Twin deep eutectic mixtures of gabapentin and citric acid: Controlledselective synthesis of ۱,۸-dioxo-octahydroxanthenes, ۴Hbenzo[b]pyrans

Two deep eutectic mixtures of gabapentin and citric acid have been detected. These twinmixtures, irrespective of having different compositions, melt at close temperatures and slight differencescan be noticed in their thermogravimetric and differential calorimetric curves. Yet, they impose differentselective promotions on the reaction between malononitrile, arylaldehyde, and dimedone. As the reactionmixture selectively gives tetrahydrobenzo[b]pyran-۲H-ones in ۲/۱ ratio of gabapentin/citric acid eutecticmelt and majorly yields ۱,۸-dioxo-octahydroxanthenes in ۱/۲ ratio of gabapentin/citric acid under similarconditions. All of the reactions were carried out without further hazardous organic solvents, and theproducts were simply isolated and purified, and deep eutectic solvents were easily reused.

Keywords:

Deep eutectic solvent , Heteroaromatic compound , Ionic liquid , Organic solvent.