Solvent-Free Three Component Synthesis of N-alkylated Derivatives of N-Acylhydrazones from Hydrazides, Aldehydes and α,β-unsaturated Esters

A number of new N-alkylated derivatives of N-acylhydrazones have been prepared via one pot three-component reaction between hydrazide, aldehyde, and α,β-unsaturated ester using 1,4-diazabicyclo[ 2,2,2]octane (DABCO), as an inexpensive base and tetrabutylammonium bromide (TBAB), an ionic organic salt media, under solvent-free conditions. In case of 2-hydroxy benzaldehyde, the reaction proceeds with the exclusive formation of the N-alkyl derivative without any concurrent O-alkylation side reaction.