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31.
Akira Watanabe 《Tetrahedron letters》2004,45(33):6229-6233
Oxovanadium(V)(salen) complex 4 was found to catalyze Meerwein-Ponndorf-Verley cyanation of aliphatic aldehydes with good to high enantioselectivity. This cyanation showed a positive nonlinear effect. 相似文献
32.
33.
A sensitive and specific method using gas chromatography and negative-ion chemical ionization mass spectrometry is described for the determination of 5-fluoro-2'-deoxyuridine (FdUrd) in plasma. The method is based on the formation of the pentafluoropropionyl derivative of FdUrd and of its stable isotope as internal standard after sample clean-up by solid-phase extraction and purification by high-performance liquid chromatography. Quantification in plasma was possible down to 300 pg/ml. The method was applied to the analysis of plasma levels of FdUrd in mice and dogs. 相似文献
34.
Kazuhiro Endo Hideo Ihara Kazuhiro Watanabe Shun-Ichi Gonda 《Journal of solid state chemistry》1982,44(2):268-272
X-Ray photoelectron spectra of TiS3 with a one-dimensional structure were measured. TiS3 may be regarded as Ti4+(S2)2?S2? with pairs of S atoms (S2) and isolated S atoms. The spectra of the sulfur core-levels are assigned by comparison with those of TiS2, where all S atoms are largely separated. The binding energy of the S2 pairs is found to be 1.4 eV higher than that of the isolated S atoms, which is consistent with the larger negative charge of the isolated atoms. The structures of the valence band of TiS3 are discussed in terms of a molecular orbital scheme for the S2 pairs. 相似文献
35.
2-Alkyl-1-alkylthioisoquinolinium salts were readily prepared from 2-alkyl-1(2H)-isoquinolones via 2-alkyl1(2H)-thioisoquinolones in two steps. Under mild conditions, the reaction of 2-alkyl-1-alkylthioisoquinolinium salts with active methylene compounds in the presence of sodium hydride afforded 2-alkyl-1-(substituted methylene)iso-quinolines in good yields. Pyrrolo[2,1-a]isoquinolines were synthesized by the cyclization of 2-benzyl-1-(substituted methylene)isoquinolines using acetic anhydride. 相似文献
36.
37.
Tetsuo Miyazaki Shigeru Nagasaka Isao Maeda Takuro Matsumoto Shinji Koyama Seiji Kodama Masami Watanabe 《Radiation Physics and Chemistry》1996,47(6):817-819
Emission from high-energy-electron-irradiated golden hamster embryo (GHE) cells has been studied over the temperature range 12–300 K both by a one-shot-single-photon-counting method and by photocurrent measurements with an oscilloscope. Emission from the irradiated phosphate buffered saline (PBS) also has been studied. The emission spectra from PBS at 12 and 77 K show a maximum around 330 and 380 nm, respectively, which are the same spectra as those from irradiated pure H2O. The emission from irradiated GHE consists of the new band at 480 nm in addition to the emission from H2O. The 480 nm emission is observed at the temperature range of 12–300 K, though the emission at 300 K is much lower than that at low temperature. The 480 nm emission is ascribed to the transition from excited organic substances in GHE cells. The intensity of 480 nm emission at 300 K increases linearly with increasing irradiation-dose in the range of 11–600 Gy. 相似文献
38.
Yoshikatsu Ito Meng Ji-Ben Shin Suzuki Yoshitaka Kusunaga Teruo Matsuura Keiichi Fukuyama 《Tetrahedron letters》1985,26(17):2093-2096
In contrast to simple imidazoles, 1-methy1–2,4,5-triphenylimidazole () produced stable oxetane photoadducts - with good efficiency upon irradiation in the presence of benzophenone derivatives - in acetonitrile solution. Irradiation in the solid-phase was also studied. The oxetanes - readily underwent cycloreversion by acid catalysis or by heating. 相似文献
39.
Masatoshi Sakae Masanori Katsurada Mayumi Watanabe Fumio Yoneda Sadao Nishigaki Toshimasa Ishida 《Journal of heterocyclic chemistry》1997,34(1):157-160
The reaction of 2-bromoethylamine 1 with methylisothiocyanate 2 under mild condition gave 2-methyl-amino-2-thiazoline 3 as the major product together with two kinds of byproducts, 3-(N-methylthiocar-bamoyl)-2-methyliminothiazolidine 4 and N,N′-dimethyl-N-(2-thiazolin-2-yl)thiourea 5. Thermal isomer-ization of 5 to 4 was observed. The structures of the byproducts were confirmed by X-ray crystallography. 相似文献
40.
Otaka A Yukimasa A Watanabe J Sasaki Y Oishi S Tamamura H Fujii N 《Chemical communications (Cambridge, England)》2003,(15):1834-1835
Gamma-acetoxy-alpha,beta-enoates were easily reduced by samarium diiodide (SmI2) in THF to generate samarium dienolates which were kinetically trapped with ease at their alpha-positions by electrophiles (proton, aldehydes or ketones) to yield (E)-alkene dipeptide isosteres or gamma-amino acid derivatives in high chemical yields. 相似文献