The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Peter Langer - One of the best experts on this subject based on the ideXlab platform.
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one pot cyclization of dilithiated nitriles with isothiocyanates and Epibromohydrin synthesis of 2 cyano 1 hydroxymethyl cyclopropanes and 2 cyanomethylidene 4 hydroxymethyl thiazolidines
Tetrahedron, 2006Co-Authors: Uwe Albrecht, Ilia Freifeld, Helmut Reinke, Peter LangerAbstract:Abstract The cyclization of dilithiated nitriles with Epibromohydrin afforded 2-cyano-1-(hydroxymethyl)cyclopropanes. 2-Cyanomethylidene-(4-hydroxymethyl)thiazolidines were prepared by one-pot cyclization of dilithiated nitriles with isothiocyanates and Epibromohydrin.
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Synthesis of 5-(hydroxymethyl)pyrrolidin-2-ones by cyclization of amide dianions with Epibromohydrin
Synthesis, 2006Co-Authors: Ilia Freifeld, Holger Armbrust, Peter LangerAbstract:The reaction of amide and thioamide dianions with Epibromohydrin resulted in regioselective formation of 5-(hydroxy-methyl)pyrrolidin-2-ones (pyroglutaminols) and -thiones. The cyclization of the dianion of N-(2-tert-butylphenyl)acetamide with Epibromohydrin afforded racemic axially chiral 1-(2-tert-butylphenyl)-5-(hydroxymethyl)pyrrolidin-2-one with high diastereoselectivity.
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one pot cyclizations of dilithiated oximes and hydrazones with Epibromohydrin efficient synthesis of 6 hydroxymethyl 5 6 dihydro 4h 1 2 oxazines and oxazolo 3 4 b pyridazin 7 ones
Journal of Organic Chemistry, 2006Co-Authors: Tuan Thanh Dang, Uwe Albrecht, Katrin Gerwien, Melanie Siebert, Peter LangerAbstract:The one-pot cyclization of dilithiated oximes with Epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with Epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.
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synthesis of 6 hydroxymethyl 5 6 dihydro 4h 1 2 oxazines by one pot cyclization of dilithiated oximes with Epibromohydrin
Tetrahedron Letters, 2005Co-Authors: Uwe Albrecht, Katrin Gerwien, Peter LangerAbstract:6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines were regioselectively prepared by one-pot cyclization of dilithiated oximes with Epibromohydrin.
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synthesis of 2 alkylidene 4 hydroxymethyl thiazolidines by one pot cyclization of dilithiated arylmethylnitriles with isothiocyanates and Epibromohydrin
Synlett, 2004Co-Authors: Uwe Albrecht, Peter LangerAbstract:2-Alkylidene-(4-hydroxymethyl)thiazolidines were regioselectively prepared by one-pot cyclization of dilithiated arylmethylnitriles with isothiocyanates and Epibromohydrin.
Tadatomi Nishikubo - One of the best experts on this subject based on the ideXlab platform.
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One-pot synthesis of poly(cyclic ortho ester)s by the reaction of potassium perfluoroalkanoates with Epibromohydrin using two-step catalysis of quaternary onium salts
Tetrahedron, 1999Co-Authors: Atsushi Kameyama, Nobuyuki Kijima, Hiroyuki Hashikawa, Tadatomi NishikuboAbstract:Abstract One-pot synthesis of poly(cyclic ortho ester)s by the reaction of potassium perfluoroalkanoates with Epibromohydrin (EBH) using quaternary onium salts is described. The reaction of potassium trifluoroacetate (KTFA) with EBH using quaternary onium salts such as tetrabutylphosphonium bromide (TBPB) produces the polymer with five-membered cyclic ortho ester structure in the backbone. This means that quaternary onium salts act as phase-transfer catalysts in the first step and polymerization catalysts in the second step during the reaction.
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synthesis of poly cyclic orthoester s by the one pot reaction of potassium perfluoroalkylcarboxylates with Epibromohydrin using two step catalysis of quaternary onium salts
Polymer Journal, 1995Co-Authors: Atsushi Kameyama, Nobuyuki Kijima, Hiroyuki Hashikawa, Tadatomi NishikuboAbstract:Synthesis of Poly(cyclic orthoester)s by the One-Pot Reaction of Potassium Perfluoroalkylcarboxylates with Epibromohydrin Using Two-Step Catalysis of Quaternary Onium Salts
Roya Jahanshahi - One of the best experts on this subject based on the ideXlab platform.
