Heterogeneous ditopic ZnFe2O4catalyzed synthesis of 4H-pyrans: further conversion to 1,4-DHPs and report of functional group interconversion from amide to ester
A green one-pot three-component synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives using a Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–imid–PMA<sup>n</sup> magnetic nanocatalyst under ultrasonic irradiation or reflux conditions
An efficient and environmentallybenign procedure for the synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives has been developed by a one-pot three-component reaction of various aldehydes, malononitrile, and dimedone or hydroxycoumarin in the presence of Fe3O4@SiO2–imid–PMAn nanoparticles as magnetic catalysts under ultrasonic irradiation or reflux conditions in water
通过在锅中各种醛,丙二腈,二甲酮或羟基香豆素的一锅三组分反应,开发了一种有效的,对环境无害的合成四氢苯并[ b ]吡喃和3,4-二氢吡喃并[ c ]色烯衍生物的方法。 Fe 3 O 4 @SiO 2-亚胺基-PMA n的存在超声辐射或水中回流条件下,纳米颗粒作为磁性催化剂。该新方法具有显着的优点,例如操作简单,产率高,反应时间短以及无需任何繁琐的后处理或纯化。另外,在水介质中的优异催化性能以及催化剂的易于制备,热稳定性和分离使其成为良好的非均相体系,并且是其他非均相催化剂的有用替代品。同样,该催化剂可以很容易地通过磁场回收并在连续的八个反应循环中重复使用而没有明显的活性损失。
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
Another application of (NH<sub>4</sub>)<sub>42</sub>[Mo<sup>VI</sup><sub>72</sub>Mo<sup>V</sup><sub>60</sub>O<sub>372</sub>(CH<sub>3</sub>COO)<sub>30</sub>(H<sub>2</sub>O)<sub>72</sub>] as a highly efficient recyclable catalyst for the synthesis of dihydropyrano[3,2-<i>c</i>]chromenes
catalyst for the synthesis of heterocyclic compounds, in this paper, we report another application of this attractive catalyst in the synthesis of 2‐amino‐5‐oxo‐4,5‐dihydropyrano[3,2‐c]chromene‐3‐carbonitriles via a one‐pot three‐component reaction of 4‐hydroxycoumarin, aldehydes and malononitrile. The reactions occur in ethanol–water as solvent at room temperature and the process is operative with
Green chemistry approach: sodium fluoride-catalyzed highly efficient microwave irradiation-assisted synthesis of substituted chromene derivatives in aqueous medium
作者:K. Fabitha、C. G. Arya、Munugala Chandrakanth、Janardhan Banothu
DOI:10.1007/s11164-022-04929-w
日期:2023.3
applications in medicinal chemistry. The multicomponent Knoevenagel–Michael reaction is one of the most efficient strategies to construct these two scaffolds. Previous efforts have been made in converting the traditional organicsolvents to eco-friendly solvents including H2O generally in the presence of complex catalysts. Here we present our work of using sodium fluoride (NaF) as the catalyst to synthesize
2-Amino-4 H -benzo[ H ]chromene-3-carbonitrile 和 2-amino-5-oxo-4 H ,5 H -pyrano[3,2- c ]chromene-3-carbonitrile 是两个重要的药效团,具有广泛的在药物化学中的应用。多组分 Knoevenagel-Michael 反应是构建这两种支架的最有效策略之一。之前已经在将传统有机溶剂转化为包括 H 2在内的环保溶剂方面做出了努力O 通常在复杂的催化剂存在下。在这里,我们介绍了我们使用氟化钠 (NaF) 作为催化剂从 α-或 β-萘酚或 4-羟基香豆素开始合成范围广泛的两种底物的工作。在微波辐射条件下使用 12 mol% NaF,反应在 15-25 分钟内完成,所有产率均超过 85%。通过用H 2 O洗涤简单地纯化反应产物并且可以通过用MeOH结晶进一步纯化。对绿色化学相关参数的分析表明,目前