A new zwitterionic nano-titania supported Keggin phosphotungstic heteropolyacid: an efficient and recyclable heterogeneous nanocatalyst for the synthesis of 2,4,5-triaryl substituted imidazoles

Nickel(II) Schiff base complex supported on nano‐titanium dioxide: A novel straightforward route for preparation of supported Schiff base complexes applying 2,4‐toluenediisocyanate

“…In continuation of our current programmes for the procurement of novel heterogeneous catalysts for organic reactions by applying TDI, we report the synthesis and application of Ni(II)–Schiff base complex supported on nano‐TiO 2 (nano‐TiO 2 ‐SA‐Ni(II)) as a novel, efficient and recyclable nanocatalyst. For the first time, TDI was employed as a precursor of amine groups for preparation of the Schiff base ligand.…”

“…In continuation of our efforts towards expanding the application of 2,4‐toluenediisocyanate (TDI) in heterogeneous catalyst synthesis, in the work reported in this paper, for the first time, we successfully synthesized a novel nickel(II) Schiff base complex, applying TDI as a covalently bound linker and precursor of amine groups immobilized on nano‐titania support. TDI is highly accessible, of low cost and very active due to its reactive unsaturated bonds and was used as a bridge between the surface of nano‐titania and nickel(II) ion to improve the recyclability and life span of the inorganic–organic hybrid catalyst.…”

Deep eutectic solvent‐assisted synthesis of highly efficient nanocatalyst (n‐TiO2@TDI@DES (ZnCl2:urea)) for chemoselective oxidation of sulfides to sulfoxides

“…Then, the combined organic layer was dried over anhydrous Na 2 SO 4 , and the pure products were obtained in 87-99% yields by evaporation of diethyl ether under reduced pressure. [69] 3 | RESULTS AND DISCUSSION To develop our current programs [70][71][72][73] on the use of support-immobilized DES in different organic reactions, the preparation of LADESs was addressed on nano-TiO 2 . In this reaction, nano-TiO 2 served as a novel, high-efficiency, and recyclable nanocatalyst.…”

Organocatalyzed Solvent Free and Efficient Synthesis of 2,4,5‐Trisubstituted Imidazoles as Potential Acetylcholinesterase Inhibitors for Alzheimer's Disease

“…To obtain good yields, the reaction is generally catalyzed by the selection of different compounds such as silica gel, BF 3 ·SiO 2 , molecular iodine, zirconium (IV) acetylacetonate Zr(acac) 4 3 , silica chloride, silica bonded propyl-Nsulfamic acid nanocatalyst (NHSO 3 H-KIT-5), Ce (SO 4 ) 2 · 4H 2 O, Keggin-structured phosphotungstic acid (HPW). [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] All these new methodologies have their own advantages but most of these are associated with drawbacks like use of toxic solvents, prolong times, complicated work-up, purification difficulties, poor yields, expensive reagents, hence there is a dire need to develop such synthetic routes that are environmentally friendly and economically. Various organocatalysts are being used nowadays to accelerate chemical reaction with easy handling.…”

“…Synthesis of 2,4,5‐trisubstituted imidazoles is usually carried out by cyclocondensation of three components, i. e., an aldehyde and ammonium acetate with a 1,2‐diketone, α ‐hydroxyketone or α ‐ketomonoxime ( Scheme ). To obtain good yields, the reaction is generally catalyzed by the selection of different compounds such as silica gel, BF 3 ⋅SiO 2 , molecular iodine, zirconium (IV) acetylacetonate Zr(acac) 4 , silica sulfuric acid, scolecite, ammonium chloride, nanocrystalline magnesium chloride, TiCl 4 ⋅SiO 2 , tetrabutylammonium hexatungstate ([TBA] 2 [W 6 O 19 ]), ZnO nanorods, Eu(OTf) 3 , silica chloride, silica bonded propyl‐ N ‐sulfamic acid nanocatalyst (NHSO 3 H‐KIT‐5), Ce(SO 4 ) 2 ⋅ 4H 2 O, Keggin‐structured phosphotungstic acid (HPW) …”