九州大学 研究者情報
論文一覧
秋田 健行(あきた たけゆき) データ更新日:2019.08.22

助教 /  薬学研究院 創薬科学部門 生体分子情報学講座


原著論文
1. Manabu Nakazono, Shinkoh Nanbu, Takeyuki Akita, Kenji Hamase, Synthesis, chemiluminescence, and application of 2,4-disubstituted phenyl 10-methyl-10λ4-acridine-9-carboxylates, Dyes and Pigments, 10.1016/j.dyepig.2019.107628, 170, 2019.11, [URL], 2,4-Disubstituted phenyl 10-methyl-10λ4-acridine-9-carboxylate derivatives were synthesized and the chemiluminescence of each was measured at pH 6–9. The introduction of electron-withdrawing groups at 2,4-positions in the phenyl moiety intensified chemiluminescence. 2,4-(Dimethoxycarbonyl)phenyl 10-methyl-10λ4-acridine-9-carboxylate trifluoromethanesulfonate salt produced long-lasting chemiluminescence emission, showed maximum chemiluminescence intensities at pH 8 and was used in simple chemiluminescence assays of hydrogen peroxide and choline under neutral conditions. The linear calibration range and detection limit of choline at pH 8 were 0.1–1000 μM and 0.01 μM, respectively..
2. Chin-Ling HSIEH, Po-Yeh LIN, Takeyuki AKITA, Masashi MITA, Tomomi IDE, Jen-Ai LEE, Kenji HAMASE, Development of a three-dimensional HPLC system for the simultaneous determination of lactate and 3-hydroxybutyrate enantiomers in mammalian urine, Chromatography, 10.15583/jpchrom.2018.021, 25-32, 40, 25-32 (2019), 2019.01.
3. Chiharu Ishii, Takeyuki Akita, Masashi Mita, Tomomi Ide, Kenji Hamase, Development of an online two-dimensional high-performance liquid chromatographic system in combination with tandem mass spectrometric detection for enantiomeric analysis of free amino acids in human physiological fluid, Journal of Chromatography A, 10.1016/j.chroma.2018.07.076, 1570, 91-98, 2018.10, [URL], An automated two-dimensional HPLC-MS/MS system was designed and developed for the highly selective determination of trace levels of D-amino acids. As the targets, frequently observed ones in mammalian physiological fluids, Ala, Asp, Glu, Leu, Pro and Ser, were selected because these D-amino acids are the potential biomarkers for the early and sensitive diagnoses of various diseases. The target analytes were derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), then isolated by a reversed-phase column in the first dimension. The NBD-amino acid fractions were automatically collected into the multi-loop device, and introduced into the enantioselective column in the second dimension to separate the D- and L-forms followed by detection by an MS/MS. The obtained resolution values of the enantiomers were 1.87–5.17 and the calibration lines, precision and accuracy were practically sufficient. By using the present 2D HPLC-MS/MS system, trace levels of D-amino acids in complex biological matrices were determined without disturbance by the intrinsic interfering compounds, and successfully applied to the analysis of the human clinical samples (plasma and urine)..
4. Aogu FURUSHO, Reiko KOGA, Takeyuki AKITA, Yurika MIYOSHI, Masashi MITA, Kenji HAMASE, Development of a highly-sensitive two-dimensional HPLC system with narrowbore reversed-phase and microbore enantioselective columns and application to the chiral amino acid analysis of the mammalian brain, Chromatography, 10.15583/jpchrom.2018.007, 39, 83-90, 2018.04.
5. Nutchaya SEREEKITTIKUL, Reiko KOGA, Takeyuki AKITA, Aogu FURUSHO, Roland REISCHL, Masashi MITA, Akira FUJII, Kazunori HASHIGUCHI, Masanobu NAGANO, Wolfgang LINDNER, Kenji HAMASE, Multi-dimensional HPLC analysis of serine containing chiral dipeptides in Japanese traditional amber rice vinegar, Chromatography, 10.15583/jpchrom.2018.002, 39, 59-66, 2018.03.
