Catalyst-free 1,3-dipolar cycloaddition of 3-nitrochromen with sodium azide: a facile method for the synthesis of 4-aryl-1,4-dihydrochromeno[4,3-d][1,2,3]triazole derivatives
摘要:
1,3-Dipolar cycloaddition of 3-nitrochromen with sodium azide under catalyst-free conditions afforded 4-aryl-1,4-dihydrochromeno[4,3-d][1,2,3]triazole derivatives at 80 degrees C in DMSO is described. The generality of this reaction was demonstrated by synthesizing an array of 4-aryl-1,4-dihydrochromeno[4,3d][1,2,3]triazole derivatives. Clean reaction conditions, easy isolation, and good yields of the triazoles are the salient features of the methodology. (C) 2009 Elsevier Ltd. All rights reserved.
triazolochromenes were formed with complete regioselectivity and new biologically relevant structures were synthesized via extension of the developed procedure and via postfunctionalization. The mechanochemical synthesis was carried out for several salicylaldehydes and gave a clear improvement in the yield of the corresponding triazolochromenes and consequently showed to be a viable alternative for solid salicylaldehydes
Augmentation of Enantioselectivity by Spatial Tuning of Aminocatalyst: Synthesis of 2-Alkyl/aryl-3-nitro-2<i>H</i>-chromenes by Tandem Oxa-Michael–Henry Reaction
作者:Rahul Mohanta、Ghanashyam Bez
DOI:10.1021/acs.joc.9b03366
日期:2020.4.3
The asymmetric oxa-Michael addition of salicylaldehyde to conjugatednitroalkenes often suffers from poor reactivity and selectivity and a long reaction time. Because of the formation of an iminium ion with aminocatalyst, the nucleophilicity of the phenolic hydroxy group in salicylaldehyde reduces further to make the oxa-Michael reaction reversible. Here, we report a structurally simple and easily
Synthesis of substituted chiral chromans via organocatalytic kinetic resolution of racemic 3-nitro-2-aryl-2H-chromenes with ketones catalyzed by pyrrolidinyl-camphor-derived organocatalysts
作者:Dhananjay R. Magar、Kwunmin Chen
DOI:10.1016/j.tet.2012.05.019
日期:2012.7
pyrrolidinyl-camphor derivative 2b as a bifunctionalorganocatalyst under neat conditions in the presence of AcOH at 0 °C. In general, the organocatalyticasymmetricMichaeladdition of ketones proceeded smoothly to give the functionalized Michael adducts (3a–n) with good-to-high diastereo- and enantioselectivities (up to 92:8 dr, 93% ee, and 47% yield). The less reactive chromenes (S)-1a–h, k, l and (R)-1i–j were
“On-Water”-Promoted<i>C</i>-Alkylation of Indoles with 2-Aryl-3-nitro-2<i>H</i>-chromenes under Catalyst-Free Conditions
作者:Pateliya Mujjamil Habib、Veerababurao Kavala、B. Rama Raju、Chun-Wei Kuo、Wen-Chang Huang、Ching-Fa Yao
DOI:10.1002/ejoc.200900207
日期:2009.9
An environmentally benign method for the synthesis of indolyl(nitro)chromans from indoles and 2-aryl-3-nitro-2Hchromenes undercatalyst-freeconditions by use of an “onwater” concept is described. The salient features of the methodology are its clean reaction conditions, the eco-friendly
3-Nitro-2H-chromenes in [3+2] cycloaddition reaction with azomethine ylides derived from N-unsubstituted α-amino acids and isatins: regio- and stereoselective synthesis of spirochromeno[3,4-c]pyrrolidines
作者:Igor B. Kutyashev、Alexey Yu. Barkov、Vladislav Yu. Korotaev、Vyacheslav Ya. Sosnovskikh
DOI:10.1007/s10593-019-02490-w
日期:2019.6
A regio- and stereoselective method was developed for the synthesis of tetrahydro-4H-spiro[chromeno[3,4-c]pyrrole-1,3'-indolin]-2'-ones in 72−96% yields, using a three-component reaction of 3-nitro-2-trifluoromethyl- and 3-nitro-2-phenyl-2H-chromenes with azomethineylides that were generated in situ from N-unsubstituted α-amino acids and isatins.
开发了一种区域选择性和立体选择性的方法,可以使用72-96%的产率合成四氢-4 H-螺[chromeno [3,4- c ]吡咯-1,3'-吲哚啉] -2'-一。 3-硝基-2-三氟甲基和3-硝基-2-苯基-2 H-色烯的三组分反应与由N-未取代的α-氨基酸和靛红素原位生成的偶氮甲亚胺。