抗氧化剂由于其许多健康益处而已成为人们广泛研究的主题。在这项工作中,合成了一系列新型的羟基酪醇和香豆素共轭物,并对其体外自由基清除,毒性和抗氧化机理进行了评估。在DPPH自由基和ABTS +自由基阳离子清除试验中,所有目标化合物14a–t均表现出比BHT,羟基酪醇和香豆素更好的自由基清除活性。结构-活性关系研究表明,香豆素环上羟基的数量和位置对于良好的抗氧化能力至关重要。此外,最有前途的化合物14q在正常的WI-38和GES细胞中,溶血试验显示的毒性比BHT弱,抗增殖作用较弱,并且H 2 O 2诱导的HepG2细胞活力增强。另外,14q降低了HepG2细胞的凋亡百分比,减少了ROS的产生和LDH的释放,并改善了H 2 O 2处理的HepG2细胞中的GSH和SOD水平。最后,在甲醇溶液中,14q比羟基酪醇具有更高的稳定性。这些结果表明,羟基酪醇和香豆素的结合物显示出更好的抗氧化能力,并且是发现新型潜在抗氧化剂的有效方法。
FeCl3-catalyzed multicomponentreaction was developed for the facile synthesis of coumarin-3-carboxylic ester derivatives in a highly atom-economic and environmentally friendly way. Using simple and cheaply available salicylaldehydes, Meldrum's acid and alcohols as the starting materials, the method needs no extra additives and features wide substrate scope, good functional group tolerance and mild reaction conditions
An unexpected cascade reaction of 3-hydroxyoxindoles with coumarin-3-carboxylates to construct 2,3-dihydrobenzofuran spirooxindoles
作者:Kuan Zhang、Huabin Han、Lele Wang、Ziying Zhang、Qilin Wang、Wenjing Zhang、Zhanwei Bu
DOI:10.1039/c9cc07114h
日期:——
An unexpected Michael addition-inspired ring-opening/closure cascade reaction of 3-hydroxyoxindoles with coumarin-3-carboxylates was developed to access new dihydrobenzofuran or dihydrobenzothiophene spirooxindoles in 68–98% yields. This reaction not only provides an expedient and convenient method to assemble dihydrobenzofuran spirooxindoles, but also establishes a new reaction mode of coumarin-3-carboxylates
dihydrobenzofuran-fused pyridones in moderate to good yields with good functional group compatibility. The reaction likely involves a radical relay annulation, leading to the ring opening of the lactone moiety of the coumarins, and simultaneous formation of three new bonds. The investigation of photoluminescent properties reveals that several obtained compounds may have potential as fluorescent materials.
Anionic condensations of 3,5-di-tert-butyl-4(2)-hydroxybenzaldehydes in the presence of weak bases
作者:V. B. Vol’eva、I. S. Belostotskaya、N. L. Komissarova、L. N. Kurkovskaya
DOI:10.1134/s1070428008060043
日期:2008.6
Products of the reactions of 4- and 2-hydroxy-3,5-di-tert-butyl-benzaldehydes with malonic acid, diethyl malonate, and acetic anhydride in the presence of weak bases were isolated and identified. The reactions of 3,5-di-tert-butyl-4-hydroxybenzaldehyde with malonic acid and acetic anhydride in the presence of sodium acetate and piperidine gave 3,5-di-tert-butyl-4-hydroxycinnamic acid. The reaction of its 2-hydroxy isomer with acetic anhydride stopped at the stage of formation of the corresponding O-acetyl derivative, while in the reaction with malonic acid the corresponding substituted cinnamic acid and its lactone (coumarin derivative) were formed as intermediate products in a transformation sequence finally leading to 3-(3,5-di-tertbutyl-2-hydroxyphenyl)-3-piperidinopropionic acid and 6,8-di-tert-butyl-2-oxo-3,4-dihydro-2H-chromen-4-ylacetic acid. Analogous differences were typical of reactions of isomeric 4- and 2-hydroxy-3,5-di-tert-butylbenzaldehydes with diethyl malonate. The transformations of the 2-hydroxy isomer were accompanied by hydrolysis and formation of an adduct of intermediate coumarin derivative with diethyl malonate and piperidine.