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.