共查询到19条相似文献，搜索用时 234 毫秒
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表没食子儿茶素没食子酸酯(EGCG)经甲基化后在抗过敏、降血脂等方面具有更高的生物活性。但茶叶中甲基化EGCG含量较低,为进一步研究其生物活性,本文对其半合成路线进行了优化。先以EGCG为原料制得五苄基化的表没食子儿茶素(EGC),然后将没食子酸丙酯经4-甲氧基苯甲醛二甲缩醛保护,甲基化,脱保护,苄基化,水解得到3,4-二苄氧基-5-甲氧基苯甲酸,再与苄基化EGC酯化和脱苄基得到表没食子儿茶素3-O-甲基没食子酸酯(3″-Me-EGCG);同样将没食子酸丙酯经全乙酰化、选择性甲基化、脱除乙酰基、苄基化、水解得到3,5-二苄氧基-4-甲氧基苯甲酸,再与苄基化EGC酯化和脱苄基得到表没食子儿茶素4-O-甲基没食子酸酯(4″-Me-EGCG);总产率分别为53%和57%。 相似文献
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以N-羟甲基苯甲酰胺和取代芳烃为原料,合成了N-(3-苯甲酰胺甲基-2-羟基-4,5-二甲基苄基)苯甲酰胺(A)、N-(3-苯甲酰胺甲基-2-羟基-4,6-二甲基苄基)苯甲酰胺(B)、N-(4-苯甲酰胺甲基-2-羟基-3,6-二甲基苄基)苯甲酰胺(C)、N-(3-甲基-5-苯甲酰胺甲基-2-羟基苄基)苯甲酰胺(D)、N-(4-甲基-5-苯甲酰胺甲基-2-羟基苄基)苯甲酰胺(E)、N-(5-苯甲酰胺甲基-2-羟基-3-甲氧基苄基)苯甲酰胺(F)和N-(5-苯甲酰胺甲基-2-甲氧基-4-甲基苄基)苯甲酰胺(G)共7种双苯甲酰胺基取代的类辣素结构化合物。通过红外光谱(IR)和核磁氢谱(1 H NMR)对其结构进行了表征。抑菌试验结果表明化合物F和化合物G对2种受试菌金黄色葡萄球菌和大肠杆菌的抑制活性最高,最小抑菌浓度均可达到0.125mg/mL。以该7种化合物为辅助防污剂,复合氧化亚铜制备海洋防污涂料,实海挂板120天后,除含D试片外其余6个试片均表面光洁无污损生物附着,表现出优良的防污性能。 相似文献
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从松节藻中分离的含卤素化合物表现出显著PTP1B抑制活性。其中BPN效果最佳。为研究BPN侧链基团极性对其抑制活性的影响,本文以香兰素(1)为起始原料,经过溴代、氧化、还原、傅克烷基化以及酯化等反应,成功合成了新化合物2,3-二溴-1-(2-溴-3,4-二甲氧基-6-((4-硝基苯氧基)甲基)苯甲基)-4,5-二甲氧基苯(10)、4-((3-溴-2-(2,3-二溴-4,5-二甲氧基苄基)-4,5-二甲氧基苄基)醚)苯胺(11)、4-((3-溴-2-(2,3-二溴-4,5-二甲氧基苄基)-4,5-二甲氧基苄基)醚)-4-乙酰乙酸(12)和3-溴-2-(2,3-二溴-4,5-二甲氧基苄基)-4,5-二甲氧基苯甲醛肟(14)。通过1 H-NMR,13C-NMR等方法对目标产物进行了结构表征。并对化合物进行了PTP1B酶抑制活性的测定,结果表明化合物侧链极性对PTP1B酶抑制活性有显著影响。 相似文献
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完成呋喃甾烷型甾体皂苷甲基Funlioside B的合成。在三氟化硼乙醚促进下,薯蓣皂苷元与乙酸酐反应以55%的产率得到3,16-二-氧-乙酰基-22-羟基-胆甾烷13。以三甲基硅基三氟甲磺酸酯为促进剂,化合物13与葡萄糖三氯亚胺酯给体11进行糖苷化反应以83%的产率得到单糖苷15。最后,在甲醇中,用氢氧化锂脱除酰基保护基团后并在无水甲醇中回流反应,以95%的产率得到甲基Funlioside B。 相似文献
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壳聚糖硫酸酯制备方法 总被引：8，自引：0，他引：8
壳聚糖是甲壳素脱乙酰基的产物，本身可生物降解，具有良好的生物相容性。经过硫酸化引入SO4^2-基团。给予化合物重要生理功能，使其具有增强机体免疫力，抑制肿瘤，抑制病毒，降糖降脂，抗凝血，防治血栓，治疗溃疡和肾衰等方面的作用，国内外对其开发十分活跃，作者就壳聚糖硫酸酯的理化性质和几种制备方法进行介绍。 相似文献
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基于自动识别系统的海缆保护方法研究 总被引：2，自引：0，他引：2
针对海缆在使用过程中经常出现的锚损现象，通过对自动识别系统（AIS）功能和海缆保护要求的分析，重点利用AIS广播信息中包含船舶经纬度的特点，提出了一种利用AIS进行六点布控的海缆保护监测方法。六点布拉法可以弥补一般人工监测和摄像机监测等方法的不足，真正实现海缆的实时和动态保护。 相似文献
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Studies of xenobiotic metabolism and the regulation of enzyme systems for their metabolism (Phase I and II enzyme systems) require large numbers of animals, intensive use of experimental aquarium systems and in some instances can pose major problems when the compounds are scarce, expensive or too toxic to be disposed of easily. Previous studies have demonstrated the usefulness of isolated primary hepatocytes of fish for metabolic and enzyme induction studies. Functionally and structurally competent hepatocytes were isolated from juvenile plaice and after overnight acclimation to culture conditions, were exposed to a variety of PAHs for 24h. The levels of CYP1A1, phenol UDPGT and GST-A mRNAs were then estimated by slot blotting and hybridisation to their cDNA probes. The method enabled rapid and easy determination of the structure/activity relationships of these compounds as inducers of these key Phase I and II enzymes, and is potentially useful for screening large numbers of compounds both as an invitro toxicity test and for mechanistic studies. 相似文献
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由２，２—双（羟甲基）—１，３—丙二醇开始，经溴代，磷酰氯化，和酰基化等步骤，合成三种新的２，２—双（溴甲基）—１，３—丙二醇和多溴代酚的环状磷酸酯，即：５，５—双（溴甲基）—１，３—二氧—２—磷酰基—２—（２，４，６—三溴苯氧基）环已烷；５，５—双（溴甲基）—１，３—二氧—２—磷酰基—２—（２，３，４，５，６—五溴苯氧基）环已烷；双［５，５—双（溴甲基）—１，３—二氧—２—磷酰基］—２—（２，３，５，６—四溴苯氧基）环已烷。通过对产物元素分析，ＩＲ和质子ＮＭＲ测定，对其结构进行了鉴定 相似文献
