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Mitsuo Sekine - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and properties of nucleoside derivatives acylated by chemically stable 2-(trimethylsilyl)Benzoyl Group.
Bioorganic & Medicinal Chemistry, 2009Co-Authors: Ken Yamada, Haruhiko Taguchi, Akihiro Ohkubo, Kohji Seio, Mitsuo SekineAbstract:We report the synthesis and properties of nucleoside derivatives acylated by 2-(trimethylsilyl)Benzoyl (TMSBz) that proved to be extremely stable under basic conditions when introduced into the 5′-hydroxyl Group of thymidine, the 4-amino Group of deoxycytidine and the 2′-hydroxyl Group of uridine. In particular, 2′-O-TMSBz-uridine could be isolated and was more stable in pyridine, while it isomerized in CH2Cl2 in the presence of Et3N to yield a mixture of the 2′-O- and 3′-O-acylated species.
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Synthesis and properties of oligonucleotides having a chemically stable 2-(trimethylsilyl)Benzoyl Group
Nucleic Acids Symposium Series, 2008Co-Authors: Ken Yamada, Haruhiko Taguchi, Akihiro Ohkubo, Kohji Seio, Mitsuo SekineAbstract:Acyl Groups such as Benzoyl and phenoxyacetyl have been used as a fundamental tool for protection of reactive hydroxyl and amino Groups in chemical synthesis of DNA and RNA oligomers. It is well known that such protecting Groups can be easily cleaved under basic conditions. Here we report 2-(trimethylsilyl)Benzoyl (TMSBz), i.e., a chemically stabilized Benzoyl Group that is substituted with a trimethylsilyl Group at its 2-position. To the best of our knowledge, the TMSBz Group is the most resistant to basic conditions as an acyl Group in nucleic acid chemistry.
Masayasu Nakano - One of the best experts on this subject based on the ideXlab platform.
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Structural Significance of the Benzoyl Group at the C-3′-N Position of Paclitaxel for Nitric Oxide and Tumor Necrosis Factor Production by Murine Macrophages☆☆☆
Biochemical and biophysical research communications, 1998Co-Authors: Teruo Kirikae, Iwao Ojima, Fumiko Kirikae, Yoshikazu Hirai, Masayasu NakanoAbstract:Abstract The antitumor agent paclitaxel (Taxol) mimics the actions of lipopolysaccharide (LPS) on murine macrophages (Mφ). Recently, we have shown that the Benzoyl Group at the C-3′ position of paclitaxel is the most important site to induce nitric oxide (NO) and tumor necrosis factor (TNF) production by C3H/HeN Mφ (Biochem. Biophys. Res. Commun.210, 678–686, 1996). In the present study, synthetic analogs of paclitaxel with replacement of the C-3′-N position were examined for their potencies to induce NO and TNF production by peritoneal Mφ of LPS-responsive C3H/HeN mice and LPS-hyporesponsive C3H/HeJ mice, by human blood cells and human Mφ. In this structure-activity relationship study, we found that (i) thep-substitution of the Benzoyl Group definitely affects the activity to activate C3H/HeN Mφ, (ii) the analogs having a methyl or chloro Group at thep-position exhibit stronger activity than that of paclitaxel, (iii) there is good correlation between NO and TNF production by the Mφ in response to compounds, (iv) the compounds tested do not induce either NO or TNF production by C3H/HeJ Mφ or TNF production by human cells, (v) a previous treatment of C3H/HeN Mφ with the inactive compounds can hardly affect either paclitaxel- or LPS-induced TNF production by the Mφ, (vi) paclitaxel and its analogs marginally affect LPS-induced TNF production by human blood cells, and (vii) there is no correlation between the NO/TNF inducibility to C3H/HeN Mφ and growth inhibitory activity against Mφ-like J774.1 and J7.DEF3 cells.
