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Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group
α-Nitrocinnamate underwent the conjugate addition of an active methylene compound such as nitroacetate, 1,3-dicarbonyl compound, or α-nitroketone, and the following ring closure afforded functionalized heterocyclic frameworks. The reaction of cinnamate with nitroacetate occurs via nucleophilic subst...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248694/ https://www.ncbi.nlm.nih.gov/pubmed/32353998 http://dx.doi.org/10.3390/molecules25092048 |
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author | Mukaijo, Yusuke Yokoyama, Soichi Nishiwaki, Nagatoshi |
author_facet | Mukaijo, Yusuke Yokoyama, Soichi Nishiwaki, Nagatoshi |
author_sort | Mukaijo, Yusuke |
collection | PubMed |
description | α-Nitrocinnamate underwent the conjugate addition of an active methylene compound such as nitroacetate, 1,3-dicarbonyl compound, or α-nitroketone, and the following ring closure afforded functionalized heterocyclic frameworks. The reaction of cinnamate with nitroacetate occurs via nucleophilic substitution of a nitro group by the O-attack of the nitronate, which results in isoxazoline N-oxide. This protocol was applicable to 1,3-dicarbonyl compounds to afford dihydrofuran derivatives, including those derived from direct substitution of a nitro group caused by O-attack of enolate. It was found the reactivity was lowered by an electron-withdrawing group on the carbonyl moiety. When α-nitroketone was employed as a substrate, three kinds of products were possibly formed; of these, only isoxazoline N-oxide was identified. This result indicates that the substituting ability of nitronate is higher than that of enolate for the direct S(N)2 substitution of a nitro group. |
format | Online Article Text |
id | pubmed-7248694 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-72486942020-08-13 Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group Mukaijo, Yusuke Yokoyama, Soichi Nishiwaki, Nagatoshi Molecules Article α-Nitrocinnamate underwent the conjugate addition of an active methylene compound such as nitroacetate, 1,3-dicarbonyl compound, or α-nitroketone, and the following ring closure afforded functionalized heterocyclic frameworks. The reaction of cinnamate with nitroacetate occurs via nucleophilic substitution of a nitro group by the O-attack of the nitronate, which results in isoxazoline N-oxide. This protocol was applicable to 1,3-dicarbonyl compounds to afford dihydrofuran derivatives, including those derived from direct substitution of a nitro group caused by O-attack of enolate. It was found the reactivity was lowered by an electron-withdrawing group on the carbonyl moiety. When α-nitroketone was employed as a substrate, three kinds of products were possibly formed; of these, only isoxazoline N-oxide was identified. This result indicates that the substituting ability of nitronate is higher than that of enolate for the direct S(N)2 substitution of a nitro group. MDPI 2020-04-28 /pmc/articles/PMC7248694/ /pubmed/32353998 http://dx.doi.org/10.3390/molecules25092048 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Mukaijo, Yusuke Yokoyama, Soichi Nishiwaki, Nagatoshi Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group |
title | Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group |
title_full | Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group |
title_fullStr | Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group |
title_full_unstemmed | Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group |
title_short | Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group |
title_sort | comparison of substituting ability of nitronate versus enolate for direct substitution of a nitro group |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248694/ https://www.ncbi.nlm.nih.gov/pubmed/32353998 http://dx.doi.org/10.3390/molecules25092048 |
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