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601.
Many drugs or physiologically important compounds are chiral molecules and the optical isomers of them may differ in their pharmacological activities. In some instances differences in undesirable side-effects of these enantiomers are important. So the separation of chiral compounds is becoming increasingly important. Liquid chromatography (LC) is well known as an excellent method for separating and analyzing mixtures of stereoisomers. For resolving the ionic chiral compounds it is available t… 相似文献
602.
Yu Han GUO Tian Sheng SU* Center for Molecule Science Institute of Chemistry The Chinese Academy of Sciences Beijing 《中国化学快报》2001,(1)
The cross-linked polymer beads with reactive groups as active supports have been widely used in many fields such as chromatographic separation, solid phase synthesis, catalytic reaction, ion exchange and adsorption etc. In resent years, the synthesis and application of monodisperse polymer beads with different structures have been rapidly developed1~4. It is obvious that this type of monosized resin as matrix of active supports will be even more advantageous in some applications. This paper pr… 相似文献
603.
Xia Juan ZOU Gui Yu JIN* Institute of Elemento-Organic Chemistry National Key Laboratory Nankai University Tianjin 《中国化学快报》2001,(5)
Pyridazine derivatives represent one of the most active classes of compounds possessing a wide spectrum of biological activity. They are widely used in pharmaceuticals and agrochemicals1. On the other hands, 1,3,4-thiadiazole derivatives exhibit a broad spectrum of biological activity2-5. In view of these facts and in continuation of our interest in the chemistry of pyridazines, it was attempted to synthesize novel tri-heterocyclic compounds containing both pyridazinone and 1,3,4-thiadiazole m… 相似文献
604.
Yong FENG Hai Ming ZHANG Lei LIU Yong Hui WANG Zhao Xiong LIANG Qing Xiang GUO* Department of Chemistry University of Science Technology of China Hefei 《中国化学快报》2001,(7)
It is well known that a substituted cyclodextrin (CD) can often form a self-included complex, in which the substituent group is incarcerated into the CD cavity1. The phenomenon is interesting, as the self-inclusion is a nice model of protein folding2 and it has also been successfully used in the construction of various molecular devices3. Studies have showed that van der Waals force, hydrophobic effect, and electrostatic interaction are the major driving forces leading to the self-inclusion4… 相似文献
605.
Microwave-assisted Polymerization of D,L-Lactide with Stannous Octanoate as Catalyst 总被引:1,自引:0,他引:1
Li Jian LIU* Chao ZHANG Li Qiong LIAO Xu Li WANG Ren Xi ZHUO Department of Polymer Science College of Chemistry Molecular Science Wuhan University The Research Laboratory of SEDC of Biomedical Polymer Materials at Wuhan University Wuhan 《中国化学快报》2001,(8)
Poly (lactic acid) (PLA) is an important member of the polyesters which are used as biomedical materials in bioresorbable suture, implantates and drug controlled release systems1. PLA is prepared by two routs2: ring-opening polymerization of dimeric cyclic lactide or direct polycondensation of lactic acid. The ring-opening polymerization has attracted much more scientific and industrial interests than the later one, but both methods need long time for the polymerization reactions to be compl… 相似文献
606.
Tian Yu WANG Jing Rong CHEN Jin Shi MA* Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing Technical Institute of Physics Chemistry Chinese Academy of Sciences Beijing 《中国化学快报》2001,(8)
5, 15-Diphenylporphyrin (DPP), a novel porphyrin model compound, was always inaccessible in quantities suitable for study1 because the difficulty of synthesis. So that the characteristic of this molecule had not been explored until a novel method developed for the preparation of DPP recently2. Therefore it will be possible for the synthesis of DPP-based photosensitizers, and investigation of their photodynamic properties. Here we reported the synthesis of novel photosensitizers 5, 15-diphe… 相似文献
607.
The hydrogen abstraction from methanol by atomic chlorine can proceed via two possible channels: CH3OH + Cl → CH2OH + HCl (i) → CH3O + HCl (ii)In 2000, Ahmed et al1. reported their investigation for the H abstraction dynamics of the CH3OH+Cl reaction by crossed molecular beams in conjunction with velocity map imaging. Hydroxymethyl (CH2OH) was detected in their experiments. In 1998, Jodkowski et al2. reported their theoretical study on the CH3OH+Cl reactions. They located inte… 相似文献
608.
Xian LUO Jian De LU Xiao Yun FU* Analytical Testing Center Zhejiang University Hangzhou 《中国化学快报》2001,(7)
Glutathione (GSH) protects human and animal's cells by the exchange with reversible oxidized glutathione (GSSG) when cells meet with oxidants, such as hydrogen peroxide (H2O2) and lipid peroxide. But when GSH meets with hypochlorous acid (HOCl), via the myeloperoxidase-catalysed oxidation of chloride by H2O2, the amount of GSSG formed does not account for all the GSH lost, which is quite different from that we has investigated in the reaction of GSH with H2O21. Prutz proposed the fo… 相似文献
609.
Thalliumisatoxicmetal.Becauseitsconcentrationinenvironmentalandbiologicalsam plesisinthe 1ng/grangeorless[1] ,itisdifficulttodeterminethemetalbyusingconventionalelectroanalysismethods .Differentialpulseanodicstrippingvoltammetry(DPASV )isasensitivemethodfor… 相似文献
610.
Stabilization of Cu/ZnO Based Catalysts by Nickel Additive in Methanol Decomposition 总被引:1,自引:0,他引:1
A series of Cu/Zn based catalysts with and without Ni, prepared by the co-precipitation method, has been studied for methanol decomposition. CO and H2 are the major products. The Cu/Zn catalysts show a low initial activity and a poor stability. The formation of the CuZn alloys was observed in the deactivated Cu/Zn catalysts which were used for methanol decomposition at 250 . When small amounts of Ni were added in the catalyst, the Cu/Zn/Ni(molar ratio 5/4/ x) catalysts showed a high activity at a low temperature. The activity and the stability of the catalyst depend on the nickel content. The activity of the Cu/Zn/Ni catalysts was maintained at a. relatively stable value of 78% conversion of methanol with 95% selectivity of H2, 93% selectivity of CO, and a more than 70% yield of hydrogen was obtained at 250 C when x >1. The stability of the Cu/Zn/Ni (molar ratio 5/4/x) catalysts showed the maximum (ca 88%) when x=1. The stabilization effect of nickel on the Cu/Zn based catalysts may lead to the increasin 相似文献