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11.
A series estrogen-imidazolium cyclophanes have been synthesized for the first time by direct quaternization of 2,4-bis(N-imidazolylmethyl)estrogens and corresponding dibromides in highly diluted acetonitrile solution in excellent yields. All new compounds were characterized by MS, 'HNMR and elemental analysis. 相似文献
12.
A Mild and Simple One‐pot Synthesis of 2‐Substituted Benzimidazole Derivatives Using DDQ as an Efficient Oxidant at Room Temperature
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A series of 2‐substituted benzimidazoles were prepared through one‐pot reaction of o‐phenylenediamine with various aryl aldehydes in the presence of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) in acetonitrile as solvent at room temperature. The reactions were smoothly preceded in excellent yields and short reaction times with an easy work‐up. The pure benzimidazoles as products were confirmed and characterized by physical and spectral data. 相似文献
13.
Fenton反应中拓展pH的研究进展 总被引:1,自引:0,他引:1
Fenton技术是一种处理难生物降解有机污染物的有效方法,它可以在较温和的条件下反应,但其缺点是适用pH范围窄。本文讨论了改进催化剂和氧化剂以拓展pH范围的不同方法,并概述了拓宽pH的反应机理。催化剂的改进包括使用负载型催化剂、铁及含铁矿物催化剂、改性催化剂、非铁金属活性位催化剂等代替Fe(Ⅱ),这些催化剂在较宽的pH范围内具有较高的催化活性,可以拓宽Fenton反应的pH范围。对氧化剂的改进包括使用含有H_2O_2的固体氧化剂如过碳酸盐和过硫酸盐等,利用其自身的性质以达到拓宽pH范围的目的。通过对催化剂与氧化剂的同时改进,能有效拓宽Fenton反应的pH范围,同时也会避免生成铁泥。 相似文献
14.
Synthesis of poly(o-phenylenediamine) hollow spheres and nanofibers using different oxidizing agents
Jie Han 《European Polymer Journal》2007,43(10):4229-4235
Poly(o-phenylenediamine) (PoPD) hollow spheres (ca. 800 nm in outer diameter) were synthesized by a simple solution route using ammonium persulfate (APS) as the oxidizing agent, whereas PoPD nanofibers (0.5-2 μm in width and more than 100 μm in length) and gold nanoparticles (200-500 nm) were obtained when changing the oxidizing agent of APS to chlorauric acid (HAuCl4). The chemical structures of PoPD hollow spheres and nanofibers were characterized by FTIR and XRD spectra. When using HAuCl4 as the oxidizing agent, the products of PoPD nanofibers and gold nanoparticles could be separated by chemical methods. The monomer droplets were proposed to act as template to the formation of polymer hollow spheres while the oriented growth of polymer nanofibers might be catalyzed by gold nanoparticles. 相似文献
15.
Highly photostable supramolecular photosensitizing ‘lighted metal-free’ assemblies of DPZ-Th have been developed which show strong absorption in the visible region and excellent electron transportation potential from donor to acceptor units. The as-prepared assemblies of DPZ-Th activate aerial oxygen to generate Type I reactive oxygen species (ROS) under visible-light irradiation in mixed aqueous media. Owing to these properties, the as-prepared DPZ-Th assemblies exhibit high photocatalytic activity in catalyzing the aerobic oxidative coupling of benzylamines and synthesis of quinazolines. Various spectroscopic studies support the participation of Type I reactive species in the reaction mechanism. The ‘pure’ oxygen environment was not needed for carrying out these transformations and all the reactions proceed very well under aerial conditions to furnish the desired products in high yields. 相似文献
16.
Yan Yang Xiaojia Yuan Qian Wang Shipeng Wan Cheng Lin Siyu Lu Prof. Qin Zhong Prof. Kan Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(9):e202314383
Directional organic transformation via a green, sustainable catalytic reaction has attracted a lot of attention. Herein, we report a photoelectrochemical approach for highly selective epoxidation of alkenes in a salt solution using Co2(OH)3Cl (CoOCl) as a bridge of photo-generated charge, where the lattice Cl− of CoOCl can be oxidized to generate HClO by the photo-generated holes of BiVO4 photoanode and be spontaneously recovered by Cl− of a salt solution, which then oxidizes the alkenes into the corresponding epoxides. As a result, a series of water-soluble alkenes, including 4-vinylbenzenesulfonic acid sodium, 2-methyl-2-propene-1-sulfonic acid sodium, and 3-methyl-3-buten-1-ol can be epoxidized with near 100 % conversion rate and selectivity. Through further inserting a MoOx protection layer between BiVO4 and CoOCl, the stability of CoOCl−MoOx/BiVO4 can be maintained for at least 120 hours. This work opens an avenue for solar-driven organic epoxidation with a possibility of on-site reaction around the abundant ocean. 相似文献
17.
