Studies on propafenone-type modulators of multidrug resistance VI. Synthesis and pharmacological activity of compounds with varied spacer length between the central aromatic ring and the nitrogen atom
A series of propafenone-type modulators of multidrug resistance (MDR) with varied spacer length between the central aromatic ring and the positively chargeable nitrogen atom was synthesized and tested for their ability to block P-glycoprotein-mediated transport of daunomycin out of tumor cells. Synthesis was achieved by O-alkylation of o-hydroxy-3-phenylpropiophenone with dibromoalkanes and subsequent nucleophilic substitution of the bromine with piperidine. All compounds showed high MDR-modulating activity with EC50 values from 1.45-0.15 mu M Generally, activity increased with increasing number of methylene groups, whereby it reaches a plateau for compounds with more than five methylene groups between the ether oxygen and the nitrogen atom. (C) 1998 Elsevier Science S.A. All rights reserved.
Chemoselective Hydrosilylation of the α,β-Site Double Bond in α,β- and α,β,γ,δ-Unsaturated Ketones Catalyzed by Macrosteric Borane Promoted by Hexafluoro-2-propanol
作者:Xiao-Yu Zhan、Hua Zhang、Yu Dong、Jian Yang、Shuai He、Zhi-Chuan Shi、Lei Tang、Ji-Yu Wang
DOI:10.1021/acs.joc.0c00568
日期:2020.5.15
The B(C6F5)3-catalyzed chemoselective hydrosilylation of α,β- and α,β,γ,δ-unsaturated ketones into the corresponding non-symmetric ketones in mild reaction conditions is developed. Nearly 55 substrates including those bearing reducible functional groups such as alkynyl, alkenyl, cyano, and aromatic heterocycles are chemoselectively hydrosilylated in good to excellent yields. Isotope-labeling studies