6. Chin-Ling Hsieh, Aogu Furusho, Takeyuki Akita, Masashi Mita, Tomomi Ide., Jen-Ai Lee, Kenji Hamase, Enantioselective and simultaneous determination of lactate and 3-hydroxybutyrate in human plasma and urine using a narrowbore online two-dimensional HPLC system, Journal of Separation Science, 10.1002/jssc.201701283, 41, 1298-1306, 2018.01.
7. Naoto Hayashi, Akifumi Kanda, Taku Kamoto, Hiroyuki Higuchi, Takeyuki Akita, Effect of aryl substituents on intramolecular cyclization of 2,2′-biphenoquinones, Heterocycles, 10.3987/COM-08-S(D)57, 79, C, 865-872, 2009.01, [URL], Effect of aryl substituents on intramolecular cyclizations of 3,3′,5,5′-tetraaryl-2,2′-biphenoquinones (Ar = phenyl (la) and 4-methoxyphenyl (1b)) has been studied. In benzene, 1a gave 2,4,6,8-tetraphenyldibenzofuran-1-ol (10) gradually as a main product, indicating the phenyl substituents preferred to stabilize the intermediate by derealization of the negative charge rather than that of the positive one. In contrast, the reaction of 1b occurred spontaneously in order to give a complex mixture, which should be due to 4-methoxyphenyl substituent at the 3 position..
8. Junzo Hirano, Kenji Hamase, Takeyuki Akita, Kiyoshi Zaitsu, Structural and photophysical properties of novel dual fluorescent compounds, 1-aryl-substituted 6-methoxy-4-quinolones, Luminescence, 10.1002/bio.1044, 23, 5, 350-355, 2008.10, [URL], Dual fluorescent compounds are useful platforms for the development of ratiometric probes and sensors. We have developed a new series of dual fluorescent compounds, 1-aryl-substituted 6-methoxy-4-quinolones, and investigated their structural and photophysical properties. The X-ray crystallographic analysis and ab initio quantum chemical calculations revealed that the developed compounds exhibited 60-75° twisted structures. The dual fluorescence of the compounds were observed in polar solvents, and the ratiometric fluorescence responses to alterations in the acidity and temperature were obtained..
9. Takeyuki Akita, Noboru Koga, Magnetic properties of dendritic polycarbenes substituted by bulky peripheral groups, Polyhedron, 10.1016/j.poly.2005.03.067, 24, 16-17, 2321-2325, 2005.11, [URL], As photo-reactive precursors of high-spin organic compounds sterically separated from surroundings by bulky peripheral groups, diphenyldiazomethane derivatives substituted by tetrakis{3,5-bis(benzyloxy)benzyloxy} groups 1, by tetrakis[3,5-bis{3′,5′-bis(benzyloxy)benzyloxy}bezyloxy] groups 2, and nonakisdiazo compound associated with ferromagnetic spin couplers substituted by dodecakis{3,5-bis(benzyloxy)benzyloxy} groups 3, were prepared and their magnetic properties after irradiation in their own condensed films were investigated. Field dependences of magnetization and temperature dependences of χT value after irradiation of 1 and 2 clearly exhibited that spin centers i.e., diphenylcarbene parts of 1 and 2 were magnetically isolated from surrounding molecules each other by steric hindrance of the peripheral bulk substituents even in the neat films. In the case of 3, some part of molecules interacted antiferromagnetically with neighboring molecules but a fatal strong antiferromagnetic interaction was also avoided..
10. Junzo Hirano, Kenji Hamase, Takeyuki Akita, Kiyoshi Zaitsu, Crystal structure of 6-methoxy-4-quinolone, C10H9NO2·2H2O, Analytical Sciences: X-ray Structure Analysis Online, 10.2116/analscix.21.x45, 21, 3, x45, 2005.01, [URL], The title compound, 6-methoxy-4-quinolone (3), was synthesized by the oxidation of 5-methoxyindole-3-acetic acid (2), and its crystal structure was determined by X-ray diffraction analysis. The compound crystallized in the monoclinic system, space group P21/n, with cell parameters of a = 4.547(2)Å, b = 16.328(8)Å, c = 13.731(4)Å, β = 92.38(2)°, and Z = 4. The final residual factor was 0.064. 2005.
