查询词典 coumarin

Result: Five flavonoids and two coumarins were isolated from Phellinus igniarius and their structures were identified as naringenin, sakuranetin, aromadendrin, folerogenin, eriodictyol, coumarin and scopoletin.

结果 ：从桑黄中分离鉴定了 5个黄酮和两个香豆素类化合物，分别为柚皮素、樱花亭、二氢莰非素、7 甲氧基二氢莰非素、北美圣草素、香豆素及莨菪亭。

Some coumarin derivatives are synthesized through Pechmann reaction with catalytical amount of sulfuric acid.

在催化量硫酸的存在下，用微波辐射进行Pechmann反应，制备香豆素衍生物，获得中等至良好的产率。

Aqua, Sorbitol, PPG-1 PEG-9 Lauryl glycol ether, Hydrolyzed elastin, Hydrolyzed wheat gluten, Hydrolyzed collagen, Hydrolyzed glycosamino-glycans, Humulus lupulus, Propylene glycol, Triethanolamine, Sodium hydroxide, Carbomer, Maris limus extract, Ostrea extract, Imidazolidinyl urea, Parfum, Benzyl salicylate, Coumarin, Alpha isomethyl ionone, Hexyl cinnamal, Buthylphenylmethylpropionate, Linalol, Methylisothiazolinone, Methylchloroisothiazolinone.

水，山梨醇， PPG 公司- 1聚乙二醇- 9十二烷基醇醚，水解弹性蛋白，水解小麦面筋蛋白，水解胶原蛋白水解粘多糖，多聚糖，啤酒花提取物花，丙二醇，三乙醇胺，氢氧化钠，卡波姆，马里斯提取物，牡蛎提取物，咪唑烷基脲，香水，水杨酸苄酯，香豆素，阿尔法 l 紫罗兰酮，己基肉桂醛，丁苯基甲基丙醛，芳樟醇，甲基异噻唑啉酮，甲基氯异塞唑晽酮。

The UV and IR spectroscopic studies of the monomer films showed that the photoreaction ratio of monomer (about 50%) was higher than the corresponding photosensitive polymer (about 10%, PVCi). The polarized IR spectra proved that obvious anisotropic absorption was displayed in the irradiated photosensitive film. With polarizing microscopy method, we found that these kinds of photoalignment films exhibited good alignment ability, and the stability of the photoalignment film could reach about 100℃. 2 A photosensitive self-assembled monolayer was fabricated that contained photo-cycloadditable groups, such as, coumarin and cinnamate. The reaction process were detected by contact angle method because the IR absorption of monolayer was very weak. The photosensitive self-assembled monolayer promote uniform alignment of nematic liquid crystals by LPUV, and it thermal stability could reach about 130℃. 3 A cationic bolaform amphiphiles was synthesized that had two photosensitive double bonds, and can be polymerized by ultraviolet. A layer-by-layer self-assembled deposition film was prepared in aqueous solution by using this material and poly (sodium 4-styrenesulfonate). The UV-Vis. spectra proved that the multilayers film was uniform and layer-by-layer. When LPUV irradiated the film, the photopolymerizable double bond underwent [2+2] cycloaddition, and the production of the reaction distributed along the polarized direction of incident LPUV. Polarized UV-Vis. spectra indicated that the irradiated self-assembled multiplayer film was anisotropic, and the dichromic ration is about 0.09, it is higher than the spin-coating method of photosensitive polymer or monomer. We used this anisotropic film as alignment layer of nematic liquid crystals, and obtained a uniform and stability alignment result, the static contrast ratio is about 100, which is very close to application of liquid crystal device. This thesis is an instance that the photochemical material was used in the physics region of liquid crystals, the route that was from photosensitive monomer, self-assembled monolayer film to self-assembled multiplayer film was undergone, by this logical research method photoailgnment of liquid crystal was extended and consummated.

围绕上述思路开展了如下工作：1合成了三种可进行光二聚反应的光敏小分子单体，LPUV 辐照制作了光控取向膜；用紫外-可见光谱法和红外光谱法分析了薄膜中的光化学反应，发现小分子的光反应程度可达到50%以上，至少比光敏高分子高出5倍；薄膜的偏振红外光谱证实，经过LPUV 辐照后薄膜出现了明显的各向异性；将小分子光控取向膜制成液晶器件，在偏光显微镜下观察看到均匀一致的液晶取向；并且热稳定性达到100℃左右，接近实用化要求。2制备了含肉桂酸、香豆素基团的自组装单层膜；采用接触角的方法监测自组装反应的动力学过程；紫外-可见光谱证实了自组装单层膜在石英基板表面形成；自组装单层膜经LPUV 辐照后能诱导液晶均匀取向，而且热稳定性可达130℃，热稳定性进一步提高。3合成了含有光敏双键的双季铵盐，在水溶液状态下将它和聚乙烯基苯磺酸钠沉积生成layer-by-layer 自组装多层膜，紫外-可见光谱证实这是一个逐层均匀的沉积；在LPUV 照射下，自组装膜中的光敏双键按照偏振方向发生[2+2]环加成反应，形成取向膜，用二向色性值评价的分子取向度高于高分子及小分子光控取向膜的水平；实验证明用自组装多层膜制成的液晶器件亮暗态均匀，静态对比度约为100，达到实用化器件的水平。

