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Vladimir S Moshkin - One of the best experts on this subject based on the ideXlab platform.
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3 cyanochromones in 3 2 cycloadditions with an azomethine ylide derived from sarcosine and formaldehyde a short synthesis of 1 benzopyrano 2 3 c 3 4 c dipyrrolidines
Tetrahedron Letters, 2014Co-Authors: Vyacheslav Ya. Sosnovskikh, Mikhail Yu Kornev, Vladimir S MoshkinAbstract:Abstract Reactions of 3-cyanochromones with sarcosine and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[2,3- c ]pyrrolidines and tetrahydro-1 H -spiro[chromeno[2,3- c ]pyrrol-9,5′-oxazolidine]-9a-carbonitriles, depending on the reactant ratio, as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the double bond and carbonyl group of the chromone system. The latter undergoes demethylenation and recyclization into a novel hexahydrochromeno[2,3- c :3,4- c ′]Dipyrrole tetracyclic system on heating with hydrochloric acid.
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3-Cyanochromones in [3+2] cycloadditions with an azomethine ylide derived from sarcosine and formaldehyde. A short synthesis of 1-benzopyrano[2,3-c:3,4-c′]dipyrrolidines
Tetrahedron Letters, 2014Co-Authors: Vyacheslav Ya. Sosnovskikh, Mikhail Yu Kornev, Vladimir S MoshkinAbstract:Abstract Reactions of 3-cyanochromones with sarcosine and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[2,3- c ]pyrrolidines and tetrahydro-1 H -spiro[chromeno[2,3- c ]pyrrol-9,5′-oxazolidine]-9a-carbonitriles, depending on the reactant ratio, as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the double bond and carbonyl group of the chromone system. The latter undergoes demethylenation and recyclization into a novel hexahydrochromeno[2,3- c :3,4- c ′]Dipyrrole tetracyclic system on heating with hydrochloric acid.
Richard Goddard - One of the best experts on this subject based on the ideXlab platform.
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synthesis and solid state structure of tetrabutylammonium imidazolate Dipyrrole formed by self assembly
European Journal of Organic Chemistry, 2009Co-Authors: Manfred T. Reetz, Martin H Herzog, Richard GoddardAbstract:The reaction of imidazole with an excess of pyrrole in the presence of tetrabutylammonium hydroxide affords, in high yield by a self-assembly process, tetrabutylammonium imidazolate–Dipyrrole, as shown by an X-ray structure analysis. The two pyrroles form hydrogen bonds with the two nitrogen atoms of the imidazole anion, and the tetrabutylammonium counterion also forms hydrogen bonds to the same nitrogen atoms, with the formation of a structurally unique supramolecular compound.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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Synthesis and Solid‐State Structure of Tetrabutylammonium Imidazolate–Dipyrrole Formed by Self Assembly
European Journal of Organic Chemistry, 2009Co-Authors: Manfred T. Reetz, H. Martin Herzog, Richard GoddardAbstract:The reaction of imidazole with an excess of pyrrole in the presence of tetrabutylammonium hydroxide affords, in high yield by a self-assembly process, tetrabutylammonium imidazolate–Dipyrrole, as shown by an X-ray structure analysis. The two pyrroles form hydrogen bonds with the two nitrogen atoms of the imidazole anion, and the tetrabutylammonium counterion also forms hydrogen bonds to the same nitrogen atoms, with the formation of a structurally unique supramolecular compound.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Vyacheslav Ya. Sosnovskikh - One of the best experts on this subject based on the ideXlab platform.
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3 cyanochromones in 3 2 cycloadditions with an azomethine ylide derived from sarcosine and formaldehyde a short synthesis of 1 benzopyrano 2 3 c 3 4 c dipyrrolidines
Tetrahedron Letters, 2014Co-Authors: Vyacheslav Ya. Sosnovskikh, Mikhail Yu Kornev, Vladimir S MoshkinAbstract:Abstract Reactions of 3-cyanochromones with sarcosine and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[2,3- c ]pyrrolidines and tetrahydro-1 H -spiro[chromeno[2,3- c ]pyrrol-9,5′-oxazolidine]-9a-carbonitriles, depending on the reactant ratio, as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the double bond and carbonyl group of the chromone system. The latter undergoes demethylenation and recyclization into a novel hexahydrochromeno[2,3- c :3,4- c ′]Dipyrrole tetracyclic system on heating with hydrochloric acid.
