2D network structure of zinc(II) complex: A new easily accessible and efficient catalyst for the synthesis of pyrazoles

Abstract

A Zn(II) coordination polymer {[Zn3(paz)(btc)2(H2O)8]·4H2O}n (noted as ZnPB), where paz = pyrazine, H3btc = trimesic acid, was synthesized and characterized by single‐crystal X‐ray diffraction, elemental analysis, infrared spectroscopy and powder X‐ray diffraction analyses. ZnPB shows a (3,3)‐connected 2D network with a point symbol of (63)2. Hydrogen bonds and π···π interactions connect adjacent 2D network to form a 3D packing structure. This compound exhibits excellent catalytic activity in the reaction of condensation and cyclization of sulfonyl hydrazides with 1,3‐diketones for the synthesis of pyrazoles. This solvent‐free and halogen‐free catalytic system represents an effective economic and environmentally friendly method for the construction of pyrazoles.

Ag2O-Induced Regioselective Huisgen Cycloaddition for the Synthesis of Fully Substituted Pyrazoles as Potential Anticancer Agents

“…Given the importance and the increasing demand for such scaffolds, efforts directed to the development of new methods and the improvement of structural diversity of pyrazoles are welcome and encouraged . The predominant synthetic approaches toward pyrazoles include condensation reactions of hydrazines with 1,3-dicarbonyl compounds and 1,3-dipolar cycloaddition reactions of hydrazonoyl chlorides with unsaturated bond-bearing substances, such as alkynes and alkenes with leaving group . Although the aforementioned protocols have realized high efficiency, such procedures often suffer from regioselectivity issues and tedious multistep synthesis, which greatly reduce their attractiveness.…”

Nickel-Catalyzed, One-Pot Synthesis of Pyrazoles

“…Today, as a privileged structure, it can be synthesized by the reaction of 1,3-dipolar cycloaddition of diazo compounds [34], acetylenone, [35] N-sulfonylhydrazone, [36] or chalcone [37], and hydrazine [38]. In this regard, various catalysts have been investigated to catalyze the formation of pyrazoles: Cao and his colleagues used Zn complexe [39]; El-Remaily and his group used thiazole complexes under ultrasonic reaction conditions [40]; Amirnejat et al [41] used Superparamagnetic Fe 3 O 4 @Alginate supported L-arginine; and recently, nano SiO 2 was used by Abou Elmaaty and his group [42].…”