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121.
Araceli Núñez 《Tetrahedron》2004,60(29):6217-6224
Tris(trimethylsilyl)silane (TTMSS) and azabisisobutyronitrile (AIBN) promoted the intermolecular arylation of aryl and heteroaryl bromides onto aromatic solvents under thermal conditions via a radical pathway. 相似文献
122.
D. K. Rohrbaugh H. D. Durst F. R. Longo S. Munavalli 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2639-2650
Treatment of 1, 3-cyclohexadiene with CF 3 SCl at m 80°; furnishes 15 compounds. All but the two dimerized adducts arise from the free radical catalyzed addition of CF 3 S and Cl radicals to carbon-carbon double bonds. One dimerized product arises via dimerization of the substrate itself, while the other results from the cross-coupling of the substrate with the reaction product. The same reaction with 1, 4-cyclohexadiene gives 14 compounds. The mass spectral characterization of various compounds and their probable mechanism of formation are presented in this article. 相似文献
123.
Sanju Das Sushanta Kumar Parida Tanumoy Mandal Laxmikanta Sing Suman De Sarkar Sandip Murarka 《化学:亚洲杂志》2020,15(5):568-572
An organophotoredox catalyzed efficient and robust approach for the synthesis of highly important 3‐alkyl substituted chroman‐4‐one scaffold is developed using visible light induced radical cascade cyclization strategy. The reaction is initiated through the generation of alkyl radicals from N‐(acyloxy)phthalimides under photoredox conditions, which subsequently undergo intermolecular cascade radical cyclization on 2‐(allyloxy)arylaldehydes to afford chroman‐4‐one scaffolds. The presented strategy is attractive with regard to mild reaction conditions, operational simplicity, high functional group tolerance and broad substrate scope. 相似文献
124.
Crystals of the 4‐halo‐1,2,3,5‐dithiadiazolyl radicals (X = F, Cl, Br) were obtained by sublimation at 80 °C and 10?2 Torr, and the structures were determined by X‐ray diffraction. The fluoro derivative crystallizes as a cisoid dimer in the space group P21/n, whereas the chloro and bromo derivatives crystallize isomorphous as twisted dimers in the space group C2/c. The chloro and bromo derivatives show the shortest intradimer S···S contacts of all known 1,2,3,5‐dithiadiazolyl dimers. In addition the obtained structure of ClCN2S2? represents the fifth polymorph of ClCN2S2? characterized by X‐ray crystallography. The structures and the packing including secondary interactions are discussed. 相似文献
125.
Sébastien Balieu Krimo ToutahLaura Carro Lise-Marie ChamoreauHélène Rousselière Christine Courillon 《Tetrahedron letters》2011,52(22):2876-2880
A straightforward formation of six- and eight-membered rings via the radical cyclization of specifically designed ynamides is reported. This strategy provides a protoberberine analog in only three steps by a radical cyclization cascade. 相似文献
126.
127.
液相隔膜辉光放电等离子体自由基发射光谱研究 总被引:2,自引:0,他引:2
为了更好了解液相隔膜辉光放电等离子体引发的化学反应机理,运用发射光谱法研究了稀硫酸溶液隔膜辉光放电等离子体产生的自由基,估算了电子温度与电子密度。结果表明:当电压超过700 V时,观察到了羟基自由基和氢原子的发射光谱;当电压超过750 V时,除了羟基自由基和氢原子外,还观察到了氧原子的发射光谱;这些自由基的发射强度随电压升高而升高;稀硫酸溶液隔膜辉光放电等离子体的平均电子温度与平均电子密度分别为1.3×104 K与7.8×1017 cm-3。 相似文献
128.
The photo-Fenton degradation of carbamazepine (CBZ) assisted with ultrasound radiation (US/UV/H2O2/Fe) was tested in a lab thin film reactor allowing high TOC removals (89% in 35 min). The synergism between the UV process and the sonolytic one was quantified as 55.2%.To test the applicability of this reactor for industrial purposes, the sono-photo-degradation of CBZ was also tested in a thin film pilot plant reactor and compared with a 28 L UV-C conventional pilot plant and with a solar Collector Parabolic Compound (CPC). At a pilot plant scale, a US/UV/H2O2/Fe process reaching 60% of mineralization would cost 2.1 and 3.8 €/m3 for the conventional and thin film plant respectively. The use of ultrasound (US) produces an extra generation of hydroxyl radicals, thus increasing the mineralization rate.In the solar process, electric consumption accounts for a maximum of 33% of total costs. Thus, for a TOC removal of 80%, the cost of this treatment is about 1.36 €/m3. However, the efficiency of the solar installation decreases in cloudy days and cannot be used during night, so that a limited flow rate can be treated. 相似文献
129.
Jan Světlík František Tureček Katarzyna Hartwich Krzysztof Kozieł Paweł Pakulski Aleksandra Pałasz Justyna Kalinowska-Tłuścik Dariusz Cież 《Tetrahedron》2019,75(18):2652-2663
Ceric ammonium nitrate-mediated oxidative cyclizations of CH-acids with terpenes and terpene like substrates were investigated. Dimedone, acetylacetone, and methyl nitroacetate were condensed with pinene, norbornene, nopol, camphene, and carvone and the reaction stereoselectivity was examined. Condensation with endocyclic double bonds in pinene and nopol displayed stereoselectivity, resulting in the formation of pure enantiomers. Condensation with exocyclic double bonds in camphene and carvone produced enantiomer mixtures. The mechanism of the intramolecular annulation in a nopol derivative is discussed with the help of DFT and ab initio calculations. 相似文献
130.
The first controlled synthesis of the title radical, 1, was achieved by oxidation of a hydroxylamine precursor; the radical itself can thus readily be isolated, studied by ESR and UV-vis, and compared to results of computational modeling. The benzothiazole ring induces substantial delocalization of the nitroxide spin density (a(NO) = 9.2 G, a(ring N) = 2.7 G, about 10% more than is seen in the benzimidazole nitroxide analog. 相似文献