Article Details


Microwave-Assisted Aminolysis of Lactones Under Solvent- and Catalyst- Free Conditions

[ Vol. 4 , Issue. 2 ]

Author(s):

Angelica de Fatima S. Barreto, Carlos Eduardo M. Salvador, Thaissa Pasquali F. Rosalba and Carlos Kleber Z. Andrade   Pages 168 - 172 ( 5 )

Abstract:


Background: Aminolysis of lactones is an important reaction for the synthesis of hydroxy amides. This reaction generally requires rather harsh conditions, such as high pressure and temperature or strong alkali metal catalysts. Microwave-assisted reactions have provided a great impetus to organic synthesis, especially for accelerating the reactions. The combination of microwave heating and solventfree conditions is a particularly attractive methodology in modern organic synthesis because it leads to enhanced conversion rates, easier work-up, higher yields and in general cleaner reactions.

Methods: A simple, efficient and eco-friendly procedure was developed for the preparation of hydroxy amides from a variety of amines and lactones using microwave irradiation under solvent- and catalystfree conditions.

Results: In the synthesis of hydroxy amides described herein, the reactions were conducted using microwave irradiation at temperatures of 130 °C and reaction times of 30-60 min. We investigated reactions of lactones with amines of different nucleophilic character and steric hindrance. Primary, secondary, aliphatic, aromatic and cyclic amines (2 equiv.) were used in the reactions with γ-butyrolactone or γ-valerolactone (1 equiv.). The yields of the purified products were generally very good and varied according to the amine used in most cases. An important feature is that despite no additive/catalyst is used the reaction times were shorter compared to all the works described so far. Neither an inert atmosphere nor solvent and additives/catalysts are required in this microwave irradiation procedure.

Conclusion: In summary, we have demonstrated a simple and efficient method for the preparation of hydroxy amides, employing a green methodology. Simple work-up procedure and high yields obtained using MW irradiation, under solvent-, support and catalyst-free conditions show the superiority of this work over the existing methods.

Keywords:

Aminolysis, lactones, microwave irradiation, hydroxy amides.

Affiliation:

Laboratório de Química Metodológica e Orgânica Sintética (LaQMOS), Instituto de Química, Universidade de Brasília, C.P. 4478, 70910-970, Brasília, DF, Laboratório de Química Metodológica e Orgânica Sintética (LaQMOS), Instituto de Química, Universidade de Brasília, C.P. 4478, 70910-970, Brasília, DF, Laboratório de Química Metodológica e Orgânica Sintética (LaQMOS), Instituto de Química, Universidade de Brasília, C.P. 4478, 70910-970, Brasília, DF, Laboratório de Química Metodológica e Orgânica Sintética (LaQMOS), Instituto de Química, Universidade de Brasília, C.P. 4478, 70910-970, Brasília, DF

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