共查询到20条相似文献,搜索用时 31 毫秒
1.
Dr. Andrea Olmos Dr. Benoit Louis Prof. Dr. Patrick Pale 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(16):4894-4901
This study demonstrates the first zeolite‐catalyzed synthesis of piperidine derivatives, including peptidomimetics and indoloquinolizidine alkaloids. The approach developed utilizes a highly effective one‐pot reaction cascade, through imine formation and imino‐Diels–Alder reactions, promoted by scandium‐loaded zeolites as a heterogeneous catalyst. The methodology described benefits from very low catalyst loadings (≤5 mol % of ScIII), commercially and readily available starting materials, and mild reaction conditions. Furthermore, the ScIII‐zeolite catalyst can be readily reused more than 10 times without any loss in efficiency. 相似文献
2.
SBA‐15‐functionalized melamine–pyridine group‐supported palladium(0) as an efficient heterogeneous and recyclable nanocatalyst for N‐arylation of indoles through Ullmann‐type coupling reactions 下载免费PDF全文
SBA‐15‐functionalized melamine–pyridine group‐supported palladium(0) was found to serve as a heterogeneous and recyclable nanocatalyst for N‐arylation of indoles with aryl iodides under a low catalyst loading (0.3 mol% of Pd) through Ullmann‐type C? N coupling reactions. A variety of aryl iodides could be aminated to provide the N‐arylated products in good to excellent yields without the need of an inert atmosphere. Also, this catalyst was found to be an efficient system for the N‐arylation of other nitrogen‐containing heterocycles with aryl iodides. The heterogeneous palladium catalyst could be recovered by simple filtration of the reaction solution and reused for six cycles without significant loss in its activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
3.
Immobilized palladium nanoparticles on MNPs@A‐N‐AEB as an efficient catalyst for C‐O bond formation in water as a green Solvent 下载免费PDF全文
Palladium nanoparticles immobilized on the magnetic nanoparticles@2‐amino‐N‐(2‐aminoethyl) benzamide (MNPs@A‐N‐AEB.Pd0) have been presented as an efficient, and reusable magnetically heterogeneous catalyst for the C‐O coupling reaction, namely Ullmann condensation reactions in an aqueous medium. This heterogeneous catalyst shows superior reactivity for the C‐O arylation of different aryl halide (chloride, bromide, and iodide) with phenol derivatives to afford the desired products in good to excellent yields within short reaction time. Moreover, the catalyst can be easily recovered and reused for seven runs without loss of catalytic activity. The catalyst was characterized by several techniques, such as FT‐IR, SEM, TEM, EDS, XRD, TGA and ICP‐OES. 相似文献
4.
A diversity‐oriented synthesis strategy to produce three types of structurally drug‐like N‐heterocyclic‐fused rings has been developed from abundant biomass‐derived d ‐glucal, aniline and water in a stereoselective manner. The overall transformation which entails a cascade of Ferrier reaction and 4π conrotatory imino‐Nazarov cyclization was performed in one‐pot allowing convenient preparation of scaffolds of high molecular complexity from relatively simple starting materials. While indoline‐fused products were readily accessible using ortho‐unsubstituted secondary anilines as substrates, reactions with ortho‐hydroxyl‐anilines furnished fused 1,4‐benzoxazines instead. In both cases, InBr3 acted as the Lewis acid catalyst. By altering InBr3 to Ln(OTf)3, the indoline‐fused products could be further converted into tetrahydroquinoline‐fused cyclopentenones via ensuing retro‐ene rearrangement. 相似文献
5.
Hsiang‐Chun Chang Jia‐Qi Li Ching‐Kai Lin Yu‐Jung Hsu Tsung‐Han Tu Yi‐Liang Hsieh Hsiu‐Hao Hsu Gene‐Hsiang Lee Yi‐Hung Liu Chi‐How Peng 《中国化学会会志》2019,66(9):1119-1133
Poly(di(pyridin‐2‐yl)methyl acrylate) (PDPyMA), which was obtained by the free radical polymerization of designed coordinative monomer of di(pyridin‐2‐yl)methyl acrylate, is able to coordinate with various metal ions to form heterogeneous catalysts for diverse catalytic reactions. The Pd and Cu complexes supported by PDPyMA were developed for the heterogeneous Suzuki‐Miyaura reaction and Friedel‐Crafts alkylation, respectively. The PDPyMA‐based catalysts showed no significant decline of reactivity after five times recycling. However, the hydrolysis of the PDPyMA backbone under alkaline conditions limited the catalytic efficiency of this heterogeneous catalyst so that the coordinative monomer was redesigned as 1,1‐di(pyridine‐2‐yl)‐2‐(4‐vinylphenyl)ethan‐1‐ol and then 2,2′‐(1‐methoxy‐2‐(4‐vinylphenyl)ethane‐1,1‐diyl)dipyridine (MVPhDPy). With copolymerization of N‐isopropyl acrylamide (NIPAM), the efficiency of polymer‐based heterogeneous catalysts could be further raised, demonstrated by the increased turn over number in the Suzuki‐Miyaura reaction, which approached 5,260 by using the catalyst formed from poly(MVPhDPy‐co‐NIPAM) and Pd(OAc)2. poly(MVPhDPy‐co‐NIPAM) copolymer, therefore, could be a versatile platform to support different metal ions for various heterogeneous catalytic reactions. 相似文献
6.
