A tandem [3 + 2] cycloaddition/reductive cyclization of nitrochalcones with activated methylene isocyanides for the efficient synthesis of pyrrolo[2,3-b]quinolones is reported. In this reaction, the in situ generated dihydropyrroline acts as the internal reductant to convert the nitro into an electrophilic nitroso group, which undergoes subsequent C–N bond formation. Transition-metal-free, simple experimental
报道了用活化的亚甲基异氰酸酯串联硝唑烷的[3 + 2]环加成/还原环化反应,可有效合成吡咯并[2,3- b ]喹诺酮。在该反应中,原位生成的二氢吡咯啉充当内部还原剂,将硝基转化为亲电的亚硝基,随后发生C–N键的形成。不含过渡金属,简单的实验程序以及易于使用的起始材料构成了目前的转化方式。
Cu-Catalyzed one-pot synthesis of thiochromeno-quinolinone and thiochromeno-thioflavone <i>via</i> oxidative double hetero Michael addition using <i>in situ</i> generated nucleophiles
作者:Nallappan Sundaravelu、Govindasamy Sekar
DOI:10.1039/d0cc03210g
日期:——
catalyzed three-component synthesis of π-conjugated tetracyclic thiochromeno-quinolinone and thiochromeno-thioflavone was established via oxidative double hetero Michael additionusing in situ generated nucleophiles. Xanthate plays a dual role as an odourless sulfur source and a chemoselective reducing agent. The in situ formed iodine plays a crucial role in the oxidation step.
An efficient one-step synthesis of 2-arylquinolin-4(1H)-ones with the aid of a low-valent titanium reagent
作者:Fang Sun、Xuan Zhao、Daqing Shi
DOI:10.1016/j.tetlet.2011.08.089
日期:2011.10
A short and facile synthesis of a series of 2-arylquinolin-4(1H)-ones was accomplished in good yields via the novel reductive cyclization of 2-nitrochalcones promoted by TiCl4/Zn. This method has the advantages of accessible starting materials, one-step procedure, convenient manipulation, and moderate to high yields.
Effective Synthesis of 4-Quinolones by Reductive Cyclization of 2′-Nitrochalcones Using Formic Acid as a CO Surrogate
作者:Francesco Ferretti、Manar Ahmed Fouad、Cecilia Abbo、Fabio Ragaini
DOI:10.3390/molecules28145424
日期:——
4-Quinolones are the structural elements of many pharmaceutically active compounds. Although several approaches are known for their synthesis, the introduction of an aryl ring in position 2 is problematic with most of them. The reductive cyclization of o-nitrochalcones by pressurized CO, catalyzed by ruthenium or palladium complexes, has been previously reported to be a viable synthetic strategy for
4-喹诺酮类是许多药物活性化合物的结构元素。尽管已知有几种合成方法,但在 2 位引入芳环对大多数方法来说都是有问题的。此前曾报道,在钌或钯配合物的催化下,通过加压 CO 进行邻硝基查耳酮的还原环化是实现这一目标的可行合成策略,但对加压 CO 管线和高压釜的需求阻碍了其广泛使用。在本文中,我们描述了使用甲酸/乙酸酐混合物作为 CO 替代物,这使得我们能够在廉价且市售的厚壁玻璃管中进行反应,而无需添加任何气态试剂。所获得的产率通常很高,与之前报道的使用加压 CO 的产率相比毫不逊色。该方法适用于从市售且廉价的生物碱 Graveoline 试剂进行三步合成。
Synthesis of 2-carboxyaniline-substituted maleimides from 2′-nitrochalcones
作者:Nicolai A. Aksenov、Dmitrii A. Aksenov、Daniil D. Ganusenko、Igor A. Kurenkov、Alexander V. Leontiev、Alexander V. Aksenov
DOI:10.1039/d3ob00197k
日期:——
A practical, one-pot approach to 3-anilino-4-(het)arylmaleimides by simple heating of aqueous DMSO solution of 2′-nitrochalcones with potassiumcyanide in the presence of formic acid has been developed. This new reaction provides effective access to a variety of β-substituted α-aminomaleimides which have recently become a subject of growing interest as small, easily modified and environmentally responsive