The hypoxanthine/XO reaction in the DMPO-ESR technique was used to correlate the effect on enzyme inhibition and ROS suppression by these coumarin derivatives, and the results showed that esculetin and 4-methylesculetin were the two most potent agents among the tested compounds.

最后以电子自旋共振法，利用 Hypoxanthine/ Xanthine Oxidase反应体系，产生之O2-自由基，去评估香豆素及其衍生物对於黄嘌呤氧化酶活性抑制和自由基清除的能力的整体表现，结果显示esculetin 和 4-methylesculetin具有最佳的活性。

Aβ（β-amyloid peptide） induce neuronal cell damage by increasing the generation of ROS. Therefore, we further assessed the effects of test compounds on living cells. Esculetin was the most potent agent at protecting cells against Aβ induced cell cytotoxisity via inhibiting the generation of ROS or ROS scavenging among the tested coumarin derivatives.

由於Aβ肽造成神经细胞伤害涉及自由基的过度生成，因此我们将上述结构-活性关系结论进一步应用在活体细胞实验的表现，结果显示esculetin可以透过抑制自由基生成或自由基清除作用而降低Aβ所引发的细胞毒性。

Seauckthorn juice can be appropriate drinks afer the diluting, which could block the N-nitroso Synthesis and also can block N-dimethylnitrosaminewhich can lead to cancer.The flavone of Seabuckthorn contains coumarin, isocoumarin, furan coumarins, lignin, as well as bitter polyphenols, 5 - serotonin, which are benefited for anti-cancer.

沙棘汁经稀释成宜引用的浓度后，能阻断N-亚硝酸的合成，另外沙棘汁对致癌物N二甲基亚硝胺也有阻断与防护的作用；沙棘黄酮中含有香豆素，异香豆素，呋喃香豆素，苦木素以及多酚类，5-色胺等具有综合抗癌作用的成分。

Acidic ion-acidic resin can also be used as a catalyst for organic synthesis, it's used instead of concentrated sulfuric acid can be catalyzed synthesis of dihydro-coumarin compounds [1], High purity isopropenyl acetate [2] and other organic compounds.

酸性离子酸性树脂也可作为一种有机合成催化剂，用它替代浓硫酸可催化合成二氢香豆素类化合物[1]，乙酸异丙烯酯[2]等有机化合物。

The first synthetic route uses 1,2,4-trimethoxybenzene and chloroacetonitrile in forming 2,4,5-trimethoxy-a-chlor-acetophenone under the anhydrous condition, then the intermediate condensates with papaverine forming the core pyrro[2,l-a]isoquinoline, followed by formation and lactonization to form the lactone ring. The second synthetic route uses prepared aldehyde with prepared ethyl nitroacetate by Knoevenagel condensation to obtain 2-Nitro-3-(2,4,5-tris-methoxy-phenyl)-acrylic acid ethyl ester and 2-Nitro-3-(2,4,5-tris-benzyloxy -phenyl)-acrylic acid ethyl ester etal intermediates. The lamellarin skeleton could arise from condensation of the papaverine and these intermediates by Michael reaction, the ester group is provided for subsequent lactonization. The third synthetic route uses coumarin or indan-l,3-dione derivatives and papaverine to form lamellarin under basic conditions.

第一条路线首先从1，2，4-三甲氧基苯出发与卤乙腈作用合成卤代芳酮中间体，然后与罂粟碱反应合成开链片螺素，最后经乙酰化、去保护、成内酯环得到片螺素；第二条路线由制备的芳醛和制备的硝基乙酸乙酯经缩合得到2-硝基-3-芳基丙烯酸乙酯，然后由该中间体与罂粟碱反应，在完成关环的同时也引入酯基，最后去保护、成内酯环得到片螺素；第三条路线是由香豆素或茚二酮出发，经溴代后的中间体与罂粟碱反应，得到片螺素的基本框架。

From Leontopodium nanum (collected from Zhang County, Gansu Province), 12 compounds were isolated, of which 9 compounds have been identified. Among them, a derivative of coumarin is new.

从采自甘肃漳县的矮火绒草全草的甲醇提取物中，采用同样方法共分离纯化得到12个化合物，鉴定了9个化合物的结构，其中有1个新化合物，命名为6，7-并二氧六环[2-（1-甲酯基-1-甲基）-甲烯基]-香豆素（1）。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。