The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Masayuki Shirai - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of benzothiophene free naphthalene over charcoal supported metal catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2007Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Mitsumasa Osada, Masayuki ShiraiAbstract:Abstract Hydrogenation of benzothiophene-free naphthalene was examined over various transition metal (rhodium, ruthenium, palladium, and platinum) catalysts supported on charcoal in supercritical carbon dioxide (scCO 2 ) solvent at low temperature (313 K). Among these, a charcoal-supported rhodium catalyst was found to be the most active, while a charcoal-supported ruthenium catalyst was found to give the highest cis -decahydronaphthalene ( cis -decalin) selectivity. A systematic investigation of hydrogenations of naphthalene and tetrahydronaphthanele (tetralin) in scCO 2 revealed that naphthalene hydrogenation is a consecutive and cis - and trans -decalin were formed via tetralin.
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low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give Trans-Decalin could be prevented.
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Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide
Catalysis Letters, 2006Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Tomoya Inoue, Masayuki ShiraiAbstract:Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis -, trans -Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis -decalin in supercritical carbon dioxide than that in an organic solvent.
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stereoselective hydrogenation of tetralin to cis decalin over a carbon supported rhodium catalyst in supercritical carbon dioxide solvent
Chemistry Letters, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:cis-Decalin was selectively obtained with high cis/trans ratio (83%) over a carbon-supported rhodium catalyst at 333 K under 6 MPa of hydrogen and 15 MPa of carbon dioxide.
Norihito Hiyoshi - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of benzothiophene free naphthalene over charcoal supported metal catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2007Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Mitsumasa Osada, Masayuki ShiraiAbstract:Abstract Hydrogenation of benzothiophene-free naphthalene was examined over various transition metal (rhodium, ruthenium, palladium, and platinum) catalysts supported on charcoal in supercritical carbon dioxide (scCO 2 ) solvent at low temperature (313 K). Among these, a charcoal-supported rhodium catalyst was found to be the most active, while a charcoal-supported ruthenium catalyst was found to give the highest cis -decahydronaphthalene ( cis -decalin) selectivity. A systematic investigation of hydrogenations of naphthalene and tetrahydronaphthanele (tetralin) in scCO 2 revealed that naphthalene hydrogenation is a consecutive and cis - and trans -decalin were formed via tetralin.
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low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give Trans-Decalin could be prevented.
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Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide
Catalysis Letters, 2006Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Tomoya Inoue, Masayuki ShiraiAbstract:Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis -, trans -Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis -decalin in supercritical carbon dioxide than that in an organic solvent.
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stereoselective hydrogenation of tetralin to cis decalin over a carbon supported rhodium catalyst in supercritical carbon dioxide solvent
Chemistry Letters, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:cis-Decalin was selectively obtained with high cis/trans ratio (83%) over a carbon-supported rhodium catalyst at 333 K under 6 MPa of hydrogen and 15 MPa of carbon dioxide.
Chandrashekhar V Rode - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of benzothiophene free naphthalene over charcoal supported metal catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2007Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Mitsumasa Osada, Masayuki ShiraiAbstract:Abstract Hydrogenation of benzothiophene-free naphthalene was examined over various transition metal (rhodium, ruthenium, palladium, and platinum) catalysts supported on charcoal in supercritical carbon dioxide (scCO 2 ) solvent at low temperature (313 K). Among these, a charcoal-supported rhodium catalyst was found to be the most active, while a charcoal-supported ruthenium catalyst was found to give the highest cis -decahydronaphthalene ( cis -decalin) selectivity. A systematic investigation of hydrogenations of naphthalene and tetrahydronaphthanele (tetralin) in scCO 2 revealed that naphthalene hydrogenation is a consecutive and cis - and trans -decalin were formed via tetralin.
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low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give Trans-Decalin could be prevented.
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Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide
Catalysis Letters, 2006Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Tomoya Inoue, Masayuki ShiraiAbstract:Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis -, trans -Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis -decalin in supercritical carbon dioxide than that in an organic solvent.
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stereoselective hydrogenation of tetralin to cis decalin over a carbon supported rhodium catalyst in supercritical carbon dioxide solvent
Chemistry Letters, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:cis-Decalin was selectively obtained with high cis/trans ratio (83%) over a carbon-supported rhodium catalyst at 333 K under 6 MPa of hydrogen and 15 MPa of carbon dioxide.
Osamu Sato - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of benzothiophene free naphthalene over charcoal supported metal catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2007Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Mitsumasa Osada, Masayuki ShiraiAbstract:Abstract Hydrogenation of benzothiophene-free naphthalene was examined over various transition metal (rhodium, ruthenium, palladium, and platinum) catalysts supported on charcoal in supercritical carbon dioxide (scCO 2 ) solvent at low temperature (313 K). Among these, a charcoal-supported rhodium catalyst was found to be the most active, while a charcoal-supported ruthenium catalyst was found to give the highest cis -decahydronaphthalene ( cis -decalin) selectivity. A systematic investigation of hydrogenations of naphthalene and tetrahydronaphthanele (tetralin) in scCO 2 revealed that naphthalene hydrogenation is a consecutive and cis - and trans -decalin were formed via tetralin.
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low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent
Applied Catalysis A-general, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give Trans-Decalin could be prevented.
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Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide
Catalysis Letters, 2006Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Tomoya Inoue, Masayuki ShiraiAbstract:Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis -, trans -Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis -decalin in supercritical carbon dioxide than that in an organic solvent.
