排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
A general method for acylation of indoles at the 3-position with acyl chlorides in the presence of dialkylaluminum chloride 总被引:1,自引:0,他引:1
[reaction--see text] Indoles are selectively acylated at the 3-position in high yields on treatment with a wide variety of acyl chlorides in CH(2)Cl(2) in the presence of diethylaluminum chloride or dimethylaluminum chloride. The reaction proceeds under mild conditions and is applicable to indoles bearing various functional groups without NH protection. 相似文献
2.
3.
Yusuke Yamauchi Toshiyuki Momma Hiroki Kitoh Tetsuya Osaka Kazuyuki Kuroda 《Electrochemistry communications》2005,7(12):1364-1370
We have proposed a novel convenient pathway via solvent-evaporation-mediated direct physical casting (SEDPC) for the fabrication of mesoporous metals in a micrometer scale. We have presented the successful deposition of highly ordered mesoporous Pt into micrometer channels prepared by lithography. The direct observation by a high-resolution scanning microscope (HR-SEM) showed the formation of highly ordered 2D-hexagonal (p6mm) mesoporous metals onto such substrates. The cyclic voltammogram of the mesoporous Pt in sulfuric acid revealed a typical feature which can identify the clean Pt surface. Moreover, mesoporous Pt exhibits an effective reduction of dissolved dioxygen molecules. It is proved that mesoporous Pt deposited in a very confined area via the SEDPC method possesses electrocatalytic performance owing to Pt. 相似文献
4.
Kamata J Okada T Kotake Y Niijima J Nakamura K Uenaka T Yamaguchi A Tsukahara K Nagasu T Koyanagi N Kitoh K Yoshimatsu K Yoshino H Sugumi H 《Chemical & pharmaceutical bulletin》2004,52(9):1071-1081
As part of a series of studies to discover new topoisomerase II inhibitors, novel pyrimidoacridones, pyrimidophenoxadines, and pyrimidocarbazoles were synthesized, and in vitro and in vivo antitumor activities and DNA-protein and/or DNA-topoisomerase II cross-linking activity as an indicator of topoisomerase II-DNA cleavable complex formation were evaluated. The pyrimidocarbazoles possessed high in vitro and in vivo potencies. Compound 26 (ER-37326), 8-acetyl-2-[2-(dimethylamino)ethyl]-1H-pyrimido[5,6,1-jk]carbazole-1,3(2H)-dione, showed in vitro growth inhibitory activity with respective IC(50) values of 0.049 microM and 0.35 microM against mouse leukemia P388 and human oral cancer KB. In vivo, this compound inhibited the tumor growth of mouse sarcoma M5076 implanted into mice with T/C values of 42% and 13% at 3.13 and 6.25 mg/kg/d respectively without significantly affecting the body weight. In addition, compound 26 (ER-37326) increased the formation of DNA-topoisomerase II cross-linking in P388 cells. 相似文献
5.
We have realized a novel Mach-Zehnder interferometer (MZI) thermo-optic switch that can operate over a much wider wavelength range than a conventional MZI switch. We constructed the novel MZI switch by incorporating a phase-generating coupler (PGC) as an optical coupler. The PGC generates a nonlinear wavelength-dependent phase, which functions as a virtual wavelength-dependent delay part that cancels out the wavelength dependence of a MZI. We fabricated the novel MZI switch on a silica-based planar light-wave circuit and achieved a low insertion loss of less than 1.6 dB and a high extinction ratio of 30 dB over a wide wavelength range of 160 nm. 相似文献
6.
We demonstrate an optical orthogonal frequency division multiplexing (OFDM) demultiplexer with an optical discrete Fourier transform circuit fabricated using silica planar lightwave circuit technology. This compact device can process an arbitrary number of subcarriers. The operation of a ten-channel device is demonstrated by demultiplexing a 100 Gbit/s (10 subcarrier × 10 Gbits/s) OFDM signal. We also discuss a main factor affecting characteristics degradation of the device. 相似文献
7.
