Three-component synthesis of 4H-pyran scaffolds accelerated by a gabapentin-based natural deep eutectic solvent

Abstract

The development of environmentally benign synthetic protocols has attracted increasing attention in recent organic syntheses. As a part of this concept, our group synthesized a new natural deep eutectic solvent (NADES) by using gabapentin and choline chloride. After characterization by FTIR, ¹H and ¹³C NMR, and mass spectra, the prepared NADES was utilized as an efficacious catalyst for the synthesis of 4H-pyran scaffolds such as tetrahydrobenzo[b]pyran and pyrano[2,3-d]pyrimidinone(thione) derivatives. The use of inexpensive and bio-compatible reagents for the synthesis of the catalyst, a simple and green procedure for the preparation of the catalyst and products, short reaction times, high yields of the products, and applicability to large-scale synthesis are the prominent features of this protocol. Also, the catalyst could be recovered easily and recycled up to five times without significant loss of its catalytic activity.