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Jinzhu Chen - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of substituted pyridyl ureas by Selenium Dioxide-catalyzed carbonylation
Applied Catalysis A: General, 2004Co-Authors: Jinzhu ChenAbstract:A series of commercially useful substituted pyridyl ureas have been synthesized via Selenium Dioxide-catalyzed reductive carbonylation of substituted nitrobenzene or substituted nitropyridine with amine as co-reagent and carbon monoxide as carbonyl reagent instead of phosgene in one-pot reaction. The recycling reusability of catalyst was also tested. It was also found that Selenium Dioxide-catalyzed reductive carbonylation of nitroaromatics exhibited reaction-controlled phase-transfer phenomena of the catalyst.
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synthesis of new unsymmetric n n dipyridylurea derivatives by Selenium and Selenium Dioxide catalyzed reductive carbonylation of substituted nitropyridines
Tetrahedron, 2003Co-Authors: Jinzhu Chen, Gang LingAbstract:Abstract Without using phosgene, a series of new unsymmetric N , N ′-dipyridylurea derivatives have been synthesized in moderate to good yields by the one-pot reductive carbonylation of substituted nitropyridines. These reactions utilize Selenium or Selenium Dioxide as the catalyst, aminopyridine derivatives as co-reagents, and carbon monoxide as the carbonyl source.
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synthesis of n phenyl n pyrimidylurea derivatives by Selenium or Selenium Dioxide catalyzed reductive carbonylation of nitroaromatics
European Journal of Organic Chemistry, 2003Co-Authors: Jinzhu Chen, Gang LingAbstract:Forty unsymmetric N-phenyl-N′-pyrimidylurea derivatives were synthesized in moderate-to-good yields by one-pot reductive carbonylation of nitroaromatics using Selenium or Selenium Dioxide as the catalyst, aminopyrimidine derivatives as co-reagents, and carbon monoxide as the carbonyl source. The reaction parameters were investigated, as was the reusability of the catalysts. We found that Selenium- or Selenium Dioxide-catalyzed reductive carbonylation of the nitroaromatics exhibited reaction-controlled phase-transfer phenomena of the catalysts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
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Synthesis of N‐Phenyl‐N′‐pyrimidylurea Derivatives by Selenium‐ or Selenium Dioxide‐Catalyzed Reductive Carbonylation of Nitroaromatics
European Journal of Organic Chemistry, 2003Co-Authors: Jinzhu Chen, Gang LingAbstract:Forty unsymmetric N-phenyl-N′-pyrimidylurea derivatives were synthesized in moderate-to-good yields by one-pot reductive carbonylation of nitroaromatics using Selenium or Selenium Dioxide as the catalyst, aminopyrimidine derivatives as co-reagents, and carbon monoxide as the carbonyl source. The reaction parameters were investigated, as was the reusability of the catalysts. We found that Selenium- or Selenium Dioxide-catalyzed reductive carbonylation of the nitroaromatics exhibited reaction-controlled phase-transfer phenomena of the catalysts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Siegfried R. Waldvogel - One of the best experts on this subject based on the ideXlab platform.
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Facile and Selective Cross-Coupling of Phenols Using Selenium Dioxide
European Journal of Organic Chemistry, 2016Co-Authors: Thomas Quell, Katrin Marie Dyballa, Robert Franke, Nicole Beiser, Siegfried R. WaldvogelAbstract:Nonsymmetric biphenols are important structural motifs in organic chemistry. Therefore, an easy and versatile protocol for oxidative cross-coupling is essential to generate these so-called “privileged ligands”. We developed an efficient and selective oxidative pathway to synthesize 2,2′-biphenols as well as 2,4′- and 4,4′-biphenols. The use of Selenium Dioxide, a stable, powerful, and commercially available oxidizer, in 1,1,1,3,3,3-hexafluoroisopropanol allowed the oxidative coupling of alkyl-, alkoxy-, and halogen-substituted phenols.
