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1.
Facile Yb(OTf)3 promoted one-pot synthesis of polyhydroquinoline derivatives through Hantzsch reaction 总被引:1,自引:0,他引:1
Yb(OTf)3 catalyzed efficient Hantzsch reaction via four-component coupling reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate at ambient temperature was described as the preparation of polyhydroquinoline derivatives. The process presented here is operationally simple, environmentally benign and has excellent yield. Furthermore, the catalyst can be recovered conveniently and reused efficiently. 相似文献
2.
1,2,3,5-Tetrasubstituted pyridinium amino acid isodesmosine is a crosslinking amino acid of elastin and is an attractive biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD). Herein, we report an application of the Chichibabin pyridine synthesis to the total synthesis of isodesmosine. Specifically, the appropriate protected lysine and the corresponding aldehyde were reacted using Pr(OTf)3 in H2O/MeOH. 相似文献
3.
SUN Ling-na WANG Ke-li LUO Sheng-jun GUO Qing-rong HU Chang-wen 《高等学校化学研究》2007,23(5):508-510
β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction(SAED),and gas chromatograph. 相似文献
4.
Salvatore GenoveseFrancesco Epifano Maria Carla MarcotullioCaroline Pelucchini Massimo Curini 《Tetrahedron letters》2011,52(27):3474-3477
Quinolines have been synthesized in very good yields from 2-aminoarylketones and differently substituted carbonyl compounds in the presence of Yb(OTf)3 as the catalyst. The method is applicable to both cyclic and acyclic carbonyl compounds with only slight differences in the experimental procedure. 相似文献
5.
Kumkum KumariDushyant Singh Raghuvanshi Viatcheslav JouikovKrishna Nand Singh 《Tetrahedron letters》2012,53(9):1130-1133
An efficient, rapid, and green synthesis of functionalized pyrazoles has been accomplished under solvent-free conditions by the reaction of phenyl hydrazine, aldehydes and ethyl acetoacetate. This approach exploits the synthetic potential of microwave irradiation and scandium triflate combination and offers many advantages such as excellent product yields, shorter reaction time, easy isolation of products, and environmentally benign reaction conditions. 相似文献
6.
Changning Wang 《Tetrahedron》2006,62(50):11657-11662
Gb3 and isoGb3 are both biologically important oligosaccharides. A new efficient synthesis of Gb3 and isoGb3 trisaccharide analogues has been achieved by one-pot sequential glycosylation strategy starting from simple monosaccharide building blocks promoted by N-(phenylthio)-?-caprolactam at room temperature. 相似文献
7.
Conjugate addition of indoles and thiols with a variety of electron-deficient olefins mediated by a catalytic amount of Bi(OTf)3 at ambient temperature to afford the corresponding Michael adducts in good to excellent yields with high selectivity is reported. 相似文献
8.
Madabhushi Sridhar Mallu Kishore Kumar ReddyVangipuram Venkata Sairam Jillella RaveendraKondal Reddy Godala Chinthala NarsaiahBeeram China Ramanaiah Cirandur Suresh Reddy 《Tetrahedron letters》2012,53(27):3421-3424
An efficient method for the preparation of nitriles directly from aldehydes by reaction with AHA using Bi(OTf)3 as the catalyst is described. Bi(OTf)3 is shown to be an efficient catalyst also for the conversion of aldoximes into nitriles. 相似文献
9.
Bharat Kumar AllamKrishna Nand Singh 《Tetrahedron letters》2011,52(44):5851-5854
The present Letter highlights a versatile synthetic protocol for the one-pot synthesis of primary amides employing scandium(III) triflate as a catalyst in water under controlled MW. This methodology offers excellent yields in shorter reaction times with enhanced selectivity. 相似文献
10.
Abstract Carbonyl compounds were regenerated from corresponding dithioacetals via refluxing with FeCl3/KI and methanol as a solvent. 相似文献
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在离子液体BMImPF6中, 用不同的钯催化剂和Lewis酸三氟甲磺酸铜Cu(OTf)2共催化苯乙烯二聚反应, 发现用Pd(OAc)2/Cu(OTf)2作催化剂, Pd/Cu物质的量之比为1~4时, 可高产率高选择性地获得苯乙烯二聚产物1,3-二苯基-1-丁烯. BMImPF6对催化剂有较好的溶解性, 可固定催化剂体系, 使催化剂有效地与产品分离. 同时, α-甲基苯乙烯的二聚反应表明, 室温下不发生反应, 提高温度有利于反应进行. 相似文献
14.
