Synthesis of Novel Azo-Linked 5-Amino-Pyrazole-4-Carbonitrile Derivatives Using Tannic Acid-Functionalized Silica-Coated Fe3O4 Nanoparticles as a Novel, Green, and Magnetically Separable Catalyst.

Farhad Sedighi Pashaki,Mohammad Nikpassand

doi:10.3389/fchem.2021.724745

Farhad Sedighi Pashaki, Mohammad Nikpassand

Open Access

https://doi.org/10.3389/fchem.2021.724745

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Journal: Frontiers in Chemistry	Publication Date: Nov 12, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Islamic Azad University Rasht Branch

Abstract

Tannic acid–linked silica-coated Fe3O4 nanoparticles (Fe3O4@SiO2@Tannic acid) were prepared and characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FE-SEM), X-ray powder diffraction (XRD), X-ray spectroscopy (EDX), vibrating sample magnetometry (VSM), and Fourier transform infrared (FT-IR) spectroscopy. Fe3O4@SiO2@Tannic acid supplies an environmentally friendly procedure for the synthesis of some novel 5-amino-pyrazole-4-carbonitriles through the three-component mechanochemical reactions of synthetized azo-linked aldehydes, malononitrile, and phenylhydrazine or p-tolylhydrazine. These compounds were produced in high yields and at short reaction times. The catalyst could be easily recovered and reused for six cycles with almost consistent activity. The structures of the synthesized 5-amino-pyrazole-4-carbonitrile compounds were confirmed by 1H NMR, 13C NMR, and FTIR spectra, and elemental analyses.

Highlights

One of the largest groups of heterocyclic compounds is five-membered rings with more than one heteroatom
A mixture of synthesized azo-linked salicylaldehyde (1 mmol), phenylhydrazine (1 mmol, 0.108 g), or paratolylhydrazine (1 mmol, 0.120 g), malononitrile (1 mmol, 0.065 g), and 0.1 g Fe3O4@SiO2@Tannic acid was added to a Retsch 50-ml screwtop vessel equipped with a 20-mm stainless steel ball, and set to shake for the required reaction time (Table 2)
Nikpassand, 2020), we wish to report the synthesis of novel azo-linked 5-amino-pyrazole-4-carbonitriles catalyzed by tannic acid–functionalized silica-coated Fe3O4 nanoparticles (Fe3O4@ SiO2@Tannic acid)

Summary

INTRODUCTION

One of the largest groups of heterocyclic compounds is five-membered rings with more than one heteroatom. Different methods have been proposed to synthesize diverse pyrazole derivatives (Salaheldin et al, 2007) These include the synthesis of 4-substituted pyrazoles during the 1,3dipolar ring-forming reaction between diazo compounds with triple bonds (Martin et al, 2006); the three-component reaction between aromatic aldehydes, malononitrile, and phenylhydrazine (Bhale et al, 2014); the Michael addition reaction using 2-methyl3-nitrochrome as a starting material (Takagi et al, 1987); the preparation of oxoalkanenitrile or aminonitrile derivatives (AlQalaf et al, 2009), from a four-component reaction with aryl aldehydes, hydrazines, ethylacetoacetate, and malononitrile (Kiyani et al, 2013), and the reaction of enamines with hydroxylamine hydrochloride (Tominaga et al, 1990). We report the mechanochemical synthesis of new 5-amino-pyrazole4-carbonitriles with azo-linked aldehydes, malononitrile, and phenylhydrazine or p-tolylhydrazine at room temperature in the presence of tannic acid–functionalized silica-coated Fe3O4 nanoparticles (Fe3O4@SiO2@Tannic acid)

Material and Method

RESULTS AND DISCUSSION

CONCLUSION