The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Hans-joachim Knölker - One of the best experts on this subject based on the ideXlab platform.
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Total synthesis of glycomaurrol and eustifoline-C by DIBAL-H promoted reductive Ring opening of Pyrano[2,3-c]carbazoles ☆
Tetrahedron, 2015Co-Authors: Ronny Hesse, Arndt W. Schmidt, Hans-joachim KnölkerAbstract:Abstract The palladium-catalyzed construction of the carbazole framework provides an efficient access to 3-hydroxy-6-methylcarbazole (glycozolinine) (5). Regioselective annulation of a Pyran Ring at glycozolinine (5) using either a C5- or a C10-building block leads to the Pyrano[2,3-c]carbazole alkaloids glycomaurin (5,6-Pyranoglycozoline, eustifoline-A) (2) and eustifoline-B (4), respectively. Reductive opening of the Pyran Ring with DIBAL-H in the presence of an additional Lewis acid transformed 2 into the 5-prenyl-substituted carbazole alkaloid glycomaurrol (1) and 4 into the 5-geranyl-substituted homologue eustifoline-C (3).
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synthesis of prenyl and geranyl substituted carbazole alkaloids by dibal h promoted reductive Pyran Ring opening of dialkylPyrano 3 2 a carbazoles
Chemistry: A European Journal, 2014Co-Authors: Ronny Hesse, Olga Kataeva, Arndt W. Schmidt, Hans-joachim KnölkerAbstract:The DIBAL-H promoted reductive Pyran Ring opening of dialkylPyrano[3,2-a]carbazoles provides a direct access to a broad range of prenyl- and geranyl-substituted carbazoles. Formation of a Pyran Ring followed by reductive Ring opening represents a new method for the introduction of prenyl and geranyl groups. In the course of the present work, we achieved the first total syntheses of the following eight carbazole alkaloids: clauraila-E, 7-hydroxyheptaphylline, 7-methoxyheptaphylline, mukoenine-B (clausenatine-A), mukoenine-A (girinimbilol), mahanimbinol (mahanimbilol), euchrestine-A, and isomurrayafoline-B.
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Synthesis of Prenyl‐ and Geranyl‐Substituted Carbazole Alkaloids by DIBAL‐H Promoted Reductive Pyran Ring Opening of DialkylPyrano[3,2‐a]carbazoles
Chemistry: A European Journal, 2014Co-Authors: Ronny Hesse, Olga Kataeva, Arndt W. Schmidt, Hans-joachim KnölkerAbstract:The DIBAL-H promoted reductive Pyran Ring opening of dialkylPyrano[3,2-a]carbazoles provides a direct access to a broad range of prenyl- and geranyl-substituted carbazoles. Formation of a Pyran Ring followed by reductive Ring opening represents a new method for the introduction of prenyl and geranyl groups. In the course of the present work, we achieved the first total syntheses of the following eight carbazole alkaloids: clauraila-E, 7-hydroxyheptaphylline, 7-methoxyheptaphylline, mukoenine-B (clausenatine-A), mukoenine-A (girinimbilol), mahanimbinol (mahanimbilol), euchrestine-A, and isomurrayafoline-B.
V. Sughanya - One of the best experts on this subject based on the ideXlab platform.
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9-(4-Formylphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione
IUCrData, 2018Co-Authors: R. Kalaivanan, V. Sughanya, N. SureshbabuAbstract:In the title compound, C24H26O4, the central 4H-Pyran Ring adopts a flattened boat conformation, with the mean and maximum deviations of the Ring being 0.0582 (6) and 0.1012 (3) A, respectively. The two cyclohexenone Rings on opposite sides of the Pyran Ring each adopt an envelope conformation; the C atom beaRing a dimethyl substituent is the flap atom in each case. The mean planes of the Pyran Ring and the substituent benzene Ring subtend a dihedral angle of 86.45 (2)°. In the crystal, molecules are linked into inversion dimers via pairs of C—H⋯O hydrogen bonds.