An alternative approach to develop a Pd catalyst based on dendrimer‐functionalized graphene oxide for C‐C cross‐coupling reactions is reported. Pd@MGO‐D‐NH2 has been synthesized by incipient wet impregnation method. The structure of the catalyst was thoroughly characterized by a set of analytical techniques such as TEM, BET, SEM/EDS, FTIR, and elemental mapping analysis. Then, the catalytic activity of the catalyst was scrutinized for promoting sonogashira C‐C coupling reaction. The results manifested that Pd@MGO‐D‐NH2 was able to catalyze the coupling reaction to obtain high coupling yields in short reaction time. The results of present work are hoped to aid the development of new class of heterogeneous catalysts as the high performance candidate for industrial applications. 相似文献
7.
Takato MitsudomeTsuyoshi Matsuno Shoichiro SueokaTomoo Mizugaki Koichiro JitsukawaKiyotomi Kaneda 《Tetrahedron letters》2012,53(39):5211-5214
Titanium cation-exchanged montmorillonite acts as an efficient heterogeneous catalyst for the Beckmann rearrangement of a wide range of ketoximes including aromatic, aliphatic, and alicyclic ketoximes under mild reaction conditions. After the rearrangement reaction, titanium cation-exchanged montmorillonite is easily separated by simple filtration, and can be reused with retention of high efficiency. 相似文献
8.
An efficient and green approach is reported for the rapid synthesis of spirocyclic 2‐oxindole using triethylenediamine or imidazole Brønsted acidic ionic liquids supported in Zr metal–organic framework (TEDA/IMIZ‐BAIL@UiO‐66) as a novel, superior and retrievable heterogeneous catalyst under ultrasonic irradiation. Heterocyclic compounds including pyrido[2,3‐d:6,5‐d′]dipyrimidines and indeno[2′,1′:5,6]pyrido[2,3‐d]pyrimidines were obtained by the one‐pot condensation reaction of 6‐amino‐1,3‐dimethyluracil, isatins and cyclic 1,3‐diketone (barbituric acid or 1,3‐indanedione). The reusability of the catalyst, low catalyst loading, short reaction times, excellent yields, simple work‐up, and use of sonochemical procedure as a mild process and an alternative energy source are some of the advantages of this method. Furthermore, the novel heterogeneous nanocomposite was fully characterized using various techniques. 相似文献
9.
The Design and Synthesis of Novel 2,3‐Dihydrobenzo[f]isoquinolin‐4(1H)‐ones via Sequential Ugi–Heck Reactions by Using an Efficient Heterogeneous Palladium Nanocatalyst 下载免费PDF全文
Mohammad Ali Rasouli Simin Miri Parviz Rashidi Ranjbar 《Journal of heterocyclic chemistry》2015,52(6):1864-1870
A facile and efficient synthesis of N‐alkyl‐2‐(1, 2 dihydro‐1‐methylene‐4‐oxobenzo[f] isoquinoline‐3(4H)‐yl)‐2‐phenylacetamides is performed by the consecutive, two‐step procedure that consists of Ugi and Heck reactions. The Heck reaction was performed both by homogenous and a designed heterogeneous catalyst. The heterogeneous catalyst is a coordinated palladium to 1, 10‐phenanthroline attached to chitosan@Fe3O4 magnetite nanoparticles, which was shown to be more efficient than the homogenous Pd(OAc)2/PPh3 catalyst with good to excellent yields. 相似文献
10.
Synthesis and characterization of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles: A heterogeneous,reusable and magnetically separable catalyst for the solvent‐free synthesis of 2‐amino‐4H‐chromene derivatives 下载免费PDF全文
An efficient and facile method was used for the synthesis of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles. The structure of this nanoparticle was characterized by scanning electron microscopies, X‐ray diffraction, energy‐dispersive X‐ray, Fourier transform infrared spectroscopies and vibrating sample magnetometry. Then, this compound was used as a reusable heterogeneous catalyst for green synthesis of 2‐amino‐4H‐chromene derivatives via one‐pot three‐component reactions. This novel material showed great catalytic performance and the reactions which were carried out by this catalyst showed good to excellent yields. Besides, the catalyst could easily be separated from the reaction mixture by using an external magnetic field and it was stable enough to reuse several times without any significant reduction in the yield of reactions. Eco‐friendliness, high purity of the desired products, short reaction time and easy workup procedure can be mentioned as the other advantages of this method. 相似文献
11.
