Greener and Additive-Free Reactions in Deep Eutectic Solvent: One-Pot, Three-Component Synthesis of Highly Substituted Pyridines

One-step synthesis of highly substituted pyridines via a multicomponent reaction of structurally diverse aldehydes with various thiols and malononitrile using deep eutectic solvent (DES) as green reaction media and catalyst is presented. This catalyst-free, cost-effective, and environmentally benign protocol utilizes recyclable reaction media, it is amenable to large scale production without significant loss in efficiency giving the desired compounds in short reaction times with moderate to good yields (60-82%). The inexpensive DES showed excellent recyclability using a simple recovery and reuse system without loss of parent catalytic activity even after three cycles.