The Experts below are selected from a list of 37308 Experts worldwide ranked by ideXlab platform
Atsuhiro Osuka - One of the best experts on this subject based on the ideXlab platform.
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synthesis of a tetrabenzotetraaza 8 circulene by a fold in oxidative Fusion Reaction
Angewandte Chemie, 2015Co-Authors: Fengkun Chen, Yong Seok Hong, Soji Shimizu, Dongho Kim, Takayuki Tanaka, Atsuhiro OsukaAbstract:Tetrabenzotetraaza[8]circulene (1) has been synthesized in good yield by a “fold-in” oxidative Fusion Reaction of a 1,2-phenylene-bridged cyclic tetrapyrrole. X-ray diffraction analysis of 1 has revealed a planar square structure with a central cyclooctatetraene (COT) core that shows little alternation of the bond lengths. Despite these structural features, 1 shows aromatic-like character, such as sharp absorption bands, high fluorescence quantum yields (ΦF=0.55 in THF), and a single exponential fluorescence decay with τF=3.8 ns. These observations indicate a dominant contribution of an [8]radialene-like π conjugation and hence aromatic character of the local aromatic segments in 1.
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Synthesis of a Tetrabenzotetraaza[8]circulene by a “Fold‐In” Oxidative Fusion Reaction
Angewandte Chemie International Edition, 2015Co-Authors: Fengkun Chen, Yong Seok Hong, Soji Shimizu, Dongho Kim, Takayuki Tanaka, Atsuhiro OsukaAbstract:Tetrabenzotetraaza[8]circulene (1) has been synthesized in good yield by a “fold-in” oxidative Fusion Reaction of a 1,2-phenylene-bridged cyclic tetrapyrrole. X-ray diffraction analysis of 1 has revealed a planar square structure with a central cyclooctatetraene (COT) core that shows little alternation of the bond lengths. Despite these structural features, 1 shows aromatic-like character, such as sharp absorption bands, high fluorescence quantum yields (ΦF=0.55 in THF), and a single exponential fluorescence decay with τF=3.8 ns. These observations indicate a dominant contribution of an [8]radialene-like π conjugation and hence aromatic character of the local aromatic segments in 1.
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n Fusion Reaction sequence of heptaphyrin 1 1 1 1 1 1 1 singly doubly and quadruply n fused heptaphyrins
Chemistry: A European Journal, 2006Co-Authors: Shohei Saito, Atsuhiro OsukaAbstract:meso-Heptakis(pentafluorophenyl) heptaphyrin(1.1.1.1.1.1.1) (1) was prepared by a stepwise route in 39 % yield and its unique N-Fusion Reaction (NFR) sequence has been revealed; this Reaction leads to singly-, doubly-, and quadruply N-fused heptaphyrins (4, 5, and 6) in good yields. These transformations are facilitated by the inherent conformational distortion of 1 as well as the distorted, folded conformations of N-fused heptaphyrins 4 and 5. The proximate arrangement of the three pyrrole units in 6 allowed for the formation of the tripyrrolylboron(III) complexes 7, 8, and 9 with unique coordination features. Molecules 1, 5, and 9 were structurally characterized by X-ray crystallography. In addition, the boron complexes 7, 8, and 9 displayed weak but distinct fluorescence in the near infrared region.
Michael Decker - One of the best experts on this subject based on the ideXlab platform.
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a simple heterocyclic Fusion Reaction and its application for expeditious syntheses of rutaecarpine and its analogues
ChemInform, 2014Co-Authors: Guozheng Huang, Dominika Roos, Patricia Stadtmueller, Michael DeckerAbstract:Rutaecarpine (IIIa) and various analogs are prepared from anhydrides (I) and (VI) with cyclic imines via a simple heterocyclic Fusion Reaction which involves a spontaneous dehydrogenation.
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a simple heterocyclic Fusion Reaction and its application for expeditious syntheses of rutaecarpine and its analogs
Tetrahedron Letters, 2014Co-Authors: Guozheng Huang, Dominika Roos, Patricia Stadtmuller, Michael DeckerAbstract:Abstract In the search for new inhibitors of cholinesterases, a simple heterocyclic Fusion Reaction of isatoic anhydride 8 and 3,4-dihydroisoquinoline 22 was discovered which involves a spontaneous dehydrogenation upon heating. Applying the Reaction, the bioactive natural alkaloid rutaecarpine and several substituted derivatives out of tryptamines and anthranilic acids or isatoic anhydrides, respectively, can be synthesized without tedious chromatographic purification. This provides simple and fast access to larger amounts of compounds with this privileged structure in medicinal chemistry.
Guozheng Huang - One of the best experts on this subject based on the ideXlab platform.
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a simple heterocyclic Fusion Reaction and its application for expeditious syntheses of rutaecarpine and its analogues
ChemInform, 2014Co-Authors: Guozheng Huang, Dominika Roos, Patricia Stadtmueller, Michael DeckerAbstract:Rutaecarpine (IIIa) and various analogs are prepared from anhydrides (I) and (VI) with cyclic imines via a simple heterocyclic Fusion Reaction which involves a spontaneous dehydrogenation.
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a simple heterocyclic Fusion Reaction and its application for expeditious syntheses of rutaecarpine and its analogs
Tetrahedron Letters, 2014Co-Authors: Guozheng Huang, Dominika Roos, Patricia Stadtmuller, Michael DeckerAbstract:Abstract In the search for new inhibitors of cholinesterases, a simple heterocyclic Fusion Reaction of isatoic anhydride 8 and 3,4-dihydroisoquinoline 22 was discovered which involves a spontaneous dehydrogenation upon heating. Applying the Reaction, the bioactive natural alkaloid rutaecarpine and several substituted derivatives out of tryptamines and anthranilic acids or isatoic anhydrides, respectively, can be synthesized without tedious chromatographic purification. This provides simple and fast access to larger amounts of compounds with this privileged structure in medicinal chemistry.
