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961.
Kiyoshi Tanaka Kazuto Taguchi Satoru Iwata Takayuki Irie 《Supramolecular chemistry》2013,25(8):637-642
The benzoyl-substituted hemithioindigo 1 with Z-configuration was obtained as the sole product from the reaction of 7-ethylbenzo[b]thiophen-3(2H)-one with phenylglyoxal. Irradiation of 1 produced the [2+4] cycloadduct 2, instead of the usual Z ? E isomerization product. The cycloadduct 2 is completely dissociated back to 1 on heating; the interconversion between 1 and 2 shows good repeatability. This reversible property is applied to the molecular switch in the hydrogen-bonded quinone recognition of the 5,15-cis-bis(ureidophenyl)porphyrin 3. resulting in the release of 相似文献
962.
Kiyoshi Nomura Masuo Takeda Takeshi Iiyama Hitoshi Sakai 《Hyperfine Interactions》2005,166(1-4):657-664
In order to confirm Mössbauer spectra of Jarosite, unidentified Fe3+ species (Fe3D3) and Fe2O3 found on Martian surface, some Jarosite specimens produced on Earth were characterized by 57Fe Mössbauer spectroscopy. For comparison, anhydrous ferric sulfate minerals, Mikasaite (Fe3+ 1.56Al0.44)(SO4)3, and Yavapaiite, KFe (SO4)2 were also measured. The thermal decomposition products of Jarosite and their hydration products were also traced by scattering Mössbauer spectra (CEMS and XMS). These data are useful for the identification of hydrous and anhydrous ferric sulfate phases on Mars, including Fe3D3. 相似文献
963.
Choji Kashima Hiroyo Yokoyama Saori Shibata Kiyoshi Fujisawa Takehiko Nishio 《Journal of heterocyclic chemistry》2003,40(4):717-719
The conjugate addition of Grignard reagent ( 2 ) onto 1‐α,β‐unsaturated)acyl 3,5‐dimethylpyrazole ( 1 ) was enantioselectively catalyzed by the copper complex from cuprous compounds and 3‐phenyl‐l‐mentho‐pyrazole ( 3 ). 相似文献
964.
Masumi Takemoto Yasutaka Iwakiri Yuki Suzuki Kiyoshi Tanaka 《Tetrahedron letters》2004,45(43):8061-8064
We have developed a novel procedure for the oxidative cleavage of indole carbon double bonds in the presence of H2O2 using plant cell cultures as a catalytic system. The oxidative procedure has some advantages, such as mild reactions, good yields, easy work-up and safety. 相似文献
965.
Takahiro Gunji Masanari Yokogawa Masahiro Hongo Yoshimoto Abe 《Journal of polymer science. Part A, Polymer chemistry》2005,43(4):763-772
Polytitanasiloxanes and polyzirconasiloxanes were synthesized through the hydrolytic cocondensation of tetraethoxysilane (TEOS) and tetraisopropoxytitanium (TPT) or tetraisopropoxyzirconium (TPZ) 2‐propanol adduct (process A) and through the reaction of partially hydrolyzed TEOS with TPT or TPZ (process B) and were isolated as acetylacetonato derivatives stable against self‐condensation. In both processes, acetylacetone was added to provide acetylacetonato derivatives of polytitanasiloxanes and polyzirconasiloxanes. In process A, titanium‐ or zirconium‐rich polymetallasiloxanes were formed during the initial stage of the process, whereas the molar ratio of silicon to titanium or zirconium was gradually increased up to almost unity with an increasing reaction time. In process B, the molar ratio gradually increased below and above unity as the molar ratio of water to TEOS increased. When the acetylacetonato derivatives of polymetallasiloxanes were subjected to heat treatment, the titania or zirconia component was crystallized. The crystallization temperature increased as the silica content and the molar ratio of water to TEOS increased, and this demonstrated that the crystallization was dependent on the sequence in the main chain of the polymetallasiloxanes. The 29Si NMR spectra of the polymetallasiloxanes led to the idea that the backbone metallasiloxane linkages consisted of random and block sequences for processes A and B, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 763–772, 2005 相似文献
966.
Kiyoshi Horita Masaaki Nagasawa Shun-ichiro Hachiya Youji Sakurai Tatsuya Yamazaki Junichi Uenishi Osamu Yonemitsu 《Tetrahedron letters》1997,38(52):8965-8968
The lactone part (2) of halichondrin B (1) was synthesized by Yamaguchi macrolactonization of the seco-acid (3), which was synthesized via coupling of C1---C15(4) with C16---C36 (5), prepared through stereoselective construction of the E ring starting from C16---C26 (7) and C27---C36 (8). 相似文献
967.
