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1.
Ruifang Wang Wei Zhang Kathryn C. Golden John F. Quinn Peng Cui Dmytro O. Tymoshenko 《Tetrahedron letters》2009,50(50):7070-7073
A series of carbinamines (α,α,α-trisubstituted amines) have been prepared in a simple and efficient one-pot procedure by the addition of Grignard reagents to a series of aliphatic, aromatic and heteroaromatic nitriles. The resulting magnesium imines are subsequently converted to the desired amine after treatment with Ti(Oi-Pr)4 and additional microwave heating. Key to this procedure is the use of microwave heating for both steps of the reaction protocol, which significantly improves both reaction yields and reduces reaction times. In general, the Grignard addition reaction is complete within 5-10 min at 100 °C followed by conversion with Ti(Oi-Pr)4 and additional microwave heating to give the target amines in good yields. 相似文献
2.
纳米复合固体超强酸SO42-/CoFe2O4的制备和表征 总被引:27,自引:0,他引:27
采用纳米化学制备技术合成了新型的纳米复合团体超强酸催化剂SO42-/CoFe2O4。用XRD、TEM、XPS、红
外光谱和比表面测定等技术研究了该催化剂的结构形态,结果表明:所研制的SO42-/CoFe2O4催化剂为晶态纳
米粒子(< 50nm),比表面积很大(157m2· g-1),SO42-与氧化物的金属离子呈无机双齿螯合状配位化合物的结
合形式。以乙酸乙酯合成为模型反应考察了该催化剂的催化活性,比较了酸性和酸强度,推断出该催化剂的酸
强度H0<-14.5。 相似文献
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Aryl imines, formed in situ from aldehydes and amines undergo smoothly nucleophilic addition with trimethylsilyl cyanide on the surface of montmorillonite KSF clay under mild reaction conditions to afford the corresponding α-aminonitriles in excellent yields. The solid acid can be recovered and recycled in subsequent reactions with a gradual decrease of activity. 相似文献
5.
烯烃的Friedel-Crafts烷基化反应(以下简称F-C烷基化反应)一般采用金属卤化物和浓硫酸作催化剂,但两种情况下的后处理都比较复杂,要消耗大量溶剂,催化剂只能一次性使用。近年来,由于苯乙烯与二甲苯反应产物为具有多种工业用途的材料"PXE",国内外相继报道使用不同的催化剂来改进该反应,这些反应各有优点,但均未提及机理和与之竞 相似文献
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固体超强酸SO_4~(2-)/TiO_2对酯化反应的催化作用 总被引:9,自引:1,他引:9
1979年Hino等首先合成了SO_4~(2-)/TiO_2,SO_4~(2-)/ZrO_2等新型固体超强酸,它们有特殊的催化性能,且具有不怕水,可在高温下使用、制备方便、减少三废等优点,因此有广泛的应用前景,引起国内外催化工作者的兴趣和重视. 我们仿照Hino法合成了SO_4~(2-)/TiO_2体超强酸催化剂,测定了酸强度和比表面.本研究着眼点是取代有严重腐蚀作用的浓H_2SO_4催化剂,选用两类酯化反应考察了SO_4~(2-)/TiO_2的催 相似文献
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A. Davoodnia M. Roshani S.H. Malaeke M. Bakavoli 《中国化学快报》2008,19(5):525-528
A rapid and efficient method for the synthesis of isoxazolo[5,4-d]pyrimidin-4(5H)-ones has been developed through cyclocondensation of 5-aminoisoxazole-4-carboxamides with orthoesters under conventional heating and solvent-free microwave irradiation with solid acid catalysis. In comparison, the reactions are faster and the yields are higher under microwave irradiation. 相似文献
8.
A one-pot tandem isomerization/carbon-carbon bond forming sequence catalyzed by a ruthenium complex/Br?nsted acid binary system is demonstrated. The method enables the use of readily available allylamides to deliver reactive imines under relay catalysis using a binary catalytic system. Subsequent Br?nsted acid catalyzed carbon-carbon bond forming reactions of the generated imines with nucleophilic components afforded Friedel-Crafts and Mannich products in good yields. 相似文献
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Nádia R. Aguiam Vânia I. CastroAna I.F. Ribeiro Rui D.V. FernandesCarina M. Carvalho Susana P.G. CostaSílvia M.M.A. Pereira-Lima 《Tetrahedron》2013
The multicomponent Ugi reaction is a straightforward method that can be used for the synthesis of highly hindered C-tetrasubstituted amino acids by reacting an amine, a ketone or aldehyde, a carboxylic acid and an isocyanide. In the present work, the synthesis of several α,α-dialkylglycines (α,α-diethylglycine, Deg; α,α-dipropylglycine, Dpg; 1-amino-1-cyclohexanecarboxylic acid, Ac6c) was achieved by solid phase Ugi reaction using resins functionalized with the isocyanide group. Since no resins with these features were available commercially, the functionalization of an aminomethylated resin started by the use of glycine (Gly), β-alanine (β-Ala) and γ-aminobutyric acid (GABA) as spacers. After spacer N-formylation, followed by dehydration, isocyanide functionalised resins were obtained. The resins were then used in solid phase Ugi reaction, using phenylacetic acid as the acid component, 4-methoxybenzylamine as the amine component and different ketones, to afford the desired N-acylated α,α-dialkylglycines in good overall yields (60–80%), after acidolytic cleavage from the resin, thus proving the feasibility of this approach. 相似文献
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镝对固体超强酸催化剂ZrO2-Dy2O3/SO42--HZSM-5的酸性和稳定性的影响 总被引:9,自引:0,他引:9
合成了固体超强酸催化剂ZrO2-Dy2O3/SO4^2-,并将其负载于分子筛HZSM-5上,制成复合型固体超强酸催化剂ZrO2-Dy2O3/SO4^2-HZSM-5)以下简称催化剂ZDSH),采用Hammett批示剂法,吸附吡淀的TPD法,考察催化剂ZDSH的酸强度及其分布;通过热重分析(TGA)、差热分析(DTA)方法,考察镝对催化剂ZDSH稳定性的作用;运用红外光谱(IR)法,分析催化剂ZDS 相似文献
12.
