A Synthesis of Cyanolide A by Intramolecular Oxa-Michael Addition
摘要:
A synthesis of cyanolide A, a diolide natural product, has been achieved using a diastereoselective Barbier reaction, early-stage glycosylation, and intramolecular oxa-Michael addition to form the THP ring.
A class of compounds useful in pharmaceutical compositions and methods for treating or preventing cancer is described. Analogs of Mycalolide B have been prepared and tested in breast and ovarian cancer cell lines. The compounds show utility for inhibition of survival and proliferation of tumor cells. The compounds have been shown to disrupt actin.
Identification of a Thioesterase Bottleneck in the Pikromycin Pathway through Full-Module Processing of Unnatural Pentaketides
作者:Douglas A. Hansen、Aaron A. Koch、David H. Sherman
DOI:10.1021/jacs.7b06432
日期:2017.9.27
Polyketide biosynthetic pathways have been engineered to generate natural product analogs for over two decades. However, manipulation of modular typeIpolyketidesynthases (PKSs) to make unnatural metabolites commonly results in attenuated yields or entirely inactive pathways, and the mechanistic basis for compromised production is rarely elucidated since rate-limiting or inactive domain(s) remain
二十多年来,聚酮化合物生物合成途径已被设计为生成天然产物类似物。然而,操纵模块化 I 型聚酮化合物合酶 (PKS) 以制造非天然代谢物通常会导致产量减弱或完全失活,并且由于限速或失活域仍未确定,因此很少阐明影响生产的机制基础。因此,我们合成并分析了一系列模拟早期通路工程的修饰 pikromycin (Pik) pentaketides,以在体外探测 PikAIII-TE 模块的底物耐受性。截短的五肽以不同的效率加工成相应的大环内酯,而具有差向异构化手性中心的五肽被 PikAIII-TE 加工不良,无法生成 12 元环产物。扩展但过早卸载的分流产物的分离和鉴定表明,Pik 硫酯酶 (TE) 域具有有限的底物灵活性,并在非天然底物的加工中起到看门人的作用。具有差向异构化亲核羟基的类似六酮化合物的合成允许直接评估切除的 TE 结构域的底物立体选择性。差向异构化的六酮化合物没有进行环化,而是完全水解,证实了
Enantio- and Diastereoselective Synthesis of 1,5-<i>syn</i>-(<i>Z</i>)-Amino Alcohols via Imine Double Allylboration: Synthesis of <i>trans</i>-1,2,3,6-Tetrahydropyridines and Total Synthesis of Andrachcine
作者:Christophe Allais、William R. Roush
DOI:10.1021/acs.orglett.7b00995
日期:2017.5.19
A stereoselective synthesis of trans-1,2,3,6-tetrahydropyridines 8 is described. This synthesis proceeds via intramolecular Mistunobu reactions of 1,5-syn-(Z)-amino alcohols 7, which were prepared by a highly diastereo- and enantioselective double-allylboration reaction of aldehyde 5 and silylimine 6. The chiral bifunctional γ-borylallylborane 9E was generated in situ by hydroboration of allene 3 with
Synthesis and Biological Evaluation of Dichlorinated Chondramide Derivatives
作者:Dominic Becker、Uli Kazmaier
DOI:10.1002/ejoc.201500369
日期:2015.7
Straightforward synthetic protocols for the synthesis of new ethyl-substituted dichlorinatedchondramides with different methyl-substitution patterns in the polyketide fragment have been developed. The methyl groups at the ϵ-position can be removed completely without a significant influence on the biological activity. In contrast, after removal of the α-methyl group, a significant drop in activity