共查询到20条相似文献,搜索用时 500 毫秒
1.
Jie Lei Jiang-Ping Meng Dian-Yong Tang Brendan Frett Zhong-Zhu Chen Zhi-Gang Xu 《Molecular diversity》2018,22(2):503-516
Isocyanide-based multicomponent reactions are among the most powerful synthetic tools available. Particularly, the isocyanide-based Ugi reaction can allow rapid preparation of \(\alpha \)-aminoacyl amide derivatives and polyazaheterocycles with extensive pharmaceutical applications. Moreover, bridged polyazaheterocycles, including one or more quaternary carbon centers, can be constructed via the Ugi cascade reaction in a few steps. This review will emphasize synthesis and bioactivities of bridged compounds with quaternary centers constructed through Ugi cascade reactions. 相似文献
2.
Maciej Dawidowski Sławomir Sobczak Marcin Wilczek Artur Kulesza Jadwiga Turło 《Molecular diversity》2014,18(1):61-77
Various symmetrical and unsymmetrical ketones were successfully coupled with secondary amino acids in the course of Ugi five-center, four-component reaction (U-5C-4CR), thus expanding the molecular diversity possible to be achieved by the reaction. The chemical yields depended on the degree of hindrance of the components employed and were satisfactory in view of possible steric interactions in the U-5C-4CR zwitterionic intermediate. The sense of diastereoinduction for reactions employing unsymmetrical ketones was examined by converting the resulting Ugi adducts into the corresponding rigid 2,6-diketopiperazine derivatives. 相似文献
3.
Nianjin Liu Song Cao Jingjing Wu Li Shen Jinlong Yu Jian Zhang Hui Li Xuhong Qian 《Molecular diversity》2010,14(3):501-506
Six novel monofluorinated α-lactam pseudopeptide derivatives were synthesized via Ugi reaction using gem-difluoromethylene-containing isocyanide as a key component, followed by dehydrofluorination of Ugi products in one pot without
additional base. 相似文献
4.
This review details a now established area within the isonitrile multi-component reaction (IMCR) field of study, namely employing
bi-functional reagents in the Ugi reaction for the construction of screening sets with the additional element or even possibly
‘metric’ of enhanced ‘iterative efficiency potential’ The concept of ‘iterative efficiency’ will be briefly introduced, coupled
with discussion on new synthetic routes to select bi-functional IMCR precursors and their use in the generation of pharmacologically
relevant ‘molecular diversity’ 相似文献
5.
B.?Beck S.?Srivastava K.?Khoury E.?Herdtweck Alexander?D?mling 《Molecular diversity》2010,14(3):479-491
We designed two novel thiolactone scaffolds. Both scaffolds can be accessed by a convergent Ugi multicomponent reaction (MCR)
and are, thus, amenable to library synthesis. Design, stereoselectivity, structures, full experimental details, and virtual
libraries will be reported. 相似文献
6.
A facile synthetic approach to 2,5-diketopiperazines 4 by the Ugi four-center three-component reaction using commercially available dipeptides as a bifunctional component, aldehydes, and isocyanides was described. 相似文献
7.
Stanley N. S. Vasconcelos Evelin Fornari Ignez Caracelli Hélio A. Stefani 《Molecular diversity》2017,21(4):893-902
The Ugi multicomponent reaction has been used as an important synthetic route to obtain compounds with potential biological activity. We present the rapid and efficient synthesis of \(\upalpha \)-amino-1,3-dicarbonyl compounds in moderate to good yields via Ugi flow chemistry reactions performed with a continuous flow reactor. Such \(\upalpha \)-amino-1,3-dicarbonyl compounds can act as precursors for the production of \(\upalpha \)-amino acids via hydrolysis of the ethyl ester group as well as building blocks for the synthesis of novel compounds with the 1,2,3-triazole ring. The \(\upalpha \)-amino acid derivatives of the Ugi flow chemistry reaction products were then used for dipeptide synthesis. 相似文献
8.
A novel four-component reaction approach to the efficient synthesis of triamide and amidodiester derivatives using amines or alcohols, aldehydes and alkyl or aryl isocyanides in the presence of Meldrum's acid as a CH acid, instead of carboxylic acid of Ugi four-component reaction, was studied. 相似文献
9.
