Bifunctional catalysts bearing two catalytic sites, Lewis acidic organometallic titanocene and Brønsted acidic COOH, have been assembled in situ from Cp2TiCl2 with carboxylic acid ligands, showing high catalytic activity over an intramolecular Mannich reaction towards synthesis of 2‐aryl‐2,3‐dihydroquinolin‐4(1H)‐ones. The determination of the bifunctional catalyst Cp2Ti(C8H4NO6)2 was elucidated by
具有羧酸催化配体的Cp 2 TiCl 2原位组装了带有两个催化位点的Lewis酸性有机金属钛茂和Brønsted酸性COOH双功能催化剂,在分子内曼尼希反应中对2-芳基-2,3的合成显示出高催化活性。 -dihydroquinolin-4(1H)-1。双功能催化剂Cp 2 Ti(C 8 H 4 NO 6)2的测定单个X射线HRMS和催化行为的研究阐明了这一点。特别是,用休眠的COOMe掩盖布朗斯台德酸性COOH催化位点会大大降低反应产率,这表明两个催化位点共同作用以保持高催化效率。
Ruthenium-catalyzed, site-selective C–H activation: access to C5-substituted azaflavanone
作者:Manickam Bakthadoss、Tadiparthi Thirupathi Reddy、Duddu S. Sharada
DOI:10.1039/d0ra06580c
日期:——
A site-selective ruthenium-catalyzed keto group assisted C–H bond activation of 2-aryl tetrahydroquinoline (azaflavanone) derivatives has been achieved with a variety of alkenes for the first time. A wide range of substrates was utilized for the synthesis of a wide variety of alkenylated azaflavanones. This simple and efficient protocol provides the C5-substituted azaflavanone derivatives in high yields
Abstract Lithium tetrafluoroborate has been demonstrated for the first time to be an efficient catalyst in intermolecular aza-Michael addition aromatic amines to electron deficient alkenes. Suitability of the same catalyst in intramolecular aza-Michael addition leading 2-aryl-2,3-dihydroquinolin-4(1H) ones has also been described.
(±)-2-Aryl-2,3-dihydro-4(1H)-quinolinones by a tandem reduction-Michael addition reaction
作者:Richard A. Bunce、Baskar Nammalwar
DOI:10.1002/jhet.624
日期:2011.5
(±)‐2‐aryl‐2,3‐dihydro‐4(1H)‐quinolinones has been developed from chalcones prepared from 2′‐nitroacetophenone and a series of substituted benzaldehydes. The cyclization sequence is initiated by reduction of the nitro group under dissolving metal conditions using iron powder in concentrated hydrochloric acid. Milder conditions, using acetic acid or acetic acid–phosphoric acid as the reaction medium, were less
In an attempt to develop non‐purine‐based xanthineoxidase (XO) inhibitors, keeping in view the complications reported with the use of purine‐based XO inhibitors, the flavone framework (a class possessing XO inhibitory potential) was used as lead structure for further optimization. By means of structure‐based classical bioisosterism, quinolone was used as an isoster for chromone (a bicyclic unit present
为了开发非基于嘌呤的黄嘌呤氧化酶 (XO) 抑制剂,考虑到使用基于嘌呤的 XO 抑制剂报告的并发症,黄酮框架(一类具有 XO 抑制潜力)被用作先导结构进一步优化。由于喹诺酮类的生物活性潜力和类药物特性,通过基于结构的经典生物等排体,喹诺酮被用作色酮(黄酮中的双环单元)的等排体。这种类型的置换不会改变 XO 抑制所需的形状和结构特征,还提供了一些额外的相互作用位点,而不会丢失氢键和疏水性和芳烃-芳烃相互作用。在本研究中,合理设计了一系列 2-芳基/杂芳基-4-喹诺酮类(黄酮的氮杂类似物),合成并评估体外 XO 抑制活性。提出了一些关于结构-活性关系的概念,表明 2-芳环的性质对抑制活性的影响。最活跃的化合物 3l (IC50 = 6.24 µM) 与 XO 活性位点的氨基酸残基之间的重要相互作用是通过分子模型计算出来的。