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9-(2,4-Dinitrophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione
Acta Crystallographica Section E-structure Reports Online, 2013Co-Authors: N. Sureshbabu, V. SughanyaAbstract:In the title compound, C23H24N2O7, the central 4H-Pyran Ring adopts a flattened boat conformation, whereas both cyclohexenone Rings adopt envelope conformations, the C atom beaRing the dimethyl substituent being the flap atom in each case. The mean and maximum deviation of the Pyran Ring are 0.0379 (4) and 0.0605 (3) A. The mean plane of the Pyran Ring and the dinitrobenzene Ring make a dihedral angle of 85.88 (2)°.
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9-(2,4-Dinitro-phen-yl)-3,3,6,6-tetra-methyl-3,4,5,6,7,9-hexa-hydro-1H-xanthene-1,8(2H)-dione.
Acta crystallographica. Section E Structure reports online, 2013Co-Authors: N. Sureshbabu, V. SughanyaAbstract:In the title compound, C(23)H(24)N(2)O(7), the central 4H-Pyran Ring adopts a flattened boat conformation, whereas both cyclo-hexenone Rings adopt envelope conformations, the C atom beaRing the dimethyl substituent being the flap atom in each case. The mean and maximum deviation of the Pyran Ring are 0.0379 (4) and 0.0605 (3) Å. The mean plane of the Pyran Ring and the dinitro-benzene Ring make a dihedral angle of 85.88 (2)°.
N. Sureshbabu - One of the best experts on this subject based on the ideXlab platform.
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9-(4-Formylphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione
IUCrData, 2018Co-Authors: R. Kalaivanan, V. Sughanya, N. SureshbabuAbstract:In the title compound, C24H26O4, the central 4H-Pyran Ring adopts a flattened boat conformation, with the mean and maximum deviations of the Ring being 0.0582 (6) and 0.1012 (3) A, respectively. The two cyclohexenone Rings on opposite sides of the Pyran Ring each adopt an envelope conformation; the C atom beaRing a dimethyl substituent is the flap atom in each case. The mean planes of the Pyran Ring and the substituent benzene Ring subtend a dihedral angle of 86.45 (2)°. In the crystal, molecules are linked into inversion dimers via pairs of C—H⋯O hydrogen bonds.
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9-(2,4-Dinitrophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione
Acta Crystallographica Section E-structure Reports Online, 2013Co-Authors: N. Sureshbabu, V. SughanyaAbstract:In the title compound, C23H24N2O7, the central 4H-Pyran Ring adopts a flattened boat conformation, whereas both cyclohexenone Rings adopt envelope conformations, the C atom beaRing the dimethyl substituent being the flap atom in each case. The mean and maximum deviation of the Pyran Ring are 0.0379 (4) and 0.0605 (3) A. The mean plane of the Pyran Ring and the dinitrobenzene Ring make a dihedral angle of 85.88 (2)°.
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9-(2,4-Dinitro-phen-yl)-3,3,6,6-tetra-methyl-3,4,5,6,7,9-hexa-hydro-1H-xanthene-1,8(2H)-dione.
Acta crystallographica. Section E Structure reports online, 2013Co-Authors: N. Sureshbabu, V. SughanyaAbstract:In the title compound, C(23)H(24)N(2)O(7), the central 4H-Pyran Ring adopts a flattened boat conformation, whereas both cyclo-hexenone Rings adopt envelope conformations, the C atom beaRing the dimethyl substituent being the flap atom in each case. The mean and maximum deviation of the Pyran Ring are 0.0379 (4) and 0.0605 (3) Å. The mean plane of the Pyran Ring and the dinitro-benzene Ring make a dihedral angle of 85.88 (2)°.
Ronny Hesse - One of the best experts on this subject based on the ideXlab platform.
