Harnessing Cascade Suzuki-Cyclization Reactions of Pyrazolo[3,4-<i>b</i>]pyridine for the Synthesis of Tetracyclic Fused Heteroaromatics
作者:Hubert Lavrard、Florence Popowycz
DOI:10.1002/ejoc.201601242
日期:2017.1.18
Numerous procedures have been described for the functionalization of pyrazolo[3,4-b]pyridine, mainly nucleophilic substitutions on C-4 position and esterifications/amidations on C-5 position. Thus, we report herein a robust, easy to implement protocol for the Suzuki cross-coupling reaction of the chloroarene 2, followed by in situ lactonisation to provide chromenopyrazolopyridines. The extension of
Non-naturally occuring dynemicin analogs are provided, which are useful as DNA cleaving agents, cytotoxic agents, and/or anti-tumor compounds. Methods of making dynemicin analogs are also provided.
Synthesis, topoisomerase-targeting activity and growth inhibition of lycobetaine analogs
作者:Simone A. Baechler、Markus Fehr、Michael Habermeyer、Andreas Hofmann、Karl-Heinz Merz、Heinz-Herbert Fiebig、Doris Marko、Gerhard Eisenbrand
DOI:10.1016/j.bmc.2012.11.011
日期:2013.2
The plant alkaloid lycobetaine has potent topoisomerase-targeting properties and shows anticancer activity. Based on these findings, several lycobetaine analogs were synthesized mainly differing in their substituents at 2, 8 and 9 position and their biological activities were evaluated. The topoisomerase-targeting properties and cytotoxicity of these structural analogs were assessed in the human gastric carcinoma cell line GXF251L. Performing a plasmid relaxation assay, an increased inhibition of topoisomerase I was found with N-methylphenanthridinium chlorides bearing a 8,9-methylenedioxy moiety or a methoxy group in 2-position. Furthermore, quaternized phenanthridinium derivatives bearing either a 2-methoxy or a 8,9-methylenedioxy moiety in conjunction with a 2-hydroxy or 2-methoxy group display potent topoisomerase II inhibition as shown by decatenation of kinetoplast DNA. In general, the N-methylphenanthridinium chlorides possess more potency in inhibiting topoisomerase I than topoisomerase II. All quaternized derivatives also exhibited potent inhibition of tumor cell growth in the low micromolar concentration range. Hence, N-methylphenanthridinium compounds were found to represent a promising class of compounds, potently inhibiting both, topoisomerases I and II, and may be further developed into clinically useful topoisomerase inhibitors. (C) 2012 Elsevier Ltd. All rights reserved.
SIDDIOUI, M. A.;SNIECKUS, V., TETRAHEDRON LETT., 29,(1988) N 43, C. 5463-5466