A novel gentisic acid-based deep eutectic solvent (ETPPBr/GA-DES) was prepared by mixing of ethyltriphenylphosphonium bromide (ETPPBr) and gentisic acid (GA = 2,5-dihydroxy-benzoic acid), and its structure fully investigated by using the FT-IR, TGA/DTA, densitometer and 1 HNMR techniques. Different mole ration of ETPPBr to GA were examined and the eutectic point phase diagram showed that the best ratio for the synthesis of a novel gentisic acid-based DES is the one-to-one mole ratio of the two starting materials (ETPPBr and GA). Then, ETPPBr/GA-DES was used as a novel and capable catalyst for the green synthesis of diverse Nsubstituted decahydroacridine-1,8-diones a(1¡12) from the three-component condensation reaction of aromatic aldehyde, aromatic amine and dimedone in solvent-free conditions at 80 ◦C.