《Arabian Journal of Chemistry》2020,13(1):1105-1119
The present study was carried out in order to identify and characterize the compounds of Rosa canina fruits by HPLC-UV-MS. The total phenolic determiner by a new Fast Blue method (FBBB), which detects phenolic directly, reported an average total phenolic concentration of 1.7 folds greater than Folin-Ciocalteu (F-C), which indicates that an indirect detection method of total phenolic should be replaced in future studies by the FBBB method. TPC of the ethanolic extract was positively correlated with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging effect. The DPPH activity of R. canina extract which is higher than the IC50 of the ascorbic acid and Butylated Hydroxytoluene (BHT), but lower than the IC50 of quercetin and trolox. The determination of intracellular reactive oxygen species (ROS) proved the antioxidant effect of the extract on HepG2 and SH-SY5Y cells. A concentration of 1.63 μg/ml on HepG2 cells had an oxidizing effect instead of the antioxidant effect, which is due to the existence of a tert-butyl group in sesquiterpene identified by HPLC-UV-MS method. These results indicate that the fruits of R. canina can be used as a natural source of antioxidants against oxidative stress and some types of cancer. 相似文献
18.
Beytiye Özgün Ayşe Yaylaoglu Kıvılcım Şendil 《Monatshefte für Chemie / Chemical Monthly》2007,138(2):161-163
Summary. A new chromium(VI) reagent, 4-benzylpyridinium fluorochromate, was prepared and used for oxidation of various organic substrates
under solvent-free conditions. The reagent selectively converts primary benzylic alcohols to their corresponding carbonyl
compounds in the presence of primary aliphatic alcohols. 相似文献
19.
Josy Anteveli Osajima Hamilton M. Ishiki Keiko Takashima 《Monatshefte für Chemie / Chemical Monthly》2008,139(1):7-11
Summary. The degradation of imazapyr, an imidazolinone herbicide, in aqueous solution has been investigated with TiO2 slurry as photocatalyst at 30°C under UV radiation. The depletion of imazapyr concentration in an aqueous suspension followed
1st order kinetic behavior. The influence of pH and the charge densities of imazapyr geometries were calculated at the semi-empirical AM1 level, and the effect of temperature
was investigated. The addition of electron acceptors such as potassium persulfate and hydrogen peroxide showed that the rate
constant doubled at least. At higher persulfate concentrations the herbicide degradation was more efficient in direct photolysis
than TiO2-photocatalysis. The degradation rate constant increased by 38% upon variation of the temperature between 20.0 and 50.0°C
and displayed non-Arrhenius behavior. 相似文献
20.
Jiani Ye Dongsheng Zhang Sofia Salli Yajiao Li Feiyu Han Yuanqiang Mai Prof. Dr. Federico Rosei Prof. Dr. Yongwang Li Prof. Dr. Yong Yang Prof. Dr. Flemming Besenbacher Prof. Dr. Hans Niemantsverdriet Dr. Emma Richards Prof. Dr. Ren Su 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302994
Environmental-friendly halogenation of C−H bonds using abundant, non-toxic halogen salts is in high demand in various chemical industries, yet the efficiency and selectivity of laboratory available protocols are far behind the conventional photolytic halogenation process which uses hazardous halogen sources. Here we report an FeX2 (X=Br, Cl) coupled semiconductor system for efficient, selective, and continuous photocatalytic halogenation using NaX as halogen source under mild conditions. Herein, FeX2 catalyzes the reduction of molecular oxygen and the consumption of generated oxygen radicals, thus boosting the generation of halogen radicals and elemental halogen for direct halogenation and indirect halogenation via the formation of FeX3. Recycling of FeX2 and FeX3 during the photocatalytic process enables the halogenation of a wide range of hydrocarbons in a continuous flow, rendering it a promising method for applications. 相似文献