The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
Mahito Atobe - One of the best experts on this subject based on the ideXlab platform.
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A Flow Microreactor Approach to a Highly Efficient Diels–Alder Reaction with an Electrogenerated o-Quinone
Synlett, 2019Co-Authors: Kenta Tanaka, Hirona Yoshizawa, Mahito AtobeAbstract:We have demonstrated a Diels–Alder Reaction of an o-quinone generated in an electrochemical flow microreactor. In the flow microreactor system, 4-tert-butyl-o-benzoquinone was easily electrogenerated from 4-tert-butylpyrocatechol in the absence of chemical oxidants and then rapidly used, without decomposing, in a subsequent Diels–Adler Reaction with various fulvenes to give the desired products efficiently.
Qingjuan Lei - One of the best experts on this subject based on the ideXlab platform.
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Hydroxylation of cyclohexane with molecular oxygen catalyzed by highly efficient heterogeneous Mn(III) porphyrin catalysts prepared by special synthesis and immobilization method
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2012Co-Authors: Baojiao Gao, Yingjun Chen, Qingjuan LeiAbstract:A novel method to synthesize and immobilize porphyrins as well as manganese porphyrins on crosslinked polystyrene (CPS) microspheres was designed. The chloromethyl groups of chloromethylated CPS microspheres (CMCPS microspheres) were first oxidized to aldehyde groups via Kornblum oxidation Reaction, obtaining aldehyde group-functionalized microspheres, and then, the synchronous synthesis and immobilization of porphyrins on CPS microspheres were carried out via the Adler Reaction between solid–liquid phases, obtaining three kinds of functional microspheres, on which phenyl porphyrin (PP), p-chlorophenyl porphyrin (CPP) and p-nitrophenyl porphyrin (NPP) were immobilized. Finally, three manganese porphyrin-immobilized microspheres, MnPP–CPS, MnCPP–CPS and MnNPP–CPS, were prepared, these solid catalysts were used in the catalytic hydroxylation Reaction of cyclohexane with molecular oxygen as oxidant, and their catalytic performances were mainly investigated in this work. Some surprising experimental results were obtained. The prepared immobilized manganese porphyrin catalysts display amazing catalytic activity and selectivity, and cyclohexane conversion can get up to 45 % and cyclohexanol selectivity in the Reaction product can be up to 90–100 %.
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Multi-functionality of cationic porphyrin-immobilized polymeric microspheres prepared by synchronously synthesizing and immobilizing pyridylporphyrin on surfaces of polymeric microspheres
Materials Chemistry and Physics, 2012Co-Authors: Baojiao Gao, Li Fang, Jiying Men, Qingjuan LeiAbstract:Abstract Pyridylporphyrin (PyP) was synchronously synthesized and immobilized on the surfaces of crosslinked polystyrene microspheres (CPS microspheres) via an Adler Reaction between solid–liquid phases, resulting in PyP-immobilized microspheres, PyP-CPS microspheres. Then the cationic porphyrin-immobilized microspheres, MPyP-CPS microspheres (“M” represents methyl group that comes from iodomethane), was prepared via the quaternization Reaction of PyP-CPS microspheres with iodomethane as reagent. In the current work, the efficiency of the above route to immobilize pyridylporphyrin PyP on CPS microspheres was first researched by a comparison method, and then the multi-functionality of the cationic porphyrin-immobilized microspheres MPyP-CPS were mainly tested and examined from many aspects. The investigation results show that: (1) the above route to immobilize pyridylporphyrin on the surfaces of CPS microspheres is highly efficient, and the immobilization amount of PyP on CPS microspheres can get up to about 0.2 mmol g −1 ; (2) the cationic porphyrin-immobilized microspheres MPyP-CPS are a kind of multifunctional polymeric microspheres because of their special surface structure, and they can be used to construct different host-guest systems, resulting in many applications. MPyP-CPS microspheres can used as triphase-transfer catalysis in organic synthesis, can coordinate to transition metal ion to form immobilized metalloporphyrin catalysts to be used in the green catalytic oxidations, can be used as support of heteropoly acid to prepare heterogenous heteropoly acid catalyst, and MPyP-CPS microspheres also can used as solid adsorbent in the removal of toxic chromate ion from water medium. In a word, the polymeric microspheres supporting cationic porphyrin, MPyP-CPS microspheres, will have vast application prospect in various fields because they have special surface chemical structure.
