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21.
N Shimizu M Tomoda R Gonda M Kanari A Kubota A Kubota 《Chemical & pharmaceutical bulletin》1989,37(11):3054-3057
An acidic polysaccharide, named saposhnikovan C, was isolated from the roots and rhizomes of Saposhnikovia divaricata Schischk. It was homogeneous as judged by electrophoresis and gel chromatography, and showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test. It is composed of D-galacturonic acid:L-rhamnose:L-arabinose:D-galactose in a molar ratio of 27:7:8:8, and its molecular mass was estimated to be 132000. About 30% of the D-galacturonic acid residues exist as the methyl esters. O-Acetyl groups were identified, and the content amounted to 3.3%. Methylation analysis, carbon-13 nuclear magnetic resonance, and controlled Smith degradation studies indicated the structural features. It has a pectin-like rhamnogalacturonan backbone with branched arabinan and galactan side chains. 相似文献
22.
Zsombor Gonda Dr. Zoltán Novák 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(47):16801-16806
A new synthetic method was developed for the N‐arylation of pyrazoles using diaryliodonium salts. The transformation does not require any transition‐metal catalyst and provides the desired N‐arylpyrazoles rapidly under mild reaction condition in the presence of aqueous ammonia solution as a mild base without the use of inert atmosphere. The chemoselectivity of unsymmetric diaryliodonium salts was also explored with large number of examples. 相似文献
23.
Urata H Yamaguchi E Nakamura Y Wada S 《Chemical communications (Cambridge, England)》2011,47(3):941-943
In the presence of Ag(I) ions, the C-T and m(5)iC (5-methylisocytosine)-T base pairs showed comparable stability to the C-Ag(I)-C base pair, and the m(5)iC-C base pair was highly stabilized by the synergetic effect of Ag(I) coordination and possible hydrogen bonding. 相似文献
24.
A new functional low molecular-weight gelator (LMWG) based on crown-appended quaterthiophene was synthesized and investigated as a new alkali metal cation responsive material with enhanced fluorescence emission upon gel-to-sol phase transition. 相似文献
25.
Shiraki T Dawn A Le TN Tsuchiya Y Tamaru S Shinkai S 《Chemical communications (Cambridge, England)》2011,47(25):7065-7067
A thermo- and light-responsive system consisting of single-walled carbon nanotube and helical polysaccharide modified with poly(N-isopropylacrylamide) side-chains has been developed through supramolecular polymer wrapping. Coagulation of the complex can be induced by the external stimuli, which leads to a catch-and-release action of a porphyrin derivative. 相似文献
26.
Ishiuchi S Mitsuda H Asakawa T Miyazaki M Fujii M 《Physical chemistry chemical physics : PCCP》2011,13(17):7812-7820
The conformational reduction in catecholamine neurotransmitters was studied by resonance enhanced multi photon ionization (REMPI), ultraviolet-ultraviolet (UV-UV) hole burning and infrared (IR) dip spectroscopy with applying a laser desorption supersonic jet technique to DOPA, which is one of the catecholamine neurotransmitters and has one more phenolic OH group than tyrosine. It is concluded that DOPA has a single observable conformer in the gas phase at low temperature. Quantum chemical calculations at several levels with or without the dispersion correction were also carried out to study stable conformations. From the comparison between the computational IR spectra and the experimental ones, the most stable structure was determined. It is strongly suggested that the conformational reduction is caused by electrostatic interactions, such as a dipole-dipole interaction, between the chain and OH groups. 相似文献
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29.
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
30.
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