Santosh T. Kadam 《Journal of organometallic chemistry》2009,694(16):2562-381
A very efficient and mild silylation of alcohols and phenols with hexamethyldisilazane (HMDS) at rt is developed using Bi(OTf)3 as the catalyst. Primary, secondary and tertiary alcohols as well as phenols are excellently converted into corresponding TMS ethers in a very short reaction time. This procedure can also be applied to large scale silylation for industrial application. 相似文献
15.
Wei-Chieh YangXin-An Lu Suvarn S KulkarniShang-Cheng Hung 《Tetrahedron letters》2003,44(42):7837-7840
A triethylsilane-reductive etherification of the trimethylsilyl ethers with a variety of carbonyl compounds in good yields at room temperature employing 0.5 mol% Cu(OTf)2 as an extremely efficient catalyst is described here. 相似文献
16.
Ferroelastic β′-Gd2(MoO4)3, (GMO), crystals are formed through the crystallization of 21.25Gd2O3–63.75MoO3–15B2O3 glass (mol%), and two scientific curious phenomena are observed. (1) GMO crystals formed in the crystallization break into small pieces with a triangular prism or pyramid shape having a length of 50–500 μm spontaneously during the crystallizations in the inside of an electric furnace, not during the cooling in air after the crystallization. This phenomenon is called “self-powdering phenomenon during crystallization” in this paper. (2) Each self-powdered GMO crystal grain shows a periodic domain structure with different refractive indices, and a spatially periodic second harmonic generation (SHG) depending on the domain structure is observed. It is proposed from polarized micro-Raman scattering spectra and the azimuthal dependence of second harmonic intensities that GMO crystals are oriented in each crystal grain and the orientation of (MoO4)2− tetrahedra in GMO crystals changes periodically due to spontaneous strains in ferroelastic GMO crystals. 相似文献
17.
David A. Pacheco Tanaka Margot A. Llosa Tanco Junya Okazaki Yoshito Wakui Fujio Mizukami Toshishige M. Suzuki 《Journal of membrane science》2008,320(1-2):436-441
Mesoporous YSZ–γ-Al2O3 membranes were coated on α-Al2O3 (Ø2 mm) tube by dipping the α-Al2O3 support tube into mixed sol consists of nano-size YSZ and bohemite particles followed by drying and calcination at 600 °C. Addition of bohemite in YSZ sol helped a good adhesion and uniform coating of the membrane film onto α-Al2O3 support. The quality of the mesoporous YSZ–γ-Al2O3 membranes was evaluated by the gas permeability experiments. The number of defects was minimized when the γ-Al2O3 content became more than 40%. Addition of γ-Al2O3 inhibited the crystal growth of YSZ, sintering shrinkage and distortion stress. Increase of calcination temperature and time results in the increase of pore size and N2 permeance. A hydrogen perm-selective membrane was prepared by filling palladium into the nano-pores of YSZ–γ-Al2O3 layer by vacuum-assisted electroless plating. Crystal growth of palladium was observed by thermal annealing of the membrane at 600 °C for 40 h. The Pd–YSZ–γ-Al2O3 composite membrane revealed improved thermal stability allowing long-term operation at elevated temperature (>500 °C). This has been attributed to the improved fracture toughness of YSZ–γ-Al2O3 layer and matching of thermal expansion coefficient between palladium and YSZ. Although fracture of the membrane did not occur, decline of H2 flux was observed when the membrane was exposed in 600 °C. This has been attributed to the agglomeration of palladium particles by crystal growth and dense packing into the pore networks of YSZ–γ-Al2O3 by elevation of temperature. 相似文献
18.
A novel method for the synthesis of chiral α-amino acids has been developed where the acid functionality was constructed by oxidizing a hydroxymethyl group introduced by Evans’ method in the α-position of an appropriate acid substrate and the amino part came from the amide of the original carboxyl group following a modified Hofmann rearrangement reaction. 相似文献
19.
A mild and facile method for the synthesis of 3-arylbenzo[f]quinoline-1,2-dicarboxylate derivatives is reported by an imino-Diels-Alder reaction in high yields (76-92%). This procedure includes a novel three-component reaction of aromatic aldehyde, naphthalen-2-amine, and but-2-ynedioate catalyzed by Yb(OTf)3 in toluene. The results are obviously different from those of the simple substituted aniline-involved reactions catalyzed by ZnCl2 or KOH in the literature. 相似文献
20.
Xiongyu Wu 《Tetrahedron letters》2005,46(9):1501-1504
A fast and efficient microwave promoted one-pot method for deoxygenation of heterocyclic halo-benzyl alcohols has been developed. The method does not cause dehalogenation of the substrates and provides the deoxygenated products in high yield after only 30 min. 相似文献