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71.
Base-catalyzed homo-brook rearrangement of diastereomeric 7,8- epoxy-7(trimethylsilyl)-6-tridecanols
Semi-quantitative rate measurement of base-catalyzed 1,3-migration of a silyl group from carbon to oxygen (homo-Brook rearrangement) using four diastereomerically pure title compounds revealed that the aptitude for the migration depends markedly on the configurational environment around the trimethylsilyl group of the respective substrate. 相似文献
72.
Toshio Motojima Shun-ichi Ikawa Masao Kimura 《Journal of Quantitative Spectroscopy & Radiative Transfer》1981,26(3):177-185
The i.r. absorption intensities have been measured of the fundamental vibrations of water molecules in metal halide aqueous solutions. Pseudo-isosbestic points were observed in the regions of both the stretching and bending vibrations and interpreted in terms of two states of water molecules in the solutions. The intensities of the stretching vibrations of water molecules coordinated to the dissolved ions have been estimated. The intensities become stronger in the order, Li+ > Na+ > K+ for the cations and F- > Cl- > Br- > I- for the anions. These orders are consistent with the strengths of the ion-water interactions, which are related to the dynamical behavior of the water molecules in the primary hydration shell. 相似文献
73.
Shun-Ichi Ikawa Sachiko Takahasi Masao Kimura 《Journal of Quantitative Spectroscopy & Radiative Transfer》1975,15(12):1093-1099
The dielectric-field correction on i.r. band shape in the liquid has been studied by using the Lorentz internal field. The deformation of the band shape is inappreciable for a weak absorption band that becomes measurable only at a sample thickness larger than 10μ. The shapes of the strong singlet and doublet bands of hexafluorobenzene at 1530 cm?1 and near 1000 cm?1, respectively, and also of the doublet band of carbon tetrachloride near 790 cm?1 have been measured in dilute solutions and compared with those for the pure liquid. 相似文献
74.
The moment analyses were performed on the far-infrared absorption bands of CH3CN, CHCl3, CH2Cl2, and their deuterated compounds dissolved in nonpolar solvents. The values of torque acting on the solute molecules were estimated from the fourth moments. The band profiles were simulated by means of the continued-fraction representation of the time correlation function by Mori, using the moment values obtained. The third order long-time approximation of the correlation function yields essentially good simulations. The effective rotation angles of molecules between collisions were estimated from the first positive-to-negative turning points of the memory functions. The solvent effects on the torque and the rotation angle were consistent with each other. 相似文献
75.
Tadahiro Kato Yoshihiro Yamaguchi Nobunori Abe Tadao Uyehara Tsuneo Namai Mitsuaki Kodama Yoshinori Shiobara 《Tetrahedron letters》1985,26(19):2357-2360
Structural elucidation including the absolute configuration was carried out on the trihydroxy C18 -fatty acids isolated from rice plant, Sasanishiki suffered from rice blast disease. 相似文献
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79.
Phenol derivatives, which are one of the most important classes of aromatic compounds in organic chemistry, were synthesized by ruthenium-catalyzed ring-closing olefin metathesis (RCM) of 1,4,7-trien-3-ones with versatile substitution patterns. The RCM reaction for producing phenol derivatives was also successful with 1,5,7-trien-3-one as another precursor. Most of the phenols prepared here could not be obtained easily by conventional methods. 相似文献
80.
We investigate a possible dynamical mechanism for spontaneous supersymmetrybreaking in N = 1 supergravity theories in 1 + 1 space-time dimensions. It will be shown that supersymmetry is never broken at the tree level, but it can be broken for a certain class of models by quantum effects due to trace anomalies of the energy-momentum tensor and the supercurrent. 相似文献