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271.
《Comptes Rendus Chimie》2014,17(5):450-453
A task-specific ionic liquid as an environmentally eco-friendly green catalyst has been synthesized and used in the ring opening of epoxides under green conditions. In order to use protic ionic liquids (PIL), we decided to synthesize 1,2-azidoalcohols via a ring opening reaction of epoxides with 1-hydrogen-3-methylimidazolium azide ([Hmim]N3), which actually acts as a solvent, a reagent and an activator of the epoxide ring. The reaction was carried out in short times (50–70 min) at 70 °C to give 1,2-azidoalcohol in 80–94% isolated yields. 相似文献
272.
An EPDDMAC-GE polymer (hydrophilic molecule) has been synthesized based on epoxypropyl dodecyl dimethyl ammonium chloride (EPDDMAC) and gelatin. A DEEPSAC-GE polymer (hydrophobic molecule) has been synthesized based on diethyl-2,3-epoxypropyl-[3-methyldimethoxyl] silpropyl ammonium chloride (DEEPSAC) and gelatin. Compared with initial gelatin, the gelatin modified with quaternary ammonium salts containing epoxide groups exhibits stronger antibacterial activity. 相似文献
273.
《Comptes Rendus Chimie》2015,18(12):1297-1306
β-Azidoalcohols, β-cyanohydrins, and β-acetoxy alcohols have been synthesized in the presence of a Fe3O4@SiO2/bipyridinium nanocomposite (Fe3O4@SiO2/BNC) as a novel magnetic and recyclable phase-transfer catalyst (PTC) in water. The catalyst was characterized with FT–IR, SEM, XRD, VSM, and TGA. This methodology offers several advantages, including easy work-up procedure, excellent regioselectivity, high yields, short reaction times, recyclable catalyst, easy separation of the catalyst through an external magnet and eco-friendly procedure. 相似文献
274.
275.
Composites of polyaniline(PAn) and epoxide polysiloxane(EPSi) are reported for the first time. EPSi is designed, synthesized and N-grafted onto the PAn backbone through covalent bonds. As-prepared EPSi-g-PAn composites are soluble in organic solvents and the corresponding films can be easily produced via a simple solution-casting procedure. The composite films combine the mechanical characteristics of EPSi and the chemical properties of PAn, enabling the facile introduction of the noble metal particles. The successful fabrication of the composites is confirmed by the investigation of the molecular structure, crystalline structure and microstructure of the materials. The resulting composite films containing noble metal particles are employed as the catalysts for the hydrogenation of phenol to produce cyclohexanone, which exhibit the convenience and recyclability for usage as well as the high catalytic activities, including the conversion ratio of 97%-100% and the selectivity as high as 84%-98%. The present work not only provides a new method to improve the processability of the conducting polymers but also describes a kind of composite materials that may display outstanding preformances in industrial catalysis. 相似文献
276.
CongFaLI QiaoLIU HongJieCUI DiDING AiGuoJI YinBoQU 《中国化学快报》2003,14(11):1133-1134
Epoxide hydrolase-catalyzed resolution of ethyl 3-phenylglydidate was investigated using resting cells ofPseudomonas sp. BZS21. Under the present conditions 26.2 % of (2R, 3S)-ethyl 3-phenylglycidate with ee value of 94.6 % was obtained from the racemic mixture. 相似文献
277.
The reaction between N-hydroxyphthalimide and optically pure epichlorohydrin followed by addition of methanol represents a straightforward procedure for the synthesis of isoxazolidin-4-ols in high enantiomeric purity. Under the same conditions, the reaction of glycidyl arenesulfonates can lead to different products depending on the nature of the sulfonate. This property allowed the synthesis of both enantiomers of 4-methylisoxazolidin-4-ol from the same chiral epoxide starting material. 相似文献
278.
Nicolas Monfort 《Tetrahedron》2004,60(3):601-605
A highly productive bioprocess for the preparation of enantiopure azole antifungal chirons is described. These are key building blocks for the synthesis of new triazole drug derivatives known to display valuable activity against such infections as for instance fluconazole-resistant oro-oesophageal candidiasis. Using commercially available recombinant Aspergillus niger epoxide hydrolase under optimised experimental conditions, the hydrolytic kinetic resolution of 1-chloro-2-(2,4-difluorophenyl)-2,3-epoxypropane was performed in plain water, at room temperature, using a two-phase reactor. This methodology allowed the process to be run at a substrate concentration as high as 500 g/L (i.e., 2.5 M) and afforded the (unreacted) epoxide and the corresponding vicinal diol, both in nearly enantiopure form and quantitative yield. 相似文献
279.
Enantiospecific total synthesis of the phytoalexins, solavetivone, anhydro-β-rotunol, solanascone, and dehydrosolanascone, starting from the readily available monoterpene, (R)-carvone has been accomplished. 相似文献
280.
Chemical fixation of carbon dioxide to cyclic carbonates under extremely mild conditions with highly active bifunctional catalysts 总被引:6,自引:0,他引:6
Xiao-Bing Lu Ying-Ju Zhang Bin Liang Xiao Li Hui Wang 《Journal of molecular catalysis. A, Chemical》2004,210(1-2):31-34
Chemical fixation of carbon dioxide to cyclic carbonates proceeds effectively under extremely mild temperature and pressure by using a bifunctional nucleophile–electrophile catalyst system of tetradentate Schiff-base aluminum complexes ((Salen)AlX) in conjunction with a quaternary ammonium salt (n-Bu4NY) in the absence of any organic solvent. Electrophilicity of central Al3+ ion and the steric factor of substituent groups on the aromatic rings of (Salen)AlX (electrophile), and nucleophilicity and leaving ability of the anion Y− of n-Bu4NY (nucleophile) have a great effect on the catalytic activity of the bifunctional catalyst. 相似文献