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The environmental conditions around the first offshore HZ 21- 1 steel wellhead platform in the South China Sea are characterized by deep water, frequent typhoons, rough waves, high water temperature, severely corrosive seawater, and thick fouling organism attachments. The design and effectiveness of galvanic anode protection system are presented, and several methods are described, which are the calculation method of the protective current density considering the variation of water depth, the method of determining protection parameters considering various factors, the arrangement of anodes based on potential distribution and current requirements at different water depths, and the method of anode installation. Finally the effect of the accuracy of selected cathodic protection parameters on the economic benefits of offshore projects is also discussed.. 相似文献
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Factor analysis is used to study the organic compounds that have high degree of correlation with biomass in algal blooming. Based on this correlation, they are named characteristic organic compounds. The compounds found are sequalene(SQU), cedrol (CED), 2, 5-cyclohexadiene-I. 4-dione, 2, 6-his(1, 1-dimthylethyl )(PBQ), phenol. 2, 6-his (1, 1-dimethylethy-4-methyl) (BHT), 3-t-butyl-4-hydroxyanisole ( BHA ), I, 2-benzenedicarboxylie acid. his-( 2-methyl propyl ) ester(DIBP), dibutyl phthalate (DNBP), respectively. Monitoring the variations of concentration of these characteristic organic compounds in seawater may provide scientific basis for studying and forecasting red tides. 相似文献
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Phenols represent a group of organic pollutants frequently found in many near-shore marine systems. The microbial degradation of phenols, mainly by bacteria and fungi, has been extensively studied both experimentally and theoretically, but only relatively recently the capabilities of some algae for phenols biodegradation gained interest. The biodegradation of phenols by microalgae occurs only under aerobic conditions. In this paper, a dynamic energy budget model is proposed for describing aerobic biodegradation of phenolic compounds by microalgae and qualitatively validated against experimental data. A microalgal cell has the ability to produce biomass via the autotrophic assimilation (uptake of light and dissolved inorganic carbon), the heterotrophic assimilation (uptake of dissolved organic carbon) and, to a lesser extend, via the biodegradation of phenols. The rules of synthesizing units are used for the uptake and interactions of substrates and for the merging of assimilates. The model is capable of making predictions under oxygen and carbon (inorganic and organic) limiting conditions. Model predictions cover a wide range of experimental evidence, but also give a possible explanation for the inhibition of bioremoval of phenols in the presence of glucose. The dissolved oxygen profiles numerically observed show low oxygen concentration during the intermediate phase of the biodegradation process and a rapid increase after the consumption of the phenolic compound, indicating that lack of oxygen could be a limiting factor for the biodegradation of phenols. The presence of glucose increases the specific growth rate but decreases the specific biodegradation rate of the phenolic compound. Model analysis suggests that this inhibition may be due to the competition for oxygen between glucose and phenol assimilation. In general, the balance between the benefits and costs of the different types of assimilation determines the microalgal growth rates as well as the phenol biodegradation rates. Being based on general assumptions, the model can be applied to the biodegradation of a wide variety of aromatic compounds. 相似文献
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为了建立适于条斑紫菜(Porphyra yezoensis)蛋白质组学分析的的样品提取方法, 作者以条斑紫菜叶状体为材料, 比较了饱和硫酸铵沉淀法、三氯乙酸/丙酮沉淀法和酚提取方法3 种方法对条斑紫菜叶状体总蛋白的提取效果。结果表明, 针对条斑紫菜叶状体细胞中含有大量多糖, 多酚化合物, 色素等干扰物质的特点, 通过酚提取方法能有效去除这些干扰杂质, 得到清晰、稳定、干净的双向电泳图谱和相对较多的蛋白质点数, 为提高其他大型海藻的总可溶性蛋白提取效率提供了重要参考。 相似文献
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通过对青岛即墨东北部大官庄乡这一剥蚀残丘垅岗区进行地下水资源探测,发现了延伸规模较大的东西向张性断裂破碎带,并在大旱之年的枯水季节（１９９７年１２月）于有利部位打出日产４００ｍ３的富水井,确认该断裂带富水。由此,为在青岛地区寻找基岩裂隙水开辟了新的断裂构造领域。 相似文献