Copper Octoate: A Commercially Available and Cost-Effective Homogeneous Catalyst for the Facile Synthesis of 2,2’-Arylmethylenebis(3-Hydroxy-5,5-Dimethyl-2-Cyclohexene-1-Ones)

Catalytic Synthesis of 1,2,4,5‐Tetrasubstituted 1H‐Imidazole Derivatives: State of the Art

“…[29] Unfortunately, the yields were generally modest. Nevertheless, improvements in the yields and/or reaction times were obtained by using catalysts such as p-toluenesulfonic acid, [30] boric acid, [31] 2-ethylhexanoic acid, [32] molecular iodine, [33] FeCl3×6H2O, [34] ZrCl4, [35] InCl3×3H2O, [36] , cyclic phosphonic acid, [37] BiBr3, [38] citric acid, [39] 1,4-diaza[2.2.2]bicyclooctane (DABCO), [40] trityl chloride, [41] L-proline, [42] and L-proline triflate. [43] Furthermore, in 2009, 1-substituted-2-aryl-4,5diphenyl-1H-imidazoles 15a-n were synthesized in good to excellent yields through trifluoroacetic acid (TFA)-catalyzed condensation of benzil (5), primary amines 8, aryl aldehydes 14 and AcONH4 under microwave-assisted solvent-free conditions (Scheme 5).…”

Green Synthesis of 1,2,4,5‐Tetrasubstituted and 2,4,5‐Trisubstituted Imidazole Derivatives Involving One‐pot Multicomponent Reaction

“…The synthesis of 1,2,4,5‐tetrasubstituted imidazoles is carried out by four‐component cyclo‐condensation of a 1,2‐diketone/hydroxyketone with various aldehydes, primary amine, and ammonium acetate with molecular SBA‐15 mesoporous and 2,2,2‐trifluoroethanol (SBA‐15/TFE) , clay‐supported titanium and using as a catalyst. 2,4,5‐Trisubstituted imidazole derivatives are generally synthesized by three‐component condensation of a 1,2‐diketone/hydroxyketone with various aldehydes and ammonium acetate, zeolite HY with silica gel , ZrO(NO 3 ) 2 .XH 2 O , ZrO 2 ‐supported β‐cyclodextrin (ZrO 2 ‐β‐CD) , cerric ammonium nitrate (CAN) , 2,6‐dimethylpyridiniumtrinitromethanide {[2,6‐DMPyH]C(NO 2 ) 3 } , nano copperferrite , poly(4‐vinylpyridinium butane sulfonic acid) hydrogen sulfate , ZSM‐5‐SO 3 H , zinc acetate , N ‐bromosuccinimide , 2‐ethylhexanoic acid , tritylchloride (TrCl or Ph 3 CCl) , silica chloride , zeolite, nano‐crystalline sulfated zirconia ' NH 4 Fe(SO 4 ) 2 KOH , Phenoxyl Spacer , and nanocrystalline silica supported tin oxide (SiO 2 :SnO 2 ) as catalyst.…”