Combining the Ugi reaction with ring opening reaction of furans for the synthesis of novel isoquinolinone and 1,2-dihydroisoquinoline scaffolds has been developed. The isoquinolinone and 1,2-dihydroisoquinoline derivatives with unsaturated carbonyl moiety may open up many opportunities for further functionalizations. 相似文献
10.
A short (2 steps) synthesis of diverse benzoxazinones by coupling the Ugi multicomponent reaction with an intramolecular Mitsunobu substitution is reported. The cyclization step proceeds via an unexpected cine substitution. 相似文献
11.
《Current Applied Physics》2001,1(2-3):133-138
A new surface modification technique, so-called ion assisted reaction (IAR) has been developed at the Korea Institute of Science and Technology (KIST) Ion Beam Laboratory while modifying the surface of polymer results in many of industrial applications. The IAR, in which a keV ion beam is irradiated on the surface of polymer in reactive gases environment, has been developed for improving wettability of polymer surface and enhancing adhesion of other materials. The contact angles of water drops with modified polymers were significantly reduced by Ar+ ion irradiation with flowing oxygen gas environment than without flowing oxygen gas. Change of contact angles for the modified polymers was explained by a two-step chemical reaction among polymer matrix, energetic ions and oxygen gas. X-ray photoelectron analysis showed that hydrophilic groups were formed on the surface of polymers by chemical reaction between the unstable chains induced by ion irradiation and the oxygen gas, and the hydrophilic groups were identified as –(C–O)–, –(CO)– and –(CO)–O– bonds. The enhanced adhesion between metal and modified polymers was explained by the formation of charge transfer complex in polymer and electron donors in metal. Possible industrial applications of the IAR are to be discussed. 相似文献
12.
13.
采用后重氮偶合法,合成了一种新型含咔唑类聚磷腈有机光折变材料。采用氢谱核磁共振法,红外光谱法,紫外-可见吸收光谱法,热重法和差示扫描量热法对该聚合物进行表征和分析,结果表明,该聚合物具有良好的热稳定性,在230℃开始分解,450℃时基本分解完全。UV-Vis表明波长在360nm与570nm之间的宽的吸收带是由于共轭长度的增加产生的,因此可以调整参加偶合反应的重氮盐比例,来控制偶氮生色团功能组分的接入含量。在未使用外加电场及事先极化的条件下对聚合物进行了二波耦合与四波混频实验,证明了聚合物的光折变特性。得到聚合物P-2和P-3的二波耦合增益系数分别为38cm-1和53.6cm-1,聚合物P-2和P-3的四波混频衍射效率分别为2.7%和8.1%。 相似文献
14.
Mausumi Chattopadhyaya Sabyasachi Sen Md.Mehboob Alam Swapan Chakrabarti 《Journal of Physics and Chemistry of Solids》2014
The present study deals with the relative performance of the various density functional approaches in evaluating the band gap of polymer materials. Several density functional approximations that includes pure generalized gradient approximated (GGA) functional, meta-GGA, hybrid and range separated hybrid functionals have been used to evaluate the electrical band gap or transport gap of the studied polymers and compared with that obtained using Hubbard U corrected GGA functional (GGA+U). It has been observed that the experimental band gap of the polymers studied is satisfactorily reproducible when GGA+U approach is adopted. The band gap analyses further suggest that range separated hybrid functional, CAM-B3LYP, largely overestimates the band gap of all the polymers studied while the performance of hybrid B3LYP functional and other range separated hybrid functional like HSE is moderate. Better performance of the GGA+U method clearly indicates that short range coulomb correlation plays more significant role over the non-local Hartree-Fock (HF) exchange in determining the electrical band gap of polymer materials. It is also noticeable that the Hubbard U parameter used for the various polymers under consideration is relatively large, indicating the semi-empirical nature of the GGA+U level of calculations. The present finding will help us design new low band gap polymer through estimating band gap by the GGA+U method and this could be very useful for solar cell research. 相似文献
15.
