Multicomponent one pot synthesis of substituted pyridines with a highly active and recyclable hydrotalcite-lanthanum nanocatalyst

Abstract

Herein, the synthesis of 2-amino-3,5-dicyano-6-sulfanyl pyridine derivatives has been studied due to wide applications of highly substituted pyridines. At first, Hydrotalcite (HT) with various loading amounts of lanthanum (HT-La) was synthesized. Then, their catalytic activities were investigated for the condensation reaction of benzaldehyde, malononitrile, and thiophenol under reflux condition as a model reaction. The prepared HT nanocatalyst with 10 mol% of La showed the best performance in this multicomponent reaction. In addition, the reusability of the nanocatalyst was studied and the results showed, that the prepared nanocatalyst could be reused several times with an only moderate decrease in activity. Subsequently, HT-La (10 mol%) efficiently catalyzed the one-pot condensation reaction for the synthesis of highly substituted pyridines under reflux conditions. The products were produced with excellent yields, short reaction times, and easy recyclability of the nanocatalyst.