“…They have been employed as cognitive enhancers, for the treatment of neurodegenerative diseases, including Alzheimer disease, amyotrophic lateral sclerosis, Parkinson disease, and Huntington disease. [27,28] Many methods have been reported for the synthesis of chromene and benzo[b]xanthene derivatives by reaction of aldehydes, malononitrile, cyclic-1,3-dicarbonyl and α,β-unsaturated carbonyl compounds in the presence of Fe(DS) 3 , [29] Me/TaMCF, [30] sodium phthalimide/ [BMIM]BF 4 , [31] CNT@meglumune, [32] Fe 3 O 4 @SiO 2 -BenzIm-Fc[Cl]/BiOCl nanocomposite, [33] TEAA, [34] DABCO, [35] PTSA, [36] [bmim][Br], [37] PS/GaCl 3 , [38] and Fe 3 O 4 /PEG/succinic anhydride. [39] Notwithstanding all advantages of these catalysts, they mostly suffer from long reaction times, multiple reaction steps, hard workup procedures, moderate yields, and nonrecyclable ability.…”