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3-Cyanochromones in [3+2] cycloadditions with an azomethine ylide derived from sarcosine and formaldehyde. A short synthesis of 1-benzopyrano[2,3-c:3,4-c′]dipyrrolidines
Tetrahedron Letters, 2014Co-Authors: Vyacheslav Ya. Sosnovskikh, Mikhail Yu Kornev, Vladimir S MoshkinAbstract:Abstract Reactions of 3-cyanochromones with sarcosine and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[2,3- c ]pyrrolidines and tetrahydro-1 H -spiro[chromeno[2,3- c ]pyrrol-9,5′-oxazolidine]-9a-carbonitriles, depending on the reactant ratio, as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the double bond and carbonyl group of the chromone system. The latter undergoes demethylenation and recyclization into a novel hexahydrochromeno[2,3- c :3,4- c ′]Dipyrrole tetracyclic system on heating with hydrochloric acid.
Robbert Duchateau - One of the best experts on this subject based on the ideXlab platform.
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Effect of cocatalysts and solvent on selective ethylene oligomerization
Organometallics, 2015Co-Authors: Shaneesh Vadake Kulangara, D Daniël Haveman, Bala Vidjayacoumar, Ilia Korobkov, Sandro Gambarotta, Robbert DuchateauAbstract:Ethylene oligomerization activities of chromium catalysts stabilized by different Dipyrrole-based ancillary ligands, [(Ph2C(C4H4N)2)] (2), [Ph2C(C4H4N)(C5H6N)] (3), [(Et)2C(C4H4N)2] (4), and [(C6H5)(C5H4N)C(C4H4N)(C5H6N)] (5), have been investigated using different activation methods, and the results have been compared with the commercial Chevron–Phillips ethylene trimerization system. Upon activation with triethylaluminum (TEA), chromium catalysts stabilized by Dipyrrole-based ligands 2–5 showed a lower activity and selectivity compared to the Chevron–Phillips trimerization system based on 2,5-dimethylpyrrole (1) as the ancillary ligand. However, unprecedented increases in both activity and selectivity have been observed by carrying out the oligomerization in methylcyclohexane using depleted-methylaluminoxane (DMAO) along with triisobutylaluminum (TIBA) (1:2 ratio) as cocatalyst system under mild conditions, even for the Chevron–Phillips system itself. Well-defined chromium complexes, [(Ph2C(C4H3N)2)Cr(C...
Manfred T. Reetz - One of the best experts on this subject based on the ideXlab platform.
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synthesis and solid state structure of tetrabutylammonium imidazolate Dipyrrole formed by self assembly
European Journal of Organic Chemistry, 2009Co-Authors: Manfred T. Reetz, Martin H Herzog, Richard GoddardAbstract:The reaction of imidazole with an excess of pyrrole in the presence of tetrabutylammonium hydroxide affords, in high yield by a self-assembly process, tetrabutylammonium imidazolate–Dipyrrole, as shown by an X-ray structure analysis. The two pyrroles form hydrogen bonds with the two nitrogen atoms of the imidazole anion, and the tetrabutylammonium counterion also forms hydrogen bonds to the same nitrogen atoms, with the formation of a structurally unique supramolecular compound.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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Synthesis and Solid‐State Structure of Tetrabutylammonium Imidazolate–Dipyrrole Formed by Self Assembly
European Journal of Organic Chemistry, 2009Co-Authors: Manfred T. Reetz, H. Martin Herzog, Richard GoddardAbstract:The reaction of imidazole with an excess of pyrrole in the presence of tetrabutylammonium hydroxide affords, in high yield by a self-assembly process, tetrabutylammonium imidazolate–Dipyrrole, as shown by an X-ray structure analysis. The two pyrroles form hydrogen bonds with the two nitrogen atoms of the imidazole anion, and the tetrabutylammonium counterion also forms hydrogen bonds to the same nitrogen atoms, with the formation of a structurally unique supramolecular compound.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)