the allosteric binding site on the CB1 cannabinoid receptor, in which a CF3 group successfully replaced the aliphatic NO2. In general, the CF3-bearing compounds were more potent than their NO2 equivalents and also showed improved in vitro metabolic stability. The CF3 analogue (1) with the best balance of properties was selected for further pharmacological evaluation. Pilot in vivo studies showed that (±)-1 has similar activity to (±)-ZCZ011, with both showing promising efficacy in a mouse model of neuropathic pain.
- Tseng, Chih-Chung,Baillie, Gemma,Donvito, Giulia,Mustafa, Mohammed A.,Juola, Sophie E.,Zanato, Chiara,Massarenti, Chiara,Dall'Angelo, Sergio,Harrison, William T. A.,Lichtman, Aron H.,Ross, Ruth A.,Zanda, Matteo,Greig, Iain R.
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supporting information
p. 5049 - 5062
(2019/05/28)
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- Base-Promoted Aerobic Oxidation/Homolytic Aromatic Substitution Cascade toward the Synthesis of Phenanthridines
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The current protocol represents a transition metal-free synthesis of polysubstituted phenanthridines from abundant starting materials like benzhydrol and 2-iodoaniline derivatives. The reaction involves sequential oxidation of alcohol and direct condensation reaction with the amine resulting in a C?N bond formation followed by a radical C?C coupling in a cascade sequence. The used base potassium tert-butoxide plays a dual role in dehydrogenation and homolytic aromatic substitution reaction. Using this methodology, twenty substituted phenanthridine derivatives were synthesized with up to 85% isolated yield. (Figure presented.).
- Maiti, Debabrata,Halder, Atreyee,De Sarkar, Suman
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supporting information
p. 4941 - 4948
(2019/11/03)
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- Inexpensive NaX (X = I, Br, Cl) as a halogen donor in the practical Ag/Cu-mediated decarboxylative halogenation of aryl carboxylic acids under aerobic conditions
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Versatile and practical Ag/Cu-mediated decarboxylative halogenation between readily available aryl carboxylic acids and abundant NaX (X = I, Br, Cl) has been achieved under aerobic conditions in moderate to good yields. The halodecarboxylation is shown to be an effective strategy for S-containing heteroaromatic carboxylic acid and benzoic acids with nitro, chloro and methoxyl substituents at the ortho position. A gram-scale reaction and a three-step procedure to synthesize iniparib have been performed to evaluate the practicality of this protocol. A preliminary mechanistic investigation indicates that Cu plays a vital role and a radical pathway is involved in the transformation.
- Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
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supporting information
p. 5416 - 5421
(2018/08/12)
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- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
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Paragraph 0091
(2018/01/03)
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- A new regiospecific synthesis method of 1H-pyrazolo[3,4-b]quinoxalines – Potential materials for organic optoelectronic devices, and a revision of an old scheme
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A series of 6-substituted-1,3-diphenyl-1H-pyrazolo[3,4-b]quinoxalines were prepared using a new synthetic pathway: reductive cyclization of appropriate 5-(o-nitrophenyl)-pyrazoles with ferrous oxalate or triphenylphosphine. The main advantage of this procedure is that, contrary to the older protocols of pyrazolo[3,4-b]quinoxaline synthesis, this method allows for a substituent to be introduced to the carbocyclic ring without the formation of isomers. The pyrazole ring can also be modified to some extent. Furthermore, we propose a new mechanism for the oldest reported pyrazolo[3,4-b]quinoxaline synthesis, based on the condensation between o-phenylenediamine and 3,4-pyrazolin-5-diones.
- Danel, Andrzej,Wojtasik, Katarzyna,Szlachcic, Pawe?,Gryl, Marlena,Stadnicka, Katarzyna
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p. 5072 - 5081
(2017/07/28)
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- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
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Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
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p. 2794 - 2803
(2016/04/26)
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- Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with the Michael acceptor, diethyl ethoxycarbonylbutendienoate
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Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with diethyl ethoxycarbonylbutendienoate produces 2,3,3-triethoxycarbonyl-2,3- dihydro-4(1H)-quinolinone derivatives in moderate to good yields. This protocol involves Michael additio
- Okuro, Kazumi,Alper, Howard
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experimental part
p. 4420 - 4424
(2012/06/18)
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- Gold-catalyzed transformation of 2-alkynyl arylazides: Efficient access to the valuable pseudoindoxyl and indolyl frameworks
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An element of surprise: A series of functionalized 2-alkynyl arylazides has beed converted into 3-substituted indoles or 2,2-disubstituted indolin-3-ones in the presence of a gold(I) complex. Various oxygen or aryl nucleophiles can be used in this process to trap the intermediate α-imino gold carbene. The structural motifs of the products are found in a large variety of biologically active compounds and natural products. Copyright
- Wetzel, Alexander,Gagosz, Fabien
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supporting information; experimental part
p. 7354 - 7358
(2011/09/16)
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- Highly stereoselective 7-endo-trig /ring contraction cascade to construct pyrrolo[1,2- a ]quinoline derivatives
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With the cooperation of Cram's phenonium ion, a novel cascade reaction was illustrated to construct pyrrolo[1,2-a]quinolines as a sole diastereoisomer in good to excellent yields. Preliminary mechanistic studies revealed that the γ-lactam ring and electron-rich arene are important driving forces for ring contraction.