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Total synthesis of glycomaurrol and eustifoline-C by DIBAL-H promoted reductive Ring opening of Pyrano[2,3-c]carbazoles ☆
Tetrahedron, 2015Co-Authors: Ronny Hesse, Arndt W. Schmidt, Hans-joachim KnölkerAbstract:Abstract The palladium-catalyzed construction of the carbazole framework provides an efficient access to 3-hydroxy-6-methylcarbazole (glycozolinine) (5). Regioselective annulation of a Pyran Ring at glycozolinine (5) using either a C5- or a C10-building block leads to the Pyrano[2,3-c]carbazole alkaloids glycomaurin (5,6-Pyranoglycozoline, eustifoline-A) (2) and eustifoline-B (4), respectively. Reductive opening of the Pyran Ring with DIBAL-H in the presence of an additional Lewis acid transformed 2 into the 5-prenyl-substituted carbazole alkaloid glycomaurrol (1) and 4 into the 5-geranyl-substituted homologue eustifoline-C (3).
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synthesis of prenyl and geranyl substituted carbazole alkaloids by dibal h promoted reductive Pyran Ring opening of dialkylPyrano 3 2 a carbazoles
Chemistry: A European Journal, 2014Co-Authors: Ronny Hesse, Olga Kataeva, Arndt W. Schmidt, Hans-joachim KnölkerAbstract:The DIBAL-H promoted reductive Pyran Ring opening of dialkylPyrano[3,2-a]carbazoles provides a direct access to a broad range of prenyl- and geranyl-substituted carbazoles. Formation of a Pyran Ring followed by reductive Ring opening represents a new method for the introduction of prenyl and geranyl groups. In the course of the present work, we achieved the first total syntheses of the following eight carbazole alkaloids: clauraila-E, 7-hydroxyheptaphylline, 7-methoxyheptaphylline, mukoenine-B (clausenatine-A), mukoenine-A (girinimbilol), mahanimbinol (mahanimbilol), euchrestine-A, and isomurrayafoline-B.
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Synthesis of Prenyl‐ and Geranyl‐Substituted Carbazole Alkaloids by DIBAL‐H Promoted Reductive Pyran Ring Opening of DialkylPyrano[3,2‐a]carbazoles
Chemistry: A European Journal, 2014Co-Authors: Ronny Hesse, Olga Kataeva, Arndt W. Schmidt, Hans-joachim KnölkerAbstract:The DIBAL-H promoted reductive Pyran Ring opening of dialkylPyrano[3,2-a]carbazoles provides a direct access to a broad range of prenyl- and geranyl-substituted carbazoles. Formation of a Pyran Ring followed by reductive Ring opening represents a new method for the introduction of prenyl and geranyl groups. In the course of the present work, we achieved the first total syntheses of the following eight carbazole alkaloids: clauraila-E, 7-hydroxyheptaphylline, 7-methoxyheptaphylline, mukoenine-B (clausenatine-A), mukoenine-A (girinimbilol), mahanimbinol (mahanimbilol), euchrestine-A, and isomurrayafoline-B.
Jaebong Jang - One of the best experts on this subject based on the ideXlab platform.
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total synthesis of deguelin via an iterative Pyran Ring formation strategy
ChemInform, 2015Co-Authors: Hongchan An, Dongjo Chang, Jaebong JangAbstract:Enantioselective synthesis of (-)-deguelin is accomplished via an iterative Pyran-Ring formation approach.
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total synthesis of deguelin via an iterative Pyran Ring formation strategy
Chemical Communications, 2015Co-Authors: Hongchan An, Dongjo Chang, Jaebong JangAbstract:Enantioselective synthesis of (−)-deguelin was accomplished via an iterative Pyran-Ring formation approach. The key features involve the anionic addition of a chromene unit to aryloxy alkyl aldehyde for the double cyclization precursor and iterative Pyran Ring formation by Pd-catalyzed O-arylation and C-arylation, respectively.