Facile Synthesis of Chiral Spirooxindole‐Based Isotetronic Acids and 5‐1H‐Pyrrol‐2‐ones through Cascade Reactions with Bifunctional Organocatalysts 下载免费PDF全文
Wengang Guo Xu Wang Dr. Boyu Zhang Shuai Shen Dr. Xin Zhou Peng Wang Prof. Yan Liu Prof. Can Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8545-8550
Unprecedented organocatalyzed asymmetric cascade reactions have been developed for the facile synthesis of chiral spirooxindole‐based isotetronic acids and 5‐1H‐pyrrol‐2‐ones.The asymmetric 1,2‐addition reactions of α‐ketoesters to isatins and imines by using an acid–base bifunctional 6′‐OH cinchona alkaloid catalyst, followed by cyclization and enolization of the resulting adducts, gave chiral spiroisotetronic acids and 5‐1H‐pyrrol‐2‐ones, respectively, in excellent optical purities (up to 98 % ee). FT‐IR analysis supported the existence of hydrogen‐bonding interaction between the 6′‐OH group of the cinchona catalyst and an isatin carbonyl group, an interaction that might be crucial for catalyst activity and stereocontrol. 相似文献
12.
Iron‐catalyzed cross‐coupling reaction: Heterogeneous palladium and copper‐free Heck and Sonogashira cross‐coupling reactions catalyzed by a reusable Fe(III) complex 下载免费PDF全文
An interesting silica‐supported iron catalyst was successfully prepared and demonstrated as an efficient heterogeneous catalyst for cross‐coupling reactions of aryl halides. The as‐prepared nanocatalyst was well characterized and found to be highly efficient in Heck reaction under mild and sustainable conditions (water as solvent at 80 °C in short reaction time). Furthermore, the obtained catalyst was used as an efficient, inexpensive and green heterogeneous catalyst for Sonogashira cross‐coupling reactions of various aryl iodides and provided the corresponding products with moderate to good yields. This phosphine, copper and palladium‐free catalyst was simply recovered from the reaction mixture and recycled five times without substantial decrease in its catalytic activity. 相似文献
13.
《应用有机金属化学》2017,31(1)
A new protocol is reported for the synthesis of a heterogeneous palladium nanocomposite stabilized with a terephthalic acid‐derived ligand (N ,N ‐bis(4‐hydroxy‐3‐methoxybenzylidene)terephthalohydrazide). This is a highly insoluble ligand in common organic solvents, except dimethylformamide and dimethylsulfoxide. The resulting palladium nanocomposite acts as an efficient catalyst precursor for Mizoroki–Heck coupling reactions conducted under various reaction conditions. The spectral data suggest that the rate, yield and recycling of the catalyst are more effective for C–C coupling reactions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
14.
Zhiguo Zhang Junlong Li Guoqing Huang Kai Sun Guisheng Zhang Nana Ma Qingfeng Liu Tongxin Liu 《中国化学》2016,34(12):1309-1320
A convenient copper‐catalyzed approach has been developed for the synthesis of substituted spiro‐fused pyrazolin‐5‐ones from readily available cyclopropyl O‐acyl ketoximes via an intramolecular N? N bond formation reaction. These catalytic reactions proceed in excellent yields with a broad scope. 相似文献
15.
Palladium Supported on Zinc Oxide Nanoparticles as Efficient Heterogeneous Catalyst for SuzukiMiyaura and Hiyama Reactions under Normal Laboratory Conditions 下载免费PDF全文
Nanoscale Pd supported on ZnO was prepared by a facile coprecipitation method. Pd/ZnO Nanoparticles were characterized by using XRD, TEM, SEM, XPS, BET specific surface area measurement, and thermogravimetric analysis. This catalyst was used as novel and excellent heterogeneous catalyst for ligand‐free C? C bond‐formation particularly in the synthesis of unsymmetrical biaryls by Suzuki? Miyaura and Hiyama cross‐coupling reactions under air atmosphere without use of any Ar or N2 flow. The catalyst can be recovered and recycled several times without marked loss of activity. 相似文献
16.
《应用有机金属化学》2017,31(8)
Superparamagnetic CuCl nanoparticles were prepared and identified as an effective heterogeneous catalyst for the tandem transformation of methylarenes and 1,3‐dicarbonyl compounds into the corresponding enole esters by the use of tert ‐butyl hydroperoxide as an external oxidant. The catalyst can be removed from the reaction medium simply by use of an external magnet. As a consequence, various derivatives of enol esters were synthesized in moderate to good yields. 相似文献
17.
