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111.
Three new apianen lactones Maomailiaoine I ( 1 ), Maomailiaoine II ( 2 ) and Maoimaliaoine III ( 3 ), together with one known apianen lactone, five known flavonoids and three other known compounds were isolated from Polgonum ciliinerve Ohwi. Their structures were deduced from spectroscopic methods and 2D NMR techniques. 相似文献
112.
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114.
We have encapsulated several hemoproteins in the sol-gel glass to catalyze the oxidation reaction of dibenzothiophene (model
for organic sulfur compounds in coal) with hydrogen peroxide. In addition to cytochrome c and myoglobin, which have previously
been encapsulated in sol-gel glasses, two other hemoproteins, horseradish peroxidase and bovine blood hemoglobin, have now
been successfully immobilized in sol-gel media with the retention of their spectroscopic properties. All four hemoproteins
studied also demonstrate similar catalytic activities toward the oxidation of dibenzothiophene as compared with the results
obtained with the proteins in solution. In the case of encapsulated cytochrome c, the more water-soluble S-oxide was obtained
with much higher selectivity over the less water-soluble sulfone (S-oxide/sulfone = 7.1) as compared to what was obtained
in the aqueous/organic medium (S-oxide/sulfone = 2.3). Because of the advantage of easy separation of the encapsulated proteins
from the liquid reaction mixture, it is clear from these studies that the immobilization of active hemoproteins in the solid
glass media could serve as more practical biocatalysts. 相似文献
115.
Neferine and isoliensinine are the two major compositions of the Chinese medicine lotus plumule. They have extensive cardiovascular activity, such as antiarrhythmic, antithrombic and antihypertensive. In order to confirm the structures reported in the literature by explicit 1H and 13C assignments, we used a series of NMR experiments including 1H, 1H-COSY, HSQC and HMBC. The absolute configuration of neferine (C-1 and C-1') was determined as R and S and that of isoliensinine (C-1 and C-1') was determined as R and R. 相似文献
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117.
Yi Ming Liu Sui Ping Deng Hui Zheng Jian Ming Ouyang 《中国化学快报》2007,18(3):345-348
The ring patterns of calcium oxalate crystals were induced by domains in Langmuir-Blodgett (LB) films of dipalmitoylpho- sphatidylcboline (DPPC). The result was explained by the defects at the ring boundaries of liquid condensed (LC) and liquid expanded (LE) phases of LB film. These boundaries could provide less free energy and much more nucleating sites for COM crystals. 相似文献
118.
Total synthesis of polycavernoside A, a lethal toxin of the red alga Polycavernosa tsudai 总被引:1,自引:0,他引:1
Blakemore PR Browder CC Hong J Lincoln CM Nagornyy PA Robarge LA Wardrop DJ White JD 《The Journal of organic chemistry》2005,70(14):5449-5460
[structure: see text] Two approaches to the synthesis of the aglycon 120 of polycavernoside A (1) were developed, only one of which was completed. The successful "second-generation" route assembled the aglycon seco acids 102 and 106 via Nozaki-Hiyama-Kishi coupling of aldehyde 70, prepared from methyl (S)-3-hydroxy-2-methylpropionate (72) and (S)-pantolactone (73), with vinyl bromide 71. The latter was obtained from a sequence which commenced from the silyl ether 24 of 3-hydroxypropionaldehyde and entailed cyclization of (Z)-zeta-hydroxy-alpha,beta-unsaturated ester 82. Regioselective Yamaguchi lactonization of trihydroxycarboxylic acids 102 and 106 and subsequent functional-group adjustments led to macrolactone 120, to which the fucopyranosylxylopyranoside moiety was attached. Stille coupling of the glycosidated aglycon 128 with dienylstannane 129 furnished polycavernoside A in a synthesis for which the longest linear sequence was 25 steps. The overall yield to lactone 120 was 4.7%. 相似文献
119.
Densities have been measured for the electrolyte (NaCl, NaBr and NaI)‐monosaccharide (D ‐mannose and D‐ribose)‐water solutions at 298.15 K. These data have been used to calculate the apparent molar volumes of the saccharides (VΦ,S) and electrolytes (VΦ,E) in the studied solutions. Infinite dilution apparent molar volumes, VΦ,S0 and VΦ,E0, have been evaluated, together with the standard transfer volumes of the saccharides (ΔtVS0) from water to aqueous electrolyte solutions and those of the electrolytes (ΔtVE0) from water to aqueous saccharide solutions. It was shown that both the ΔtVS0 and ΔtVE0 values are positive and increase with increasing molalities of sodium halides and saccharides, respectively. Overall, the ΔtVS0 and ΔtVE0 values have the order of NaCl > NaBr > NaI except for NaI‐ribose and NaI‐ribose. Volumetric interaction parameters for the electrolyte‐monosaccharide pairs in water were obtained and interpreted by the stereochemistry of the monosaccharide molecules and the structural interaction model. 相似文献
120.
Huan Yang QI Chao Feng ZHANG Mian ZHANG Jian Qun LIU Zheng Tao WANG 《中国化学快报》2005,16(8):1050-1052
Three new anthraquinones, emodin-8-β-D-(2"-O-coumarate)glucoside 1, emodin-8-β-D-(6'-O-acetyl)glucoside 2 and physicon-8-β-D-(6'-O-acetyl)glucoside 3, were isolated from the roots of Polygonum cillinerve and their structures were established by spectroscopic methods. The biological activity indicated that compound 1 had the scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (the IC50 = 8.5 μmol/L), and compound 1-3 showed no activities against HL-60 and BCJC-823 cells by MTT method in vitro. 相似文献