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.
Reduction of α,β-unsaturated nitroalkenes with borane and borohydrides. A convenient route to 3-nitro-, 3-hydroxylamino-, and 3-amino-2h-1-benzopyran derivatives
作者:Rajender S. Varma、Yuan-Zhu Gai、George W. Kabalka
DOI:10.1002/jhet.5570240343
日期:1987.5
The borohydride catalyzed boranereduction of 3-nitrochromenes provided a facile route to a variety of 3-hydroxylamino- 5 and 3-amino-2H-1-benzopyranes 6. Reduction with methoxyborohydride species, on the other hand, provided 3-nitrochromans 2,4.
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