Study on Multicomponent Coupling of Aldehyde, Alkyne and Amine

Abstract

The coupling of aldehyde, an amine and an alkyne (known as A3 -coupling) is a versatile strategy for the synthesis of propargylamine which are important precursors for various biologically active molecules. Various transition metal catalysts of Cu, Ag, Au, Fe, Ni, Zn, Co along with a variety of solvents have been reported for this reaction. However, metal/solvent waste and their disposal is one of the major challenges faced by chemical industries. Moreover, trapping of traces of metal impurity in the final product could be harmful. In this work, we have explored various environmental friendly solvents such as ionic liquids and water for the multicomponent coupling of hydroxybenzaldehyde with amine and alkyne. When there is OH group at ortho position of benzaldehyde, the reaction can be carried out without the presence of metal-catalyst. We found that this reaction can proceed even under solvent-less condition without the need of any metal catalyst. For comparison purpose, the effect of various molecule solvents on the yield of reaction has also been explored.