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1.
A simple and efficient procedure for the preparation of silica-bound N-propyl triethylenetetramine sulfamic acid(SBPTETSA) by the reaction of silica-bound N-propyl triethylenetetramine(SBPTET) with chlorosulfonic acid in chloroform is described.Silica-bound N-propyl triethylenetetramine sulfamic acid was employed as a recyclable catalyst for the synthesis of 2-amino-4,6-diarylnicotinonitriles from the multi-component reaction of an acetophenone derivative,an aromatic aldehyde,malononitrile,and ammonium acetate under solvent-free conditions at 100 °C.The heterogeneous catalyst was recycled for five consecutive runs in the optimized multi-component reaction of 4-chloroacetophenone,4-chloroenzaldehyde,malononitrile,and ammonium acetate without significant loses to its catalytic activity.  相似文献   

2.
Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneous solid base catalyst for the synthesis of 3,4‐dihydropyrano[c]chromenes, 2‐amino‐4H‐pyrans, 1,4‐dihydropyrano[2,3‐c]pyrazoles, and 2‐amino‐4H‐benzo[e]‐chromenes via the condensation reaction of dimedone, ethyl acetoacetate, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐ one, and α‐naphthol, respectively, with aromatic aldehydes and malononitrile in refluxing aqueous ethanol. The heterogeneous solid base showed similar efficiency when reused in consecutive reactions.  相似文献   

3.
A sulfonated carbon material was shown to be a highly efficient,eco-friendly,and recyclable solid acid catalyst for the Biginelli reaction of β-ketoester,aldehyde,and urea or thiourea under solvent-free conditions.It gave 3,4-dihydropyrimidin-2(1H)-ones and-thiones in good to excellent yields.This method has the advantages of a simple procedure with easy work-up,short reaction time,and high yields.The catalyst can be recycled after a simple work-up and was reused four times without substantial reduction in activity.  相似文献   

4.
Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.  相似文献   

5.
A series of 1,4-dihydropyridines have been prepared by a one-pot condensation of aldehydes,ethyl acetoacetate,and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at room temperature under solvent-free condition. This new protocol has the advantage of short reaction time and excellent yields,and is an environmentally benign route to the synthesis of 1,4-dihydropyridines.  相似文献   

6.
Preparation of perchloric acid supported on alumina and its primary application as a solid supported heterogeneous catalyst to the synthesis of α-(α-amidobenzyl)-β-naphthols by a one-pot, three-component condensation of benzaldehydes, β-naphthol and acetamide or benzamide under thermal solvent-free conditions were described. The present methodology offers several advantages such as simple procedure, shorter reaction time, and excellent yields.  相似文献   

7.
A coprecipitation method was used to synthesize superparamagnetic CoFe2O4 nanoparticles without using any capping agents/surfactants. The prepared nanoparticles were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, a vibrating sample magnetometer (VSM), N2 adsorption and thermogravimetric/differential thermal analysis/differential thermal gravimetry techniques. The synthesized spinel CoFe2O4 nanoparticles had an average size of 2-8 nm with a high surface area (140.9 m2/g). The field-dependent magnetization, demonstrated by VSM and saturation magnetization, was found to be 1.77 emu/g. An efficient method was used for the synthesis of arylidene barbituric acid derivatives using CoFe2O4 magnetic nanoparticles as a magnetically separable and reusable catalyst in aqueous ethanol. The attractive features of this synthetic protocol were very short reaction time, high yields, high turnover frequency, simple work-up procedure, economy, a clean reaction methodology, and chemoselectivity, as well as provision of an ecofriendly and green synthesis.  相似文献   

8.
Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transmission electron microscopy(TEM), X-ray diffraction, reflective ultravio-let-visible spectrophotometry, and spectrofluorimetry. Calculations based on the SEM and TEM images showed that the sizes of the SnS -NPs immobilized on the AC were 30–70 nm. The prepared nanocomposite was used as a heterogeneous Lewis acid catalyst for the three-components one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol at 80 ℃. The reactions were efficiently performed in the presence of the prepared catalyst in short reaction times, and gave the desired products in high yields. This catalyst can be easily recovered by simple filtration and recycled up to eight consecutive times without significant loss of its efficiency.  相似文献   

9.
An efficient method for the synthesis of 2-amino-3-cyano-4-aryl-5,10-dioxo-5,10-dihydro-4H- ben-zo[g]chromenes and hydroxy-substituted naphthalene-1,4-dione derivatives, using silica-bonded propylpiperazine-N-sulfamic acid as a solid acid, green, heterogeneous catalyst, under ambient and solvent-free conditions, is described. A simple procedure, high yields, short reaction time, safety, and reusability of the catalyst are advantages of these protocols.  相似文献   

10.
120℃、无溶剂条件下,硅胶键合N-丙基氨基磺酸可有效催化芝麻酚、芳香醛和米氏酸三组分一锅法合成8-芳基-7,8-二氢-[1,3]二氧杂环戊烯并[4,5-g]苯并吡喃-6-酮类化合物.考察了温度及催化剂用量对产率的影响.产物的结构经1H NMR,13C NMR,质谱和元素分析进行了表征.  相似文献   

11.
Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl)ester is employed as a recyclable catalyst for the condensation reaction between aromatic aldehydes and 3-methyl-l-phenyl-5-pyrazolone. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4'-alkylmethylene-bis(3-methyl-5-pyrazolones) in 74-90% yields. The heterogeneous catalyst was recycled and used in eleven runs for the reaction between benzaldehyde and 3-methyl-l-phenyl-5-pyrazolone without losing catalytic activity.  相似文献   