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cu ii immobilized on guanidinated Epibromohydrin functionalized γ fe2o3 tio2 γ fe2o3 tio2 eg cu ii a highly efficient magnetically separable heterogeneous nanocatalyst for one pot synthesis of highly substituted imidazoles
Applied Organometallic Chemistry, 2018Co-Authors: Mahdi Nejatianfar, Batool Akhlaghinia, Roya JahanshahiAbstract:A simple, efficient and eco-friendly procedure has been developed using Cu(II) immobilized on guanidinated Epibromohydrin-functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-Cu(II)) for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles, via the condensation reactions of various aldehydes with benzil and ammonium acetate or ammonium acetate and amines, under solvent-free conditions. High-resolution transmission electron microscopy analysis of this catalyst clearly affirmed the formation of a γ-Fe2O3 core and a TiO2 shell, with mean sizes of about 10–20 and 5–10 nm, respectively. These data were in very good agreement with X-ray crystallographic measurements (13 and 7 nm). Moreover, magnetization measurements revealed that both γ-Fe2O3@TiO2 and γ-Fe2O3@TiO2-EG-Cu(II) had superparamagnetic behaviour with saturation magnetization of 23.79 and 22.12 emu g−1, respectively. γ-Fe2O3@TiO2-EG-Cu(II) was found to be a green and highly efficient nanocatalyst, which could be easily handled, recovered and reused several times without significant loss of its activity. The scope of the presented methodology is quite broad; a variety of aldehydes as well as amines have been shown to be viable substrates. A mechanism for the cyclocondensation reaction has also been proposed.
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cu ii grafted sba 15 functionalized s methylisothiourea aminated Epibromohydrin sba 15 e smtu cuii a novel and efficient heterogeneous mesoporous catalyst
New Journal of Chemistry, 2017Co-Authors: Roya Jahanshahi, Batool AkhlaghiniaAbstract:Cu(II)-grafted SBA-15 functionalized S-methylisothiourea aminated Epibromohydrin (SBA-15/E-SMTU-CuII) as a novel and efficient, heterogeneous mesoporous catalyst was synthesized and characterized by different techniques, such as FT-IR, BET, small-angle XRD, FE-SEM, TEM, TGA, ICP-OES and CHNS analysis. The as-synthesized catalyst revealed a superior catalytic activity towards the one-pot synthesis of tetrahydropyridine derivatives through the pseudo five-component reactions of aromatic aldehydes, aromatic amines and ethyl/methyl acetoacetate, in ethanol at room temperature. Importantly, the synthesized mesoporous catalyst can be recovered and reused at least ten times without any appreciable loss in its catalytic reactivity. Moreover, a TEM image of the recovered catalyst after ten consecutive runs clearly proved the advantageous durability and stability of the presented catalyst under the applied reaction condition.
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cuii immobilized on guanidinated Epibromohydrin functionalized γ fe2o3 tio2 γ fe2o3 tio2 eg cuii a novel magnetically recyclable heterogeneous nanocatalyst for the green one pot synthesis of 1 4 disubstituted 1 2 3 triazoles through alkyne azide cycl
RSC Advances, 2016Co-Authors: Roya Jahanshahi, Batool AkhlaghiniaAbstract:CuII immobilized on guanidinated Epibromohydrin functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-CuII) as a novel magnetically recyclable heterogeneous catalyst was synthesized and characterized by various techniques such as FT-IR, TGA/DTA, HRTEM, XRD, EDX, VSM, ICP and elemental analysis. The catalyst demonstrated a superior catalytic activity towards the green one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles via the three-component reaction between terminal alkynes, organic bromides, and sodium azide, in water. This method avoids isolation and handling of organic azides, because of their in situ generation. Importantly, the synthesized catalyst was separated easily by using an external magnet and recycled for six runs without appreciable leaching of copper from the surface of the catalyst.
Batool Akhlaghinia - One of the best experts on this subject based on the ideXlab platform.
