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141.
功能化SBA-15的合成、表征及其在Knoevenagel缩合反应中溶剂效应的研究 总被引:2,自引:1,他引:1
利用后接枝法合成了含有N-丙基苄胺、N-丙基邻羟基苄胺、N-丙基对羟基苄胺功能化的SBA-15,通过傅里叶红外、X射线衍射、N2-吸附脱附、元素分析对功能化SBA-15的表征表明,功能化的SBA-15保持了规整有序的介孔孔道;同时考察了3种功能化SBA-15对Knoevenagel缩合反应的催化性能,结果表明,三种催化剂都具有较高的催化活性,在以乙醇为溶剂,50℃反应6h的条件下,苯甲醛和氰乙酸乙酯的反应产率均达到80%左右,在该反应体系中有明显的溶剂化效应,质子化溶剂更有利于Knoevenagel缩合反应的进行. 相似文献
142.
Christopher C. McAtee Duncan C. Ellinwood Rory C. McAtee Corinna S. Schindler 《Tetrahedron》2018,74(26):3306-3313
We report herein the intramolecular α-tert-alkylation of unsaturated β-ketoesters which gives rise to highly functionalized cyclopentanes. This transformation is characterized by its operational simplicity, mild reaction conditions and the use of scandium (III) triflate as a Lewis acid catalyst. Of interest, cyclopentanes bearing heterocycles, sites for post reaction functionalization and spirocyclic architectures are accessible with this strategy. 相似文献
143.
144.
Jun Ding Ying Guo Ling-Yan Shao Fei-Yi Zhao Dao-Hua Liao Hong-Wei Liu Ya-Fei Ji 《中国化学快报》2016,27(10):1617-1621
A palladium-catalyzed multi-acetoxylation of 1,3-disubstituted 1H-pyrazole-5-carboxylate derivatives containing multiple potential reactive sites is described. Therein, the sequence of this process has been appropriately investigated. The protocol mainly provides the di- and tri-acetoxylated products for 1,3-diarylpyrazoles. Besides, it is found that the acetoxylation of C(sp3)-H bond is prior to that of C(sp2)-H bond under structurally competitive conditions. 相似文献
145.
Yuan-Qin Zheng Chun-Feng Luan Zhi-Jing Wang Yong-Qi Yao Zhi-Chuan Shi Xue-Feng Li Zhi-Gang Zhao Feng Chen 《中国化学快报》2016,27(1):25-30
2-Amino-3-nitrile-chromenes with potential antitumor activity were constructed by a novel catalytic system. In combination with α-naphthol, quinine could effectively promote the Michael-cyclization process of malononitrile with functionalized chalcones in high yields and moderate to good enantioselectivity(up to 84% ee). It is notable that the enantioselectivity could be greatly improved when α-naphthol was employed as additive. 相似文献
146.
Marie-Agnés Lacour Anne-Marie Caminade Marc Taillefer Jean-Pierre Majoral 《Tetrahedron letters》2009,50(34):4870-4873
Synthesis of unprecedented phosphorus dendrimers from generations 1 to 3 capped with functionalized phosphonium units bearing both P-C and P-N bonds is reported. 相似文献
147.
T. Trimaille C. Chaix T. Delair C. Pichot H. Teixeira C. Dubernet P. Couvreur 《Colloid and polymer science》2001,279(8):784-792
Cationic nanoemulsions containing an oily core as potential carriers of nucleic acids were prepared by a solvent displacement
method in the presence of a nonionic surfactant (Pluronic F68). With a view to functionalize such nanoemulsions for further
incorporation of a fusogenic peptide, a poly(maleic anhydride-alt-methyl vinyl ether) (M
n=67,000) grafted with variable amount of acetylspermine (or acetylspermidine) and decylamine was nanodeposited during the
nanoemulsion formation step. Functionalized nanoemulsions were characterized in terms of particle size (by quasi-elastic light
scattering and electron microscopy), electrophoretic mobility and long-term stability as a function of the amount of polymer
used in the formulation. It was found that increases in the level of the copolymer led to a reduction in the particle size
and a decrease in colloidal stability. In addition, the incorporation of the grafted copolymers at the interface of the nanoemulsions
was clearly evidenced, a shift towards low pH at the point of zero charge being attributed to the formation of carboxylic
groups induced by hydrolysis of the residual maleic anhydride groups of the copolymer.
Received: 1 September 2000 / in revised form: 29 November 2000 Accepted: 12 December 2000 相似文献
148.
N‐Arylaminomethyl‐3H‐1,3,4‐oxadiazole‐2‐thiones 2a,b were prepared from the corresponding N‐arylglycinoylhydrazides. A number of their thioglycoside derivatives 4–7a–c and S‐functionalized analogs 8–11a,b were synthesized by the reaction with different acetobromosugars and acyclic hydroxyalkylating agents. The antiviral activity of a number of the synthesized compounds against herpes simplex virus type 1 (HSV‐1) and hepatitis A virus (HAV) was evaluated. Compounds 5a and 5b showed promising results against HAV. 相似文献
149.
The heterogeneous carbonyl allylation of aldehydes and ketones with allylic chlorides was achieved in DMF using SnCl2 as reducing agent at 25-40 °C in the presence of a 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized palladium(II) complex [MCM-41-2N-Pd(II)], yielding a variety of homoallylic alcohols in good to high yields. This heterogeneous palladium catalyst exhibited higher activity than (N-propylethylenediamine)PdCl2 and can be recovered and recycled by a simple filtration of the reaction solution and used for at least 5 consecutive trials without any decreases in activity. 相似文献
150.
In this work, an advanced sandwich-type electrochemical aptasensor for thrombin was proposed by integrating hemin/G-quadruplex with functionalized graphene-Pd nanoparticles composites (PdNPs-RGs). The hemin/G-quadruplex formed by intercalating hemin into thrombin binding aptamer (TBA), firstly acted as a NADH oxidase, assisting the oxidation of NADH to NAD+ accompanying with the generation of H2O2 in the presence of dissolved O2. Subsequently, the hemin/G-quadruplex acted as HRP-mimicking DNAzyme that rapidly bioelectrocatalyze the reduction of the produced H2O2. At the same time, the Pd nanoparticles supported on p-iodoaniline functionalized graphene were also adopted to catalyze the reduction of H2O2. Thus, with the dual catalysis, a dramatically amplified electrochemical signal could be obtained. Besides, the avidin–biotin system for binding aptamer sequences on electrodes not only improved the sensitivity of thrombin analysis but also obtained an acceptable repeatability of the aptasensor. With several factors mentioned above, a wide linear ranged from 0.1 pM to 50 nM was acquired with a relatively low detection limit of 0.03 pM (defined as S/N = 3). These excellent performances provided our approach a promising way for ultrasensitive assay in electrochemical aptasensors. 相似文献