S. Kitoh H. Senda K.‐K. Kunimoto S. Maeda A. Kuwae K. Hanai 《Crystal Research and Technology》2004,39(4):375-381
Crystal structures of (R)‐ and (rac)‐4‐phenyl‐1,3‐oxazolidin‐2‐one (4‐POO) have been determined by X‐ray diffraction and characterized by the solid state 13C NMR and IR spectra. Molecular geometries and intermolecular interactions in (R)‐ and (rac)‐4‐POO crystals are very similar to each other; 4‐POO molecules are linked via the N‐H…O intermolecular hydrogen bonds to form the chained structure. Chemical shifts of the solid state 13C NMR spectra are very similar to each other, whereas the 1H spin‐lattice relaxation times (T1H) value for (R)‐4‐POO is five times as large as that for (rac)‐4‐POO, reflecting the more restricted mobility of the (R)‐4‐POO chain. Although both crystals contain an unique molecule in the asymmetric unit, a doublet feature is observed for the C=O stretching mode in the IR spectra of (R)‐ and (rac)‐4‐POO crystals. The frequency gap of the C=O bands are correlated with the strength of the dipole‐dipole interactions between the neighboring C=O groups. © 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 相似文献
8.
A Strap Strategy for Construction of an Excited‐State Intramolecular Proton Transfer (ESIPT) System with Dual Fluorescence 下载免费PDF全文
Naoya Suzuki Prof. Dr. Aiko Fukazawa Dr. Kazuhiko Nagura Dr. Shohei Saito Dr. Hirotaka Kitoh‐Nishioka Prof. Dr. Daisuke Yokogawa Prof. Dr. Stephan Irle Prof. Dr. Shigehiro Yamaguchi 《Angewandte Chemie (International ed. in English)》2014,53(31):8231-8235
An amine‐embedded flexible alkyl strap has been incorporated into an emissive boryl‐substituted dithienylpyrrole skeleton as a new entity of excited‐state intramolecular proton transfer (ESIPT) chromophores. The π‐electron system shows a dual emission, which covers a wide range of the visible region depending on the solvent polarity. The incorporation of the aminoalkyl strap as well as the terminal boryl groups efficiently stabilize the zwitterionic excited‐state species resulting from the ESIPT even in an aqueous medium. 相似文献
9.
Shin-ichiroh Kitoh Hiroki Tokuoka Jun Hasegawa Tetsuo Nonami Takashi Obi Masahiro Yamaguchi Nagaaki Ohyama 《Optical Review》1998,5(6):352-357
In endoscopic diagnosis, there has been a strong requirement to measure the internal surface topography of the rectum or esophagus. Accurate measurement, however, is very difficult, because the object is usually observed from an inclined view. In this paper, we propose a method to overcome this difficulty utilizing sequential stereo-pair images; the relative shape is roughly measured from sequential images taken by one of the change coupled device (CCD) cameras, and the size is determined by stereo-pair matching using the measured shape. A coarse-to-fine approach is also used to improve the resolution of topographic measurement. Through a basic experiment using a monocular CCD endoscope and a polyp phantom, the proposed method is confirmed to improve measurement accuracy in comparison with conventional methods. 相似文献
10.
Soh-ichi Kitoh Ko-Ki Kunimoto Norio Funaki Hitoshi Senda Akio Kuwae Kazuhiko Hanai 《Journal of chemical crystallography》2002,32(12):547-553
The crystal structures of (rac)- and (R)-4-phenyl-1,3-oxazolidine-2-thione (4-POT) have been determined by X-ray diffraction. The structure of (rac)-4-POT is monoclinic P21/n with a = 11.9096(9) Å, b = 5.9523(6) Å, c = 12.3563(8) Å, = 91.054(6)°, V = 875.8(1) Å3, and Z = 4. The structure of (R)-4-POT is orthorhombic P212121 with a = 7.7197(6) Å, b = 21.603(2) Å, c = 5.4613(9) Å, V = 910.8(2) Å3, and Z = 4. (rac)-4-POT and (R)-4-POT crystals are shown to have different hydrogen-bonding patterns. In the racemic crystals, the enantiomeric (R)- and (S)-4-POT molecules are connected to form a cyclic dimer via the N–H S hydrogen bond of the cis thioamide moiety [N Si 3.438(2) Å, N–H Si 176(2)° symmetry code: (i) 1 – x, 1 – y, 1 – z]. In the chiral (R)-4-POT crystals, the N–H S intermolecular hydrogen bond forms a zigzag chain around the twofold screw axis [N Sii 3.347(3) Å, N–H Sii 161(3)° symmetry code: (ii) 1/2 + x, 1/2 – y, 2 – z]. Observed difference of 46°C in the melting points between the (rac)-4-POT and (R)-4-POT crystals is correlated with difference in the crystal packing. Vibrational spectra of (rac)- and (R)-4-POT crystals are discussed both in the solid state and in solution. 相似文献