Inverting the Selectivity of the Newman–Kwart Rearrangement via One Electron Oxidation at Room Temperature
作者:Stephan K. Pedersen、Anne Ulfkjær、Madeleine N. Newman、Sarangki Yogarasa、Anne U. Petersen、Theis I. Sølling、Michael Pittelkow
DOI:10.1021/acs.joc.8b01800
日期:2018.10.5
The discovery that the Newman–Kwartrearrangement can be performed at room temperature by action of a simple and readily available oxidant, cerium ammonium nitrate, is described. The conditions give clean conversion when using electron-rich aromatic substrates, and the reactions are often quantitative. Computational studies support a reaction mechanism where the O-thiocarbamate is first oxidized to
Ambient-Temperature Newman–Kwart Rearrangement Mediated by Organic Photoredox Catalysis
作者:Andrew J. Perkowski、Cole L. Cruz、David A. Nicewicz
DOI:10.1021/jacs.5b11800
日期:2015.12.23
The Newman-Kwartrearrangement is perhaps the quintessential method for the synthesis of thiophenols from the corresponding phenol. However, the high thermal conditions required for the rearrangement of the requisite O-aryl carbamothioates often leads to decomposition. Herein, we present a general strategy for catalysis of O-aryl carbamothioates to S-aryl carbamothioates using catalytic quantities
Substituted 2-(3′,4′,5′-trimethoxybenzoyl)-benzo[b]thiophene derivatives as potent tubulin polymerization inhibitors
作者:Romeo Romagnoli、Pier Giovanni Baraldi、Maria Dora Carrion、Olga Cruz-Lopez、Manlio Tolomeo、Stefania Grimaudo、Antonietta Di Cristina、Maria Rosaria Pipitone、Jan Balzarini、Andrea Brancale、Ernest Hamel
DOI:10.1016/j.bmc.2010.05.068
日期:2010.7
The central role of microtubules in cell division and mitosis makes them a particularly important target for anticancer agents. On our early publication, we found that a series of 2-(3',4',5'-trimethoxybenzoyl)-3-aminobenzo[b]thiophenes exhibited strong antiproliferative activity in the submicromolar range and significantly arrested cells in the G2-M phase of the cell cycle and induced apoptosis. In order to investigate the importance of the amino group at the 3-position of the benzo[b] thiophene skeleton, the corresponding 3-unsubstituted and methyl derivatives were prepared. A novel series of inhibitors of tubulin polymerization, based on the 2-(3,4,5-trimethoxybenzoyl)-benzo[b] thiophene molecular skeleton with a methoxy substituent at the C-4, C-5, C-6 or C-7 position on the benzene ring, was evaluated for antiproliferative activity against a panel of five cancer cell lines, for inhibition of tubulin polymerization and for cell cycle effects. Replacing the methyl group at the C-3 position resulted in increased activity compared with the corresponding 3-unsubstituted counterpart. The structure-activity relationship established that the best activities were obtained with the methoxy group placed at the C-4, C-6 or C-7 position. Most of these compounds exhibited good growth inhibition activity and arrest K562 cells in the G2-M phase via microtubule depolymerization. (C) 2010 Elsevier Ltd. All rights reserved.