Synthesis and in vitro antitumor activity of asperphenamate derivatives as autophagy inducer
作者:Lei Yuan、Yanchun Li、Chunyang Zou、Chao Wang、Jian Gao、Caixia Miao、Enlong Ma、Tiemin Sun
DOI:10.1016/j.bmcl.2012.01.101
日期:2012.3
In an effort to improve the aqueous solubility and the antitumor activity of natural product asperphenamate, we have designed and synthesized three series of asperphenamate derivatives, including series I (simplifying molecular skeleton series), series II (introducing a hydroxyl group to A-phenyl ring series) and series III (disrupting molecular planarity series). All derivatives have displayed a significantly increased solubility compared with asperphenamate. Their growth inhibitory activities in vitro were screened by the standard MTT method in MCF-7, HeLa, and BEL-7402 cell lines. With the exception of the derivatives in series I, most of derivatives in series II and series III showed growth inhibitory activity. Among all derivatives, IM23b in series III showed the greatest potency in human breast cancer MCF-7 cells. The cellular potency of IM23b was approximately 1.5-fold more potent than that of cisplatin. The mechanism of cell death induced by IM23b in human breast cancer MCF-7 cells was further investigated. We concluded that the cell death was induced by autophagy instead of apoptosis or cell cycle arrest. (C) 2012 Elsevier Ltd. All rights reserved.
Catalytic Asymmetric Hydrogenation of N-Boc-Imidazoles and Oxazoles
作者:Ryoichi Kuwano、Nao Kameyama、Ryuhei Ikeda
DOI:10.1021/ja201543h
日期:2011.5.18
Substituted imidazoles and oxazoles were respectively hydrogenated into the corresponding chiral imidazolines and oxazolines (up to 99% ee). The highly enantioselective hydrogenation was achieved by using the chiral ruthenium catalyst, which is generated from Ru(eta(3)-methallyl)(2)(cod) and a trans-chelating chiral bisphosphine ligand, PhTRAP. This is the first successful catalytic asymmetric reduction of 5-membered aromatic rings containing two or more heteroatoms.
Chiral Auxiliaries as Docking/Protecting Groups in Biohydroxylation: The Hydroxylation of Enantiopure Spirooxazolidines Derived from Cyclopentanone UsingBeauveria bassiana ATCC 7159
作者:Anna de Raadt、Barbara Fetz、Herfried Griengl、Markus Florian Klingler、Irene Kopper、Birgit Krenn、Dieter Franz Münzer、René Georg Ott、Peter Plachota、Hans Jörg Weber、Gerhard Braunegg、Winfried Mosler、Robert Saf
before the fermentation was found to have a major effect on the course of the biohydroxylation relative to the achiral analogue 3a (Table 1, entry 1). The nature of R1/R2 influenced both the product yield and the optical purity of the products (e.g. Table 1, entry 2). In addition, the absolute configuration of the final product 6 could be dictated solely by the nature of the docking/protecting group