Syntheses and photophysical properties of fluorescent 2-aryl-3-hydroxy-4-chromenones
作者:Joel M. Kauffman、Mohammed A. Aziz
DOI:10.1002/jhet.5570300617
日期:1993.12
fluors soluble in styrene are required which have improved light output and response time. New 2-aryl-3-hydroxy-4-chromenones related to 3-hydroxyflavone were prepared which displayed these improved properties. Improved solvent systems for chromenone formation were essential in the synthesis of two of the chromenones. One chromenone produced fluorescence emission at 560 nm with a quantum yield of 0.53
IR spectroscopy applied subsequent to a proton transfer reaction in the excited state of isolated 3-hydroxyflavone and 2-(2-naphthyl)-3-hydroxychromone
IR/R2PI-spectroscopy has been applied to the electronic ground and electronically excited states of 3-hydroxyflavone (3-HF) and 2-(2-naphthyl)-3-hydroxychromone (2-NHC) in a supersonic jet yielding direct structural information on the educt and product of a proton transfer reaction. We show that IR spectra of the electronically excited states can be recorded subsequent to a photoinduced chemical reaction, in this case a proton transfer. In combination with DFT and TDDFT calculations structural assignments are performed.
A novel flavone-based ESIPT ratiometric fluorescent probe for selective sensing and imaging of hydrogen polysulfides
作者:Linlin Yang、Nan Yang、Pengli Gu、Chuang Wang、Beining Li、Yihua Zhang、Liguo Ji、Guangjie He
DOI:10.1016/j.saa.2022.120962
日期:2022.4
changes of H2Sn level in vivo is highly desired. Herein we design a simple ratiometric fluorescent probe based on flavone skeleton for highly selectivedetection of H2Sn. The probe HF-NA-MC bearing 2-fluoro-5-nitrobenzoic acid group inhibited the intramolecular ESIPT process, which show the blue fluorescence of adjacent naphthalene unit. In the presence of H2Sn, the enol form of probe is converted to conjugated
多硫化氢(H 2 S n)作为活性硫物种的重要成员,与氧化还原稳态和代谢中的许多生理功能密切相关。双通道监测体内H 2 Sn水平的变化是非常需要的。在此,我们设计了一种基于黄酮骨架的简单比率荧光探针,用于高选择性检测H 2 S n。带有2-氟-5-硝基苯甲酸基团的探针HF-NA-MC抑制了分子内ESIPT过程,显示出相邻萘单元的蓝色荧光。在 H 2 S n的存在下,探针的烯醇形式转化为共轭酮形式,导致从 450nm 到 540nm 的荧光发射发生 90 nm 的红移。该探针的比率强度(I 540 /I 450 )在0-120μM范围内与H 2 S n呈现良好的线性关系,检测限估计为0.63μM。与其他相关的活性硫物质相比,比率荧光探针对 H 2 Sn具有高特异性和抗干扰能力。HF-NA-MC探针显示出良好的前景,可应用于Hela细胞中双发射通道的H 2 Sn共焦成像。
Identification of bicyclic compounds that act as dual inhibitors of Bcl-2 and Mcl-1
Elevated expression of anti-apoptotic proteins, such as Bcl-2 and Mcl-1 contributes to poor prognosis and resistance to current treatment modalities in multiple cancers. Here, we report the design, synthesis and characterization of benzimidazole chalcone and flavonoid scaffold-derived bicyclic compounds targeting both Bcl-2 and Mcl-1 by optimizing the structural differences in the binding sites of both these proteins. Initial docking screen of Bcl-2 and Mcl-1 with pro-apoptotic protein Bim revealed possible hits with optimal binding energies. All the optimized bicyclic compounds were screened for their in vitro cytotoxic activity against two oral cancer cell lines (AW8507 and AW13516) which express high levels of Bcl-2 and Mcl-1. Compound 4d from the benzimidazole chalcone series and compound 6d from the flavonoid series exhibited significant cytotoxic activity (IC50 7.12 μM and 17.18 μM, respectively) against AW13516 cell line. Time Resolved-Fluorescence Resonance Energy Transfer (TR-FRET) analysis further demonstrated that compound 4d and compound 6d could effectively inhibit the Bcl-2 and Mcl-1 proteins by displacing their BH3 binding partners. Both compounds exhibited potent activation of canonical pathway of apoptosis evident from appearance of cleaved Caspase-3 and PARP. Further, treatment of oral cancer cells with the inhibitors induced dissociation of the BH3 only protein Bim from Mcl-1 and Bak from Bcl-2 but failed to release Bax from Bcl-xL thereby confirming the nature of compounds as BH3-mimetics selectively targeting Bcl-2 and Mcl-1. Our study thus identifies bicyclic compounds as promising candidates for anti-apoptotic Bcl-2/Mcl-1 dual inhibitors with a potential for further development.
Transient absorption and two-step laser-induced fluorescence studies on the intramolecular excited-state proton transfer and relaxation process in 2-naphthyl-3-hydroxychromones