11. Junzo Hirano, Kenji Hamase, Takeyuki Akita, Kiyoshi Zaitsu, Crystal structure of N-[(6-methoxy-4-oxo-1,4-dihydroquinolin-3-yl) methyl]-2,2-dimethylpropanamide, Analytical Sciences: X-ray Structure Analysis Online, 10.2116/analscix.20.x115, 20, 3, x115-x116, 2004.01, [URL], The crystal structure of N-[(6-methoxy-4-oxo-1,4-dihydroquinolin-3-yl)methyl]-2,2-dimethylpropanamide (2) was determined by X-ray diffraction analysis. The compound crystallized in the triclinic system, space group P1, with cell parameters of a = 7.829(3)Å, b = 8.995(4)Å, c = 10.646(5)Å, α = 85.86(2)o, β = 86.99(1)o, γ = 88.00(2)o, and Z = 2. The structure was refined by full-matrix least-squares to final values of R1 = 0.049 and wR2 = 0.103. The intermolecular hydrogen bonds of the type N-H···O were observed in the structure. 2004.
12. Jingping Zhang, Madoka Suehiro, Akira Sakane, Satoru Karasawa, Takeyuki Akita, Noboru Koga, Theoretical study on the exchange interaction between metal ion and organic radical through pyridine, bipyridine and terpyridine ligands, Molecular Crystals and Liquid Crystals, 10.1080/10587250210747, 376, 431-436, 2002.12, [URL], Ab initio total energy calculations with the DFT framework based on the geometries obtained by X-ray data were carried out for five complexes composed by copper(II) ion and organic radicals (eg. aminoxyl and carbene) through pyridine, bipyridine and terpyridine rings. It was found that the copper(II) complex having radical substituted at 4-position of aromatic ligand favors ferromagnetic coupling between organic radical and paramagnetic copper(II) ion..
13. Takeyuki Akita, Noboru Koga, Magnetic properties after irradiation of poly(m-phenyleneethynylene) having diazo and nitronylnitroxide groups and its model compounds, Polyhedron, 10.1016/S0277-5387(01)00638-6, 20, 11-14, 1475-1477, 2001.05, [URL], In order to achieve a pure organic high-spin molecule, poly(m-phenyleneethynylene) derivative 1 having diazo groups and nitronyl nitroxide moieties alternately were designed. Its three model compounds, diphenylacetylene derivative 2, bis(phenylethynyl)benzene derivative 3, and oligomeric compound 4 having partial structure of 1 have been prepared by the coupling reaction of ethynyl derivatives of phenylnitronylnitroxide and iodo derivatives of diphenyldiazomethane. Field dependence of magnetization after irradiation of 2 and 3 in frozen solutions suggested that the photo-generated species have quartet and quintet ground states with J/kB values of + 1.75 and + 1.09 K, respectively. However, spin interaction between carbene and nitronylnitroxide through 3,3-diphenylacetylene moiety is not strong enough to form high-spin chain having long correlation length for 4..
14. Y. Pontillon, Takeyuki Akita, A. Grand, K. Kobayashi, E. Lelievre-Berna, J. Pecaut, E. Ressouche, J. Schweizer, Erratum
Experimental and theoretical spin density in a ferromagnetic molecular complex presenting interheteromolecular hydrogen bonds (Journal of American Chemical Society (1999) 121 (10126-10133)), Journal of the American Chemical Society, 121, 47, 1999.12.
