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991.
Qingxiang Wang Yingtao Ding Feng Gao Shulian Jiang Bin Zhang Jiancong Ni Fei Gao 《Analytica chimica acta》2013
A novel DNA biosensor was fabricated through a facile sulfamide coupling reaction. First, the versatile sulfonic dye molecule of 1-amino-2-naphthol-4-sulfonate (AN-SO3−) was electrodeposited on the surface of a glassy carbon electrode (GCE) to form a steady and ordered AN-SO3− layer. Then the amino-terminated capture probe was covalently grafted to the surface of SO3−-AN deposited GCE through the sulfamide coupling reaction between the amino groups in the probe DNA and the sulfonic groups in the AN-SO3−. The step-by-step modification process was characterized by electrochemistry and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Using Ru(NH3)63+ as probe, the probe density and the hybridization efficiency of the biosensor were determined to be 3.18 × 1013 strands cm−2 and 86.5%, respectively. The hybridization performance of the biosensor was examined by differential pulse voltammetry using Co(phen)33+/2+ (phen = 1,10-phenanthroline) as the indicator. The selectivity experiments showed that the biosensor presented distinguishable response after hybridization with the three-base mismatched, non-complementary and complementary sequences. Under the optimal conditions, the oxidation peak currents of Co(phen)33+/2+ increased linearly with the logarithm values of the concentration of the complementary sequences in the range from 1.0 × 10−13 M to 1.0 × 10−8 M with a regression coefficient of 0.9961. The detection limit was estimated to be 7.2 × 10−14 M based on 3σ. 相似文献
992.
M.C. Menet C.H. Cottart M. Taghi V. Nivet-Antoine D. Dargère F. Vibert O. Laprévote J.-L. Beaudeux 《Analytica chimica acta》2013
Resveratrol is a polyphenol that has numerous interesting biological properties, but, per os, it is quickly metabolized. Some of its metabolites are more concentrated than resveratrol, may have greater biological activities, and may act as a kind of store for resveratrol. Thus, to understand the biological impact of resveratrol on a physiological system, it is crucial to simultaneously analyze resveratrol and its metabolites in plasma. This study presents an analytical method based on UHPLC-Q-TOF mass spectrometry for the quantification of resveratrol and of its most common hydrophilic metabolites. The use of 13C- and D-labeled standards specific to each molecule led to a linear calibration curve on a larger concentration range than described previously. The use of high resolution mass spectrometry in the full scan mode enabled simultaneous identification and quantification of some hydrophilic metabolites not previously described in mice. In addition, UHPLC separation, allowing run times lower than 10 min, can be used in studies that requiring analysis of many samples. 相似文献
993.
Heterogeneous catalysts were developed by supporting palladium nanoparticles on modified cross‐linked polyacrylamide and successfully applied in Suzuki‐Miyaura cross‐coupling reactions. These catalysts are stable to air and moisture, and no sign of metal leaching was detected during the reactions as judged by elemental analysis of palladium by ICP‐OES technique and hot filtration test, which demonstrates the heterogeneous character of the catalysts. High yields of desired products were resulted by using these phosphine‐free catalysts at temperatures below 80 °C without aid of any additional ligands. The heat stability of the catalysts at the operating temperature was confirmed by thermogravimetric analysis (TGA). These catalysts are easy to use and cost effective. They can be recovered from reaction mixture by a simple filtration and reused in more successive reactions without significant loss in activity. The catalyst activity was restored by an ultrasonication program after deactivation in 10 cycles. 相似文献
994.
Protocols for the synthesis of cage-substituted 1-vinylsilatranes have been developed and updated. The 1-vinylsilatranes with organic substituents attached to silatrane cage were functionalized in ruthenium-catalyzed trans-silylation with olefins, leading to novel styrylsilatranes in high yields. 相似文献
995.
Sonogashira coupling of (E)-α-iodovinylsilanes 1 with (trimethylsilyl)-acetylene gave (Z)-1,3-bis(trimethylsilyl)alk-3-en-1-ynes 2, which underwent a desilylation reaction to afford (Z)-3-(trimethylsilyl)alk-3-en-1-ynes 3 in good yields. (1E,3Z)-1-Arylseleno-3-(trimethylsilyl)-substituted 1,3-dienes 5 could be synthesized stereoselectively via hydrozirconation of (Z)-3-(trimethylsilyl)alk-3-en-1-ynes 3, followed by trapping with arylselenenyl bromides. 相似文献
996.
Masanori Miura Takanori Koike Tsukasa Ishihara Fukushi Hirayama Shuichi Sakamoto Minoru Okada 《合成通讯》2013,43(24):3809-3820
A one‐pot synthetic procedure for 2,2′‐disubstituted biaryls was developed via a Suzuki cross‐coupling reaction of aryl triflates in a biphasic solvent system. The effects of various bases and solvents were investigated. Results showed that the Na2CO3–toluene/H2O combination gave the highest yields. 相似文献
997.
An improved, mild procedure for the CuI‐catalyzed coupling reactions of aryl iodides with aliphatic and aromatic thiols, using L ‐proline as the ligand, is reported. This procedure is noteworthy given its high generality and exceptional level of functional group toleration. 相似文献
998.
Treatment of 1H-4,5-dihydro-3-aryl-5-(2-hydroxyaryl)pyrazole with o-dibromoxylene under liquid-liquid phase transfer catalytic conditions using tetra-n-butylammonium hydrogen sulphate or [18]-crown-6 as PT catalyst, benzene/chloroform as organic phase and 50% aqueous potassium hydroxide as second phase, afforded novel 2,5,9,10-tetrahydro [7,8-g] benzo-8-arylpyrazolo[4,5-e] [1,5-b] benzoxazonines. 相似文献
999.
Pinacol-type coupling reaction products presenting a high meso-diastereoselectivity (the ratio dl/meso was 4/96 up to 1/99) were obtained in fair to good yields (24–69%) using several aromatic aldehydes as starting materials and aluminium powder/copper sulfate as catalysts, in water, under reflux conditions. 相似文献
1000.
Chariklia Sotiriou-Leventis Xiaojiang Wang Sudhir Mulik Arumugam Thangavel Nicholas Leventis 《合成通讯》2013,43(14):2285-2298
Immobilization of catalysts on solid supports is a promising approach to combine the advantages of heterogeneous and homogeneous catalysts. Pd(PPh3)2Cl2, known as an extremely active homogeneous catalyst for the Sonogashira coupling reaction, has been immobilized on high-surface-area MCF (mesocellular foams)–type mesoporous silica powder modified with 3-aminopropyltriethoxysilane and subsequently with diphenylphosphine. The functionalized MCF-type silica and supported catalysts have been characterized by x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), elemental analysis, nitrogen sorption porosimetry, and scanning electron microscopy (SEM). Such supported Pd catalysts have proven to be useful recyclable reagents for copper- and amine-free Sonogashira coupling reactions of haloaromatic compounds with terminal alkynes. 相似文献