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cu ii immobilized on guanidinated Epibromohydrin functionalized γ fe2o3 tio2 γ fe2o3 tio2 eg cu ii a highly efficient magnetically separable heterogeneous nanocatalyst for one pot synthesis of highly substituted imidazoles
Applied Organometallic Chemistry, 2018Co-Authors: Mahdi Nejatianfar, Batool Akhlaghinia, Roya JahanshahiAbstract:A simple, efficient and eco-friendly procedure has been developed using Cu(II) immobilized on guanidinated Epibromohydrin-functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-Cu(II)) for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles, via the condensation reactions of various aldehydes with benzil and ammonium acetate or ammonium acetate and amines, under solvent-free conditions. High-resolution transmission electron microscopy analysis of this catalyst clearly affirmed the formation of a γ-Fe2O3 core and a TiO2 shell, with mean sizes of about 10–20 and 5–10 nm, respectively. These data were in very good agreement with X-ray crystallographic measurements (13 and 7 nm). Moreover, magnetization measurements revealed that both γ-Fe2O3@TiO2 and γ-Fe2O3@TiO2-EG-Cu(II) had superparamagnetic behaviour with saturation magnetization of 23.79 and 22.12 emu g−1, respectively. γ-Fe2O3@TiO2-EG-Cu(II) was found to be a green and highly efficient nanocatalyst, which could be easily handled, recovered and reused several times without significant loss of its activity. The scope of the presented methodology is quite broad; a variety of aldehydes as well as amines have been shown to be viable substrates. A mechanism for the cyclocondensation reaction has also been proposed.
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cu ii grafted sba 15 functionalized s methylisothiourea aminated Epibromohydrin sba 15 e smtu cuii a novel and efficient heterogeneous mesoporous catalyst
New Journal of Chemistry, 2017Co-Authors: Roya Jahanshahi, Batool AkhlaghiniaAbstract:Cu(II)-grafted SBA-15 functionalized S-methylisothiourea aminated Epibromohydrin (SBA-15/E-SMTU-CuII) as a novel and efficient, heterogeneous mesoporous catalyst was synthesized and characterized by different techniques, such as FT-IR, BET, small-angle XRD, FE-SEM, TEM, TGA, ICP-OES and CHNS analysis. The as-synthesized catalyst revealed a superior catalytic activity towards the one-pot synthesis of tetrahydropyridine derivatives through the pseudo five-component reactions of aromatic aldehydes, aromatic amines and ethyl/methyl acetoacetate, in ethanol at room temperature. Importantly, the synthesized mesoporous catalyst can be recovered and reused at least ten times without any appreciable loss in its catalytic reactivity. Moreover, a TEM image of the recovered catalyst after ten consecutive runs clearly proved the advantageous durability and stability of the presented catalyst under the applied reaction condition.
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cuii immobilized on guanidinated Epibromohydrin functionalized γ fe2o3 tio2 γ fe2o3 tio2 eg cuii a novel magnetically recyclable heterogeneous nanocatalyst for the green one pot synthesis of 1 4 disubstituted 1 2 3 triazoles through alkyne azide cycl
RSC Advances, 2016Co-Authors: Roya Jahanshahi, Batool AkhlaghiniaAbstract:CuII immobilized on guanidinated Epibromohydrin functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-CuII) as a novel magnetically recyclable heterogeneous catalyst was synthesized and characterized by various techniques such as FT-IR, TGA/DTA, HRTEM, XRD, EDX, VSM, ICP and elemental analysis. The catalyst demonstrated a superior catalytic activity towards the green one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles via the three-component reaction between terminal alkynes, organic bromides, and sodium azide, in water. This method avoids isolation and handling of organic azides, because of their in situ generation. Importantly, the synthesized catalyst was separated easily by using an external magnet and recycled for six runs without appreciable leaching of copper from the surface of the catalyst.
Atsushi Kameyama - One of the best experts on this subject based on the ideXlab platform.
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One-pot synthesis of poly(cyclic ortho ester)s by the reaction of potassium perfluoroalkanoates with Epibromohydrin using two-step catalysis of quaternary onium salts
Tetrahedron, 1999Co-Authors: Atsushi Kameyama, Nobuyuki Kijima, Hiroyuki Hashikawa, Tadatomi NishikuboAbstract:Abstract One-pot synthesis of poly(cyclic ortho ester)s by the reaction of potassium perfluoroalkanoates with Epibromohydrin (EBH) using quaternary onium salts is described. The reaction of potassium trifluoroacetate (KTFA) with EBH using quaternary onium salts such as tetrabutylphosphonium bromide (TBPB) produces the polymer with five-membered cyclic ortho ester structure in the backbone. This means that quaternary onium salts act as phase-transfer catalysts in the first step and polymerization catalysts in the second step during the reaction.
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synthesis of poly cyclic orthoester s by the one pot reaction of potassium perfluoroalkylcarboxylates with Epibromohydrin using two step catalysis of quaternary onium salts
Polymer Journal, 1995Co-Authors: Atsushi Kameyama, Nobuyuki Kijima, Hiroyuki Hashikawa, Tadatomi NishikuboAbstract:Synthesis of Poly(cyclic orthoester)s by the One-Pot Reaction of Potassium Perfluoroalkylcarboxylates with Epibromohydrin Using Two-Step Catalysis of Quaternary Onium Salts