A novel cubic Zn‐citric acid‐based MOF as a highly efficient and reusable catalyst for the synthesis of pyranopyrazoles and 5‐substituted 1H‐tetrazoles

Abstract

A highly stable and efficient heterogeneous catalyst was successfully prepared by hydrothermal reaction of Zinc nitrate with citric acid. To produce a novel Zn-based MOF catalyst, Zn ions were coordinated with the ligand functional groups that can be regarded as an alpha-hydroxy acid containing three carboxylic acids (COOH) and one hydroxyl (OH) group attached to the three-carbon skeleton. It was found that the Zn-CA-MOFs compound can participate as a catalyst in the synthesis of 5-substituted 1H-tetrazole and pyranopyrazole molecules, selectively and efficiently with high yield in a short period of time.As presented, the catalyst demonstrates excellent reusability and stability and can be recycled up to five times without significant loss of reactivity. Heterogeneity analysis showed that no leaching of active Zn species occurred during the recycling process of the heterogeneous Zn-CA-MOFs.

Phosphomolybdic acid hydrate encapsulated in MIL-53 (Fe): a novel heterogeneous heteropoly acid catalyst for ultrasound-assisted regioselective nitration of phenols

“…[30][31][32][33][34][35][36] During recent years, metal-organic frameworks (MOFs) have been regarded as one of the most popular and useful catalysts for laboratory and commercial scale organic synthesis. [37][38][39][40][41][42][43][44][45][46][47] On the ecological side, MOFs have been known as the low-cost and green solid supports, applied to immobilize the soluble catalysts due to their crucial role in lowering the toxicity, having heterogeneous 48,49 high specic surface area, possessing porous nature and also structural diversity, being economically viable and also having safe and recyclable characteristics to synthesize organic moleculesleading to the synthesis of a wide variety of MOF catalysts, 50,51 i.e. MIL-53 (Fe) which is an Fe-based MOF with high thermal stability and a very high surface area.…”

New ecofriendly heterogeneous nano-catalyst for the synthesis of 1-substituted and 5-substituted 1H-tetrazole derivatives

“… Entry Catalyst Conditions Time (min) Yield (%) a Refs. 1 Cu (OAC) 2 EDS (chcl-urea), 100 °C 720 90 51 2 La/THH-CO 2 H@Fe 3 O 4 PEG-600, 100 °C 300 90 52 3 Pd‐isatin‐boehmite PEG-400, 120 °C 480 94 53 4 Fe 3 O 4 @SiO 2 -TCT-GA-Cu(II) Ethylene glycol/H 2 O (1 : 1), 90 °C 90 97 54 5 PDNPs@CS-Zeo DMF, 120 °C 720 90 55 6 Zn-CA-MOFs DMF, 120 °C 480 97 56 7 Cu Nano-catalyst Solvent-free, 100 °C 85 89 57 8 Nano-Fe 3 O 4 /In Solvent-free, 100 °C 150 90 ...…”

Design and characterization of an urea-bridged PMO supporting Cu(II) nanoparticles as highly efficient heterogeneous catalyst for synthesis of tetrazole derivatives

“…Due to the use of copper complexes in various chemical reactions such as hydroboration of alkenes 79 , 80 , β-boration of α,β-unsaturated esters 81 , direct addition of terminal alkynes to imines 82 , 83 , alkyne-azide cycloaddition 84 , 85 and allylic alkylation reactions 86 , special attention has been paid to copper complexes as catalysts for these reactions. Furthermore, the Cu(I)-assisted click chemistry (CuACC) of azide–nitrile cycloaddition for synthesis of corresponding heterocyclic compounds, namely tetrazole derivatives, has received much attention in recent years 87 – 91 . Tetrazole derivatives are an important class of nitrogen-rich heterocyclic nucleus with significant applications in the medicinal chemistry.…”