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stereoselective hydrogenation of tetralin to cis decalin over a carbon supported rhodium catalyst in supercritical carbon dioxide solvent
Chemistry Letters, 2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:cis-Decalin was selectively obtained with high cis/trans ratio (83%) over a carbon-supported rhodium catalyst at 333 K under 6 MPa of hydrogen and 15 MPa of carbon dioxide.
Roger Bouillon - One of the best experts on this subject based on the ideXlab platform.
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Biological activity and conformational analysis of C20 and C14 epimers of CD-ring modified Trans-Decalin 1α,25-dihydroxyvitamin D analogs ☆
The Journal of Steroid Biochemistry and Molecular Biology, 2004Co-Authors: Pierre J. De Clercq, Yong-jun Chen, Ling-jie Gao, Ibrahim Murad, Annemieke Verstuyf, L Verlinden, C. Verboven, Dirk Van Haver, Maurits Vandewalle, Roger BouillonAbstract:Abstract In the context of our ongoing study of vitamin D structure–function relationships and in an attempt to obtain a better dissociation of their prodifferentiating (HL-60) and/or antiproliferative (MCF-7) activities and their calcemic activity, further 20- epi and 14- epi modifications were made to three trans -decalin CD-ring analogs of 1,25-dihydroxyvitamin D 3 , the hormonally active metabolite of vitamin D 3 , possessing a natural 20 R side chain and featuring additional structural modifications in the seco -B-ring and in the A-ring. Following a previously observed trend and in agreement with the conformational analysis results, all three 20- epi derivatives show substantially lower biological activities, opposite to what is usually observed for analogs having the natural CD-ring. The 14- epi modification ( cis -decalins) has little effect on the biological activity of the ynediene type and the saturated derivative, but results in an approximate 10-fold reduction in activity of the previtamin derivative. No better dissociation of the prodifferentiating and/or antiproliferative activities and the calcemic activity was achieved.
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Biological activity and conformational analysis of C20 and C14 epimers of CD-ring modified Trans-Decalin 1alpha,25-dihydroxyvitamin D analogs.
The Journal of steroid biochemistry and molecular biology, 2004Co-Authors: Pierre J. De Clercq, Yong-jun Chen, Ling-jie Gao, Ibrahim Murad, Annemieke Verstuyf, L Verlinden, C. Verboven, Dirk Van Haver, Maurits Vandewalle, Roger BouillonAbstract:In the context of our ongoing study of vitamin D structure-function relationships and in an attempt to obtain a better dissociation of their prodifferentiating (HL-60) and/or antiproliferative (MCF-7) activities and their calcemic activity, further 20-epi and 14-epi modifications were made to three Trans-Decalin CD-ring analogs of 1,25-dihydroxyvitamin D(3), the hormonally active metabolite of vitamin D(3), possessing a natural 20R side chain and featuring additional structural modifications in the seco-B-ring and in the A-ring. Following a previously observed trend and in agreement with the conformational analysis results, all three 20-epi derivatives show substantially lower biological activities, opposite to what is usually observed for analogs having the natural CD-ring. The 14-epi modification (cis-decalins) has little effect on the biological activity of the ynediene type and the saturated derivative, but results in an approximate 10-fold reduction in activity of the previtamin derivative. No better dissociation of the prodifferentiating and/or antiproliferative activities and the calcemic activity was achieved.
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From the ‡Laboratorium voor Experimentele Geneeskunde en Endocrinologie, Herestraat 49 and ¶Laboratorium voor
2003Co-Authors: Genomic Activity, Roger Bouillon, Analytische Chemie, Medicinale Fysicochemie, Van Evenstraat, B- LeuvenAbstract:Deletion of C19 in the structure of 1,25-dihydroxyvi-tamin D3 [1,25(OH)2D3] does not substantially alter the biological potency but prevents the conversion between the vitamin and the previtamin form. Hence, this modi-fication allows the study of locked previtamin and vita-min forms. The locked 19-nor-1,25(OH)2-previtamin D3 analog (19-nor-previtamin D) had a low biological activity and was a rather weak activator of the genomic signal transduction pathway. 19-Nor-Trans-Decalin-1,25(OH)2-vitamin D3 (19-nor-TD-vitamin D), character-ized by the presence of a trans-fused decalin CD-ring system, was 10-fold more potent than the parent com-pound and was a potent activator of the genomic signal transduction pathway. Surprisingly, the previtamin, 19-nor-Trans-Decalin-1,25(OH)2-previtamin D3 (19-nor-TD
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Synthesis, biological activity, and conformational analysis of CD-ring modified Trans-Decalin 1 alpha,25-dihydroxyvitamin D analogs.
Organic & biomolecular chemistry, 2002Co-Authors: Yong-jun Chen, Roger Bouillon, Ling-jie Gao, Ibrahim Murad, Annemieke Verstuyf, L Verlinden, C. Verboven, Davide Viterbo, Marco Milanesio, Dirk Van HaverAbstract:A novel series of analogs of 1,25-dihydroxyvitamin D3, the hormonally active metabolite of vitamin D3, characterised by the presence of a trans-fused decalin CD-ring system, possesses surprising biological activities in combination with specific structural modifications in the flexible parts of the molecule, when compared with the natural hydrindane derivatives. (1) A large difference in biological activity is observed between the 20-epimeric Trans-Decalin analogs that follows a pattern opposite to what is usually observed for the natural ring size. (2) Several Trans-Decalin analogs that are modified in the seco-B-ring region, including previtamin derivatives, possess a pronounced vitamin D-like activity, whereas the corresponding hydrindane derivatives are inactive. The molecular origin of this behavior is still under study.
