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. 2025 Aug;14(8):e202500024.
doi: 10.1002/open.202500024. Epub 2025 May 13.

SiO2@Benzothiazole-Cl@Fc as an Efficient Heterogeneous Catalyst for the Synthesis of 1,3,5-Trisubstituted Pyrazoles by A3 Coupling

Fadhil Faez Sead  1   2   3 , Vicky Jain  4 , Roopashree R  5 , Aditya Kashyap  6 , Suman Saini  7 , Girish Chandra Sharma  8 , Pushpa Negi Bhakuni  9   10 , Mosstafa Kazemi  11 , Ramin Javahershenas  12
Affiliations

SiO2@Benzothiazole-Cl@Fc as an Efficient Heterogeneous Catalyst for the Synthesis of 1,3,5-Trisubstituted Pyrazoles by A3 Coupling

Fadhil Faez Sead et al. ChemistryOpen. 2025 Aug.

Abstract

This research introduces the preparation and analysis of a newly heterogeneous catalyst developed silica nanospheres supporting a ferrocene-containing ionic liquid (IL) (SiO2@Benzothiazole-Cl@Fc) for the A3 coupling reaction. The catalyst facilitates the efficient synthesis of 1,3,5-trisubstituted pyrazoles from aromatic hydrazides, aldehydes, and aromatic alkynes. Incorporating ferrocene enhances the catalytic activity. Comprehensive characterization techniques, including NMR, Fourier transform infrared, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy, confirm the successful functionalization of silica nanospheres. The catalytic performance was evaluated under various reaction conditions, demonstrating high yields and selectivity for the desired pyrazole products. This work highlights the potential of ferrocene-based ILs in green chemistry applications, providing a sustainable approach to synthesizing valuable heterocyclic compounds.

Keywords: A3 coupling; ferrocene; heterogeneous catalyst; ionic liquid; pyrazole synthesis; silica nanospheres.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Some bioactive compounds contain structures containing substituted pyrazoles derivatives.
Scheme 1
Scheme 1
Preparation steps for synthesis of SiO2@Benzothiazole‐Cl@Fc nanocatalyst.
Scheme 2
Scheme 2
A plausible mechanism for the synthesis of polyfunctionalized 1,3,5‐trisubstituted pyrazoles derivatives.
Figure 2
Figure 2
FTIR spectrum of a) SiO2, b) SiO2@Cl, and c) SiO2@Benzothiazole‐Cl@Fc nanocatalyst.
Figure 3
Figure 3
XRD analysis of SiO2@Benzothiazole‐Cl@Fc nanocatalyst.
Figure 4
Figure 4
The N2 adsorption‐desorption isotherm of SiO2@Benzothiazole‐Cl@Fc nanocatalyst.
Figure 5
Figure 5
SEM and TEM images of SiO2@Benzothiazole‐Cl@Fc nanocatalyst.
Figure 6
Figure 6
SEM and TEM images of SiO2 NPs.
Figure 7
Figure 7
TGA analysis of SiO2@Benzothiazole‐Cl@Fc nanocatalystat.
Figure 8
Figure 8
EDX analysis of SiO2@Benzothiazole‐Cl@Fc nanocatalystat.
Figure 9
Figure 9
Elemental mapping of the SiO2@Benzothiazole‐Cl@Fc nanocatalystat.
See this image and copyright information in PMC

References

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