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Realizing porphyrin‐functionalization of crosslinked polystyrene microspheres via two special polymer Reactions
Polymers for Advanced Technologies, 2011Co-Authors: Baojiao Gao, Yingjun Chen, Qingjuan LeiAbstract:A novel route to make crosslinked polystyrene (CPS) microspheres to be porphyrin-functionalized via two special polymer Reactions, Kornblum Reaction and Adler Reaction, was designed and founded. The chloromethyl groups of chloromethylated crosslinked polystyrene (CMCPS) microspheres were first oxidized to aldehyde groups by dimethyl sulfoxide as oxidant via Kornblum oxidation Reaction, obtaining aldehyde group-modified microspheres, ALCPS microspheres, in which, a great quantity of benzaldehyde groups suspend from the main chain, and the effects of the main factors including the Reaction temperature, the addition of KI as catalyst and the used amount of NaHCO3 as acid acceptor on the oxidation Reaction were examined. Subsequently, the synchronic synthesizing and immobilizing of porphyrins on CPS microspheres were carried out via the Adler Reaction between solid and liquid phases, in which, ALCPS microspheres, pyrrole and benzaldehyde or benzaldehyde analog in a solution were used as co-reactants, resulting in porphyrin-functionalized microspheres, and the influence of diverse factors including the acidity of the protonic acid catalyst, the substituent structure of benzaldehyde analog, and the polarity of the solvent as well as the swelling property of the solvent for CPS microspheres on the process of synchronously synthesizing and immobilizing porphyrins on CPS microspheres were investigated in depth. The experimental results indicate that via the designed route, the porphyrin-functionalization of CPS microspheres can successfully be realized. For the Kornblum oxidation Reaction, under the optimal Reaction conditions, the conversion of chloromethyl groups can reach 90%. For the Adler Reaction between solid and liquid phases, the fitting protonic acid catalyst is lactic acid, appropriate solvent is a mixture of dimethyl sulfoxide and xylene, and using 4-chlorobenzaldehyde as a benzaldehyde analog reactant in the solution is in favor of the porphyrin-functionalization of CPS microspheres. Under these specific conditions, the immobilized amount of porphyrin can get up to 23.33 mmol/100 g. Copyright © 2011 John Wiley & Sons, Ltd.
Mark S. Workentin - One of the best experts on this subject based on the ideXlab platform.
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A retro-Diels-Alder Reaction to uncover maleimide-modified surfaces on monolayer-protected nanoparticles for reversible covalent assembly.
Organic letters, 2006Co-Authors: Jun Zhu, And Arnold J. Kell, Mark S. WorkentinAbstract:Maleimide-modified monolayer-protected gold nanoparticles (MPGN) are prepared from the protected furan−maleimide via the thermally reversible Diels−Adler Reaction when required. These maleimide-MPGNs serve as a general platform allowing for a Diels−Alder Reaction with furan-modified MPN to prepare larger 3D networks reversibly.
Baojiao Gao - One of the best experts on this subject based on the ideXlab platform.
