Synthesis and anti-migrative evaluation of moverastin derivatives
摘要:
Cell migration of tumor cells is essential for invasion of the extracellular matrix and for cell dissemination. Inhibition of the cell migration involved in the invasion process represents a potential therapeutic approach to the treatment of tumor metastasis; therefore, a novel series of derivatives of moverastins (moverastins A and B), an inhibitor of tumor cell migration, was designed and chemically synthesized. Among these moverastin derivatives, several compounds showed stronger cell migration inhibitory activity than parental moverastins, and UTKO1 was found to have the most potent inhibitory activity against the migration of human esophageal tumor EC17 cells in a chemotaxis cell chamber assay. Interestingly, although moverastins are considered to inhibit tumor cell migration by inhibiting farnesyltransferase (FTase), UTKO1 did not inhibit FTase, indicating that UTKO1 inhibited tumor cell migration by a mechanism other than the inhibition of FTase. (C) 2011 Elsevier Ltd. All rights reserved.
Synthesis of 9-Substituted Tetrahydrodiazepinopurines: Studies toward the Total Synthesis of Asmarines
摘要:
A methodology for the preparation of asmarine analogues has been developed. The asmarines are cytotoxic marine alkaloids with a unique tetrahydro[1,4]diazepino[1,2,3-g,h]purine (THDAP) structure. Three cyclization methods were applied for the preparation of the 9,9-disubstituted 10-hydroxy-THDAP system, namely, aminomercurization, iodocyclization, and acid-catalyzed cyclization. The DMPM group of the NOH functionality and cyanoethyl group of the N-9 atom were found to be the most suitable protecting groups. The structures of all compounds were mainly determined from NMR measurements including N-15 chemical shifts obtained from (NH)-N-15 HMBC spectra. The end products are at least about 1 order of magnitude less active than the natural product asmarine B.
Decarboxylative Giese-Type Reaction of Carboxylic Acids Promoted by Visible Light: A Sustainable and Photoredox-Neutral Protocol
作者:Nieves P. Ramirez、Jose C. Gonzalez-Gomez
DOI:10.1002/ejoc.201601478
日期:2017.4.18
for decarboxylative generation of radicals from carboxylicacids and their 1,4-addition to Michael acceptors. The Fukuzumi catalyst ([Acr+-Mes]) enabled this transformation under visiblelight irradiation, at room temperature and with CO2 as the only byproduct. Scope and limitations of this protocol were examined using a range of Michael acceptors (15 examples) and a diverse array of carboxylic acids
这项工作描述了一种无过渡金属的方法,用于从羧酸中脱羧生成自由基及其与迈克尔受体的 1,4-加成。Fukuzumi 催化剂 ([Acr+-Mes]) 在可见光照射下、在室温下和 CO2 作为唯一副产物的情况下实现了这种转变。使用一系列迈克尔受体(15 个示例)和各种羧酸(18 个示例)检查了该协议的范围和限制。在该协议中使用 3-羟基新戊酸允许直接形成非对映异构纯 δ-内酯。此外,当使用高烯丙酸时,会发生自由基级联反应,形成三个 CC 键。
Catalyst-Controlled C–H Functionalization of Adamantanes Using Selective H-Atom Transfer
作者:Hai-Bin Yang、Abigail Feceu、David B. C. Martin
DOI:10.1021/acscatal.9b01394
日期:2019.6.7
been developed using photoredox and H atom transfer catalysis. This C–H alkylation reaction has excellent chemoselectivity for the strong 3° C–H bonds of adamantanes in polyfunctional molecules. In substrate competition reactions, a reversal in selectivity is observed for the new H-atom transfer catalyst reported here in comparison to five known photochemical systems. Derivatization of a broad scope
Direct Construction of Quaternary Carbons from Tertiary Alcohols via Photoredox-Catalyzed Fragmentation of <i>tert</i>-Alkyl <i>N</i>-Phthalimidoyl Oxalates
作者:Gregory L. Lackner、Kyle W. Quasdorf、Larry E. Overman
DOI:10.1021/ja408971t
日期:2013.10.16
A convenientmethod for the direct construction of quaternary carbons from tertiary alcohols by visible-light photoredox coupling of tert-alkyl N-phthalimidoyl oxalate intermediates with electron-deficient alkenes is reported.
1-Ethylpiperidium Hypophosphite: A Practical Mediator for Radical Carbon-Carbon Bond Formation
作者:Doo Ok Jang、Dae Hyan Cho、Chan-Moon Chung
DOI:10.1055/s-2001-18781
日期:——
1-Ethylpiperidium hypophosphite could be used efficiently as radical chain carrier in the intermolecular carbon-carbon bond formation without using excess of alkenes under mild reaction conditions.
Silylated Cyclohexadienes as New Radical Chain Reducing Reagents: Preparative and Mechanistic Aspects
作者:Armido Studer、Stephan Amrein、Florian Schleth、Tobias Schulte、John C. Walton
DOI:10.1021/ja0341743
日期:2003.5.1
superior tin hydride substitutes for the conduction of various radical chain reductions. Debrominations, deiodinations, and deselenations can be performed using these environmentally benign reagents. Furthermore, Barton-McCombie-type deoxygenations using silylated cyclohexadienes are described. Radical cyclizations, ring expansions, and Giese-type addition reactions with the new tin hydride substitutes