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991.
Qiong Wu Hui Feng Dong‐Dong Guo Mian‐Shuai Yi Xing‐Han Wang Bo Jiang Shu‐Jiang Tu 《Journal of heterocyclic chemistry》2013,50(3):599-602
A green and highly efficient method for the synthesis of polyfunctionalized indoline‐spiro fused pyran derivatives has been established. This reaction was conducted by reacting readily available and inexpensive starting materials, such as isatins, cyclic‐1,3‐dicarbonyl compounds, and malononitrile in aqueous media without any catalysts under microwave irradiation. The present green synthesis shows fascinating properties such as the use of water as the reaction solution, concise one‐pot conditions, short reaction periods (8–14 min), and easy purifications. The synthesis could also set a good example to GAP (Group‐Assistant‐Purification) chemistry in which purification via chromatography can be avoided and the pure products can be easily acquired only by washing the crude products with 95% EtOH. 相似文献
992.
We describe a rapid and convenient colorimetric method for the detection of oxidative DNA damage caused by peroxynitrite (ONOO?) using unmodified gold nanoparticles (AuNPs). AuNPs are stable in the presence of single-stranded DNA (ssDNA) against the aggregation induced by a high ionic strength. If adsorbed ssDNA are cleaved by ONOO? to form smaller fragments, the AuNPs rapidly aggregate due to electrostatic attraction. As a result, the color of the solution changes from red to blue, and this can be seen with bare eyes. We also have evaluated the activity of the antioxidants gallic acid, ascorbic acid and caffeic acid to scavenge ONOO?. This method therefore also can be applied to screen for anti-oxidation drugs and agents. Figure
ONOO?-induced ssDNA cleavage can be visually detected by a red-to-blue color change of AuNPs. 相似文献
993.
Shanshan Zhu Ning Gan Daodong Pan Yi Li Ting Yang Futao Hu Yuting Cao Dazhen Wu 《Mikrochimica acta》2013,180(7-8):545-553
We have prepared core-shell magnetic molecularly imprinted polymer nanoparticles for recognition and extraction of tributyl tin (TBT). The use of particles strongly improves the imprinting effect and leads to fast adsorption kinetics and high adsorption capacities. The functional monomer acrylamide was grafted to the surface of Fe3O4 nanospheres in two steps, and MIP layers were then formed on the surface by creating a MIP layer on the surface consisting of poly(ethyleneglycol dimethacrylate) with a TBT template. The particles were characterized in terms of morphological, magnetic, adsorption, and recognition properties. We then have developed a method for the extraction of TBT from spiked mussel (Mytilidae), and its determination by liquid chromatography-tandem mass spectrometry. The method has a limit of detection of 1.0 ng?g?1 (n?=?5) of TBT, with a linear response between 5.0 and 1,000 ng?g?1. The proposed method was successfully applied to the determination of trace TBT in marine food samples with recoveries in the range of 78.3–95.6 %. Figure
The preparation procedures of core-shell magnetic molecularly imprinted polymer nanoparticles for recognition and extraction of tributyl tin (TBT) in seafood 相似文献
994.
Y. Z. Song F. X. Zhu Y. Song J. F. Zhou X. Z. Chu F. Y. Wu A. F. Zhu C. M. Wei J. Song X. Li J. Xu 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(1):80-83
A sensor based on gold nanoparticle on the surface of L-cysteine modified gold electrode is prepared. Electrochemical behavior of dopamine hydrochloride is investigated. The linear relation between peak current of dopamine hydrochloride and scan speed in the range of 10 to 1000 mV s?1 indicates that a diffusion-adsorption controls the process. The linearity range is 1.05 × 10?5–7.38 × 10?4 M with detection limit of 1.05 × 10?6 M. The recoveries were in the range from 99.8 to 101.5% with relative standard deviations of 1.3 ~ 2.3% (n = 6). The modified electrode under ambient conditions over a period of 2 weeks has an excellent repeatability and reproducibility. 相似文献
995.
β-hydroxy ketones were obtained in good yields by the “tin-ene” reactions of α-bromoacetophenone and metallic tin with aldehydes. 相似文献
996.
The chloromethylation of aromatic hydrocarbons proceeded efficiently using the reusable ionic liquid [emim]BF4 as promoter. The reactions were completed in 5 h at 70°C with good yields and easy workup. 相似文献
997.
A facile and efficient synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes has been accomplished by treatment of β-naphthol with aryl or alkyl aldehydes catalyzed by 2-1′-methylimidazolium-3-yl-1-ethyl sulfate in ionic liquid [BMIM][BF4] at 80°C. The luminescence of products was studied in detail. 相似文献
998.
An efficient and facile route for the synthesis of coumarins via the Pechmann reaction catalyzed by molecular iodine or AgOTf was described. 相似文献
999.
A variety of 2-(1-arylcarbonyl-1-arylazomethylidene)-thiazolidenes were synthesized in excellent yields by the reaction of 2-(arylcarbonylmethylidene)thiazolidines with diazobenzenes. 相似文献
1000.
A series of cholesterylated thiogalactosides L1 –L6 the cell targeting ligands for gene delivery to hepatocytes, was synthesized. Related poly(ethylene glycol) chain was used as a bridge for the attachment of galactoside on one hydroxyl end, while the other hydroxyl end was linked with cholesterol. This design provided an effective entry for the synthesis of a poly(ethylene glycol) compound with the hepatocyte targeting. 相似文献