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Hydroxylation of cyclohexane with molecular oxygen catalyzed by highly efficient heterogeneous Mn(III) porphyrin catalysts prepared by special synthesis and immobilization method
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2012Co-Authors: Baojiao Gao, Yingjun Chen, Qingjuan LeiAbstract:A novel method to synthesize and immobilize porphyrins as well as manganese porphyrins on crosslinked polystyrene (CPS) microspheres was designed. The chloromethyl groups of chloromethylated CPS microspheres (CMCPS microspheres) were first oxidized to aldehyde groups via Kornblum oxidation Reaction, obtaining aldehyde group-functionalized microspheres, and then, the synchronous synthesis and immobilization of porphyrins on CPS microspheres were carried out via the Adler Reaction between solid–liquid phases, obtaining three kinds of functional microspheres, on which phenyl porphyrin (PP), p-chlorophenyl porphyrin (CPP) and p-nitrophenyl porphyrin (NPP) were immobilized. Finally, three manganese porphyrin-immobilized microspheres, MnPP–CPS, MnCPP–CPS and MnNPP–CPS, were prepared, these solid catalysts were used in the catalytic hydroxylation Reaction of cyclohexane with molecular oxygen as oxidant, and their catalytic performances were mainly investigated in this work. Some surprising experimental results were obtained. The prepared immobilized manganese porphyrin catalysts display amazing catalytic activity and selectivity, and cyclohexane conversion can get up to 45 % and cyclohexanol selectivity in the Reaction product can be up to 90–100 %.
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Multi-functionality of cationic porphyrin-immobilized polymeric microspheres prepared by synchronously synthesizing and immobilizing pyridylporphyrin on surfaces of polymeric microspheres
Materials Chemistry and Physics, 2012Co-Authors: Baojiao Gao, Li Fang, Jiying Men, Qingjuan LeiAbstract:Abstract Pyridylporphyrin (PyP) was synchronously synthesized and immobilized on the surfaces of crosslinked polystyrene microspheres (CPS microspheres) via an Adler Reaction between solid–liquid phases, resulting in PyP-immobilized microspheres, PyP-CPS microspheres. Then the cationic porphyrin-immobilized microspheres, MPyP-CPS microspheres (“M” represents methyl group that comes from iodomethane), was prepared via the quaternization Reaction of PyP-CPS microspheres with iodomethane as reagent. In the current work, the efficiency of the above route to immobilize pyridylporphyrin PyP on CPS microspheres was first researched by a comparison method, and then the multi-functionality of the cationic porphyrin-immobilized microspheres MPyP-CPS were mainly tested and examined from many aspects. The investigation results show that: (1) the above route to immobilize pyridylporphyrin on the surfaces of CPS microspheres is highly efficient, and the immobilization amount of PyP on CPS microspheres can get up to about 0.2 mmol g −1 ; (2) the cationic porphyrin-immobilized microspheres MPyP-CPS are a kind of multifunctional polymeric microspheres because of their special surface structure, and they can be used to construct different host-guest systems, resulting in many applications. MPyP-CPS microspheres can used as triphase-transfer catalysis in organic synthesis, can coordinate to transition metal ion to form immobilized metalloporphyrin catalysts to be used in the green catalytic oxidations, can be used as support of heteropoly acid to prepare heterogenous heteropoly acid catalyst, and MPyP-CPS microspheres also can used as solid adsorbent in the removal of toxic chromate ion from water medium. In a word, the polymeric microspheres supporting cationic porphyrin, MPyP-CPS microspheres, will have vast application prospect in various fields because they have special surface chemical structure.
