The Experts below are selected from a list of 163371 Experts worldwide ranked by ideXlab platform
Vadim A Soloshonok - One of the best experts on this subject based on the ideXlab platform.
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biomimetic reductive amination under the continuous Flow Reaction conditions
Journal of Fluorine Chemistry, 2010Co-Authors: Vadim A Soloshonok, Hector T Catt, Taizo OnoAbstract:This study present a full account of continuous-Flow Reaction conditions for biomimetic reductive amination of fluorinated carbonyl compounds to corresponding amines and amino acids of biomedical importance. We demonstrate that simple silica-adsorbed DBU can be used as efficient catalysts for on-column 1,3-proton shift Reaction, a key transformation in the biomimetic reductive amination process. This new on-column process features operationally convenient conditions, higher chemical yields, enantioselectivity and purity of the corresponding products as compared with traditional in-flask Reactions. Moreover the removal of base-catalyst, the most delicate problem of the in-flask Reactions, is not an issue in the on-column process, as the silica-adsorbed DBU or polymer-bound guanidine remains on the column and can be reused. This feature renders the overall process substantially more economical and synthetically efficient, in particular, for large-scale synthesis of the corresponding fluorinated amines and amino acids target.
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continuous Flow asymmetric biomimetic transamination
Journal of Fluorine Chemistry, 2009Co-Authors: Vadim A Soloshonok, Hector T Catt, Taizo OnoAbstract:This study has demonstrated that conceptually new continuous-Flow Reaction procedure for biomimetic transamination of perfluoroalkyl-containing ketones is substantially more efficient as compared with conventional in-flask approach, allowing preparation of the target fluorinated amines with generally improved chemical yields and enantioselectivity.
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first example of continuous Flow Reaction conditions for biomimetic reductive amination of fluorine containing carbonyl compounds
Journal of Fluorine Chemistry, 2008Co-Authors: Vadim A SoloshonokAbstract:Abstract This study presents the first example of continuous-Flow Reaction conditions for biomimetic reductive amination of fluorinated carbonyl compounds using silica-adsorbed DBU as catalyst for on-column process. This new on-column process features operationally convenient conditions, higher chemical yields and purity of products as compared with traditional in-flask Reactions. Furthermore the removal of base-catalyst is not an issue in this process at all, as the catalyst (DBU) remains on the column in the “Reaction zone”, the feature which makes the overall process substantially more efficient and inexpensive, in particular, for large-scale synthesis of the target α-perfluoroalkyl amines.
Taizo Ono - One of the best experts on this subject based on the ideXlab platform.
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biomimetic reductive amination under the continuous Flow Reaction conditions
Journal of Fluorine Chemistry, 2010Co-Authors: Vadim A Soloshonok, Hector T Catt, Taizo OnoAbstract:This study present a full account of continuous-Flow Reaction conditions for biomimetic reductive amination of fluorinated carbonyl compounds to corresponding amines and amino acids of biomedical importance. We demonstrate that simple silica-adsorbed DBU can be used as efficient catalysts for on-column 1,3-proton shift Reaction, a key transformation in the biomimetic reductive amination process. This new on-column process features operationally convenient conditions, higher chemical yields, enantioselectivity and purity of the corresponding products as compared with traditional in-flask Reactions. Moreover the removal of base-catalyst, the most delicate problem of the in-flask Reactions, is not an issue in the on-column process, as the silica-adsorbed DBU or polymer-bound guanidine remains on the column and can be reused. This feature renders the overall process substantially more economical and synthetically efficient, in particular, for large-scale synthesis of the corresponding fluorinated amines and amino acids target.
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continuous Flow asymmetric biomimetic transamination
Journal of Fluorine Chemistry, 2009Co-Authors: Vadim A Soloshonok, Hector T Catt, Taizo OnoAbstract:This study has demonstrated that conceptually new continuous-Flow Reaction procedure for biomimetic transamination of perfluoroalkyl-containing ketones is substantially more efficient as compared with conventional in-flask approach, allowing preparation of the target fluorinated amines with generally improved chemical yields and enantioselectivity.
Shengzhong Frank Liu - One of the best experts on this subject based on the ideXlab platform.
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thinness and shape controlled growth for ultrathin single crystalline perovskite wafers for mass production of superior photoelectronic devices
Advanced Materials, 2016Co-Authors: Yucheng Liu, Yunxia Zhang, Zhou Yang, Dong Yang, Xiaodong Ren, Liuqing Pang, Shengzhong Frank LiuAbstract:Thinness-controlled perovskite wafers are directly prepared using a geometry-regulated dynamic-Flow Reaction system. It is found that the wafers are a superior material for photodetectors with a photocurrent response ≈350 times higher than that made of microcrystalline thin films. Moreover, the wafers are compatible with mass production of integrated circuits.
Masakatsu Shibasaki - One of the best experts on this subject based on the ideXlab platform.
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anti selective catalytic asymmetric nitroaldol Reaction of α keto esters intriguing solvent effect Flow Reaction and synthesis of active pharmaceutical ingredients
Journal of the American Chemical Society, 2018Co-Authors: Tomoya Karasawa, Naoya Kumagai, Raphael Oriez, Masakatsu ShibasakiAbstract:A rare-earth metal/alkali metal bimetallic catalyst proved particularly effective for enantioselectively coupling nitroalkanes and α-keto esters in an anti-selective manner to afford synthetically versatile, densely functionalized, and optically active α-nitro tertiary alcohols. A chiral diamide ligand captured two distinct metal cations, giving rise to a catalytically competent solid-phase heterobimetallic catalyst by simple mixing via self-assembly. The advantage of the solid-phase asymmetric catalyst was realized by successful application to the enantio- and diastereoselective Reaction in a continuous-Flow platform. The use of closely related solvents in terms of structures and polarity parameters, THF and its methylated congener 2-Me-THF, had an unexpectedly large solvent effect both on the Reaction rate and the stereoselectivity. The nitroaldol products share a privileged unit for active pharmaceutical ingredients, as demonstrated by the streamlined enantioselective synthesis of the marketed antifungal agents efinaconazole and albaconazole.
