Applied Catalysis O: Open (Jan 2025)
A pyromellitic acid-based Deep Eutectic Solvent as a new and powerful catalyst for the synthesis of tetrahydropyridines
Abstract
Based on the results obtained from the eutectic points phase diagram, a novel deep eutectic solvent (ChCl/PYRO-DES) was prepared with two to one molar ratio of choline chloride (ChCl) to pyromellitic acid (1,2,4,5-benzenetetra-carboxylic acid, PYRO) at 140 °C in a cheap, simple, and non-toxic method and characterized by FT-IR, densitometer, TGA-DTA and 1H NMR techniques. Then, it was used as a capable and new catalyst for the synthesis of alkyl 1,2,6-trisubstituted-4-[(hetero)-arylamino]-1,2,5,6-tetrahydropyridine-3-carboxylates 3(a-j) from the mixture of β-keto-ester, anilines, and aromatic aldehyde at 80 °C in solvent-free conditions, short reaction times, high yields, and easy recycling and separation of the DES catalyst.