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Catalytic activity of immobilized metalloporphyrins prepared by synchronously synthesizing and immobilizing porphyrins on polymeric microspheres
Journal of Applied Polymer Science, 2011Co-Authors: Baojiao Gao, Jing ZhaoAbstract:A novel route to immobilize metalloporphyrins on polymeric supports was put forward, and it is the way to synchronously synthesize and immobilize porphyrins on polymeric microspheres, followed by metal salt coordination Reaction. Copolymeric microspheres (GMA/MMA) of glycidyl methacrylate (GMA) and methyl methacrylate (MMA) were prepared, and then via the ring-opening Reaction of the epoxy groups on GMA/MMA microspheres, parahydroxybenzaldehyde (HBA) was bond onto the microspheres, obtaining the modified microspheres HBA-GMA/MMA. Subsequently, the Adler Reaction between solid-liquid phases was carried out with HBA-GMA/MMA microspheres and pyrrole as well as benzaldehyde derivate in a solution as coreactants. As a result, it was successfully realized to synchronously synthesize and immobilize porphyrin on the surfaces of GMA/MMA microspheres, resulting in three porphyrin-immobilized microspheres, PP-GMA/MMA (PP: phenyl porphyrin), CPP-GMA/MMA (CPP: 4-chlorophenyl porphyrin) and NPP-GMA/MMA (NPP: 4-nitrophenyl porphyrin). Further, the coordination Reaction of these immobilized porphyrins with cobalt salt was conducted, obtaining three supported cobalt porphyrin catalysts, CoPP-GMA/MMA, CoCPP-GMA/MMA and CoNPP-GMA/MMA. The catalytic properties of these supported mettaloporphyrin catalysts were examined in the catalytic oxidation of ethylbenzene to acetophenone by dioxygen. The experimental results indicate: (1) the prepared three solid catalysts are effective in the catalytic oxidation of ethylbenzene to acetophenone by dioxygen; (2) for these polymer-supported metalloporphyrin catalysts, some factors, such as the substitute species on phenyl ring in the macrocycle, the immobilization density of metalloporphyrin and the added amount of the catalyst in the Reaction system, affect the catalytic activity greatly; (3) the prepared supported metalloporphyrin catalysts have fine recycle and reuse property. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
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Realizing porphyrin‐functionalization of crosslinked polystyrene microspheres via two special polymer Reactions
Polymers for Advanced Technologies, 2011Co-Authors: Baojiao Gao, Yingjun Chen, Qingjuan LeiAbstract:A novel route to make crosslinked polystyrene (CPS) microspheres to be porphyrin-functionalized via two special polymer Reactions, Kornblum Reaction and Adler Reaction, was designed and founded. The chloromethyl groups of chloromethylated crosslinked polystyrene (CMCPS) microspheres were first oxidized to aldehyde groups by dimethyl sulfoxide as oxidant via Kornblum oxidation Reaction, obtaining aldehyde group-modified microspheres, ALCPS microspheres, in which, a great quantity of benzaldehyde groups suspend from the main chain, and the effects of the main factors including the Reaction temperature, the addition of KI as catalyst and the used amount of NaHCO3 as acid acceptor on the oxidation Reaction were examined. Subsequently, the synchronic synthesizing and immobilizing of porphyrins on CPS microspheres were carried out via the Adler Reaction between solid and liquid phases, in which, ALCPS microspheres, pyrrole and benzaldehyde or benzaldehyde analog in a solution were used as co-reactants, resulting in porphyrin-functionalized microspheres, and the influence of diverse factors including the acidity of the protonic acid catalyst, the substituent structure of benzaldehyde analog, and the polarity of the solvent as well as the swelling property of the solvent for CPS microspheres on the process of synchronously synthesizing and immobilizing porphyrins on CPS microspheres were investigated in depth. The experimental results indicate that via the designed route, the porphyrin-functionalization of CPS microspheres can successfully be realized. For the Kornblum oxidation Reaction, under the optimal Reaction conditions, the conversion of chloromethyl groups can reach 90%. For the Adler Reaction between solid and liquid phases, the fitting protonic acid catalyst is lactic acid, appropriate solvent is a mixture of dimethyl sulfoxide and xylene, and using 4-chlorobenzaldehyde as a benzaldehyde analog reactant in the solution is in favor of the porphyrin-functionalization of CPS microspheres. Under these specific conditions, the immobilized amount of porphyrin can get up to 23.33 mmol/100 g. Copyright © 2011 John Wiley & Sons, Ltd.
Kenta Tanaka - One of the best experts on this subject based on the ideXlab platform.
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A Flow Microreactor Approach to a Highly Efficient Diels–Alder Reaction with an Electrogenerated o-Quinone
Synlett, 2019Co-Authors: Kenta Tanaka, Hirona Yoshizawa, Mahito AtobeAbstract:We have demonstrated a Diels–Alder Reaction of an o-quinone generated in an electrochemical flow microreactor. In the flow microreactor system, 4-tert-butyl-o-benzoquinone was easily electrogenerated from 4-tert-butylpyrocatechol in the absence of chemical oxidants and then rapidly used, without decomposing, in a subsequent Diels–Adler Reaction with various fulvenes to give the desired products efficiently.
