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。
A new reaction of 4-arylidene-3-methylisoxazol-5(4H)-one or 4-arylidene-2-phenyloxazol-5(4H)-one with 2,6-diaminopyrimidin-4(3H)-one is described and a number of new pyrido[2,3-d]pyrimidine-4,7-dione derivatives are synthesized. This protocol has the advantages of good yields, broad substrate scope and simple work-up.
Quinine-catalyzed asymmetric domino Michael-cyclization reaction for the synthesis of spirocyclic oxindoles bearing two spiro quaternary centers and three consecutive stereocenters
An efficient organocatalytic diastereo- and enantioselective method for the construction of spirocyclic oxindole derivatives bearing twospiroquaternarycenters and three consecutive stereocenters via a domino Michael/cyclization process has been developed. Using commercially available quinine as catalyst, the reactions of 3-isothiocyanato oxindoles with unsaturated pyrazolones and unsaturated isoxazolones
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
<i>N</i>-Allylation <i>versus C</i>-allylation of intermediates from aza-Michael adducts of arylideneisoxazol-5-ones
作者:Shu-Hao Wan、Xuan-An Li、Yi-Hung Liu、Shiuh-Tzung Liu
DOI:10.1039/d0ob01998d
日期:——
Reactions of arylidene-isoxazol-5-ones with intermediates from palladium-catalysed decarboxylation of allyl carbamates proceeded through aza-Michael addition and N-allylation to give the corresponding bis-adducts, β-amido-N-allylated products, in good yields. In similar reactions with 4-vinyl-1,4-dihydro-2H-3,1-benzoxazin-2-one, a cyclic allyl carbamate, C-allylation took place to yield a series of
亚芳基-异恶唑-5-酮与钯催化的烯丙基氨基甲酸酯脱羧中间体的反应通过氮杂迈克尔加成和N-烯丙基化得到相应的双加合物,即β-酰胺基-N-烯丙基化产物,收率良好。在与环状氨基甲酸烯丙酯 4-vinyl-1,4-dihydro-2 H -3,1-benzoxazin-2-one 的类似反应中,发生C-烯丙基化,生成一系列螺[isoxazole-4,3' -quinolin]-5-ones 的高产率。区域选择性N -与 C -烯丙基化发生在分子内时尚。这些产品的结构和立体化学由 NMR 光谱确定,并通过 X 射线晶体学进一步证实。这项工作为制备各种取代的异恶唑-5-酮提供了一种极好的方法。
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.