Jin‐Jun Wang Kimiaki Imafuku Yong Key Shim Gui‐Ji Jiang 《Journal of heterocyclic chemistry》2005,42(5):835-840
Methyl E/Z‐pyropheophorbide‐a 131‐ketoximes 2a,b and their O‐acetyl derivatives 3a,b were oxidized with osmium(VIII) oxide to give aldehydes 4a,b and 5a,b , respectively. The Wittig reactions of the aldehyde chlorines 4a,b and 5a,b with benzyltriphenylphosphonium chloride were performed to form the corresponding methyl (31E/Z,131E/Z)‐32‐phenylpyropheophorbide‐a 131‐ketoximes 6aa‐bb and their O‐acetyl derivatives 7aa‐bb ; hydrolysis of these ketoximes 6aa,ba and 6ab,bb in formic acid produced methyl (E/Z)‐32‐phenylpyropheophorbide‐a's 8a,b . 相似文献
18.
Manjunatha Kempasiddhaiah Vishal Kandathil Ramesh B. Dateer Balappa S. Sasidhar Shivaputra A. Patil Siddappa A. Patil 《应用有机金属化学》2019,33(5)
In this paper, a highly active, air‐ and moisture‐stable and easily recoverable magnetic nanoparticles tethered mesoionic carbene palladium (II) complex (MNPs‐MIC‐Pd) as nanomagnetic catalyst was successfully synthesized by a simplistic multistep synthesis under aerobic conditions using commercially available inexpensive chemicals for the first time. The synthesized MNPs‐MIC‐Pd nanomagnetic catalyst was in‐depth characterized by numerous physicochemical techniques such as FT‐IR, ICP‐AES, FESEM, EDS, TEM, p‐XRD, XPS, TGA and BET surface area analysis. The prepared MNPs‐MIC‐Pd nanomagnetic catalyst was used to catalyze the Suzuki–Miyaura and Mizoroki–Heck cross‐coupling reactions and exhibited excellent catalytic activity for various substrates under mild reaction conditions. Moreover, MNPs‐MIC‐Pd nanomagnetic catalyst could be easily and rapidly recovered by applying an external magnet. The recovered MNPs‐MIC‐Pd nanomagnetic catalyst exhibited very good catalytic activity up to ten times in Suzuki–Miyaura and five times in Mizoroki–Heck cross‐coupling reactions without considerable loss of its catalytic activity. However, MNPs‐MIC‐Pd nanomagnetic catalyst shows notable advantages such as heterogeneous nature, efficient catalytic activity, mild reaction conditions, easy magnetic work up and recyclability. 相似文献
19.
A tandem transformation that involves the formation of three bonds and two heterocyclic rings in a one‐pot fashion through amino‐alkylation of an ionic‐liquid‐immobilized diamine with keto acids followed by successive double intramolecular cyclizations to afford a tricyclic framework has been explored. This tandem cyclization has been utilized to develop a rapid and efficient method to synthesize various pyrrolo[1,2‐a]benzimidazolones and pyrido[1,2‐a]benzimidazolones on an ionic‐liquid support by using focused microwave irradiation. The application of this tandem cyclization was further extended to the aromatic keto acids to provide isoindolinone‐fused benzimidazoles, a structurally heterogeneous library with skeletal diversity. The outcome of the cascade reaction was confirmed by the X‐ray crystallographic study of the product directly attached to the ionic‐liquid support. Use of the ionic liquid as a soluble support facilitates purification by simple precipitation along with advantages like high loading capacity, homogeneous reaction conditions, and monitoring of the reaction progress by regular conventional spectroscopic methods, whereas application of microwave irradiation greatly accelerates the rate of the reactions. 相似文献
20.
Efficient Synthesis of Dimeric Oxazoles,Piperidines and Tetrahydroisoquinolines from N‐Substituted 2‐Oxazolones 下载免费PDF全文
Prof. Dr. Yun He Dr. Piyush K. Agarwal Dr. I. N. Chaithanya Kiran Ruocheng Yu Bei Cao Cheng Zou Xinghua Zhou Huacheng Xu Biao Xu Lei Zhu Prof. Dr. Yu Lan Prof. Dr. K. C. Nicolaou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7696-7701
A mild and practical method for the construction of heterocycles from N‐substituted 2‐oxazolones through cascade, BF3?Et2O/H2O‐catalyzed reactions involving iminium ion generation and trapping by external or internal olefinic and aryl moieties is described. Mechanistic and computational studies revealed the strong protic acid HBF4 as the initiating catalyst for these cascade reactions. Providing access to novel molecular diversity, these processes may facilitate chemical biology studies, drug discovery efforts and natural products synthesis. 相似文献