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anti selective catalytic asymmetric nitroaldol Reaction of α keto esters intriguing solvent effect Flow Reaction and synthesis of active pharmaceutical ingredients
Journal of the American Chemical Society, 2018Co-Authors: Tomoya Karasawa, Naoya Kumagai, Raphael Oriez, Masakatsu ShibasakiAbstract:A rare-earth metal/alkali metal bimetallic catalyst proved particularly effective for enantioselectively coupling nitroalkanes and α-keto esters in an anti-selective manner to afford synthetically versatile, densely functionalized, and optically active α-nitro tertiary alcohols. A chiral diamide ligand captured two distinct metal cations, giving rise to a catalytically competent solid-phase heterobimetallic catalyst by simple mixing via self-assembly. The advantage of the solid-phase asymmetric catalyst was realized by successful application to the enantio- and diastereoselective Reaction in a continuous-Flow platform. The use of closely related solvents in terms of structures and polarity parameters, THF and its methylated congener 2-Me-THF, had an unexpectedly large solvent effect both on the Reaction rate and the stereoselectivity. The nitroaldol products share a privileged unit for active pharmaceutical ingredients, as demonstrated by the streamlined enantioselective synthesis of the marketed antifung...
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asymmetric Flow catalysis mix and go solid phase nd na catalyst for expeditious enantioselective access to a key intermediate of azd7594
Tetrahedron, 2017Co-Authors: Akihito Nonoyama, Naoya Kumagai, Masakatsu ShibasakiAbstract:Abstract An anti-selective catalytic asymmetric nitroaldol Reaction was implemented in a continuous-Flow Reaction platform for the synthesis of a key intermediate of a drug candidate. The requisite solid-phase catalyst was readily prepared by mixing an amide-based chiral ligand and inexpensive inorganic salts, NdCl3•6H2O and NaOtBu, without covalent bond linkages. The Flow system was operated with 2-Me-THF as the eluent for ca. 400 h to provide a crude nitroaldol adduct in a highly stereoselective manner with no work-up procedure, reaching turnover number over 1600. Facile reduction of the nitro group of the product afforded a key intermediate of AZD7594, a therapeutic candidate for asthma and chronic obstructive pulmonary disease.
Sunwoo Lee - One of the best experts on this subject based on the ideXlab platform.
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continuous Flow Reactions in water for the synthesis of propargylamines via a metal free decarboxylative coupling Reaction
ChemInform, 2015Co-Authors: Bongkyun Jung, Kyung Ho Park, Kwang Ho Song, Sunwoo LeeAbstract:Alkynyl carboxylic acids undergo decarboxylative coupling with amines and paraformaldehyde, using a continuous Flow Reaction system to give propargylamines in excellent yields.
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continuous Flow Reactions in water for the synthesis of propargylamines via a metal free decarboxylative coupling Reaction
Tetrahedron Letters, 2015Co-Authors: Bongkyun Jung, Kyung Ho Park, Kwang Ho Song, Sunwoo LeeAbstract:Abstract A range of propargylamines was synthesized via the metal-free decarboxylative coupling of alkynyl carboxylic acids with amines and paraformaldehyde in water, using a continuous Flow Reaction system. Aryl- and alkyl-substituted propiolic acids were found to react with secondary amines in the presence of paraformaldehyde, at 140 °C in water to give the desired propargylamines in good yield.
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efficient synthesis of unsymmetric diarylalkynes from decarboxylative coupling in a continuous Flow Reaction system
ChemInform, 2012Co-Authors: Hee Joon Lee, Kyung Ho Park, Goun Bae, Jaehoon Choe, Kwang Ho Song, Sunwoo LeeAbstract:Only trace amounts of symmetrical diarylalkynes are obtained in some cases as by- products.
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efficient synthesis of unsymmetric diarylalkynes from decarboxylative coupling in a continuous Flow Reaction system
Tetrahedron Letters, 2011Co-Authors: Hee Joon Lee, Kyung Ho Park, Goun Bae, Jaehoon Choe, Kwang Ho Song, Sunwoo LeeAbstract:Abstract Unsymmetric diaryl alkynes were synthesized from the palladium-catalyzed decarboxylative coupling of aryl halides and propiolic acid using a continuous Flow Reaction system. This Flow chemistry system continuously gave the desired products in moderate to good yields, and produced less byproduct than was formed in the batch Reaction.
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silica supported palladium catalyzed hiyama cross coupling Reactions using continuous Flow system
ChemInform, 2010Co-Authors: Ga Ram Yang, Goun Bae, Jaehoon Choe, Sunwoo Lee, Kwang Ho SongAbstract:Reactions have been used in the continuous Flow Reaction with a variety of immobilized palladium catalysts.To the best of our knowledge, the Hiyama cross-coupling Reaction has never been used in a continuous micro-Flow re-action, despite the many advantages of the silyl reagent such as its stability in air stable, nontoxicity and easy availability.