Abdul Waheed - One of the best experts on this subject based on the ideXlab platform.
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imaging of Fusion Reaction zone in plasma focus
Physics of Plasmas, 1999Co-Authors: M Zakaullah, Ijaz Akhtar, Ghulam Murtaza, Abdul WaheedAbstract:In a low energy (2.3 kJ) Mather-type deuterium plasma focus, neutron and charged particle emission is investigated by using time-resolved neutron detectors and time-integrated charged particle pinhole imaging camera. The time-integrated charged particle pinhole images demonstrate the varying influence of magnetohydrodynamic (MHD) instabilities vis-a-vis filling pressure. The neutron production mechanism at play strongly depends upon the pressure. At lower pressure, the plasma column is highly unstable due to MHD instabilities and the neutron emission is found to be low with fluence anisotropy exceeding 3.5. At optimum pressure (2.5 mbar for this system), an almost stable dense plasma of about 17 mm3 volume is formed about 5 mm away from the anode, with neutron emission at its highest and the fluence anisotropy lowest. At higher pressure, the plasma column is stable, although it moves away from the anode like a jet and may then be called a moving boiler. In this case, the neutron emission is lowered compared to its optimum value and fluence anisotropy is increased. The data suggest beam-target mechanism at low pressure, trapped gyrating particles at optimum pressure and a jetlike moving boiler at higher pressure.In a low energy (2.3 kJ) Mather-type deuterium plasma focus, neutron and charged particle emission is investigated by using time-resolved neutron detectors and time-integrated charged particle pinhole imaging camera. The time-integrated charged particle pinhole images demonstrate the varying influence of magnetohydrodynamic (MHD) instabilities vis-a-vis filling pressure. The neutron production mechanism at play strongly depends upon the pressure. At lower pressure, the plasma column is highly unstable due to MHD instabilities and the neutron emission is found to be low with fluence anisotropy exceeding 3.5. At optimum pressure (2.5 mbar for this system), an almost stable dense plasma of about 17 mm3 volume is formed about 5 mm away from the anode, with neutron emission at its highest and the fluence anisotropy lowest. At higher pressure, the plasma column is stable, although it moves away from the anode like a jet and may then be called a moving boiler. In this case, the neutron emission is lowered compar...
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imaging of Fusion Reaction zone in plasma focus
Physics of Plasmas, 1999Co-Authors: M Zakaullah, Ijaz Akhtar, Ghulam Murtaza, Abdul WaheedAbstract:In a low energy (2.3 kJ) Mather-type deuterium plasma focus,neutron and charged particle emission is investigated by using time-resolved neutrondetectors and time-integrated charged particle pinhole imaging camera. The time-integrated charged particle pinhole images demonstrate the varying influence of magnetohydrodynamic(MHD)instabilities vis-a-vis filling pressure. The neutron production mechanism at play strongly depends upon the pressure. At lower pressure, the plasma column is highly unstable due to MHDinstabilities and the neutron emission is found to be low with fluence anisotropy exceeding 3.5. At optimum pressure (2.5 mbar for this system), an almost stable dense plasma of about 17 mm3 volume is formed about 5 mm away from the anode, with neutron emission at its highest and the fluence anisotropy lowest. At higher pressure, the plasma column is stable, although it moves away from the anode like a jet and may then be called a moving boiler. In this case, the neutron emission is lowered compared to its optimum value and fluence anisotropy is increased. The data suggest beam-target mechanism at low pressure, trapped gyrating particles at optimum pressure and a jetlike moving boiler at higher pressure.
Fengkun Chen - One of the best experts on this subject based on the ideXlab platform.
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synthesis of a tetrabenzotetraaza 8 circulene by a fold in oxidative Fusion Reaction
Angewandte Chemie, 2015Co-Authors: Fengkun Chen, Yong Seok Hong, Soji Shimizu, Dongho Kim, Takayuki Tanaka, Atsuhiro OsukaAbstract:Tetrabenzotetraaza[8]circulene (1) has been synthesized in good yield by a “fold-in” oxidative Fusion Reaction of a 1,2-phenylene-bridged cyclic tetrapyrrole. X-ray diffraction analysis of 1 has revealed a planar square structure with a central cyclooctatetraene (COT) core that shows little alternation of the bond lengths. Despite these structural features, 1 shows aromatic-like character, such as sharp absorption bands, high fluorescence quantum yields (ΦF=0.55 in THF), and a single exponential fluorescence decay with τF=3.8 ns. These observations indicate a dominant contribution of an [8]radialene-like π conjugation and hence aromatic character of the local aromatic segments in 1.
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Synthesis of a Tetrabenzotetraaza[8]circulene by a “Fold‐In” Oxidative Fusion Reaction
Angewandte Chemie International Edition, 2015Co-Authors: Fengkun Chen, Yong Seok Hong, Soji Shimizu, Dongho Kim, Takayuki Tanaka, Atsuhiro OsukaAbstract:Tetrabenzotetraaza[8]circulene (1) has been synthesized in good yield by a “fold-in” oxidative Fusion Reaction of a 1,2-phenylene-bridged cyclic tetrapyrrole. X-ray diffraction analysis of 1 has revealed a planar square structure with a central cyclooctatetraene (COT) core that shows little alternation of the bond lengths. Despite these structural features, 1 shows aromatic-like character, such as sharp absorption bands, high fluorescence quantum yields (ΦF=0.55 in THF), and a single exponential fluorescence decay with τF=3.8 ns. These observations indicate a dominant contribution of an [8]radialene-like π conjugation and hence aromatic character of the local aromatic segments in 1.
