One-pot synthesis of highly substituted pyridines has been demonstrated via multicomponent reaction of aldehydes, malononitrile and thiophenol using Mg-Al hydrotalcite as a solid base and reusable catalyst. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the Mg/Al: 5 catalyst. The catalyst could be reused for further run without a significant loss in activity. The protocol was also applicable for various aromatic aldehydes which affords desired product in good to excellent yield.

The Mg/Fe = 3 hydrotalcite as reusable solid catalyst was found to be an excellent heterogeneous base catalyst for the synthesis of 3,4-dihydropyrimidinones/thiones, a multicomponent reaction using substituted aromatic aldehyde, ethyl acetoacetate and urea/thiourea. The work has been carried out under thermal solvent free conditions. Mg/Fe = 3 hydrotalcite heterogeneous solid catalyst offers simple means of recovery and the isolated catalyst was reused for number of times without significant loss of catalytic activity.