15. Yves Pontillon, Takeyuki Akita, Andre Grand, Keiji Kobayashi, Eddy Lelievre-Berna, Jacques Pécaut, Eric Ressouche, Jacques Schweizer, Experimental and theoretical spin density in a ferromagnetic molecular complex presenting interheteromolecular hydrogen bonds, Journal of the American Chemical Society, 10.1021/ja991042u, 121, 43, 10126-10133, 1999.11, [URL], The association of phenylboronic acid (no unpaired electron, compound 1) with the free radical phenyl nitronyl nitroxide (PNN, S = 1/2 , compound 2) constitutes an interheteromolecular hydrogen bonding system displaying ferromagnetic intermolecular interactions. We have investigated its spin density distribution to visualize the pathway of these magnetic interactions. This complex crystallizes at room temperature in the monoclinic space group P21/n. The unit cell includes one pair (1 + 2). The molecule (1) bridges two radicals (2) by hydrogen bonds OH···ON: the two different hydrogen bond lengths are quite similar (1.95 and 1.92 Å). Infinite chains of this run along the b-axis. In this structure the methyl groups of the PNN are randomly distributed in two different configurations. Below T = 220 K the compound undergoes a crystallographic phase transition due to the ordering of these methyl groups. We have determined the low-temperature structure using both X- ray and neutron diffraction. The new space group is P1̄. The global structure is preserved and infinite chains still run along the b-axis, but the unit cell now comprises two different pairs (1 + 2) instead of one, with four different hydrogen bond OH···ON distances: 1.96 and 1.84 Å for the first pair, 1.96 and 1.91 Å for the second pair. The spin density of this complex was measured at T = 1.8 K (H = 4.6 T) by polarized neutron diffraction. The data were treated using both maximum entropy approach and wave function modeling. As in the isolated PNN, the main part of the spin density is located on the O-N-C-N-O fragment of each radical in the unit cell. However, compared to the isolated case, a significant difference exists: a large unbalance is observed between the two oxygen atoms of each radical. Moreover, a positive contribution is found on the two hydrogen atoms involved on the OH···ON hydrogen bonds of each phenylboronic acid molecule. The stronger contribution corresponds to the longer hydrogen bonds. On the radical the stronger reduction is observed on the oxygen atoms involved in the shorter hydrogen bonds. The experimental results are compared to those obtained by density functional theory (DFT) calculations: on the whole, the experimental effects have been reproduced. However, if there is a good qualitative agreement, from the quantitative point of view, the DFT results are still very far from the experimental ones..
16. Yves Pontillon, Takeyuki Akita, Andre Grand, Keiji Kobayashi, Eddy Lelievre-Berna, Jacques Pécaut, Eric Ressouche, Jacques Schweizer, Experimental and Theoretical Spin Density in a Ferromagnetic Molecular Complex, Molecular Crystals and Liquid Crystals, 10.1080/10587259908023319, 334, 211-220, 1999.01, [URL], The association of phenylboronic acid (no unpaired electron) with the free radical phenyl nitronyl nitroxide (S = 1/2) constitutes an inter-heteromolecular hydrogen bonding system presenting ferromagnetic intermolecular interactions. We have investigated its spin density distribution in order to visualize the pathway of these magnetic interactions. The spin density of this complex was measured by polarized neutron diffraction. The data were treated using both direct and indirect methods. As in the isolated PNN, the main part of the spin density is located on the O-N-C-N-O fragment of the PNN radical. But, with the PNNB, the global spin density distribution give evidences that the phenylboronic acid constitutes a spin transmission path between PNN radicals via hydrogen bonds. The experimental results are compared to those obtained by density functional theory calculations..
