在测试的28种非均相和均相催化剂中,Nb 2 O 5对正十二烷酸与反应性较小的胺(苯胺)的直接酰胺化反应显示出最高的收率。由Nb 2 O 5催化的酰胺化适用于具有各种官能团的多种羧酸和胺,并且该催化剂是可重复使用的。催化研究和红外研究吸附在催化剂上的乙酸的结果比较表明,Nb 2 O 5上的路易斯酸位点活化了羧酸的羰基,这是Nb的高活性的原因。2 ø 5催化剂。动力学研究表明,Nb 2 O 5上的路易斯酸位比常规路易斯酸性氧化物(Al 2 O 3,TiO 2)具有更高的耐水性。与最新的酰胺化均相路易斯酸催化剂(ZrCl 4)相比,溶液中碱性添加剂对Nb 2 O 5的负面影响较小,这表明Nb 2 O 5对碱的耐受性更高。路易斯酸催化剂比均相路易斯酸催化剂。
Inhibitory effect of cytotoxic stilbenes related to resveratrol on the expression of the VEGF, hTERT and c-Myc genes
作者:Rosa Martí-Centelles、Eva Falomir、Juan Murga、Miguel Carda、J. Alberto Marco
DOI:10.1016/j.ejmech.2015.09.014
日期:2015.10
A group of thirty-nine stilbene derivatives, prepared by means of Heck coupling reactions, has been investigated for their cytotoxicity, as well as for their ability to inhibit the production of the vascular endothelial growth factor (VEGF) and the activation of telomerase. The ability of these compounds to inhibit proliferation of two tumoral cell lines (HT-29 and MCF-7) and one non tumoral cell line (HEK-293) was first determined. Subsequently, we determined the capacity of the compounds to inhibit the secretion of VEGF in the aforementioned cell lines and to downregulate the expression of the VEGF, hTERT and c-Myc genes, the two latter involved in the control of the activation of telomerase. One of the synthetic stilbenes, (E)-4-(4-methoxystyryl)aniline, showed strong cytotoxicity and proved able to cause a marked decrease both in the secretion of VEGF and in the expression of the hTERT and c-Myc genes, in all cases at concentrations in the low nanomolar range. (C) 2015 Elsevier Masson SAS. All rights reserved.
Hierarchical Supramolecular Self-Assembly of Nanotubes and Layered Sheets
作者:Yulan Chen、Bo Zhu、Fan Zhang、Yang Han、Zhishan Bo
DOI:10.1002/anie.200801404
日期:2008.7.28
Molecular Recognition of Anions through Hydrogen Bonding Stabilization of Anion−Ionophore Adducts: A Novel Trifluoroacetophenone-Based Binding Motif
作者:Young Kook Kim、Yun-Ho Lee、Hyang-Yeol Lee、Mi Kyoung Kim、Geun Sig Cha、Kyo Han Ahn
DOI:10.1021/ol035624z
日期:2003.10.1
A novel trifluoroacetophenone-based binding motif has been developed that recognizes anions such as carboxylates through reversible formation of anion-ionophore adducts; that are stabilized by intramolecular H-bonding. The intramolecular H-bonding resulted in more than 10-fold enhancement in the binding affinity and an enthalpy gain (DeltaHdegrees) of 3.0 kcal/mol for the binding of an acetate ion when compared to the case without the intramolecular H-bonding.
Melting Points of the p-Bromoanilides of Solid Fatty Acids<sup>1</sup>
作者:David F. Houston
DOI:10.1021/ja01862a504
日期:1940.5
Synthesis and Supramolecular Self-Assembly of Coil-Rod-Coil Molecules: The Relationship between Self-Assembled Nanostructures and Molecular Structures
作者:Yulan Chen、Fan Zhang、Bo Zhu、Yang Han、Zhishan Bo
DOI:10.1002/asia.201000567
日期:2011.1.3
rolled‐up nanotubes, nanofibers, submicron sized belts, needle‐like microcrystals, and amorphous structures. The self‐assembling behaviors of these coil‐rod‐coil molecules have been systematically investigated to reveal the relationship between the supramolecularly self‐assemblednanostructures and their chemical structures. With respect to the formation of rolled‐up nanotubes by self‐assembly of coil‐rod‐coil