G. A. Lushcheĭkin 《Physics of the Solid State》2006,48(6):1023-1025
A review is presented of the data on the design of polymer-containing piezoelectric materials: electrets exhibiting a piezoelectric effect, ferroelectric polymers, piezoelectric composites (piezoelectric ceramic + polymer), and new piezoelectric polymer materials, such as piezoelectrics based on porous polymers and elastic active dielectrics, whose piezoelectric properties considerably surpass the characteristics of conventional piezoelectric materials, as well as the characteristics of electromechanical and mechanoelectrical transducers operating in receiving, generating, and deformation-inducing modes. 相似文献
16.
凝聚态物理学与材料研究的前沿问题 总被引:3,自引:0,他引:3
讨论了凝聚态物理学在当代材料研究的前沿问题中所起的作用,首先对,于那些基本物理学业已能晓的常规材料,极好的机会在于设计并制备出微结构和纳米结构,其次,对于具有强关联电子特征的复杂材料,虽则其物理学尚在探索之中,已有迹象表明这将是新材料的“富矿区”,再次,关于有机及聚合物材料,物理学正在向这领域延拓,在设计和制备分子和超分子结构方面,将会提供许多新的可能性。 相似文献
17.
V. V. Brazhkin 《高压研究》2013,33(3):333-351
This short review covers some particular aspects of the production of new materials under high pressures. Despite the fact that there is an extremely wide range of new high-pressure synthesized substances with unique properties, a commercial synthesis has been used up to date only for producing superhard materials – these are real treasures of today’s industry. At the same time, as should be underlined here, high-pressure experiments often give scientists material with helpful hints of what new intriguing substances can exist in principle. This is true both for new superhard, semiconducting, magnetic, superconducting, optical materials already synthesized under pressure and a large number of hypothetic new polymers from low-Z elements. 相似文献
18.
Phase separation kinetics and morphology of binary polymer mixtures (A/B) in the presence of photochemical reactions were investigated by using phase-contrast optical microscopy combined with digital image analysis. The polymers were chemically designed in such a way that two types of chemical reactions, intermolecular photodimerization and intramolecular photoisomerization, of polymer segments can be induced and controled by irradiation with ultraviolet light. Unlike the conventional case, the phase separation in the presence of these reactions is spontaneously frozen due to the suppression of the long-wavelength instabilities, resulting in stationary spatial structures with intrinsic periodicities. These characteristic length scales are determined by the competition between the two antagonistic interactions: phase separation as a relatively short-range activation and the photochemical reaction as a long-range inhibition. Furthermore, it was found that the spatial symmetry breaking of concentration fluctuations can emerge from the elastic stress associated with the nonhomogeneous kinetics of the reactions. Experimental data obtained with three types of reactions: A-A only cross-link, A-A and B-B simultaneous cross-links and the reversible A<-->B photoisomerization are described. These results do not only indicate that combination of chemical reactions and phase separation could provide a novel method to control the morphology of multiphase polymer materials, but also suggest that photoreactive polymers can be used as a chemical system to study the mode-selection process in polymers far from thermodynamic equilibrium. (c) 1999 American Institute of Physics. 相似文献
19.
高分子电致发光显示器(PLED)是近几年来国际、国内的研究热点,取得了很大的进展,其中高分子化金属配合物是一类很有价值的功能材料。通过甲基丙烯酸甲酯(MMA)、苯乙烯(S)和含有8-羟基喹啉的单体共聚合成模板聚合物,再与氢氧化锂作用,实现了8-羟基喹啉锂配合物的高分子化,获得了一种能够溶解在普通的溶剂中的高相对分子质量的含喹啉锂配合物的发光聚合物,并利用元素分析、1H-NMR、FTIR、UV、PL光谱、DSC、TGA、GPC等方法对其结构和性能作了表征。紫外吸收和光致发光(PL)光谱说明合成共聚物的发光来自于Liq基团,引入的可聚合的链段以及共聚物中的甲基丙烯酸甲酯或苯乙烯链段,并没有影响发光波长的改变。亲核溶剂改变8-羟基喹啉金属配合物分子结构,使共聚物光谱明显红移20nm左右。 相似文献