968.
Yasutaka Kamei Atsushi Sudo Haruo Nishida Kiyoshi Kikukawa Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2008,46(7):2525-2535
A series of activated urethane‐type derivatives of α‐amino acids were synthesized and applied to polypeptide synthesis. The urethane used herein, N‐(4‐nitrophenoxycarbonyl)‐α‐amino acids 1 , were synthesized by N‐carbamoylation of γ‐benzyl‐L ‐glutamate, β‐benzyl‐L ‐aspartate, L ‐leucine, L ‐phenylalanine, and L ‐proline, with 4‐nitrophenyl chloroformate. When 1 was dissolved in N,N‐dimethylacetamide (DMAc) and heated at 60 °C, it was smoothly converted into the corresponding polypeptides with releasing 4‐nitrophenol and carbon dioxide. Spectroscopic analyses of the obtained polypeptides revealed that they were comparable with the authentic polypeptides synthesized by the ring‐opening polymerizations of amino acid N‐carboxyanhydrides (NCAs). Besides the successful polycondensations of a series of 1 , their polycondensations of 1a and other 1 were also successfully carried out to obtain the corresponding statistic copolypeptides. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2525–2535, 2008 相似文献
969.
Yasutaka Kamei Atsushi Nagai Atsushi Sudo Haruo Nishida Kiyoshi Kikukawa Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2008,46(8):2649-2657
A series of activated urethane‐type derivatives of γ‐benzyl‐L ‐glutamate were synthesized, and their potential as monomers for polypeptide synthesis was investigated. The derivatives of the focus of this work were a series of N‐aryloxycarbonyl‐γ‐benzyl‐L ‐glutamate 1 , of which aryl groups were phenyl, 4‐chlorophenyl, and 4‐nitrophenyl. These urethanes 1 were reactive in polar solvents such as dimethylsulfoxide, N,N‐dimethylformamide (DMF), and N,N‐dimethylacetamide (DMAc), and were efficiently converted into poly(γ‐benzyl‐L ‐glutamate) (poly(BLG)) under mild conditions; at 60 °C without addition of any catalyst. Among the three urethanes, that having 4‐nitrophenoxycarbonyl group 1c was the most reactive to give poly(BLG) efficiently, as was expected from the highly electron deficient nature of the nitrophenoxycarbonyl group. On the other hand, the urethane 1a having phenoxycarbonyl group was also efficiently converted into poly(BLG), in spite of the intrinsically less electrophilicity of the phenoxycarbonyl group. In addition, the successful formation of poly(BLG) by the reaction of 1a favored its diluted concentration (0.1 M) much more than 2.0 M, the optimum initial concentration for 1c . 1H NMR spectroscopic analyses of the reactions in situ revealed that the predominant pathway from 1 to poly(BLG) involved the intramolecular cyclization of 1 into the corresponding N‐carboxyanhydride, with release of phenol and its successive ring‐opening polymerization with release of carbon dioxide. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2649–2657, 2008 相似文献
970.
Shoji Yoshimoto Fumihiko Ohashi Tetsuya Kameyama 《Journal of Polymer Science.Polymer Physics》2005,43(19):2705-2714
Polyaniline (PANI)‐montmorillonite (MMT) nanocomposites were prepared by direct intercalation of aniline molecules into MMT galleries, followed by in situ polymerization within the nano‐interlamellar spaces under solvent‐free conditions. The basal spacing of aniline‐intercalated MMT increased gradually up to 1.5 nm with increasing amounts of aniline loaded. This result suggests that aniline molecules were adsorbed by MMT clay and that intercalated aniline likely located perpendicular to the silicate sheets. After polymerization, X‐ray diffraction and Fourier transform infrared analyses confirmed the successful synthesis of PANI chains between the MMT nano‐interlayers. The scanning electron microscopy images indicated that the surface morphologies of PANI–MMTs were strongly different depending on the PANI content. The electrical conductivities of PANI nanocomposite particles in pressed pellets ranged in the order of between 10?3 and 10?2 S/cm. UV–vis spectroscopy and doping level measurement were further used to discuss the conductivities of nanocomposites. The thermal stabilities of PANI–MMT nanocomposites were examined by using thermogravimetric‐differential thermal analysis and derivative thermogravimetric analysis, and both analyses consequently demonstrated the improved thermal stabilities of the PANI chains in the nanocomposites as compared to pure PANI. The thermal stabilities of resulting nanocomposites were strongly related to the PANI content, which increased as the PANI content decreased in the nanocomposites. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2705–2714, 2005 相似文献