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structural significance of the Benzoyl Group at the c 3 n position of paclitaxel for nitric oxide and tumor necrosis factor production by murine macrophages
Biochemical and Biophysical Research Communications, 1998Co-Authors: Teruo Kirikae, Iwao Ojima, Fumiko Kirikae, Yoshikazu Hirai, Masayasu NakanoAbstract:Abstract The antitumor agent paclitaxel (Taxol) mimics the actions of lipopolysaccharide (LPS) on murine macrophages (Mφ). Recently, we have shown that the Benzoyl Group at the C-3′ position of paclitaxel is the most important site to induce nitric oxide (NO) and tumor necrosis factor (TNF) production by C3H/HeN Mφ (Biochem. Biophys. Res. Commun.210, 678–686, 1996). In the present study, synthetic analogs of paclitaxel with replacement of the C-3′-N position were examined for their potencies to induce NO and TNF production by peritoneal Mφ of LPS-responsive C3H/HeN mice and LPS-hyporesponsive C3H/HeJ mice, by human blood cells and human Mφ. In this structure-activity relationship study, we found that (i) thep-substitution of the Benzoyl Group definitely affects the activity to activate C3H/HeN Mφ, (ii) the analogs having a methyl or chloro Group at thep-position exhibit stronger activity than that of paclitaxel, (iii) there is good correlation between NO and TNF production by the Mφ in response to compounds, (iv) the compounds tested do not induce either NO or TNF production by C3H/HeJ Mφ or TNF production by human cells, (v) a previous treatment of C3H/HeN Mφ with the inactive compounds can hardly affect either paclitaxel- or LPS-induced TNF production by the Mφ, (vi) paclitaxel and its analogs marginally affect LPS-induced TNF production by human blood cells, and (vii) there is no correlation between the NO/TNF inducibility to C3H/HeN Mφ and growth inhibitory activity against Mφ-like J774.1 and J7.DEF3 cells.
Ken Yamada - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and properties of nucleoside derivatives acylated by chemically stable 2-(trimethylsilyl)Benzoyl Group.
Bioorganic & Medicinal Chemistry, 2009Co-Authors: Ken Yamada, Haruhiko Taguchi, Akihiro Ohkubo, Kohji Seio, Mitsuo SekineAbstract:We report the synthesis and properties of nucleoside derivatives acylated by 2-(trimethylsilyl)Benzoyl (TMSBz) that proved to be extremely stable under basic conditions when introduced into the 5′-hydroxyl Group of thymidine, the 4-amino Group of deoxycytidine and the 2′-hydroxyl Group of uridine. In particular, 2′-O-TMSBz-uridine could be isolated and was more stable in pyridine, while it isomerized in CH2Cl2 in the presence of Et3N to yield a mixture of the 2′-O- and 3′-O-acylated species.
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Synthesis and properties of oligonucleotides having a chemically stable 2-(trimethylsilyl)Benzoyl Group
Nucleic Acids Symposium Series, 2008Co-Authors: Ken Yamada, Haruhiko Taguchi, Akihiro Ohkubo, Kohji Seio, Mitsuo SekineAbstract:Acyl Groups such as Benzoyl and phenoxyacetyl have been used as a fundamental tool for protection of reactive hydroxyl and amino Groups in chemical synthesis of DNA and RNA oligomers. It is well known that such protecting Groups can be easily cleaved under basic conditions. Here we report 2-(trimethylsilyl)Benzoyl (TMSBz), i.e., a chemically stabilized Benzoyl Group that is substituted with a trimethylsilyl Group at its 2-position. To the best of our knowledge, the TMSBz Group is the most resistant to basic conditions as an acyl Group in nucleic acid chemistry.
Michela Begala - One of the best experts on this subject based on the ideXlab platform.
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Unexpected migration of a Benzoyl Group in the intramolecular Wittig reaction of o-acyloxybenzylidenephosphoranes with Benzoyl chlorides: One-pot synthesis of isomeric 3-Benzoyl-2-phenylbenzofurans
Tetrahedron Letters, 2020Co-Authors: Michela Begala, Michele Mancinelli, Giovanna DeloguAbstract:Abstract The reaction of o-acyloxybenzylidenetriphenylphosphoranes with substituted Benzoyl chlorides in an aprotic solvent led, together with the expected 2-phenylbenzofuran, to isomeric 3-Benzoyl-2-phenylbenzofuran derivatives. This result formally corresponds to intramolecular migration of the Benzoyl Group from the ortho oxygen atom to the ylide carbanion via cyclization and ring opening of the starting o-acyloxybenzylidenetriphenylphosphoranes.
