Rhombic Dodecahedral Cu₂O‐Catalysed Synthesis of Novel Alkenyl Pyrazoles

Abstract

The design of efficient catalyst is of great importance in pyrazole derivatives synthesis. Herein, rhombic dodecahedra Cu2O microcrystals were successfully synthesized, and employed as catalysts in the direct synthesis of alkenyl pyrazoles. The catalytic activity of the obtained Cu2O catalyst toward the synthesis of alkenyl pyrazoles via the reaction of p‐chlorophenyl hydrazone and 2,4‐pentanedione was studied. The results showed that the high yields of alkenyl pyrazoles was achieved by using a rhombic dodecahedra Cu2O catalyst. Moreover, the rhombic dodecahedra also exhibited excellent catalytic activity for a variety of different hydrazones, which demonstrates their potential as a versatile catalyst. The Cu2O catalyst shows good reusability. Hence, the rhombic dodecahedra Cu2O microcrystals can be viewed as a highly useful catalyst for synthesis of alkenyl pyrazoles.

Update on the Synthesis of N‐Heterocycles via Cyclization of Hydrazones (2017–2021)

“…Metal catalysts are used often in various reaction methods to construct N-heterocycles due to their high catalytic activities. Since many methods such as cycloaddition and multi-component tandem cyclization have been proposed for the transition metal-catalyzed intermolecular cyclization of hydrazone with other unsaturated components, [64][65][66][67][68] all reactions that involve metal catalysis are summarized here.…”

Hydroxyl ions: flexible tailoring of Cu2O crystal morphology

“…1,2 The shape and size of inorganic materials are well-known to have great effects on their widely varying properties. 3,4 As a p-type semiconductor with direct band-gap of 2.17 eV, cuprous oxide (Cu 2 O) is a perspective material, 5 which is widely applied in solar energy conversion, 6 catalysts, 7 gas sensors, 8 templates 9 and antibacterial activity. 10 Shape-controlled synthesis of Cu 2 O crystals has attracted much attention in recent years, and Cu 2 O crystals with different morphologies have been successfully synthesized, such as cubes, 11 octahedra, 12 hollow spheres, 13 tetrapods, 14 rhombic dodecahedra, 15 hollow octadecahedra, 16 etc.…”

“… 1,2 The shape and size of inorganic materials are well-known to have great effects on their widely varying properties. 3,4 As a p-type semiconductor with direct band-gap of 2.17 eV, cuprous oxide (Cu 2 O) is a perspective material, 5 which is widely applied in solar energy conversion, 6 catalysts, 7 gas sensors, 8 templates 9 and antibacterial activity. 10 …”