Synthesis, topoisomerase-targeting activity and growth inhibition of lycobetaine analogs
摘要:
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.
An efficient palladium-catalyzed nucleophilic substitution/C–H activation/aromatization cascade reaction between readily available 2-halo-N-Ms-arylamines (Ms = methanesulfonyl) and benzyl halides/sulfonates has been described. A wide variety of phenanthridines were synthesized in a one-pot fashion in moderate to high yields (37–86 %). Notably, this method provides a straightforward, facile approach
iminyl‐radical formation has been established for the construction of pyridines, quinolines, and phenanthridines from acyl oximes. With fac‐[Ir(ppy)3] as a photoredox catalyst, the acyl oximes were converted by 1 e− reduction into iminyl radical intermediates, which then underwent intramolecular homolytic aromatic substitution (HAS) to give the N‐containing arenes. These reactions proceeded with a broad
已经建立了涉及可见光诱导的亚胺基自由基形成的统一策略,用于从酰基肟中构建吡啶,喹啉和菲啶。用FAC - [的Ir(ppy)3 ]作为催化剂photoredox,酰基肟通过1e中转化-还原成亚氨基自由基中间体,然后行分子内均裂芳族取代(HAS),得到含有N-芳烃其中。这些反应在室温下以宽范围的底物以高收率进行。这种可见光诱导的亚胺基自由基形成策略已成功地应用于五步精简合成苯并[ c ]菲啶生物碱。
Photocyclization synthesis of phenanthridine and its derivatives under direct dehydrogenation conditions
作者:Wen-Qing Zhu、Jin Zhang、Pan Fan、Lan-Ting Shi、Hong Li、Min-Ge Yang、Yang Li
DOI:10.1016/j.tetlet.2020.152734
日期:2021.2
synthesizing phenanthridines by photocyclization has been established. This method does not require inert gas protection, does not require transition metal catalysts and is environmentally friendly, efficient and convenient. It is proposed to use (E)-N,1-diphenylformimines as substrates to synthesize phenanthridine and its derivatives by ultraviolet light, which provides a new synthesis route for further research
annulation between 2-aminobiphenyls and activated olefins is disclosed for succinct synthesis of valuable phenanthridine scaffolds. The protocol avails a common organic functional group, free amine, as a directing group and represents a unique combination of C–Hactivation/annulation/C–C bond cleavage cascade that bodes well in the production of bioactive alkaloids including trisphaeridine and bicolorine
A facile and practical palladium-catalyzed nucleophilic substitution/C–H activation/aromatization cascade reaction has been developed. A range of 6-unsubstituted phenanthridines could be obtained in moderate to good yields (31–85%) with readily prepared N-Ms arylamines and commercially available 2-bromobenzyl bromide derivatives as starting materials. The potential application of the protocol was also