Air‐stable zirconium (IV)‐salophen perfluorooctanesulfonate as a highly efficient and reusable catalyst for the synthesis of 3,4‐dihydropyrimidin‐2‐(1H)‐ones/thiones under solvent‐free conditions

Abstract

An air‐stable complex of zirconium (IV)‐salophen perfluorooctanesulfonate (1) was successfully synthesized by reacting Zr (salphen)Cl2 and C8F17SO3Ag. Complex 1 was characterized and studied by different techniques (NMR, IR, HRMS, TG‐DSC, conductivity and acidity measurements), and was found to be air‐stable, water tolerant, thermally stable and strongly Lewis‐acidic. Complex 1 exhibited high catalytic efficiency for the synthesis of 3,4‐dihydropyrimidin‐2‐(1H)‐ones/thiones via the Biginelli reaction of aldehydes, 1,3‐dicarbonyl compounds and urea/thiourea under solvent‐free conditions. Furthermore, complex 1 could be reused 5 times with minimal changes in catalytic efficiency. Compared with previously reported methods, the important features of this protocol are the solvent‐free conditions, the short reaction times, the wide substrate compatibility, the high efficiency and the good reusability.

Multiweek Experiments for an Inorganic Chemistry Laboratory Course: Synthesis of Nickel Complexes Supported by a Tetradentate Ligand with a N2O2 Donor Set

“…Students can then proceed with the synthesis of the Schiff base ligand from salicylaldehyde and o -phenylenediamine (eq ). The condensation reaction has been reported to take place in ethanol under refluxing conditions for 2–12 h or at room temperature for 12 h . In our students’ hands, the room-temperature reaction was complete in 30 min.…”

Kinetic Analysis as an Optimization Tool for Catalytic Esterification with a Moisture-Tolerant Zirconium Complex

“…The required use of a dehydration technique is a common feature for protocols using early transition metal catalysts with halide and alkoxide ligands, due to their tendency to undergo hydrolytic decomposition . In contrast, analogous fluoroalkyl sulfonate complexes render moisture-tolerant catalysts for a variety of applications. , Despite the benefits that water-stable catalysts present, particularly in the context of dehydrative reactions, Lewis acidic fluoroalkyl sulfonate metal complexes remain a surprisingly understudied catalyst class with respect to (re)­activity and mechanistic action . While the use of the one-carbon trifluoromethane sulfonate (triflate) unit is unrestricted, its longer chain analogue perfluorooctane sulfonate (PFOS) displays bioaccumulative and toxic properties and is regulated by, e.g., the European Chemicals Regulation (REACH EC no.…”

Recyclable photocatalyst perovskite as a single-electron redox mediator for visible-light-driven photocatalysis gram-scale synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones in air atmosphere

“…A multitude of catalysts may be implemented in the synthetic production of 3,4-dihydropyrimidin-2-(1 H )-ones/thiones, including Cu/Cu 2 O@g-C 3 N 4 19 , N -(phenylsulfonyl)benzene sulfonamide 20 , h -BN/Fe 3 O 4 /Co 21 , Na 2 eosin Y 22 , copper(II)sulfamate 23 , bakers, yeast 24 , hydrotalcite 25 , hexaaquaaluminium (III) tetrafluoroborate 26 , TBAB 27 , copper (II) tetrafluoroborate 28 , [Btto][ p -TSA] 29 , triethylammonium acetate 30 , saccharin 31 , caffeine 32 , zirconium(IV)-salophen perfluorooctanesulfonate 33 , H 3 [PW 12 O 40 ] 34 , Dioxane-HCl 35 , 4CzIPN 36 , H 4 [W 12 SiO 40 ] 37 , Zr(H 2 PO 4 ) 2 38 , GO-chitosan 39 , and sodium dodecyl sulfate 40 . The prolonged reaction times, the exorbitant cost of reagents, tumultuous reaction mechanisms, and minimal product yields, foray into waste management concerns.…”