已经开发了使用ZnO @ Fe 3 O 4合成异恶唑5(4 H)-one衍生物的有效且环保的方法核-壳纳米催化系统。芳族/杂环醛,盐酸羟胺和乙酰乙酸乙酯的单锅多组分反应在水性条件下在略微升高的温度下以极高的收率形成标题化合物。当前的新方案对环境友好,因为它提供了一些有趣的有前途的功能,如安全性,原子效率,低成本,温和的条件,废物最少,催化剂可回收性,水为溶剂,易于加工并具有出色的官能团耐受性结构上不同的异恶唑衍生物的合成。所有产品均通过光谱和分析方法表征。用单晶X射线衍射法研究了代表性的标题衍生物的结构。
Sulfated polyborate catalyzed expeditious and efficient three-component synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones
作者:Manisha S. Patil、Chirag Mudaliar、Ganesh U. Chaturbhuj
DOI:10.1016/j.tetlet.2017.07.019
日期:2017.8
A rapid and highly efficient methodology for the synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones has been developed using sulfated polyborate as a catalyst. The multicomponent reaction of an aromatic/heterocyclic aldehyde, hydroxylamine hydrochloride, and ethyl acetoacetate under a solvent free condition at 80 °C is described. This protocol has promising features for the reaction
A bifunctional squaramide-catalysed enantioselective vinylogous Michael addition/cyclization cascade reaction of 4-unsaturated isoxazol-5-ones and α,α-dicyanoalkenes
作者:Yu Wang、Cheng Niu、Dong-Hua Xie、Da-Ming Du
DOI:10.1039/d1ob01256h
日期:——
stereoselective synthesis of spiro isoxazolone-cyclohexenimines was developed using a bifunctional squaramide-catalysed vinylogous Michael addition/cyclization cascade reaction of 4-unsaturated isoxazol-5-ones and α,α-dicyanoalkenes. The atom-economical cascade process can proceed smoothly under extremely low catalyst loading (1 mol%) and mild conditions, and the corresponding products were obtained
Highly Diastereo- and Enantioselective Synthesis of Isoxazolone-Spirooxindoles via Squaramide-Catalyzed Cascade Michael/Michael Addition Reactions
作者:Yu Wang、Da-Ming Du
DOI:10.1021/acs.joc.0c02150
日期:2020.12.4
been accomplished by squaramide-catalyzedcascadeMichael/Michael addition reactions under mild conditions. The corresponding isoxazolone-spirooxindoles with four continuous stereocenters were obtained in moderate to high yields with excellent stereoselectivities (up to >20:1 dr, 97% ee). The synthetic practicality of this methodology was illustrated by performing the reaction on a gram scale with
High diastereoselective synthesis of spiro-isoxazolonechromans via domino oxa-Michael/1,6-addition reactions of ortho-hydroxyphenylsubstituted para-quinone methides with unsaturated isoxazolones
A mild Et3N-catalyzed novel domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenylsubstituted p-QMs and unsaturated isoxazolones is described. Various new spiro-isoxazolonechromans were obtained in good yields (up to 89%) with excellent diastereoselectivities (>99:1 dr). The structure of the new compound 3a was determined by single crystal X-ray analysis.
and practical tandemreaction of 4-arylidene isoxazol-5-ones with enamino esters catalyzed by an inexpensive copper salt has been established in a ball mill. This innovative approach yields a diverse array of structurally novel pyrrole-2-carboxylic acids, showing excellent tolerance toward different functional groups. By integrating spiroannulation and ring-opening aromatization processes, this protocol