- Li, Xinyu,Li, Cheng,Zhang, Wenjing,Lu, Xiang,Han, Shiqing,Hong, Ran
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supporting information; experimental part
p. 1696 - 1699
(2010/09/05)
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- Multicomponent cascade reactions: A novel and expedient approach to functionalized indoles by an unprecedented nucleophilic addition- heterocyclization-oxidative alkoxycarbonylation sequence
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A novel multicomponent cascade process is reported, based on the sequential combination between an initial nucleophilic attack step to an imine moiety and a palladium-catalyzed oxidative heterocyclization-alkoxycarbonylation process. By this new process, five simple molecules [2-alkynylaniline imines, alcohol (ROH), carbon monoxide (CO), alcohol (ROH), and oxygen (O2)] are sequentially activated, selectively leading to high value-added functionalized indole derivatives in a single operation. Copyright
- Gabriele, Bartolo,Veltri, Lucia,Salerno, Giuseppe,Mancuso, Raffaella,Costa, Mirco
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supporting information; experimental part
p. 3355 - 3363
(2011/03/17)
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- Synthetic study on tetrapetalones: Stereoselective cyclization of N-acyliminium ion to construct substituted 1-benzazepines
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The synthesis of the tetracyclic core of complex antibiotic tetrapetalones has been achieved In three steps starting from the simple Intermediate γ-hydroxy amide, which can be accessed through a high-yielding six-step sequence. The successful synthesis relies on a novel strategy based on the N-acyliminium ion cyclizatlon.
- Cheng, Li,Xlnyu, L.I. And,Ran, Hong
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supporting information; experimental part
p. 4036 - 4039
(2009/12/09)
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- Efficient one-pot transformation of aminoarenes to haloarenes using halodimethylisulfonium halides generated in situ
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Halodimethylsulfonium halide 1, which is readily formed in situ from hydrohaloic acid and DMSO, is a good nucleophilic halide. This activated nucleophilic halide rapidly converts aryldiazonium salt prepared in situ by the same hydrohaloic acid and nitrite ion to aryl chlorides, bromides, or iodides in good yield. The combined action of nitrite ion and hydrohaloic acid in DMSO is required for the direct transformation of aromatic amines, which results in the production of aryl halides within 1 h. Substituted compounds with electron-donating or -withdrawing groups or sterically hindered aromatic amines are also smoothly transformed to the corresponding aromatic halides. The only observed by-product is the deaminated arene (usually 7%). The isolated aryldiazonium salts can also be converted to the corresponding aryl halides using 1. The present method offers a facile, one-step procedure for transforming aminoarenes to haloarenes and lacks the environmental pollutants that usually accompany the Sandmeyer reaction using copper halides.
- Baik, Woonphil,Luan, Wanqiang,Lee, Hyun Joo,Yoon, Cheol Hun,Koo, Sangho,Kim, Byeong Hyo
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p. 213 - 219
(2007/10/03)
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- Formation of Aryliodine(III) Derivatives in the Nitration of Aryl Iodides in Acetic Anhydride
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Nitration of iodobenzene, o-iodotoluene, and p-iodotoluene in acetic anhydride results in reversible oxidation to aryliodine(III) compounds prior to the formation of the expected nitro derivatives. μ-Oxo has been isolated from nitration of iodobenzene and its crystal structure determined.
- Bushnell, Gordon W.,Fischer, Alfred,Ibrahim, Prabha N.
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p. 1281 - 1286
(2007/10/02)
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- STOICHIOMETRIC AND CATALYTIC OXIDATIVE IODINATION OF AROMATIC COMPOUNDS IN THE PRESENCE OF NITROGEN-CONTAINING OXIDIZING AGENTS IN AQUEOUS TRIFLUOROACETIC ACID
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The conditions for oxidative monoiodination of benzene, halogenobenzenes, toluene, halogenotoluenes, and p-toluic acid in solvents based on trifluoroacetic acid were studied.Yields of the respective iodoarenes close to quantitative were obtained in systems containing 10-20 vol. percent of water in the solvent with equimolar amounts of alkali-metal metal iodides in relation to the substrate in the presence of stoichiometric (under anaerobic conditions) or catalytic (in the presence of oxygen or air) amounts of alkali-metal nitrates.The analogous reactions with nitrites can only be conducted under aerobic conditions.These iodinating systems are compared with systems based on acetic acid containing iodine and mixtures of sulfuric and nitric acids.The conditions for the iodination of toluene and for the transformations of the obtained iodotoluenes in the presence of nitrogen-containing oxidizing agents in trifluoroacetic acid solutions were studied in detail.It was shown that p-iodotoluene undergoes ipso-nitrodeiodination to a significant degree under these conditions.It is supposed that the iodinating agent in the investigated systems is trifluoroacetyl hypoiodite.Data on the assignment of the PMR spectra of the synthesized isomeric nitroiodotoluenes and chloroiodotoluenes by a simple additive method are given.
- Makhon'kov, D. I.,Cheprakov, A. V.,Beletskaya, I. P.
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p. 2029 - 2035
(2007/10/02)
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