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Solvent-Dependent Facile Synthesis of Diaryl Selenides and Biphenols Employing Selenium Dioxide.
ChemInform, 2016Co-Authors: Thomas Quell, Michael Mirion, Dieter Schollmeyer, Katrin Marie Dyballa, Robert Franke, Siegfried R. WaldvogelAbstract:The reaction of phenols (I) with Selenium Dioxide in pyridine leads to diaryl selenides (IIa-d), whilst the reaction in acetic acid gives rise to biphenols (III).
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solvent dependent facile synthesis of diaryl selenides and biphenols employing Selenium Dioxide
ChemistryOpen, 2016Co-Authors: Thomas Quell, Michael Mirion, Dieter Schollmeyer, Katrin Marie Dyballa, Robert Franke, Siegfried R. WaldvogelAbstract:Biphenols are important structure motifs for ligand systems in organic catalysis and are therefore included in the category of so-called "privileged ligands". We have developed a new synthetic pathway to construct these structures by the use of Selenium Dioxide, a stable, powerful, and commercially available oxidizer. Our new, and easy to perform protocol gives rise to biphenols and diaryl selenides depending on the solvent employed. Oxidative treatment of phenols in acetic acid yields the corresponding biphenols, whereas conversion in pyridine results in the preferred formation of diaryl selenides. As a consequence, we were able to isolate a broad scope of novel diaryl selenides, which could act as pincer-like ligands with further applications in organic synthesis or as ligands in transition metal catalysis.
Gang Ling - One of the best experts on this subject based on the ideXlab platform.
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synthesis of new unsymmetric n n dipyridylurea derivatives by Selenium and Selenium Dioxide catalyzed reductive carbonylation of substituted nitropyridines
Tetrahedron, 2003Co-Authors: Jinzhu Chen, Gang LingAbstract:Abstract Without using phosgene, a series of new unsymmetric N , N ′-dipyridylurea derivatives have been synthesized in moderate to good yields by the one-pot reductive carbonylation of substituted nitropyridines. These reactions utilize Selenium or Selenium Dioxide as the catalyst, aminopyridine derivatives as co-reagents, and carbon monoxide as the carbonyl source.
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synthesis of n phenyl n pyrimidylurea derivatives by Selenium or Selenium Dioxide catalyzed reductive carbonylation of nitroaromatics
European Journal of Organic Chemistry, 2003Co-Authors: Jinzhu Chen, Gang LingAbstract:Forty unsymmetric N-phenyl-N′-pyrimidylurea derivatives were synthesized in moderate-to-good yields by one-pot reductive carbonylation of nitroaromatics using Selenium or Selenium Dioxide as the catalyst, aminopyrimidine derivatives as co-reagents, and carbon monoxide as the carbonyl source. The reaction parameters were investigated, as was the reusability of the catalysts. We found that Selenium- or Selenium Dioxide-catalyzed reductive carbonylation of the nitroaromatics exhibited reaction-controlled phase-transfer phenomena of the catalysts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
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Synthesis of N‐Phenyl‐N′‐pyrimidylurea Derivatives by Selenium‐ or Selenium Dioxide‐Catalyzed Reductive Carbonylation of Nitroaromatics
European Journal of Organic Chemistry, 2003Co-Authors: Jinzhu Chen, Gang LingAbstract:Forty unsymmetric N-phenyl-N′-pyrimidylurea derivatives were synthesized in moderate-to-good yields by one-pot reductive carbonylation of nitroaromatics using Selenium or Selenium Dioxide as the catalyst, aminopyrimidine derivatives as co-reagents, and carbon monoxide as the carbonyl source. The reaction parameters were investigated, as was the reusability of the catalysts. We found that Selenium- or Selenium Dioxide-catalyzed reductive carbonylation of the nitroaromatics exhibited reaction-controlled phase-transfer phenomena of the catalysts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Thomas Quell - One of the best experts on this subject based on the ideXlab platform.
