- Ligand-Free Copper-Catalyzed Ullmann-Type C?O Bond Formation in Non-Innocent Deep Eutectic Solvents under Aerobic Conditions
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An efficient and novel protocol was developed for a Cu-catalyzed Ullmann-type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride-based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [CuI or CuII species] loading up to 5 mol% and K2CO3 as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e. g., glycerol) for the synthesis of some pharmacologically active aryloxypropanediols (Guaiphenesin, Mephenesin, and Chlorphenesin) on a 2 g scale in 70–96 % yield. Catalyst, base, and deep eutectic solvent could easily and successfully be recycled up to seven times with an E-factor as low as 5.76.
- Quivelli, Andrea Francesca,Marinò, Manuela,Vitale, Paola,García-álvarez, Joaquín,Perna, Filippo M.,Capriati, Vito
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- Multiple Mechanisms Mapped in Aryl Alkyl Ether Cleavage via Aqueous Electrocatalytic Hydrogenation over Skeletal Nickel
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We present here detailed mechanistic studies of electrocatalytic hydrogenation (ECH) in aqueous solution over skeletal nickel cathodes to probe the various paths of reductive catalytic C-O bond cleavage among functionalized aryl ethers relevant to energy science. Heterogeneous catalytic hydrogenolysis of aryl ethers is important both in hydrodeoxygenation of fossil fuels and in upgrading of lignin from biomass. The presence or absence of simple functionalities such as carbonyl, hydroxyl, methyl, or methoxyl groups is known to cause dramatic shifts in reactivity and cleavage selectivity between sp3 C-O and sp2 C-O bonds. Specifically, reported hydrogenolysis studies with Ni and other catalysts have hinted at different cleavage mechanisms for the C-O ether bonds in α-keto and α-hydroxy β-O-4 type aryl ether linkages of lignin. Our new rate, selectivity, and isotopic labeling results from ECH reactions confirm that these aryl ethers undergo C-O cleavage via distinct paths. For the simple 2-phenoxy-1-phenylethane or its alcohol congener, 2-phenoxy-1-phenylethanol, the benzylic site is activated via Ni C-H insertion, followed by beta elimination of the phenoxide leaving group. But in the case of the ketone, 2-phenoxyacetophenone, the polarized carbonyl πsystem apparently binds directly with the electron rich Ni cathode surface without breaking the aromaticity of the neighboring phenyl ring, leading to rapid cleavage. Substituent steric and electronic perturbations across a broad range of β-O-4 type ethers create a hierarchy of cleavage rates that supports these mechanistic ideas while offering guidance to allow rational design of the catalytic method. On the basis of the new insights, the usage of cosolvent acetone is shown to enable control of product selectivity.
- Hegg, Eric L.,Jackson, James E.,Klinger, Grace E.,Saffron, Christopher M.,Zhou, Yuting
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supporting information
p. 4037 - 4050
(2020/03/10)
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- Copper(ii)-catalyzed C-O coupling of aryl bromides with aliphatic diols: Synthesis of ethers, phenols, and benzo-fused cyclic ethers
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A highly efficient copper-catalyzed C-O cross-coupling reaction between aryl bromides and aliphatic diols has been developed employing a cheaper, more efficient, and easily removable copper(ii) catalyst. A broad range of aryl bromides were coupled with aliphatic diols of different lengths using 5 mol% CuCl2 and 3 equivalents of K2CO3 in the absence of any other ligands or solvents to afford the corresponding hydroxyalkyl aryl ethers in good to excellent yields. In this newly developed protocol, aliphatic diols have multilateral functions as coupling reactants, ligands, and solvents. The resulting hydroxyalkyl aryl ethers were further readily converted into the corresponding phenols, presenting a valuable alternative way to phenols from aryl bromides. Furthermore, it was demonstrated that they are useful intermediates for more advanced molecules such as benzofurans and benzo-fused cyclic ethers. This journal is
- Liu, Yajun,Park, Se Kyung,Xiao, Yan,Chae, Junghyun
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supporting information
p. 4747 - 4753
(2014/06/24)
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- Synthesis and evaluation of a novel class Hsp90 inhibitors containing 1-phenylpiperazine scaffold
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Previously, we identified 1-(2-(4-bromophenoxy)ethoxy)-3-(4-(2- methoxyphenyl)piperazin-1-yl)propan-2-ol (1) as a novel Hsp90 inhibitor with moderate activity through virtual screening. In this study, we report the optimization process of 1. A series of analogues containing the 1-phenylpiperazine core scaffold were synthesized and evaluated. The structure-activity relationships (SAR) for these compounds was also discussed for further molecular design. This effort afforded the most active inhibitor 13f with improved activity in not only target-based level, but also cell-based level compared with the original hit 1.
- Jia, Jian-Min,Liu, Fang,Xu, Xiao-Li,Guo, Xiao-Ke,Jiang, Fen,Cherfaoui, Bahidja,Sun, Hao-Peng,You, Qi-Dong
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supporting information
p. 1557 - 1561
(2014/03/21)
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- SPHINGOSINE-1 -PHOSPHATE RECEPTOR AGONIST AND ANTAGONIST COMPOUNDS
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The present invention is directed to novel, potent, and selective agents, which are agonists or antagonists of the one or more of the individual receptors of the S1P receptor family. The compounds of the invention are useful as therapeutics for treating medical conditions associated with agonism or antagonism of the individual receptors of the S1P receptor family.
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Page/Page column 72
(2008/12/07)
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- Certain aryl-aliphatic and heteroaryl-aliphatic piperazinyl pyrazines and their use in the treatment of serotonin-related diseases
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Compounds of the general formula (I): wherein the variables are as defined in the specification are useful for the prophylaxis or treatment of serotonin-related, especially 5-HT2receptor-related, diseases in human beings or animals, particularly diseases related to the 5-HT2creceptor, especially diseases such as eating disorders, memory disorders, schizophrenia, mood disorders, anxiety disorders, pain, sexual dysfunctionions, and urinary disorders.
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- Compounds having one or more aminosulfaonyloxy radicals useful as pharmaceuticals
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Methods of treating chronic arthritis and osteoporosis which utilize both known and novel compounds which would fall under the general formula:(HO)p--A--[--OS(O) 2 NR 1 R 2 ] zwherein A encompasses a wide range of values including but not limited to aryl, loweralkyl, cycloalkyl, and carbohydrates including sucrose and fructose; p is equal to the number of unreacted hydroxy groups contained on the molecule and may be zero; z is the number of --OS(O) 2 NR 1 R 2 groups and is always at least one; R 1 and R 2 are selected from hydrogen, loweralkyl, carboxy and the like; a novel process for preparing the compounds is provided wherein an appropriate sulfamic acid aryl ester is reacted with a hydroxy substituted A radical which may or may not contain thereon protected carboxyl, amino or hydroxy substituents, in an aprotic solvent containing a tertiary amine base. Pharmaceutical compositions for the treatment of chronic arthritis and osteoporosis are also provided.
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- Sulfamates as antiglaucoma agents
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Sulfamate esters of the formula where A is aryloxyalkyl, p is the number of unreacted hydroxy groups present on the alkyl moiety and may be zero, z is the number of --OS(O)2 NR1 R2 groups attached to carbons of the alkyl moiety and is always at least one; R1 and R2 are selected from hydrogen, loweralkyl, carboxy, and the like are useful in treating glaucoma.
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