17. Satoru Karasawa, Yoko Sano, Takeyuki Akita, Noboru Koga, Tetsuji Itoh, Hiizu Iwamura, Pierre Rabu, Marc Drillon, Photochemical formation of ferrimagnetic chains from a pair of polymeric complexes made of octahedral bis(hexafluoroacetylacetonato)manganese(II) with diazodi(4-pyridyl)methane in the cis and trans configurations as repeating units, Journal of the American Chemical Society, 10.1021/ja981293n, 120, 39, 10080-10087, 1998.10, [URL], Two kinds of 1:1 manganese complexes a and b of bis(hexafluoroacetylacetonato)manganese(II) coordinated with diazodi(4- pyridyl)methane (1) were prepared. Complexes a and b crystallize in the orthorhombic space group Pbca and in monoclinic C2/c, respectively. Two pyridyl nitrogen atoms from two different molecules of 1 are coordinated in the cis and trans configurations to the manganese ion to form helical and zigzag infinite chains of octahedral manganese complexes in complexes a and b, respectively. The magnetic susceptibilities (χmol) of both crystals before and after irradiation were measured on a SQUID susceptometer and revealed χ(mol)T vs T plots characteristic of ferrimagnetic chains after irradiation for 97 h; interaction between the manganese(II) ion and the photogenerated carbene is antiferromagnetic in both complexes. The antiferromagnetic exchange coupling parameters (J) in the photolyzate of complex a and b were estimated by a theoretical treatment through a procedure of extrapolation by using small rings to be J/k(B) = -34.8 ± 0.8 and -24.4 ± 0.5 K, respectively. Maximum χ(mol)T values of 210 at 5 K for cis- and 246 emu·K·mol-1 at 1.9 K for trans complexes correspond to correlation lengths of 186 and 218 manganese-carbene S = 3/2 units, respectively..
18. Takeyuki Akita, Keiji Kobayashi, Intermolecular spin-coupler
Ferromagnetic spin interactions through hydrogen bond in the complexes of arylboronic acids with aryl nitronyl nitroxides, Molecular Crystals and Liquid Crystals, 10.1080/10587259708044574, 306, 257-264, 1997.01, [URL], Two crystalline complexes, the complex of p-fluorophenylboronic acid with phenyl nitronyl nitroxide (2) and the complex of p-nitrophenylboronic acid with p-dimethylaminophenyl nitronyl nitroxide (3), were prepared. Both of those complexes as well as the complex of phenylboronic acid with phenyl nitronyl nitroxide (1) exhibit ferromagnetic spin interactions (1: J/kB=+0.65 K, 2: J/kB=+0.58 K, 3: J/kB=+1.35 K). The results are discussed based on the X-ray crystal structure..
19. Takeyuki Akita, Keiji Kobayashi, Magnetic properties of nitronyl nitroxide radicals substituted in phenylboronic acid
The BOH⋯O hydrogen bond as a constituent unit of a one-dimensional suprastructure exhibiting a ferromagnetic spin interaction, Advanced Materials, 10.1002/adma.19970090414, 9, 4, 346-349, 1997.01, [URL].
20. Junpei Fujita, Yoshihisa Matsuoka, Kenji Matsuo, Masakazu Tanaka, Takeyuki Akita, Noboru Koga, Hizu Iwamura, Molecular structure and magnetic properties of N,N-bis {4-methoxy-3,5-bis(N-tert-butyl-N-oxyamino)phenyl} aminoxyl. An approach to a stable and high-spin pentaradical, Chemical Communications, 10.1039/a704160h, 24, 2393-2394, 1997.01, [URL], A stable pentaradical, N,N-bis(4-methoxy-3,5-bis(N-tert-butyl-N-oxyamino)phenyl)]aminoxyl, is prepared and its ground state determined to be a sextet (S = 5/2) by SQUID magnetization measurements of the pentaradical diluted in poly(vinyl chloride) matrix..
21. Takeyuki Akita, Yasuhiro Mazaki, Keiji Kobayashi, Ferromagnetic spin interaction through the interheteromolecular hydrogen bond
A 1:1 crystalline complex of phenylboronic acid and phenyl nttronyl nitroxide, Molecular Crystals and Liquid Crystals, 278-279, 39-45, 1996.12, A crystalline molecular complex derived from phenyl nitronyl nitroxide (1) and phenyl boronic acid (2) exhibits a ferromagnetic spin interaction (J= +0.65 K) below 30 K: An X-ray analysis revealed the crystal structure constituted of one-dimensional array of two component molecules linked alternately by the NO-HO-B hydrogen bonds. The NO-HO-B-OH - ON linkage was suggested to act as a path for ferromagnetic spin coupling. An unusual formation of nitrosonium salt (3) was found in the reaction of 1 and BF3. Its molecular and crystal structures were determined..