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Facile and Selective Cross-Coupling of Phenols Using Selenium Dioxide
European Journal of Organic Chemistry, 2016Co-Authors: Thomas Quell, Katrin Marie Dyballa, Robert Franke, Nicole Beiser, Siegfried R. WaldvogelAbstract:Nonsymmetric biphenols are important structural motifs in organic chemistry. Therefore, an easy and versatile protocol for oxidative cross-coupling is essential to generate these so-called “privileged ligands”. We developed an efficient and selective oxidative pathway to synthesize 2,2′-biphenols as well as 2,4′- and 4,4′-biphenols. The use of Selenium Dioxide, a stable, powerful, and commercially available oxidizer, in 1,1,1,3,3,3-hexafluoroisopropanol allowed the oxidative coupling of alkyl-, alkoxy-, and halogen-substituted phenols.
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Solvent-Dependent Facile Synthesis of Diaryl Selenides and Biphenols Employing Selenium Dioxide.
ChemInform, 2016Co-Authors: Thomas Quell, Michael Mirion, Dieter Schollmeyer, Katrin Marie Dyballa, Robert Franke, Siegfried R. WaldvogelAbstract:The reaction of phenols (I) with Selenium Dioxide in pyridine leads to diaryl selenides (IIa-d), whilst the reaction in acetic acid gives rise to biphenols (III).
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solvent dependent facile synthesis of diaryl selenides and biphenols employing Selenium Dioxide
ChemistryOpen, 2016Co-Authors: Thomas Quell, Michael Mirion, Dieter Schollmeyer, Katrin Marie Dyballa, Robert Franke, Siegfried R. WaldvogelAbstract:Biphenols are important structure motifs for ligand systems in organic catalysis and are therefore included in the category of so-called "privileged ligands". We have developed a new synthetic pathway to construct these structures by the use of Selenium Dioxide, a stable, powerful, and commercially available oxidizer. Our new, and easy to perform protocol gives rise to biphenols and diaryl selenides depending on the solvent employed. Oxidative treatment of phenols in acetic acid yields the corresponding biphenols, whereas conversion in pyridine results in the preferred formation of diaryl selenides. As a consequence, we were able to isolate a broad scope of novel diaryl selenides, which could act as pincer-like ligands with further applications in organic synthesis or as ligands in transition metal catalysis.
W. Smith - One of the best experts on this subject based on the ideXlab platform.
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Raman spectra of Selenium Dioxide at low temperatures
Journal of Raman Spectroscopy, 2000Co-Authors: A. Anderson, Angela Sanders, W. SmithAbstract:Raman spectra of solid Selenium Dioxide at temperatures between 15 K and 295 K are reported. No evidence of a solid state phase transition in this range is found. Small wavenumber shifts and significant sharpening of spectral features are observed at low temperatures, the latter resulting in many more components being resolved, so that the full complement of fundamentals predicted by group theory is detected. Plausible assignments are proposed, based on the puckered chain structure containing both bridging and terminal oxygen atoms. Copyright © 2000 John Wiley & Sons, Ltd.
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Raman Spectra of Selenium Dioxide at High Pressures
Spectroscopy Letters, 2000Co-Authors: Dana Stanila, W. Smith, A. AndersonAbstract:Abstract Raman spectra of Selenium Dioxide at ambient temperature and at pressures up to 10 GPa are reported. There is no evidence of any structural phase transitions in this pressure range, and only minor perturbations of the electronic states are observed. Shifts of normal mode wavenumbers with pressure are used to deduce percentage changes in the principal force constants. Interchain interactions sharply increase with pressure, whereas the stronger interchain forces show smaller increases. the Se-O bonds in side branches slightly weaken as a result of charge transfer to neighbouring bonds. the effects of pressure and temperature on the spectra are briefly compared.