12.
通过取代芳氧乙酸与α-氨基膦酸二苯酯的缩合反应合成了12个未见报道的目标化合物,用元素分析,IR,^1H NMR确定了化合物的结构。  相似文献   

13.
The oxidation of para‐xylene to terephthalic acid has been commercialised as the AMOCO process(Co/Mn/Br) that uses a homogeneous catalyst of cobalt and manganese together with a corrosive bromide compound as a promoter. This process is conducted in acidic medium at a high tempera‐ture(175–225 °C). Concerns over environmental and safety issues have driven studies to find mild‐er oxidation reactions of para‐xylene. This review discussed past and current progress in the oxida‐tion of para‐xylene process. The discussion concentrates on the approach of green chemistry in‐cluding(1) using heterogeneous catalysts with promising high selectivity and mild reaction condi‐tion,(2) application of carbon dioxide as a co‐oxidant, and(3) application of alternative promoters. The optimisation of para‐xylene oxidation was also outlined.  相似文献   

14.
Coα, Coβ-二腈六甲基N-(3-咪唑基)丙基酰胺钴啉酯的合成   总被引:2,自引:1,他引:2  
冯亚青 《有机化学》1996,16(6):532-538
维生素B~1~2衍生物, 二腈六甲基钴啉酯单酸与3-咪唑基丙胺的反应, 合成了五个新的在钴呵啉环外围b, c, d, e, f-侧链酰胺类钴啉酯化合物3b-f, 产物结构经UV/VIS、CD、IR、^1H NMR、^1^3C NMR和MS-(FAB)分析确认。  相似文献   

15.
以对氨基苯酚(1)为原料,经氨基的羟乙基化、酚羟基的苄基保护、氯代、脱保护制得N,N-二 (2-氯乙基) -对氨基苯酚(5);在碳酸铯作用下,5与溴丙炔经O-烷基化反应合成了新化合物--O-炔丙基-N, N-二(2-氯乙基)-4-氨基苯酚,其结构经1H NMR, 13C NMR和MS表征。  相似文献   

16.
A facile synthesis of α-zirconium phosphate(ZP) nanoparticles as an effective, eco-friendly, and recyclable solid acid catalyst is reported. Polyvinylpyrrolidone(PVP) and polyvinyl alcohol(PVA) were used as organic matrix as dispersing agents and served as a template for the nanoparticles. Hydrogen bonds between ZP and PVA or PVP, along the polymer chains, appear to play an important role for improving the dispersion of in situ formed ZP. Following calcination of PVA/ZP or PVP/ZP, pure hexagonal ZP nanoparticles were obtained. The catalysts were characterized by nitrogen sorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy, and transmission electron microscopy. Pyridine-FTIR and temperature-programmed desorption of NH3 suggest the presence of Brnsted acid sites. The acidic properties of the catalyst were studied in Friedel-Crafts alkylation of phenol by tert-butanol, producing 2-tert-butylphenol, 4-tert-butylphenol, and 2,4-ditert-butylphenol. The alkylation reaction was performed in the presence of catalysts P2O5/Al2O3, P2O5/SiO2, α-ZrP(prepared in the absence of the polymers), and various ionic liquids. The use of the hexagonal ZP nanoparticle catalyst afforded an excellent phenol conversion(86%) and selectivity towards 4-tert-butylphenol(83%) under optimized reaction conditions. The catalyst was easily recovered from the reaction mixture, regenerated, and reused at least four times without significant loss in the catalytic activity.  相似文献   

17.
详细论述了乙烯齐聚合成1-己烯所用催化剂的作用机理,分析比较了三种催化剂的优缺点,提出了适合以液化天然气和石脑油为原料的三十万吨乙烯装置实际情况的催化体系,并指出了今后乙烯齐聚合成1-己烯催化剂的研究方向。  相似文献   

18.
An efficient solvent‐free protocol for the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes from the condensation of 2‐naphthol with arylaldehydes, using acetic acid functionalized imidazolium salts (1‐carboxymethyl‐3‐methylimidazolium bromide ([cmmim]Br) and 1‐carboxymethy1‐3-me-thylimidazolium tetrafluoroborate([cmmim]BF4) as reusable catalysts, has been developed. The turn over frequency on the catalysts is several times higher than the other previously reported catalysts. Also, thermal gravimetric analysis and powder X‐ray diffraction pattern of the catalysts have been studied.  相似文献   

19.
A rapid and efficient procedure for the preparation of various aryl-14H-dibenzo[a,j]xanthenes was reported.The method developed produced excellent yields via one-pot condensation of β-naphthol with various aryl-aldehydes in the presence of Keggin vanadium substituted heteropolyacid,H5PW10V2O40,as catalyst under solvent free conditions.The present methodology therefore offered several advantages but not limited to excellent yields(82%-98%),short reaction times(30-50 min),mild reaction conditions,simple work-up,as well as the utilization of cheap and environmentally benign catalyst in the absence of organic solvents.  相似文献   

20.
N-Sulfonic acid poly(4-vinylpyridinum) hydrogen sulfate has been developed as a recyclable solid acid catalyst for the acetylation of alcohols, phenols, thiols, and amines, as well as the 1,1- diacetylation of aldehydes under solvent-free conditions at room temperature. The acetylated products were formed in good to excellent yields over short reaction times, and the catalyst could be readily recovered by filtration and used several times without any discernible loss in activity. The hydrogen sulfate anion of the catalytic system was found to play a critical role in enhancing the reaction time and yield of the acetylation reaction.  相似文献   

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