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Current Microwave Chemistry


ISSN (Print): 2213-3356
ISSN (Online): 2213-3364

Letter Article

Microwave Irradiation Accelerates 4-Dimethylaminopyridine-catalyzed Michael Addition of Phenols or Anilines

Author(s): Hirokazu Iida*, Kie Takahashi, Yusuke Akatsu and Kazushi Mizukami

Volume 4, Issue 2, 2017

Page: [108 - 114] Pages: 7

DOI: 10.2174/2213335603666161125122438

open access plus


Background: The introduction of a cyano group has been widely investigated because a cyano group may easily be transformed into both a methylamino moiety and a carboxylic acid moiety. Therefore Michael addition between phenol and acrylonitrile for the introduction of a cyanoethoxy moiety has been reported by several groups, however, the long reaction time (20-40 h) of this reaction was problematic. In order to solve this difficulty, we investigated the Michael addition with the assistance of microwave irradiation.

Methods: 4-Dimethylaminopyridine was added to a mixture of phenol and acrylonitrile, and the suspension was irradiated (107-115 W) for 4 h. Reaction conversion was determined by 1H NMR analysis of the mixture.

Results: The addition reaction between phenols and acrylonitrile in the presence of 4-dimethylaminopyridine under microwave irradiation proceeded smoothly to afford the corresponding Michael adducts in good to moderate yield. Microwave-accelerated Michael addition in the presence of 4- dimethylaminopyridine proceeded more effectively without the use of additives such as solvents. This method was applicable to Michael addition between phenol and methyl acrylate, between aniline and acrylonitrile, and also between anilines and methyl acrylate.

Conclusion: We have described a highly efficient and rapid method for Michael addition between phenols and acrylonitrile, between aniline and acrylonitrile, between phenol and methyl acrylate, and between anilines and methyl acrylate. Considering the present results, it is possible that the combination of microwave irradiation and the use of DMAP as a base constitute one of the most suitable procedures for the Michael addition of phenols and anilines.

Keywords: 4-dimethylaminopyridine, acrylonitrile, aniline, methyl acrylate, Michael addition, microwave irradiation, phenol.

Graphical Abstract

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