A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles

A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)(3) in catalytic amounts is found to be t...

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Autores principales: Tran, Phuong Hoang, Tran, Hai Ngoc, Hansen, Poul Erik, Do, Mai Hoang Ngoc, Le, Thach Ngoc
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2015
Materias:
Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331820/
https://www.ncbi.nlm.nih.gov/pubmed/26516834
http://dx.doi.org/10.3390/molecules201019605
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author Tran, Phuong Hoang
Tran, Hai Ngoc
Hansen, Poul Erik
Do, Mai Hoang Ngoc
Le, Thach Ngoc
author_facet Tran, Phuong Hoang
Tran, Hai Ngoc
Hansen, Poul Erik
Do, Mai Hoang Ngoc
Le, Thach Ngoc
author_sort Tran, Phuong Hoang
collection PubMed
description A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)(3) in catalytic amounts is found to be the best catalyst together with the commercially available ionic liquid [BMI]BF(4) (1-butyl-3-methylimidazolium tetrafluoro-borate) as solvent. The reaction is completed in a very short time using monomode microwave irradiation. The catalyst can be reused up to four times without significant loss of activity. A range of substituted indoles are investigated as substrates, and thirteen new compounds have been synthesized.
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spelling pubmed-63318202019-01-24 A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles Tran, Phuong Hoang Tran, Hai Ngoc Hansen, Poul Erik Do, Mai Hoang Ngoc Le, Thach Ngoc Molecules Article A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)(3) in catalytic amounts is found to be the best catalyst together with the commercially available ionic liquid [BMI]BF(4) (1-butyl-3-methylimidazolium tetrafluoro-borate) as solvent. The reaction is completed in a very short time using monomode microwave irradiation. The catalyst can be reused up to four times without significant loss of activity. A range of substituted indoles are investigated as substrates, and thirteen new compounds have been synthesized. MDPI 2015-10-27 /pmc/articles/PMC6331820/ /pubmed/26516834 http://dx.doi.org/10.3390/molecules201019605 Text en © 2015 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 license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Tran, Phuong Hoang
Tran, Hai Ngoc
Hansen, Poul Erik
Do, Mai Hoang Ngoc
Le, Thach Ngoc
A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles
title A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles
title_full A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles
title_fullStr A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles
title_full_unstemmed A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles
title_short A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles
title_sort simple, effective, green method for the regioselective 3-acylation of unprotected indoles
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331820/
https://www.ncbi.nlm.nih.gov/pubmed/26516834
http://dx.doi.org/10.3390/molecules201019605
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