Sulfination of acetanilide using liquid coordination complexes as dual catalyst and solvent

ZnCl2/Urea Eutectic Solvent as Stable Carbonylation Source for Benign Synthesis of 2–Benzimidazolones and 2–Imidazolones: An Effective Strategy for Preventing NH3 Gas Evolution

“…[24][25][26][27][28] Despite the tremendous success of quaternary ammonium salt-based deep eutectic solvents (type I, II and III eutectics) as green reaction media in organic transformations, [29][30][31][32][33][34][35][36][37][38][39][40][41][42] the use of type IV eutectics based on metal chloride and hydrogen bond donor molecules [43] for this purpose is still limited. Indeed, only few examples have hitherto been reported with regard to their application in organic synthesis: ZnCl 2 /urea (1 : 3.5 mol ratio) for the synthesis of bis(indolyl)methanes, [44] GaCl 3 /urea (1:0.75 mol ratio) for Friedel-Crafts alkylation of benzene, [45] ZnCl 2 /dimethylurea (2 : 7 mol ratio) for the synthesis of propargyl amines, [46] ZnCl 2 /ethylene glycol (1 : 4 mol ratio) for the arylation of benzoxazoles, [47] ZrOCl 2 ⋅8H 2 O/urea (1 : 5 mol ratio) for Paal-Knorr pyrrole synthesis, [48] AlCl 3 /acetamide (1:0.65 mol ratio) for Freidel-Crafts sulfination reaction of acetanilide, [49] and FeCl 3 ⋅6H 2 O/N-methylglucamine (1 : 2 mol ratio) for the synthesis of 2,3-dihydrofurans. [50] 2-Imidazolones and 2-benzimidazolones are biologically active azaheterocyclic motifs that have attracted a great deal of attention as active drugs.…”