22. Takeyuki Akita, Keiji Kobayashi, Intramolecular spin-interactions between two nitronyl nitroxide or imino nitroxide radical units linked to thieno[2,3-b]thiophene and thieno[2,3-b]thieno[3',2'-d]thiophene chromophores, Tetrahedron, 10.1016/0040-4020(96)00324-9, 52, 20, 6893-6902, 1996.05, [URL], Diradical species 1N, 1I, 2N, and 2I, in which two nitronyl nitroxide (N) or imino nitroxide (I) radical centers are attached to thieno[23-b]thiophene (1) and thieno[23-b]thieno[3' 2' -d]thiophene (2) chromophores, respectively, were prepared and their intramolecular exchange interactions were investigated in frozen solutions by means of ESR spectroscopy and magnetic susceptibility measurements at cryogenic temperature. Temperature dependence of the ESR signal intensities due to the triplet state revealed that bis(nitronyl nitroxide) radicals, 1N and 2N, are ground-state singlet species with quite small singlet-triplet gaps. In bis(imino nitroxide) radical 1I the spin interaction was antiferromagnetic and the singlet-triplet gap was estimated to be 2J/kB= -18 K. On the other hand, bis(imino nitroxide) 21 was revealed to be a singlet-triplet degenerate species. These results are discussed in terms of the intramolecular NO - S contact along with corroboration by the semi-empirical MO calculations..
23. Takeyuki Akita, Yasuhiro Mazaki, Keiji Kobayashi, Ferromagnetic spin interaction in a crystalline molecular complex formed by inter-heteromolecular hydrogen bonding
A 1:1 complex of phenyl nitronyl nitroxide radical and phenylboronic acid, Journal of the Chemical Society, Chemical Communications, 10.1039/C39950001861, 18, 1861-1862, 1995.09, [URL], A crystalline molecular complex derived from phenyl nitronyl nitroxide and phenylboronic acid exhibits a ferromagnetic spin interaction (J = +0.65 K) below 30 K: X-ray analysis reveals the crystal structure to be constituted of a one-dimensional array of two component molecules linked alternately by the NO ⋯ HOB hydrogen bond..
24. Takeyuki Akita, Yasuhiro Mazaki, Keiji Kobayashi, Kiminori Ushida, Intramolecular spin interactions between two radical units through isomeric chromophores, thieno[3,2-b]thiophene and thieno[2,3-b]thiophene, Tetrahedron Letters, 10.1016/00404-0399(50)1047L-, 36, 31, 5543-5546, 1995.07, [URL], Diradical species which bear two nitronyl nitroxide groups or two imino nitroxide groups on thieno[3,2-b]thiophene and thieno[2,3-b]thiophene, respectively, were studied in a frozen solution by means of ESR spectroscopy to show those are the ground-state singlet species..
25. Takeyuki Akita, Yasuhiro Mazaki, Keiji Kobayashi, Noboru Koga, Hiizu Iwamura, Crystal structures and magnetic properties of nitronyl nitroxide and imino nitroxide radicals attached to thieno[3,2-b]- and thieno[2,3-b]thiophene rings, Journal of Organic Chemistry, 60, 7, 2092-2098, 1995.04, Nitronyl nitroxide (ONC=NO) and imino nitroxide (NCNO) free radicals joined to isomeric thieno-[3,2-b]thiophene and thieno[2,3-b]thiophene, respectively, were prepared and their crystal structures and magnetic properties were investigated. In all crystals of four free radical species, the ON-C-NO moieties are in the same plane as the thienothiophene ring. The coplanarity is associated with the extremely short intramolecular contact between the oxygen atom in the NO group and the sulfur atom in the thienothiophene ring. The free radicals attached to thieno[3,2-b]thiophene are arranged in a chain structure with short intermolecular NO-S contacts, while the free radicals linked to thieno[2,3-b]thiophenes make dimers with a face-to-face pairing by the use of the NO-S contacts. Among four radical species, thieno[3,2-b]thiophene-substituted nitronyl nitroxide exhibits a weak ferromagnetic interaction (J = +0.11 K/kB, H = -2JSiSj) below 40 K as revealed by a SQUID susceptometer, while others are antiferromagnetic..

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