Convenient Synthesis of 2-Aminothiophene Derivatives by Acceleration of Gewald Reaction Under Ultrasonic Aqueous Conditions

Abstract

Under ultrasound irradiation and in the presence of H₂O/Et₂NH, ethyl cyanoacetate or malononitrile can combine with α-methylene carbonyl compounds and elemental sulfur to efficiently yield 2-aminothiophene derivatives within a few minutes. Products are easily obtained by simple filtration because of their spontaneous precipitation in the reaction mixtures.

Keywords:

• 2-Aminothiophenes
• aqueous conditions
• Gewald reaction
• ultrasound irradiation

ACKNOWLEDGMENT

Partial financial support by the Ministry of Science, Research, and Technology of Iran is greatly appreciated.

Notes

^a Isolated yields.

^a Ethylenediammonium diacetate.