An efficient rhodium-catalyzed protocol for the synthesis of cyclopentenones based on a three-component reaction of acrylic acids, formaldehyde, and malonates via vinylic C–H activation is reported. Exploratory studies showed that 5-alkylation of as-prepared cyclopentenones could be realized smoothly by the treatment of a variety of alkyl halides with a Na2CO3/MeOH solution. Excess formaldehyde and
报道了一种有效的铑催化合成环戊烯酮的方案,该方案基于丙烯酸、甲醛和丙二酸酯通过乙烯基 C-H 活化的三组分反应。探索性研究表明,通过用 Na 2 CO 3 /MeOH 溶液处理各种烷基卤化物,可以顺利地实现所制备的环戊烯酮的 5-烷基化。过量的甲醛和丙二酸酯导致多组分反应,通过迈克尔加成得到多取代的环戊烯酮。
Synthesis and Biological Activity of Enantiomeric Pairs of 5-(Alk-2-enyl)thiolactomycin and 5-[(E)-Cycloalk-2-enylidenemethyl]thiolactomycin Congeners
作者:Kohei Ohata、Shiro Terashima
DOI:10.1248/cpb.57.920
日期:——
The title compounds were synthesized by the efficient route previously explored for the synthesis of enantiomeric pairs of thiolactomycin and its 3-demethyl derivative. These studies were carried out to prove the flexibility of the previously explored synthetic route to natural thiolactomycin (TLM) 1 and to examine the structure–activity relationship on the 5-position of 1. While all of the synthesized congeners lacked in vitro antibacterial activity, these studies led us to find 5-(alk-2-enyl)-TLM (ent-4d) which exhibits mammalian type I fatty acid synthase (FAS) inhibitory activity equal to that of C75, a potent inhibitor reported previously. It was also found that 5-[(E)-cycloalk-2-enylidenemethyl]-TLM (ent-5c) exhibited slightly less potent mammalian type I FAS inhibitory activity than C75.
标题化合物是通过之前探索的合成硫代霉素对映体及其 3-去甲基衍生物的高效路线合成的。虽然所有合成的同系物都缺乏体外抗菌活性,但这些研究使我们发现了 5-(alk-2-enyl)-TLM(ent-4d),它对哺乳动物 I 型脂肪酸合成酶(FAS)的抑制活性与之前报道的强效抑制剂 C75 相当。研究还发现,5-[(E)-环烷-2-亚烯基甲基]-TLM(ent-5c)对哺乳动物 I 型脂肪酸合成酶的抑制活性略低于 C75。
Synthesis of 2-Hydroxy-3-oxocarboxylic Esters From the Corresponding α,β-Unsaturated Esters by a Simple One-Step Procedure
作者:D. H. G. Crout、D. L. Rathbone
DOI:10.1055/s-1989-27142
日期:——
A convenient one-step synthesis of 2-alkyl-2-hydroxy-3-oxocarboxylic esters by potassium permanganate oxidation of the corresponding readily available α,β-unsaturated esters is described. Preparation of the latter by the phosphonate modification of the Wittig reaction is also reported.
Anionic versus photochemical diastereoselective deconjugation of diacetone d-glucose α,β-unsaturated esters
作者:Frédéric Bargiggia、Olivier Piva
DOI:10.1016/s0957-4166(03)00365-3
日期:2003.7
Deconjugation of diacetone D-glucose alpha, beta-unsaturated esters has been conducted by deprotonation using NaHMDS with HMPA as co-solvent followed by stereoselective protonation at low temperature. High selectivities (>95%) were obtained with oc-methyl linear compounds. (C) 2003 Elsevier Science Ltd. All rights reserved.
Synthesis and Antiplasmodial Activity of Bicyclic Dioxanes as Simplified Dihydroplakortin Analogues
Here we report the synthesis and evaluation of antiplasmodial activity of a novel series of bicyclic peroxides inspired by the marine natural compound dihydroplakortin. We developed a synthetic strategy leading to the dihydroplakortin-related peroxides in only a few steps. The in vitro antiplasmodial potency of the peroxides was similar to, or greater than, that of the reference natural compound, and