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Using NBS (N‐bromosuccinimide) and the ionic liquid (1‐butyl‐3‐methylimidazolium tetrafluoroborate) as an oxidation system, twelve unsymmetric azo compounds were efficiently prepared from hydrazo compounds for the first time. In contrast to the known methods, this novel access to azo compounds presented here is operationally simple, environmentally benign and has the advantage of enhanced atom utilization. Furthermore, the solvent and the basic catalyst used can be recovered conveniently and reused efficiently. 相似文献
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A NBS-mediated sequential one-pot synthesis of multifunctionalized thiazoles and thiophenes from 1,3-dicarbonyl compounds and mercaptonitrile salts has been developed under mild conditions. This transformation involves sequential bromination/SN2 alkylation/Thorpe–Ziegler cyclization/regio-selective elimination of a –COR group, affording the desired products in moderate to good yields. The sequence of the leaving reactivity of –COR groups was determined and a possible mechanism was proposed. 相似文献
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类胡萝卜素是一类奇特的色素,由高等植物和微生物光化学合成,作为防止单线氧通过光敏反应产生危害的必要基团,类胡萝卜素最近受到了关注。类胡萝卜素联于富勒烯上,既可大大增加在可见光区域光诱导电子转移的有效吸收断面,又可抑制富勒烯敏化单线氧的危害能力。合成了类胡萝卜素的相关化合物,报道的某些反应条件先进且简洁。 相似文献
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Biswanath Das Yallamalla Srinivas Harish Holla Keetha Laxminarayana Ravirala Narender 《Tetrahedron letters》2007,48(38):6681-6683
Polymethylhydrosiloxane (PMHS) in combination with (bromodimethyl)sulfonium bromide or NBS has been utilized for the first time for reductive bromination of aromatic aldehydes at room temperature to afford the corresponding benzyl bromides in excellent yields. 相似文献
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Recent advances and applications in 1,2,4,5-tetrazine chemistry 总被引:2,自引:0,他引:2
Nurullah Saracoglu Author Vitae 《Tetrahedron》2007,63(20):4199-4236
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A facile, convenient, environmentally benign, and one-pot synthesis of imidazo[1,2-a]pyridines from 2-aminopyridines and in-situ generated phenacyl bromides under microwave irradiation in polyethylene glycol (PEG-400) and water (1:2) has been developed. The protocol provides a better alternative to the existing method as it involves utilization of in-situ-generated α-bromoacetophenones, avoids the use of lachrymatric α-haloketones as well as volatile toxic organic solvents, and reduces the reaction time to obtain excellent yield. 相似文献
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Nasser Iranpoor Habib Firouzabadi Hamid Reza Shaterian M. A. Zolfigol 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):1047-1071
The use of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high yields in the presence of thiols. 相似文献