在这项工作中,将磁化水用作绿色促进介质,用于无催化剂,一锅,实用,高效,环境友好的四氢苯并[ b ]吡喃多组分合成 。一些四氢苯并[ b 通过在室温下醛,丙二腈和1,3-环己二酮或5,5-二甲基-1,3-环己二酮的三组分反应合成对吡喃衍生物。该方法具有反应时间短,成本低,定量收率,后处理简单,不需要有机溶剂的优点。因此它是环境经济的,不会产生危险废物。该系统的分子洞察力表明,磁化水对所有有机试剂之间的相互作用强度具有显着影响,并且按水与每种有机试剂之间氢键数量的顺序增加了1.2倍。在存在磁化水的情况下,试剂在模拟箱的中央更加冷凝,
Ethylenediammonium diformate (EDDF) in PEG600: an efficient ambiphilic novel catalytic system for the one-pot synthesis of 4H-pyrans via Knoevenagel condensation
作者:Anuj Thakur、Mohit Tripathi、U. Chinna Rajesh、Diwan S. Rawat
DOI:10.1039/c3ra42410c
日期:——
system was developed as a catalyst for the Knoevenagel condensation and Knoevenagel initiated three-componentone-potsynthesis of 4H-pyrans at room temperature with high yields and in short reaction times. Further, the EDDF-PEG600 catalytic system was recycled six times without any appreciable loss in its activity and hence can be termed as a green, environmentally benign catalytic system. A plausible
Anion–cation co-operative catalysis by artificial sweetener saccharine-based ionic liquid for sustainable synthesis of 3,4-dihydropyrano[<i>c</i>]chromenes, 4,5-dihydropyrano[4,3-<i>b</i>]pyran and tetrahydrobenzo[<i>b</i>]pyrans in aqueous medium
作者:Himani Sharma、Suman Srivastava
DOI:10.1039/c8ra06889e
日期:——
tetrahydrobenzo[b]pyrans scaffolds through Domino Knoevenagel–Michael reaction. The easy recovery of the catalyst and high yield of the products make the protocol attractive, sustainable and economical. A mechanistic hypothesis is discussed using the concept of cooperativecatalysis based on the dual (electrophilic/nucleophilic) activation of reactants by [Bmim]Sac. Furthermore, dual hydrogenbonding of saccharinate
在这项研究中,糖精基离子液体 [Bmim]Sac 被发现是合成 3,4-二氢吡喃[ c ]色烯、4,5-二氢吡喃[4,3- b ]吡喃和通过 Domino Knoevenagel-Michael 反应形成四氢苯并[ b ]吡喃支架。催化剂的容易回收和产品的高产率使该协议具有吸引力、可持续性和经济性。使用基于[Bmim]Sac对反应物的双重(亲电/亲核)活化的协同催化概念讨论了机械假设。此外,糖精阴离子的双氢键在亲核试剂的活化中起重要作用。
One-pot cascade synthesis of benzopyrans and dihydropyrano[c]chromenes catalyzed by lipase TLIM
作者:Yajie Fu、Zeping Lu、Xiaolong Ma、Ke Fang、Xinyi He、Huajin Xu、Yi Hu
DOI:10.1016/j.bioorg.2020.103888
日期:2020.6
Lipase TLIM was reported to be an efficient, commercially available and reusable catalyst for the Knoevenagel-Michael cascade reactions of aldehydes, malononitrile/ethyl cyanoacetate and 4-hydroxycoumarin/1, 3-cyclohexanedione/dimedone in aqueous DMSO. This methodology presents many superiorities such as simple procedure, mild reaction conditions, commercially available and reusable catalyst, high