SO2-4/ZrO2/Fe3O4/Al2O3磁性固体超强酸的制备与表征 总被引:5,自引:0,他引:5
用化学共沉淀法制备了一系列SO2-4/ZrO2/Fe3O4/Al2O3磁性固体超强酸, 利用XRD、IR、TG-DSC、VSM、TEM及HRTEM等手段对样品结构进行了表征. 结果表明, 引入一定量的Fe3O4和Al2O3有利于四方晶相ZrO2(t)结构的稳定;Fe3O4超细粒子的引入, 使固体超强酸具备了超顺磁性;HRTEM 结果显示ZrO2晶体生长趋向于ZrO2(t)的[101]方向,其(101)晶面间距为d(101)=0.29 nm, 与XRD 衍射结果一致. Hammett 指示剂测得样品SZA-20-200-800酸强度(H0<-13.8)最强, 酸性大于浓硫酸(H0=-11.9). 相似文献
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MingDeCHEN AnQiCHEN MinLIN ZhaoYingLI JinCHEN 《中国化学快报》2005,16(2):197-200
2-Diethylaminoethyl aryloxyacetates are prepared efficiently in 75~95% yields by condensation of the corresponding aryloxY2acetic acids with 2-diethylaminoethanol in the presence of catalytic amount of solid superacid SO4 ^2-/Fe2O3. 相似文献
14.
Sven Mangelinckx 《Tetrahedron letters》2007,48(37):6535-6538
Alkylation of α,α-dichloroketimines at the α-position with benzyl bromides afforded β-arylated α,α-dichloroketimines in good yields. The latter imines could be easily transformed to the corresponding alkynyl imines, a synthetically important class of compounds, via 1,2-elimination of HCl upon treatment with 2 equiv of sodium hydride in DMSO or potassium tert-butoxide in THF. 相似文献
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A new synthesis of N-(α-methoxyarylmethyl)-2,2-dimethylaziridines is presented. Different benzaldehydes were converted into the corresponding imines upon reaction with 2-bromo-2-methylpropylamine. Treatment of the latter imines with sodium methoxide afforded N-(α-methoxyarylmethyl)-2,2-dimethylaziridines in good yields. 相似文献
16.
Rapid synthesis of quinoline-4-carboxylic acid derivatives has been achieved by reaction of 2-methoxy acrylates or acrylamides with N-arylbenzaldimines in acetonitrile under InCl3 catalysis and microwave irradiation. Isolated yields up to 57% within 3 min have been obtained. The Lewis acid and the microwave activation appeared as crucial parameters for the reaction. The role of indium chloride and ytterbium triflate was specified using 13C NMR data and model theoretical studies. 相似文献
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《Green Chemistry Letters and Reviews》2013,6(1):23-27
Abstract Imines constitute a class of therapeutic agents that possess a broad spectrum of pharmacological activity. The conventional method for synthesis of imines by nucleophilic addition of amines to ketones or aldehydes requires long reaction times along with the use of organic solvents and a glacial acetic acid catalyst. We report the synthesis of Schiff's bases of isonicotinic acid hydrazide by novel, green routes using sonication, stirring, and microwave irradiation, respectively. Initial results are reported and indicate that by employing greener methods under aqueous conditions, high yields and shorter reaction times can be achieved. 相似文献
19.
Diphenyl diamine-based phosphonyl imines attached by the N-isopropyl group in the auxiliary have been synthesized in good yields under convenient reaction conditions. These new chiral N-phosphonyl imines can react with glycine enolate smoothly to give chiral α-β diamino esters in good yields (72%–90%) and up to excellent diastereoselectivity (>99:1 dr). By treatment with HBr, the chiral auxiliary can be readily removed. The absolute structure has been unambiguously determined by converting a product to a known sample. 相似文献
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Friedel-Crafts bimolecular cyclizations of cinnamic acid and cinnamoyl chloride with aromatic compounds in strong and superstrong acids in present of 1 mol% BTISA were investigated. It was demonstrated that catalytic amounts of this new superacid have essential effect on such type of reactions. Its use makes possible the preparation of indanones with quantitative yields. 相似文献