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Unexpected migration of Benzoyl Group in the synthesis of 3-Benzoyl-2-phenylbenzofurans under Wittig conditions
Proceedings, 2018Co-Authors: Giovanna Delogu, Michela BegalaAbstract:3-Aroyl[b]benzofurans represent the structural cores of a large number of bioactive molecules in current pharmaceutical use or development. As a result, numerous approaches towards the synthesis of 3-acylbenzofurans have been disclosed in the literatura. The Wittig reaction, is an easy procedure to the benzofuran ring system. In a previous paper Hercouet and Le Corre reported that the intramolecular condensation of o-acyloxybenzylidenetriphenylphosphoranes leads to the benzofuran in aprotic medium (toluene) or to acylated product in protic medium (t-BuOH). We recently found that the reaction of the triphenylphosphonium salt and aroyl chlorides leads together with the expected benzofurans, also to 3-Benzoyl-2-phenylbenzo[b]furans via ylide acylation under Wittig conditions. We hypothesised that the key intermediate that leads to the 3-Benzoyl derivatives was the o-[(Benzoyloxy)benzyl]-triphenyl-phosphoranes. It was therefore prepared starting from o-cresol, and reacted with Benzoyl chloride using Et3N in aprotic solvent i.e. toluene. In contrast with Hercouet and Le Corre findings, we obtained the 3-Benzoyl derivatives, thus confirming our hypothesis. However, when the o-(Benzoyloxy)benzyl)-triphenyl-phosphonium salt was reacted with 4-nitroBenzoyl chloride, we unexpectedly observed the formation of two 3-acyl isomers, thus suggesting that the regioselective Benzoyl Group migration occurred in some extent. Our results are of considerable interest not only because they get insights into the reactivity of o-acyloxybenzylidenetriphenylphosphoranes, but also because they allowed to discover a versatile and general approach to functionalized 3-Benzoyl-2-phenylbenzo[b]furans.
Giovanna Delogu - One of the best experts on this subject based on the ideXlab platform.
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Unexpected migration of a Benzoyl Group in the intramolecular Wittig reaction of o-acyloxybenzylidenephosphoranes with Benzoyl chlorides: One-pot synthesis of isomeric 3-Benzoyl-2-phenylbenzofurans
Tetrahedron Letters, 2020Co-Authors: Michela Begala, Michele Mancinelli, Giovanna DeloguAbstract:Abstract The reaction of o-acyloxybenzylidenetriphenylphosphoranes with substituted Benzoyl chlorides in an aprotic solvent led, together with the expected 2-phenylbenzofuran, to isomeric 3-Benzoyl-2-phenylbenzofuran derivatives. This result formally corresponds to intramolecular migration of the Benzoyl Group from the ortho oxygen atom to the ylide carbanion via cyclization and ring opening of the starting o-acyloxybenzylidenetriphenylphosphoranes.
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Unexpected migration of Benzoyl Group in the synthesis of 3-Benzoyl-2-phenylbenzofurans under Wittig conditions
Proceedings, 2018Co-Authors: Giovanna Delogu, Michela BegalaAbstract:3-Aroyl[b]benzofurans represent the structural cores of a large number of bioactive molecules in current pharmaceutical use or development. As a result, numerous approaches towards the synthesis of 3-acylbenzofurans have been disclosed in the literatura. The Wittig reaction, is an easy procedure to the benzofuran ring system. In a previous paper Hercouet and Le Corre reported that the intramolecular condensation of o-acyloxybenzylidenetriphenylphosphoranes leads to the benzofuran in aprotic medium (toluene) or to acylated product in protic medium (t-BuOH). We recently found that the reaction of the triphenylphosphonium salt and aroyl chlorides leads together with the expected benzofurans, also to 3-Benzoyl-2-phenylbenzo[b]furans via ylide acylation under Wittig conditions. We hypothesised that the key intermediate that leads to the 3-Benzoyl derivatives was the o-[(Benzoyloxy)benzyl]-triphenyl-phosphoranes. It was therefore prepared starting from o-cresol, and reacted with Benzoyl chloride using Et3N in aprotic solvent i.e. toluene. In contrast with Hercouet and Le Corre findings, we obtained the 3-Benzoyl derivatives, thus confirming our hypothesis. However, when the o-(Benzoyloxy)benzyl)-triphenyl-phosphonium salt was reacted with 4-nitroBenzoyl chloride, we unexpectedly observed the formation of two 3-acyl isomers, thus suggesting that the regioselective Benzoyl Group migration occurred in some extent. Our results are of considerable interest not only because they get insights into the reactivity of o-acyloxybenzylidenetriphenylphosphoranes, but also because they allowed to discover a versatile and general approach to functionalized 3-Benzoyl-2-phenylbenzo[b]furans.