Superior Effect of a π-Acceptor Ligand (Phosphine−Electron-Deficient Olefin Ligand) in the Negishi Coupling Involving Alkylzinc Reagents
作者:Xiancai Luo、Heng Zhang、Hui Duan、Qiang Liu、Lizheng Zhu、Tony Zhang、Aiwen Lei
DOI:10.1021/ol701995t
日期:2007.10.1
[GRAPHICS]Palladium-catalyzed Negishi cross-coupling involving primary and secondary alkyls, even in the presence of beta-H, can be achieved at ambient temperature using chelating ligands containing a phospline and an electron-deficient olefin. The superior effects of the ligands were shown not only in the desired cross-coupling product yields but also in the fast reaction at mild conditions. This reaction has been also scaled up to 50 g in 0.005 mol % catalyst (20,000 TONs) at room temperature.
Ferrocenyl chalcones versus organic chalcones: A comparative study of their nematocidal activity
作者:Saeed Attar、Zachary O’Brien、Hasan Alhaddad、Melissa L. Golden、Alejandro Calderón-Urrea
DOI:10.1016/j.bmc.2011.01.048
日期:2011.3
A series of 30 organic chlacones and 33 ferrocenyl (Fc) chalcones were synthesized and characterized by melting point, elemental analysis, spectroscopy (H-1 NMR and FTIR) and, in two cases, by X-ray crystallography. The biological activity of each compound (10(-4) M in DMSO) against the model nematode Caenorhabditis elegans was examined in terms of % mortality (percent nematodes that died) and % fecundity (percent nematodes that reproduced) and compared to that obtained for the control medium (1% DMSO) over a 14-day period. Detailed conformational analyses for two Fc-chalcones (studied also by X-ray crystallography) were performed via molecular modeling studies. In general, the organic chalcones were found to be less polar than their Fc analogs. Some structure-activity relationships (SARs) were determined: (a) The nematocidal activities of the organic chalcones in this series were found to be much greater than those of their ferrocenyl analogs. (b) The position of the carbonyl group played a central role in the biological activity of both classes of chalcones studied. (c) For both classes of chalcones, lipophilicity of a compound seemed to play a significant role in its nematocidal activity. (d) The planarity of a ferrocenyl-chlacone seems to play a role in its activity. Published by Elsevier Ltd.